Aromatic compounds

Abstract

The present invention relates to compounds of formula I:R 1 -(A 1 -Z 1 ) r -B 1 -Z L -A 2 -(Z 3 -A 3 ) s -G(I), in which the occurring radicals and parameters have the meanings given in claim 1, to the use thereof for the formation of molecular layers, in particular self-assembled monolayers, to a process for the fabrication of a switching element for a memristor device comprising said molecular layer, and to a memristor device comprising said switching element.

Description

[Technical field]

[0001] The present invention relates to aromatic compounds, to their use for the formation of molecular layers, in particular self-assembled monolayers (SAMs), to a process for the fabrication of a switching element for a memristor device comprising said molecular layer, and to a memristor device comprising said switching element. [Background technology]

[0002] In computer technology, there is a demand for storage media that allow rapid writing and reading access to the information stored. Solid-state memories or semiconductor memories allow a particularly fast and reliable storage medium to be achieved, since no moving parts are required. Currently, mainly dynamic random access memories (DRAMs) are used. DRAMs allow rapid access to the stored information, but this information must be regularly updated, which means that the stored information is lost when the power supply is cut off.

[0003] The prior art also discloses non-volatile semiconductors such as flash memory or magnetoresistive memory (MRAM), in which information is preserved even after the power supply is cut off. The disadvantage of flash memory is that write access is relatively slow and flash memory cells cannot be permanently erased. The life of flash memory is typically limited to a maximum of one million read / write cycles. MRAM can be used in a similar manner to DRAM and has a long life, but this type of memory has not been established due to the difficult production process.

[0004] A further alternative is a memory that works on the basis of a memristor. The term memoristor is a contraction of the words "memory" and "resistor" and denotes a component whose electrical resistance can be reproducibly changed between high and low electrical resistance. The respective states (high and low resistance) are retained even without a supply voltage, which means that non-volatile memories can be achieved with memristors.

[0005] WO 2012 / 127542 A1 and US 2014 / 008601 A1, for example, disclose organic molecular memories having two electrodes and an active region arranged between the two electrodes. The active region has a molecular layer of conductive aromatic alkyne whose conductivity can be changed under the influence of an electric field. A similar building block based on redox-active bipyridinium compounds is proposed in US 2005 / 0099209 A1. Known memories based on changes in conductivity or resistance have the disadvantage that free radical intermediates formed by the flow of electric current through the molecules of the molecular layer are in principle prone to decomposition processes, which have adverse effects on the lifetime of the component.

[0006] In WO 2018 / 007337 A2 an improved switching layer is described which utilizes a non-redox active molecular layer comprising dipolar compounds attached to a substrate via an aliphatic spacer group, the compounds being reversibly switched by application of an electric field which causes a reorientation of the molecular dipoles and thus enables low and high resistance states depending on the respective orientation of the molecules.

[0007] To obtain electrically switchable tunnel junctions from organic compounds with conformationally flexible dipoles, a molecular layer is required that is sandwiched between two conductive electrodes. The deposition of this molecular layer onto the electrodes is achieved by either spin-coating or dip-coating from an organic solvent. The basic principles of the resulting memory device are described in WO 2016 / 110301 A1 and WO 2018 / 007337 A2. To limit the formation of short circuits between the top and bottom electrodes, the monolayer must be as tight as possible, without pinholes that would allow penetration of the top electrode material during the deposition process. There is also a strong demand for materials that form molecular layers of acceptable quality within extremely short deposition times.

[0008] The problem to be solved by the present invention is to provide improved materials for the fabrication of switchable molecular layers. To solve the problem, there is provided a compound represented by formula I as shown below, which comprises a ring having an anchor group linked to a polar ring via a one atom linking group, wherein the compound represented by formula I can be attached onto a substrate using the anchor group.

[0009] The present invention further relates to a process for the fabrication of a switching element comprising a molecular layer obtainable from one or more compounds of formula I. The present invention further relates to a memristor device comprising said switching element. Preferred embodiments are the subject matter of the dependent claims and can also be taken from the description. Summary of the Invention

[0010] The present invention relates to a compound of formula I R 1 -(A 1 -Z 1 ) r -B 1 -Z L -A 2 -(Z 3 -A 3 ) s -G (I) During the ceremony R 1 denotes linear or branched alkyl or alkoxy, each having 1 to 20 C atoms, where one or more CH groups in these radicals are each, independently of one another, C≡C-, -CH=CH-, [ka] -O-, -S-, -CF2O-, -OCF2-, -CO-O-, -O-CO-, -SiR 0 R 00 -, -NH-, -NR 0 or -SO2- to replace the O atoms so that they are not directly bonded to each other, and wherein one or more H atoms may be replaced by halogen, CN, SCN or SF5, or alternatively, R 1 is the group Dia-Z D indicates,

[0011] Dia is derived from a diamond radical, preferably a lower diamondoid, very preferably selected from the group consisting of adamantyl, diamantyl, triamantyl, in which one or more H atoms may be replaced by alkyl or alkoxy having up to 12 C atoms, in particular [ka] indicates, Z D is Z 1 and Z 3 or denotes a spacer group,

[0012] Z 1 , Z 3 is, in each occurrence, identically or differently, a single bond, CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2O-, -OCH2-, -C(O)O-, -OC(O)-, -C(O)S-, -SC(O)-, -(CH2) n1 -, -(CF2) n2-, -CF2-CH2-, -CH2-CF2-, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF-, -(CH2) n3 O-, -O(CH2) n4 -, -C≡C-, -O-, -S-, -CH=N-, -N=CH-, -N=N-, -N=N(O)-, -N(O)=N- or -N=CC=N-; n1, n2, n3, and n4 are the same or different and each is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; Z L -O-, -S-, -CH2-, -C(O)-, -CF2-, -CHF-, -C(R x )2-, -S(O)-, -SO2-,

[0013] R 0 , R 00 denotes, identically or differently, an alkyl or alkoxy radical having 1 to 15 C atoms, in which in addition, one or more H atoms may be replaced by halogen, R x denotes a linear or branched alkyl group having 1 to 6 carbon atoms, A 1 , A 3 represents, identically or differently, in each occurrence, an aromatic, heteroaromatic, alicyclic or heteroaliphatic ring having 4 to 25 ring atoms, which may also contain fused rings, and which may be mono- or polysubstituted by Y; A 2 represents an aromatic or heteroaromatic ring having 5 to 25 ring atoms, which may also contain fused rings, and which may be mono- or polysubstituted by Y,

[0014] Y in each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or linear or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, or cycloalkyl or alkylcycloalkyl, respectively having 3 to 12 C atoms, preferably methyl, ethyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, trifluoromethyl, methoxy or trifluoromethoxy,

[0015] B 1 teeth, [ka] [ka] where the groups may be oriented in both directions,

[0016] L 1 ~L 5 are each independently F, Cl, Br, I, CN, SF5, CF3 or OCF3, preferably Cl or F, where L 3 Alternatively, H may be used. G is -CH=CH 2、 -OH, -CH(CH2OH)2, -C(CH2OH)3, -B(OH)2, -SH, -SO2OH, -OP(O)(OH)2, -PO(OH)2, -C(OH)(PO(OH)2)2, -COOH, -Si(OR x )3 or -SiCl3, -SO2OR V , -OP(O)(OR V )2, -PO(OR V )2, -C(OH)(PO(OR V )2)2, -COOR V , -Si(OR V )3, R Vdenotes alkyl having 1 to 20 C atoms, preferably secondary or tertiary alkyl having 3 to 10 C atoms, R is 0, 1 or 2, and s is 0, 1 or 2; Here, r+s≦4 The present invention relates to a compound represented by the formula:

[0017] The compounds of formula I are characterized by excellent solubility in polar aprotic solvents such as ethyl acetate, 1-methoxy-2-propanol acetate, acetone, ethyl methyl ketone, cyclohexanone, etc. Furthermore, they allow fast formation of molecular layers, fast process times for dip coating, and high quality monolayers deposited by spin coating.

[0018] The molecular layers obtained from the compounds of formula I are distinguished by a dense packing and an advantageously low water contact angle, and allow the fabrication of switching elements for memristor devices that can be patterned by photolithography using standard industrial processes. Furthermore, these monolayers have an extremely high thermal stability, even at temperatures above 300° C.

[0019] Switching devices including molecular layers derived from compounds of formula I advantageously have high current densities. [Brief description of the drawings]

[0020] BRIEF DESCRIPTION OF THE DRAWINGS The drawings show: [Figure 1] Figure 1. Schematic of the layer structure of a memristor memory element. [Diagram 2] FIG. 2 is an exemplary logarithmic plot of measured current density values ​​versus applied voltage for an exemplary embodiment of a memory device having a resistively switching memory element. [Diagram 3] FIG. 3. Exemplary logarithmic plot of measured current density versus applied voltage for a comparative resistive switching memory element.

[0021] The term "diamondoid" refers to substituted and unsubstituted cage compounds of the adamantane series, including adamantane, diamantane, triamantane, tetramantane, pentamantane, hexamantane, heptamantane, octamantane, etc., and all isomers and stereoisomers thereof. The compounds have a "diamondoid" topology, meaning that their carbon atom arrangement is superimposed on a slice of a face-centered cubic diamond lattice. Substituted diamondoids from the first series preferably have 1 to 4 independently selected alkyl or alkoxy substituents.

[0022] Diamondoids include "lower diamondoids" and "higher diamondoids" (as these terms are defined herein), as well as mixtures of any combination of lower and higher diamondoids. The term "lower diamondoids" refers to adamantane, diamantane and triamantane and any and / or all unsubstituted and substituted derivatives of adamantane, diamantane and triamantane. These lower diamondoid components do not exhibit isomerism or chirality and are easily synthesized, distinguishing them from the "higher diamondoids."

[0023] The term "higher diamondoid" refers to any and / or all substituted and unsubstituted tetramantane components; any and / or all substituted and unsubstituted pentamantane components; any and / or all substituted and unsubstituted hexamantane components; any and / or all substituted and unsubstituted heptamantane components; any and / or all substituted and unsubstituted octamantane components; and mixtures of the above, as well as isomers and stereoisomers of tetramantane, pentamantane, hexamantane, heptamantane, and octamantane.

[0024] Adamantane chemistry is discussed by Fort, Jr. et al. in "Adamantane: Consequences of the Diamondoid Structure," Chem. Rev. vol. 64, pp. 277-300 (1964). Adamantane is the smallest member of the diamondoid series and can be thought of as a single cage crystal subunit. Diamantane contains two subunits, triamantane three, tetramantane four, etc. While there is only one isomeric form of adamantane, diamantane, and triamantane, there are four different isomers of tetramantane (two of which represent a pair of enantiomers), i.e., four different possible ways or arrangements of the adamantane subunits. The number of possible isomers increases nonlinearly for each higher member of the diamondoid series: pentamantane, hexamantane, heptamantane, octamantane, etc.

[0025] As used herein, an anchor group is a functional group that allows a compound to adsorb or bind onto the surface of a substrate by physical adsorption, chemisorption, or by chemical reaction. A spacer group in the sense of the present invention is a flexible chain between two rigid groups which causes a separation between these substructures and, due to its flexibility, at the same time improves the mobility of at least one of these groups after binding to a substrate.

[0026] Z D represents a spacer group, the group is preferably selected from the formula Sp'-X', so that the radical Dia-Z of formula I D - corresponds to the formula Dia-Sp'-X'-, in which Sp' denotes a straight-chain or branched alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and in addition, one or more non-adjacent CH groups are each independently of one another -O-, -S-, -NH-, -NR 0 -, -SiR 00 R000 -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -NR 0 -CO-O-, -O-CO-NR 0 -, -NR 0 -CO-NR 0 -, -CH=CH- or -C≡C may be substituted so that the O and / or S atoms are not directly bonded to each other,

[0027] X is -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 00 -,-NR 00 -CO-, -NR 00 -CO-NR 00 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 00 -, -CY x =CY x '-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond;

[0028] R 0 , R 00 and R 000 each, independently of one another, denotes H or alkyl having 1 to 12 C atoms, and Y x and Y x each independently represents H, F, Cl or CN, X' is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -,-NR 0 -CO-, -NR 0 -CO-NR 0 - or a single bond.

[0029] A preferred spacer group Sp' is -(CH2) p1 -, -(CF2) p1 -, -(CH2CH2O)q1 -CH2CH2-, -(CF2CF2O) q1 -CF2CF2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 00 R 000 -O) p1- where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 00 and R 000 has the meaning indicated above. A specifically preferred group -X'-Sp'- is -(CH2) p1 -, -O-(CH2) p1 -, -(CF2) p1 -, -O(CF2) p1 -, -OCO-(CH2) p1 - and -OC(O)O-(CH2) p1 -, where pl has the meaning indicated above.

[0030] Specifically preferred radicals Sp' are, for example, in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, perfluoroethylene, perfluoropropylene, perfluorobutylene, perfluoropentylene, perfluorohexylene, perfluoroheptylene, perfluorooctylene, perfluorononylene, perfluorodecylene, perfluoroundecylene, perfluorododecylene, perfluorooctadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene. A specifically preferred group X' is --O-- or a single bond. The halogens are F, Cl, Br and I.

[0031] In this specification, alkyl is linear or branched and has 1 to 15 C atoms, preferably linear and, unless otherwise specified, has 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl. Branched alkyls can be racemic or non-racemic (optically active). In the present specification, an alkoxy radical is linear or branched and contains 1 to 15 C atoms. It is preferably linear and, unless otherwise specified, has 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy.

[0032] In the present specification, an alkenyl radical is preferably an alkenyl radical having 2 to 15 C atoms, which is linear or branched and contains at least one CC double bond. It is preferably linear and has 2 to 7 C atoms. Accordingly, it is preferably vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl. If two C atoms of the CC double bond are substituted, the alkenyl radical may be in the form of the E and / or Z isomers (trans / cis). Generally, the respective E isomer is preferred. Among the alkenyl radicals, prop-2-enyl, but-2- and -3-enyl, and pent-3- and -4-enyl are particularly preferred.

[0033] In the present specification, alkenyl is understood to mean an alkenyl radical having 2 to 15 C atoms, which is linear or branched and contains at least one C-C triple bond. 1- and 2-propynyl and 1-, 2- and 3-butynyl are preferred. In formula I, preferred aryl groups are derived, for example, from the parent structures benzene, naphthalene, tetrahydronaphthalene, 9,10-dihydrophenanthrene, fluorene, indene and indane.

[0034] In formula I, preferred heteroaryl groups are, for example, five-membered rings such as furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole and 1,3,4-thiadiazole, six-membered rings such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine and 1,2,3-triazine, or condensed rings such as Synthetic rings, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthomidazole, benzoxazole, naphthoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, 2H-chromene (2H-1-benzopyran), 4H-chromene (4H-1-benzopyran) and coumarin (2H-chromen-2-one), or combinations of these groups.

[0035] In formula I, preferred alicyclic groups are cyclobutane, cyclopentane, cyclohexane, cyclohexene, cycloheptane, decahydronaphthalene, bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, spiro[3.3]heptane, and octahydro-4,7-methanoindane. In formula I, preferred heteroaliphatic groups are tetrahydrofuran, dioxolane, tetrahydrothiofuran, pyran, dioxane, dithiane, silinane, piperidine and pyrrolidine.

[0036] Preferably, A 1 and A 3 may, in each occurrence, identically or differently, be selected from the group: a) 1,4-phenylene, in which one or two CH groups may be replaced by N, and in which, in addition, one or more H atoms may be replaced by Y, b) the group consisting of trans-1,4-cyclohexylene and 1,4-cyclohexenylene, in which, in addition, one or more non-adjacent CH groups may be replaced by -O- and / or -S-, and in which, in addition, one or more H atoms may be replaced by Y, and c) the group consisting of 1,3-dioxolane-2,4-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, 1,4-bicyclo[2.2.2]octanediyl, piperidine-1,5-diyl and thiophene-2,5-diyl, in which in addition one or more H atoms may be replaced by Y, wherein Y has the meaning indicated above. is selected from.

[0037] In formula I and its subformulae, very particularly preferred are A 1 and A 3 are the same or different, [ka] indicates, A 2 ~Z L teeth, [ka] indicates,

[0038] B 1 teeth, [ka] indicates,

[0039] R 1 denotes H, linear or branched alkyl, alkenyl, alkynyl, alkoxy, adamantyl or adamantylmethyloxy having up to 12 C atoms, L 1 and L 2 are the same or different and represent F or Cl, Y 1 and Y 2 has, identically or differently, one of the meanings given above for Y and preferably denotes H, F or Cl, Y 3 and Y 4 Y 3 and Y 4 has one of the meanings given above for and preferably denotes methyl, ethyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, methoxy, trifluoromethyl, trifluoromethoxy or trifluoromethylthio,

[0040] Z L indicates -O-, Z 1 , Z 2 denote, independently of one another, a single bond, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2O-, OCH2- or -CH2CH2-, in particular a single bond, and / or G represents -OP(O)(OH)2, -PO(OH)2, or -COH(PO(OH)2).

[0041] Highly preferred sub-formulae of formula I are the sub-formulae I-1 to I-6: [ka] where the occurring radicals have the meanings defined above for formula I and preferably

[0042] R1 denotes alkyl having 1 to 7 C atoms, L 1 and L 2 are the same or different and represent F or Cl, Y 3 and Y 4 has, identically or differently, one of the meanings given above and preferably denotes methyl, and G represents -PO(OH)2 or -COH(PO(OH)2)2.

[0043] In accordance with another aspect of the present invention, there are provided chiral, non-racemic compounds of formula I. Molecular layers derived from chiral compounds of formula I enable memristor devices with significantly reduced stochastic noise and faster switching, reducing the read and write error rate, which has a positive effect on energy efficiency. In addition, increased tunneling currents are observed, allowing integration into smaller junction sizes.

[0044] Preferably, the chiral compounds have an enantiomeric excess of more than 50%, preferably more than 80%, 90%, 95%, more preferably more than 97%, especially more than 98%. Chirality is hereafter referred to as R * one or more, preferably one or two, very preferably one, asymmetrically substituted carbon atoms (or: asymmetric carbon atoms, C * ) a chiral group R 1 This is achieved by:

[0045] R * In the formula (I), the asymmetric carbon atom is preferably bonded to a substituent selected from two different substituted carbon atoms, a hydrogen atom, and a group halogen (preferably F, Cl, or Br), alkyl or alkoxy having in each case 1 to 5 carbon atoms, and CN. The chiral organic radical preferably has the formula: [ka]

[0046] During the ceremony X' has the meaning defined above for formula I and preferably denotes -CO-O-, -O-CO-, -O-CO-O-, -CO-, -O-, -S-, -CH=CH-, -CH=CH-COO- or a single bond, more preferably -CO-O-, -O-CO-, -O- or a single bond, very preferably -O- or a single bond, Q represents a single bond or an optionally fluorinated alkylene having 1 to 10 carbon atoms, in which the CH group not bonded to X may also be replaced by -O-, -CO-, -O-CO-, -CO-O- or -CH=CH-, and preferably represents an alkylene having 1 to 5 carbon atoms or a single bond, particularly preferably -CH-, -CHCH- or a single bond;

[0047] Y denotes optionally fluorinated alkyl having 1 to 15 carbon atoms, where 1 or 2 non-adjacent CH groups may be replaced by -O-, -CO-, -O-CO-, -CO-O- and / or -CH=CH-, further denoting CN or halogen, preferably optionally fluorinated alkyl or alkoxy having 1 to 7 C atoms, -CN or Cl, particularly preferably -CH, -C2H, -CF or Cl, R Ch denotes an alkyl group having 1 to 15 carbon atoms, different from Y, in which one or two non-adjacent CH groups may also be replaced by -O-, -CO-, -O-CO-, -CO-O- and / or -CH=CH-, preferably a straight-chain alkyl group having 1 to 10, especially 1 to 7, carbon atoms, in which the CH group linked to the asymmetric carbon atom may be replaced by -O-, -O-CO- or -CO-O-.

[0048] R represented by formula I 1 is a group Dia-Z as defined above D In the embodiment showing the group R * is Sp *The formula Dia-Sp represents a chiral non-racemic spacer group. * has. Base Dia-Sp * is preferably of the formula: [ka] During the ceremony Dia, Q, Y and X' have the meanings defined above, and Q', identically or differently, has the meaning given above for Q; has.

[0049] The compounds of the general formula I can be prepared by methods known per se, as described in the literature (e.g. standard works such as Houben-Weyl, Methoden der organischen Chemie [Meth-ods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), under precisely known and suitable reaction conditions for the reaction. Use may also be made here of per se known variants that are not mentioned in more detail here. Chiral groups R * and Sp * is described in A. Taugerbeck, Ch. Booth, Design and Synthesis of Chiral Nematic Liquid Crystals, in: Handbook of Liquid Crystals, Volume 3, Part III, Chapter 14, Wiley VCH, Weinheim, 2014, and can be preferably synthesized according to the synthesis described therein or the references cited therein.

[0050] If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead immediately converting them further to the compounds of general formula I. A preferred synthetic route towards compounds according to the invention is shown in the scheme below and further illustrated by the examples. The synthesis can be applied to specific desired compounds of general formula I by the selection of suitable starting materials. For example, as shown in scheme 1, the reaction of phenolate or thiophenolate (1) with fluoronitroaromatic compound (2) produces aryl ether 3 by nucleophilic displacement of fluoride. Ether 3 can be converted using standard processes via iodide 4 to phosphonic acid 5.

[0051] Scheme 1 [ka]

[0052] The invention also relates to a process for the production of a switching element according to the invention, comprising at least the following steps: a) providing a first electrode having a surface; b) depositing a monolayer comprising one or more compounds of formula I on the surface of the first electrode; c) application of a second electrode; The process relates to the above process comprising: The deposition of the monolayer is carried out using pure substances or from solution, preferably from solution. Suitable deposition methods and solvents are known to those skilled in the art; examples are spin-coating or dip-coating.

[0053] According to another aspect of the invention, the monolayer comprises one or more compounds of formula I, wherein the anchor group G is -SO2OR V , -OP(O)(OR V )2, -PO(OR V )2, -C(OH)(PO(OR V )2)2, -COOR V Or -Si(OR V )3, R Vis prepared from said compounds, in which R denotes an alkyl group having 1 to 20 C atoms, preferably a secondary or tertiary alkyl group having up to 20 C atoms. These compounds are distinguished in particular by a high solubility, making them well suited for industrial processes such as spin-coating. In addition, it is possible to process these compounds by gas-phase deposition. The compounds act as precursors for the corresponding free acids, which are obtained in situ by thermal treatment of the compounds after deposition on the first electrode. The first electrode is then heated to a temperature between 60°C and 300°C, preferably between 100°C and 250°C, in particular between 140°C and 180°C.

[0054] In a preferred embodiment, the substrate is annealed after deposition of the monolayer. The annealing is carried out at a temperature higher than 20° C. and lower than 300° C., preferably higher than 50° C. and lower than 200° C., particularly preferably higher than 90° C. and lower than 150° C. The duration of the annealing is 1-48 h, preferably 4-24 h, particularly preferably 8-16 h.

[0055] The molecular layers of the present invention are layers of electrically insulating, non-conductive, and non-semiconductive organic compounds. The molecular layer preferably contains a molecule represented by formula I, and particularly preferably consists of a molecule represented by formula I. The layer thickness is preferably less than or equal to 10 nm, particularly preferably less than or equal to 5 nm, very particularly preferably less than or equal to 2 nm. The molecular layer may consist of one, two, three or more molecular layers comprising the compound of formula I.

[0056] The molecular layer employed in accordance with the present invention is preferably a monolayer of molecules. In one embodiment, the molecular layer is a self-assembled monolayer (SAM). The production of self-assembled monolayers is known to those skilled in the art; for example, it is reviewed in A. Ulman, Chem. Rev. 1996, 96, 1533-1554.

[0057] In a further embodiment, the molecular layer is attached to the substrate by chemisorption, especially by addition or condensation reactions. In a further embodiment, the molecular layer is attached to the substrate by physisorption. The degree of coverage of the substrate is preferably 90% to 100%, specifically preferably 95% to 100%, very specifically preferably 98% to 100%.

[0058] In a further embodiment, the molecular layer is covered with 1 to 10, preferably 1 to 5, particularly preferably 1 to 3, further layers of organic or inorganic adsorbates. Suitable layers include dielectrics, such as oxidized, fluorinated or nitrided materials, such as TiO2, Al2O3, HfO2, SiO2, LiF and Si3N4, or metals, such as Pt, Pd, Pb, Au, Ag, Cu, Al and Mg, and their eutectic compounds, such as PdAu 20:80. Such layers can be built up by defined and precise deposition, for example by ALD (atomic layer deposition) processes, in thicknesses of a few nanometers.

[0059] The molecules of the molecular layer are preferably covalently bound to the substrate by known methods familiar to those skilled in the art, for example by addition reaction of the compounds of formula I or by esterification with hydroxyl groups located on the surface of the substrate. For the addition reaction, a suitable substrate, preferably a silicon surface (after corresponding pretreatment with aqueous NHF solution) can be treated, for example, to obtain a hydrogen-terminated surface. The surface thus treated can then be treated at high temperature with the exclusion of oxygen, either directly with a suitable liquid compound represented by formula I or with a solution of a compound represented by formula I in a suitable solvent. According to an aspect of the present invention, the group G in formula I preferably represents -CH=CH2.

[0060] For condensation reaction, a suitable substrate, preferably a silicon surface, can be treated, for example, with oxygen plasma to obtain a hydrophilic oxide surface with a high hydroxyl group content.The surface thus treated can then be treated at high temperature directly with either a suitable liquid compound represented by formula I or a solution of a compound represented by formula I in a suitable solvent.It is clear that this type of oxide surface only serves as a surface modification for the purpose of possible derivatization via condensation reaction, and does not represent an insulating layer in the true sense.A sufficiently large tunnel current through this oxide surface is possible for a thickness as small as 1 nm.

[0061] In a switching element according to the invention, the molecules of the molecular layer are bound to a substrate or an intermediate layer located between the monolayer of molecules and the substrate. The substrate according to the invention may perform various functions depending on the structure of the switching element. For example, a conductive substrate may serve as a first electrode. Likewise, the substrate may be a layer of a diode. Suitable substrates are known to those skilled in the art. Particularly suitable substrates include: - Elemental semiconductors, such as Si, Ge, C (diamond, graphite, graphene, fullerenes), α-Sn, B, Se and Te;

[0062] - Compound semiconductors, preferably - III-V semiconductors, especially GaAs, GaP, InP, InSb, InAs, GaSb, GaN, TaN, TiN, MoN, WN, AlN, InN, Al x Ga 1-x As and In x Ga 1-x Ni, - II-VI semiconductors, especially ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, Hg (1-x) CD (x) Te, BeSe, BeTe x and HgS; - III-VI semiconductors, especially GaS, GaSe, GaTe, InS, InSe x and InTe, - IV-IV semiconductors, in particular SiC and SiGe, - IV-VI semiconductors, especially SeTe;

[0063] - organic semiconductors, in particular polythiophenes, tetracenes, pentacenes, phthalocyanines, PTCDA, MePTCDI, quinacridones, acridones, indanthrones, fulleranthrones, perinones, AlQ3, and mixed systems, in particular PEDOT:PSS and polyvinylcarbazole / TLNQ complexes; - metals, among others Ta, Ti, Co, Mo, Pt, Ru, Au, Ag, Cu, Al, W and Mg;

[0064] - conductive oxide materials, in particular indium tin oxide (ITO), indium gallium oxide (IGO), InGa-α-ZnO (IGZO), aluminium doped zinc oxide (AZO), tin doped zinc oxide (TZO), fluorine doped tin oxide (FTO) and antimony tin oxide, is selected from.

[0065] The molecular layer may optionally also be bonded to a thin (preferably 0.5-5 nm thick) oxide or fluoride intermediate layer, such as TiO2, Al2O3, HfO2, SiO2 or LiF, located on the substrate.

[0066] The counter electrode or second electrode consists of a conductive or semiconductive material or a combination (lamination) of several of these materials. Examples are materials referred to as substrate materials. Preferred are Hg, In, Ga, InGa, Ag, Au, Cr, Pt, PdAu, Pb, Al, Mg, W, Yb, Zn, CNT (carbon nanotube), graphene and conductive polymers (such as PEDOT:PSS). The production and construction of the electrodes is carried out using processes known to those skilled in the art. The fabrication and electrical characterization of the switching elements comprising molecular layers obtained from one or more compounds of formula I is carried out according to the procedures described in WO 2016 / 110301 A1 and WO 2018 / 007337 A2.

[0067] example Synthesis Example 1 Step 1: 1-(2,6-dimethyl-4-nitro-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)-benzene [ka]

[0068] A solution of 2-fluoro-1,3-dimethyl-5-nitrobenzene (24.5 g, 0.145 mol) in dimethylsulfoxide (DMSO) (245 mL) is added to a suspension of 2,3-difluoro-4-(4-pentylcyclohexyl)phenol (49.1 g, 0.174 mol) and potassium carbonate in DMSO (245 mL) and heated at 125° C. overnight under nitrogen. The mixture is cooled to 40° C. and then added to water (1.5 L) and stirred for 30 minutes. Ethyl acetate (400 mL) and brine (50 mL) are added and the layers are separated. The aqueous layer is further extracted with ethyl acetate (2×300 mL). The organics are combined, dried over magnesium sulfate and the solvent is evaporated. The crude oil is dissolved in heptane (160 mL) and purified on silica gel (200 g) eluting with heptane followed by 5% ethyl acetate / heptane, followed by recrystallization from acetonitrile to give 1-(2,6-dimethyl-4-nitro-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)-benzene as a beige solid.

[0069] 1 H NMR (400 MHz, CDCl3-d) δ ppm 0.89 (3 H, t, J=7.0 Hz), 1.00-1.15 (2 H, m), 1.17-1.35 (9 H, m), 1.35-1.46 (2 H, dd, J=12.3 Hz, 2.3 Hz), 1.86 (4 H, br. d, J=10.9 Hz), 2.25 (6 H, s), 2.77 (1 H, m), 6.12 (1 H, m), 6.75 (1 H, m), 8.02 (2 H, s). 13 C NMR (400 MHz, CDCl3-d) δ ppm 14.01, 16.36, 22.64, 32.12, 32.82, 33.30, 37.00, 37.15, 37.21, 109.16 (d, J=2.9 Hz), 120.77 (t, J=5.1 Hz), 124.34, 130.12 (dd, J=12.5 Hz, 1.5 Hz), 132.95, 140.69 (dd, J=248.7 Hz, 16.1 Hz), 143.43 (dd, J=8.8 Hz, 2.9 Hz), 144.79, 148.37 (dd, J=247.2 Hz, 10.3 Hz), 155.90. 19 F NMR (400 MHz, CDCl3-d) δ ppm -158.9 (1 F, d, J=19.1 Hz)., -141.4 (1 F, d, J=19.1 Hz).

[0070] Step 2: 4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-aniline [ka]

[0071] Pd / C (5% loaded, 50% wet, 1.95 g) is charged to a 2 L Parr pressure vessel, followed by a solution of 1-(2,6-dimethyl-4-nitro-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)-benzene (39.0 g, 90.38 mmol) in isopropanol (585 mL) and tetrahydrofuran (THF, 117 mL). Hydrogen is charged to a pressure of 5 bar. After 90 min, the pressure is reduced to .about.1 bar. Hydrogen is charged again to a pressure of 5 bar and stirred overnight. The catalyst is filtered, washed with isopropanol (50 mL) and the filtrate is concentrated to dryness to give 4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-aniline as an off-white solid.

[0072] 1 H NMR (400 MHz, DMSO-d6) δ ppm 0.85 (3 H, t, J=6.9 Hz), 0.95-1.07 (2 H, m), 1.13-1.32 (9 H, m), 1.33-1.46 (2 H, m), 1.76 (4 H, t, J=14.3 Hz), 1.90 (6 H, s), 2.67 (1 H, tm, J=12.0 Hz), 3.34 (1 H, s), 4.93 (2 H, s), 6.20 (1 H, m), 6.32 (2 H, s), 6.90 (1 H, m). 13 C NMR (400 MHz, DMSO-d6) δ ppm 13.81, 15.70, 22.14, 26.04, 31.64, 32.36, 32.88, 36.40, 36.56, 36.78, 109.27, 114.03, 121.12 (m), 127.46 (d, J=11.7 Hz), 130.19, 139.63 (dd, J=245.4 Hz, 15.8 Hz), 140.27, 145.1 (m), 146.13, 148.65 (dd, J=243.6 Hz, 10.3 Hz). 19 F NMR (400 MHz, DMSO-d6) δ ppm -160.90 (1 F, d, J=21 Hz), -143.67 (1 F, d, J=21 Hz).

[0073] Step 3: 2,3-Difluoro-1-(4-iodo-2,6-dimethyl-phenoxy)-4-(4-pentylcyclohexyl)benzene [ka]

[0074] To a solution of 4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-aniline (29.8 g, 74.22 mmol) in dichloromethane (218 mL) is added a solution of sodium nitride (25.6 g, 371.1 mmol) in water (218 mL), followed by the addition of diiodomethane (39.76 g, 148.4 mmol). The mixture is stirred for 15 minutes, then acetic acid (89.1 g, 1.48 mol) is added dropwise. The mixture is stirred at room temperature overnight. The layers are separated and the aqueous layer is extracted with dichloromethane. The organics are combined and washed with 20% sodium bisulfite and brine. The organics are dried over magnesium sulfate and concentrated to dryness to give the crude material as a red oil. The oil is purified on silica gel eluting with 2.5% dichloromethane / heptane and recrystallized from hot acetonitrile to give 2,3-difluoro-1-(4-iodo-2,6-dimethyl-phenoxy)-4-(4-pentylcyclohexyl)benzene as a white solid.

[0075] 1 H NMR (400 MHz, CDCl3-d) δ ppm 0.91 (3 H, t, J=7.0 Hz), 1.04-1.12 (2 H, m), 1.18-1.47 (11 H, m), 1.87 (4 H, br. d, J=10.8 Hz), 2.12 (6 H, s), 2.77 (1 H, tm, J=12.2 Hz), 6.14 (1 H, m), 6.72 (1 H, m), 7.46 (2 H, m). 13C NMR (400 MHz, CDCl3-d) δ ppm 14.11, 15.77, 22.69, 26.60, 32.17, 32.89, 33.37, 36.98, 37.20, 37.27, 89.70, 108.98 (d, J=3.7 Hz), 120.55 (m), 129.24 (d, J=12.5 Hz), 133.81, 137.84, 140.64 (dd, J=248.0 Hz, 16.2 Hz), 144.13 (dd, J=8.1 Hz, 2.9 Hz), 149.54 (dd, J=246.5 Hz, 10.3 Hz), 150.79. 19 F NMR (400 MHz, CDCl3-d) δ ppm -159.79 (1 F, d, J=20.5 Hz), -142.22 (1 F, d, J=20.5 Hz).

[0076] Step 4: 1-(4-diethoxyphosphoryl-2,6-dimethyl-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene [ka]

[0077] To 2,3-difluoro-1-(4-iodo-2,6-dimethyl-phenoxy)-4-(4-pentylcyclohexyl)benzene (28.5 g, 55.62 mmol) in dioxane (285 mL) is added triethyl phosphite (23.1 g, 139.05 mmol) under nitrogen. Pd(OAc)2 (1.56 g, 6.95 mmol) is added and the reaction is heated to reflux for 75 minutes. The reaction is cooled to 30° C., heptane (400 mL) and water (400 mL) are added, the layers are separated, and the aqueous layer is extracted with ethyl acetate (400 mL). The organics are combined, washed with brine, dried over magnesium sulfate, filtered, and then concentrated to dryness. The crude material is purified on silica eluting with 10% ethyl acetate / dichloromethane to give 1-(4-diethoxyphosphoryl-2,6-dimethyl-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene as an off-white solid.

[0078] 1 H NMR (400 MHz, CDCl3-d) δ ppm 0.89 (3 H, t, J=7.0 Hz), 1.02-1.10 (2 H, m), 1.15-1.45 (18 H, m), 1.84 (4 H, d, J=11.0 Hz), 2.18 (6 H, s), 2.75 (1 H, m), 4.06-4.23 (4 H, m), 6.09 (1 H, m), 6.71 (1 H, m), 7.56 (2 H, d, J=13.3 Hz. 13C NMR (400 MHz, CDCl3-d) δ ppm 13.97, 16.03, 16.25 (d, J=6.6 Hz), 22.58, 26.49, 32.06, 32.79, 32.26, 36.88, 37.09, 37.16, 62.07 (d, J=5.9 Hz), 109.08 (d, J=2.9 Hz), 120.51 (t, J=5.1 Hz), 125.15 (d, J=189.3 Hz), 129.36 (d, J=11.7 Hz), 131.82 (d, J=16.1 Hz), 132.64 (d, J=10.3 Hz), 140.58 (dd, J=248.3 Hz, 15.8 Hz), 143.82 (dd, J=8.4 Hz, 2.6 Hz), 149.47 (dd, J=246.2 Hz, 9.9 Hz), 154.16 (d, J=3.7 Hz). 19 F NMR (400 MHz, CDCl3-d) δ ppm -159.6 (1 F, d, J=19 Hz), -142.1 (1 F, d, J=19 Hz). 31 P NMR (400 MHz, CDCl3-d) δ ppm 18.80.

[0079] Step 5: [4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-phenyl]phosphonic acid [ka]

[0080] To 1-(4-diethoxyphosphoryl-2,6-dimethyl-phenoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene (22.35 g, 42.77 mmol) in dichloromethane (325 mL) is added trimethylsilyl bromide (65.82 g, 427.7 mmol). The solution is stirred at room temperature overnight. Methanol (225 mL) is added over 15 minutes and the solution is stirred for 30 minutes before being concentrated to dryness. The resulting solid is dissolved in tetrahydrofuran (325 mL) and filtered through a 0.7μ glass fiber filter. Heptane (225 mL) is added and the THF is slowly removed until solids begin to precipitate, at which point evaporation is stopped and the mixture is allowed to cool to room temperature with stirring overnight. The resulting solid is filtered, washed with heptane, and recrystallized from ethyl acetate to give [4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-phenyl]phosphonic acid as a white solid.

[0081] 1 H NMR (400 MHz, THF-d) δ ppm 0.90 (3 H, t, J=7.0 Hz), 1.03-1.14 (2 H, m), 1.21-1.35 (9 H, m), 1.42-1.52 (2 H, m), 1.85 (4 H, t, J=13.0 Hz), 2.14 (6 H, s), 2.77 (1 H, tm, J=12.1 Hz), 6.20 (1 H, m), 6.80 (1 H, m), 7.59 (2 H, d, J=13.4 Hz). 19 F NMR (400 MHz, THF-d) δ ppm -162.86 (1 F, d, J=20.4 Hz), -145.71 (1 F, d, J=20.4 Hz). 31 P NMR (400 MHz, THF-d) δ ppm 15.91. ES (-ve) MS: m / z = 465.1998, 100% [MH] - , C 25 H32 F2O4P - requires 465.2006.

[0082] In analogy to Example 1, the following compound is obtained: [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] Comparative solubility test The following reference compound 1 in various solvents: [ka] The comparative solubility of (reference from DE102017005884) and of Synthesis Example 1 at 1 mM concentration at 23° C. is experimentally determined. The samples are stirred at 23° C. for 18 hours and then visually inspected. In the table below, the expression "soluble" means that a clear solution is obtained after 18 hours. "Insoluble" means that residual solids are observed.

[0093] [Table 1]

[0094] In contrast to Reference 1, Synthesis Example 1 is soluble at 1 mM concentration in 1-methoxy-2-propanol acetate and cyclohexanone, industry-typical, environmentally acceptable CMOS process solvents.

[0095] Electrical Characterization The electrical characterization of a switching device 100 (FIG. 1) comprising a molecular layer 140 obtained from the compound [4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-phenyl]phosphonic acid (Synthesis Example 1) sandwiched between a TiN first electrode 130 (50 nm thick) and a Ti second electrode 150 (10 nm) with a gold contact 160 (80 nm) on a silicon substrate 110 with a silicon oxide layer 120 is carried out under SEM control using a nanoprobe (Hitachi High Technologies Nano-Probe N-6000SS, probe size ca. 1 μm) and an Agilent B 1500 device analyzer.

[0096] For comparison, a switching device containing a molecular layer prepared from 11-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]undecylphosphonic acid (PA-11O-YC-5, Reference Compound 1) is fabricated and characterized accordingly.

[0097] The starting material was a 6-inch diameter silicon-on-insulator wafer ("SIO wafer") having a silicon layer with a

[0100] orientation and a thickness of 110 nm on a silicon oxide layer with a thickness of 200 nm on a lightly boron-doped silicon wafer with a

[0100] orientation and a resistivity of about 20 Ωcm and a thickness of 525 μm.

[0098] The upper silicon layer is heavily boron doped by ion implantation (doping concentration c~5×10 19 cm -3 , resistance ρ~1.4 mΩ.cm). After doping, the wafer is divided into square parts ("chips") measuring 8 mm x 8 mm. The chips are cleaned first in acetone and then in isopropanol in an ultrasonic bath for 10 minutes in each case. A silicon dioxide intermediate layer 120 is produced by treatment of the wafer with oxygen plasma (200 W, 7 minutes).

[0099] The substrate is then coated with a 50 nm thick layer of TiN deposition by reactive sputtering activated by ozone / UV treatment (110 W / 300 s), followed by immersion in a 1 mM solution of phosphonic acid [4-[2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy]-3,5-dimethyl-phenyl]phosphonic acid (Synthesis Example 1) in tetrahydrofuran (THF) for 24 hours. The chip is removed from the immersion bath, dried with nitrogen, and annealed under nitrogen at 120° C. for 60 minutes. The chip is then rinsed with THF on a spin coater, followed by annealing under nitrogen at 120° C. for 5 minutes. A titanium top electrode 150 and a gold contact 160 are applied by sputtering using standard processes.

[0100] The results of electrical characterization of device 100 are shown in Figure 2. The forward scan 210 starts at 0V and increases the voltage to +3.5V; then the reverse scan 220 goes to 0V, up to -3.5V, and back to 0V. The scan speed is 300mV / s. The resulting current is measured and the results are shown in Figure 2. The device advantageously has a large memory window. 3 shows the current density of a device fabricated with a comparative compound, Reference Compound 1. The comparison shows that devices fabricated with compounds according to the invention exhibit advantageously higher current densities, roughly 1000 times higher.

Claims

1. Formula I R １ -(A １ -Z １ ) ｒ -B １ -Z Ｌ -A ２ -(Z ３ -A ３ ) ｓ -G (I) During the ceremony R １ denotes a linear or branched alkyl or alkoxy radical having 1 to 20 C atoms, where in these radicals one or more CH ２ The groups are each independently of one another -C≡C-, -CH=CH-, 【Chemistry 1】 -O-, -S-, -CF ２ O-, -OCF ２ -, -CO-O-, -O-CO-, -SiR ０ R ００ -, -NH-, -NR ０ -or-SO ２ - may be substituted so that the O atoms are not directly bonded to each other, and wherein, in addition, one or more H atoms may be replaced with halogen, CN, SCN or SF ５ may be replaced by Z Ｌ is -O-, -S-, -CH ２ -, -C(O)-, -CF ２ -, -CHF-, -C(R ｘ ) ２ -, -S(O)- or -SO ２ - indicates R ０ , R ００ denotes, identically or differently, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more H atoms may be replaced by halogen, A １ , A ３ represents, identically or differently, in each occurrence, an aromatic, heteroaromatic, alicyclic or heteroaliphatic ring having 4 to 25 ring atoms, which may also contain fused rings, and which may be mono- or polysubstituted by Y; A 2 -Z L is 【Chemistry 2】 indicates, Y, Y 3 and Y 4 in each occurrence are the same or different and each represents F, Cl, CN, SCN, SF ５ or linear or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, or cycloalkyl or alkylcycloalkyl, respectively having 3 to 12 C atoms, preferably methyl, ethyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, trifluoromethyl, methoxy or trifluoromethoxy, B １ teeth, 【Chemistry 3】 where the groups may be oriented in both directions, G is CH=CH ２、 -OH, -CH(CH ２ O.H. ２ , -C(CH ２ O.H. ３ , B(OH) ２ , -SH, -SO ２ OH, -OP(O)(OH) ２ , -PO(OH) ２ , -C(OH)(PO(OH) ２ ) ２ , -COOH, -Si(OR ｘ ) ３ or -SiCl ３ , -SO ２ OR Ｖ , -OP(O)(OR Ｖ ) ２ , -PO(OR Ｖ ) ２ , -C(OH)(PO(OR Ｖ ) ２ ) ２ , -COOR Ｖ , -Si(OR Ｖ ) ３ indicates, R Ｖ denotes alkyl having 1 to 20 C atoms, R ｘ denotes a straight-chain or branched alkyl group having 1 to 6 C atoms, and r is 0, 1 or 2; s is 0, 1 or 2; Here, r+s≦4, A compound represented by the formula:

2. A １ and A ３ may, in each occurrence, be identically or differently selected from the group: a) 1,4-phenylene, in which one or two CH groups may be replaced by N, and in which, in addition, one or more H atoms may be replaced by Y, b) the group consisting of trans-1,4-cyclohexylene and 1,4-cyclohexenylene, ２ The group may be replaced by -O- and / or -S-, and in addition, one or more H atoms may be replaced by Y, and c) the group consisting of 1,3-dioxolane-2,4-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, 1,4-bicyclo[2.2.2]octanediyl, piperidine-1,5-diyl and thiophene-2,5-diyl, in which one or more H atoms may be replaced by Y; 2. The compound according to claim 1, wherein Y has the meaning given in claim 1 and is selected from:

3. R １ 3. The compound according to claim 1 or 2, wherein each denotes a straight-chain or branched alkyl, alkenyl, alkynyl or alkoxy having up to 12 C atoms.

4. Z Ｌ The compound according to any one of claims 1 to 3, wherein represents -O-.

5. G is -OP(O)(OH) ２ , -PO(OH) ２ , -C(OH)(PO(OH) ２ ) ２ The compound according to any one of claims 1 to 4, wherein

6. The compound according to any one of claims 1 to 5, wherein s is 0.

7. Z １ The compound according to any one of claims 1 to 6, wherein represents a single bond.

8. A process for the preparation of a switching element, comprising at least the following steps: a) providing a first electrode having a surface; b) depositing a molecular layer comprising one or more compounds according to any one of claims 1 to 7 on the surface of a first electrode; c) application of a second electrode; The process comprising:

9. 9. The process of claim 8, wherein the first electrode comprises a material selected from the elemental semiconductors Si, Ge, diamond, graphite, graphene, C, Sn with alpha modification, and Se, the compound semiconductors GaAs, InAs, InP, GaSb, TaN, TiN, MoN, WN, and GaN, CdSe, and ZnS, the metals Au, Ag, Cu, Al, W, Ta, Ti, Co, Mo, Pt, Ru, and Mg, and the conductive oxide materials ITO, IGO, IGZO, AZO, and FTO.

10. A switching element comprising a molecular layer sandwiched between a first electrode and a second electrode, obtainable by the process according to claim 8 or 9.

11. The switching element according to claim 10 , wherein the molecular layer is a self-assembled monolayer.

12. A memristor device comprising a switching element according to claim 10 or 11.

Images