Heteronuclear cerium germanium complex as well as preparation method and application thereof

Abstract

The invention discloses a heteronuclear cerium-germanium complex and a preparation method and application thereof, and belongs to the technical field of organic synthesis.The heteronuclear cerium-germanium complex is a cerium-germanium complex A, a cerium-germanium complex B or a cerium-germanium complex C. Cerium and germanium centers of the complexes are in a specific space adjacent state; the cerium-germanium complex A, the cerium-germanium complex B and the cerium-germanium complex C have unique structures, so that the cerium-germanium complex A, the cerium-germanium complex B and the cerium-germanium complex C become an ideal fundamental research carrier. The method can be used for in-depth exploration of electron interaction or spin coupling possibly existing between cerium and germanium through a ligand skeleton; the two independent metal centers have synergistic reaction activity in a limited space; such structures have potential properties in molecular magnetic or luminescent materials. Therefore, the invention not only enriches the structure types of the rare earth-main group element complex, but also provides a new platform with accurate structure and adjustable performance for the basic research of multi-center metal organic chemistry, and has definite scientific significance and potential application exploration value.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a heteronuclear cerium-germanium complex, its preparation method, and its application. Background Technology

[0002] Rare earth metal-organic complexes are an important research subject in modern functional materials and homogeneous activation fields. Integrating rare earth metals with main group elements (such as germanium from group 14) into the same molecule can combine their distinct electronic properties, potentially leading to novel physicochemical properties and application potential.

[0003] Currently, most reported rare-earth-germanium direct-bonded complexes in the literature focus on heavy rare-earth elements or clusters containing rare-earth-germanium bonds. For heterobimetallic complexes with well-defined molecular structures containing cerium-germanium units, especially cases involving the precise spatial arrangement of the two metal centers using designed ligands, there are still few reports. This is mainly due to: (1) the difficulty in designing suitable ligands that can simultaneously stabilize two metal centers with different properties, cerium and germanium; and (2) the lack of efficient and step-controllable synthetic strategies to achieve the directional assembly of such complex structures.

[0004] Therefore, developing stable complexes that achieve covalent bridging through designed organic ligands, maintaining precise spatial proximity of dissimilar metal centers without direct metallic bonds, has become a highly valuable design approach. Reports of non-bonded bridging complexes with well-defined structures and fixed spatial configurations for the specific cerium-germanium combination, particularly using stepwise controllable synthesis strategies, provide an indispensable material basis for studying the intrinsic properties and applications of such special systems, possessing significant scientific value and technological necessity. Summary of the Invention

[0005] The purpose of this invention is to provide a heteronuclear cerium-germanium complex in order to address the technical deficiencies existing in the prior art.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned heteronuclear cerium-germanium complex.

[0007] Another object of the present invention is to provide the application of the above-mentioned heteronuclear cerium-germanium complex.

[0008] The technical solution adopted to achieve the purpose of this invention is: A heteronuclear cerium-germanium complex, wherein the molecular structure of the heteronuclear cerium-germanium complex is as follows: It is denoted as cerium-germanium complex A.

[0009] Another aspect of the present invention includes a heteronuclear cerium-germanium complex, obtained by reacting cerium-germanium complex A as a precursor with potassium graphite, the molecular structure of which is as follows: It is denoted as cerium-germanium complex B.

[0010] Another aspect of the present invention includes a heteronuclear cerium-germanium complex, obtained by reacting cerium-germanium complex B as a precursor with 2,2,2-caecinyl ether, the molecular structure of which is: It is denoted as cerium-germanium complex C.

[0011] In the above technical solution, the cerium-germanium complex A is a monoclinic crystal system with space group [space group number missing]. P 21, the cell parameters are a=12.9087(13) Å, b=39.6670(3) Å, c=13.9101(13) Å, α=90°, γ=90°, β=112.0191(11)°, Z=2, V=6603.18(12).

[0012] In the above technical solution, the cerium-germanium complex B is a monoclinic crystal system with space group [missing information]. P 21 / c, cell parameters are a=12.6345(2) Å, b=25.2160(3) Å, c=18.7542(3) Å, α=90°, γ=90°, β=105.887(2)°, Z=4, V=5746.71(16).

[0013] In the above technical solution, the cerium-germanium complex C is triclinic with space group [missing information]. P -1, the unit cell parameters are a=13.9521(2) Å, b=16.9413(3) Å, c=17.4375(3) Å, α=89.234(1)°, γ=86.977(1)°, β=88.171(1)°, Z=2, V=4113.53(12).

[0014] Another aspect of the present invention includes a method for preparing the cerium-germanium complex A, comprising the following steps: Step 1: Under an argon atmosphere, ligand L2, tris[N,N-bis(trimethylsilyl)amide]cerium(III) and [N,N-bis(trimethylsilyl)amide]potassium are dissolved in tetrahydrofuran for reaction. After removing the solvent and purifying, a cerium-potassium complex is obtained. The molecular structure of ligand L2 is as follows: .

[0015] Step 2: Under an argon atmosphere, the cerium-potassium complex and germanium(II) dioxane adduct are inserted into germanium via a salt elimination reaction to obtain cerium-germanium complex A.

[0016] In the above technical solution, tetrahydrofuran is used as a solvent to carry out the reaction.

[0017] Another aspect of the present invention includes the application of the heteronuclear cerium-germanium complex as a bimetallic synergistic catalytic activator in the synthesis of high-purity pharmaceutical intermediates, food additives that eliminate trans fatty acids, polymer monomers, and highly selective silicone oils.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention successfully synthesized and isolated a series of heteronuclear cerium-germanium complexes. In this series of complexes, the cerium and germanium centers are in a specific spatial proximity. The unique structures exhibited by cerium-germanium complexes A, B, and C make them ideal platforms for basic research. They can be used to explore: (a) the possible electronic interactions or spin coupling between cerium and germanium through the ligand framework; (b) the synergistic reactivity of two independent metal centers in a confined space; and (c) the potential properties of such structures in molecular magnetic or luminescent materials. Therefore, this invention not only enriches the structural types of rare earth-main group element complexes but also provides a new platform with precise structure and tunable performance for basic research in multicenter organometallic chemistry, possessing clear scientific significance and potential application exploration value. 2. The ligand L2 of this invention plays a crucial template and guiding role in the reaction through its pre-designed rigid structure and the presence of specific NH functional groups. Each of the two independent ligands in the cerium-potassium complex has two activatable NH bonds, which are selectively deprotonated at different stages of the reaction, thereby enabling the controllable and stepwise in-situ generation of two new nitrogen anion coordination sites and the introduction of germanium. This characteristic demonstrates that ligand L2 not only provides an initial stable coordination field but also exerts its potential coordination ability through the gradual release of NH, sequentially introducing heterometallic centers, stabilizing intermediates, and ultimately driving intermolecular metal rearrangement, thus precisely guiding the formation of a thermodynamically more stable binuclear target product. The core of the entire reaction process lies in the unique, stepwise activated reactive design of this dual-ligand system. 3. The unique bimetallic spatial proximity structure of the heteronuclear cerium-germanium complex of this invention is expected to serve as a bifunctional synergistic activator for the activation of unsaturated hydrocarbons. For example, the Ce(III) and Ge(II) centers in the complex can efficiently activate carbon-carbon multiple bonds in styrene or phenylacetylene through a synergistic polarization mechanism. Based on this unique activation mode, it is expected to achieve precise control of stereoselectivity in subsequent addition reactions such as hydrogenation, hydrosilylation, or hydroboration. This characteristic makes it potentially valuable in the synthesis of fine chemicals, for example, for the preparation of high-optical-purity organosilicon reagents or high-value olefin intermediates with specific configurations; 4. The unique activation of carbon-carbon unsaturated bonds in styrene and phenylacetylene by the heteronuclear cerium-germanium complex of the present invention originates from the bifunctional synergistic effect created by its non-bonded bridging structure. When the substrate molecule approaches, the cerium (III) center in the complex, acting as a hard Lewis acid, tends to interact with relatively electron-rich regions on the unsaturated bond (such as the carbon atom near the benzene ring in styrene or a specific π orbital in phenylacetylene); simultaneously, the germanium (II) center, acting as a soft Lewis base, synergistically acts on relatively electron-deficient regions on the same unsaturated bond (such as the methylene end of styrene or the other side of phenylacetylene). This "two-end synergistic" mode of action not only achieves spatial orientation locking of the substrate, but more importantly, through the "pull-pull" electronic effect, it synergistically polarizes and weakens the C=C or C≡C bond from both ends, creating a highly activated and geometrically fixed key intermediate state for subsequent selective functionalization reactions. Its essence is to utilize spatially proximate but electronically dissimilar bimetallic centers to achieve a novel activation pathway that differs from traditional strong Lewis acids or single-electron transfer mechanisms; 5. The novelty and expected advantages of the heteronuclear cerium-germanium complex of the present invention compared with existing conventional activators (such as strong Lewis acids, alkali metals, or free radical initiators) are as follows: (a) Different activation mechanisms: Traditional activators mostly rely on a single strong electrophilic, nucleophilic or free radical process, which is violent and difficult to control; while the complex of the present invention uses spatially adjacent hard-soft bimetallic centers to synergistically electrostatically polarize unsaturated bonds, which is a mild and directional electron rearrangement activation mode. (b) Selectivity Advantage: The unique directional polarization mechanism described above promises to overcome the limitations of traditional activators, which exhibit low activation efficiency and poor selectivity for nonpolar carbon-carbon bonds (e.g., C=C, C≡C). More importantly, the rigid spatial structure of this complex can pre-determine a specific geometric configuration for the activated substrate, thereby spatially guiding the attack direction of subsequent reagents. This dual control of "electronic polarization" and "spatial guidance" provides a new activation platform for achieving high regioselectivity and high stereoselectivity in subsequent functionalizations (e.g., anti-Markovnikov addition). (c) Mild activation conditions and functional group compatibility: Traditional strong activators often require harsh conditions and damage sensitive functional groups. The activation mode of the complexes of this invention is mild and is expected to achieve high chemoselectivity in complex molecules (such as pharmaceutical intermediates containing aldehydes, ketones, and halogens), activating only the target unsaturated bonds, thereby suppressing side reactions and improving synthesis efficiency; (d) Designability of structure and properties: Traditional small molecule activators (such as BF) AlCl The structure and properties of traditional cerium-germanium complexes are singular and fixed. In contrast, the cerium-germanium complex of this invention is a well-defined and designable molecular platform: by changing the structure of the bridging ligands, the distance and spatial orientation of their bimetallic centers can be controlled, thereby enabling precise regulation of their activation of different unsaturated bonds. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the crystal structure of ligand L2.

[0020] Figure 2 For ligand L2 1 H NMR spectroscopy.

[0021] Figure 3 For ligand L2 13 C10 NMR spectroscopy.

[0022] Figure 4 This is the mass spectrum of ligand L2.

[0023] Figure 5 This is a schematic diagram of the crystal structure of a cerium-potassium complex.

[0024] Figure 6 This is a schematic diagram of the crystal structure of cerium-germanium complex A.

[0025] Figure 7 This is a schematic diagram of the crystal structure of cerium-germanium complex B.

[0026] Figure 8 This is a schematic diagram of the crystal structure of cerium-germanium complex C.

[0027] Figure 9 The image shows a comparison of the UV-Vis spectra of cerium-germanium complex A, cerium-germanium complex B, and cerium-germanium complex C. A represents cerium-germanium complex A, B represents cerium-germanium complex B, and C represents cerium-germanium complex C.

[0028] Figure 10 The images show the UV-Vis spectra of the reaction between cerium-germanium complex A and styrene and phenylacetylene, where 1 represents cerium-germanium complex A, 2 represents application example 2, and 3 represents application example 3.

[0029] Figure 11 The images show the UV-Vis spectra of the reaction between cerium-germanium complex B and styrene and phenylacetylene, where 1 represents cerium-germanium complex B, 2 represents application example 4, and 3 represents application example 5.

[0030] Figure 12 The images show the UV-Vis spectra of the reaction between cerium-germanium complex C and styrene and phenylacetylene, where 1 represents cerium-germanium complex C, 2 represents application example 6, and 3 represents application example 7. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] The crystal structures of the cerium-potassium complex, cerium-germanium complex A, cerium-germanium complex B, and cerium-germanium complex C described in the examples were determined through the following experiments: single crystals of the complexes with suitable morphology and mass were selected for measurement, and nitrogen protection was used to determine the crystal structures using Bruke Smart APEX. X-ray diffraction was performed using a CCD-type single-crystal diffractometer to collect diffraction data, followed by crystal structure analysis to determine the spatial configuration of the complex. The diffractometer used monochromatic Cu-Kα radiation (λ = 1.5406 Å) on graphite, employing φ and ω scanning techniques at a scanning temperature of T = 100 K. All intensity data were corrected using the Lp factor. The crystal structure was determined using the SHELXTL-5.10 program and the heavy atom method. After multiple rounds of Fourier transformation, the coordinate parameters of all non-hydrogen atoms were obtained. The coordinates of all hydrogen atoms were obtained using the theoretical hydrogenation method. The anisotropic temperature factor of all non-hydrogen atoms was corrected using the full matrix least squares method (SHELXS-97).

[0033] Example 1 A method for preparing a cerium-germanium complex A includes the following steps: Step 1, preparation of the cerium-potassium complex, specifically includes the following steps: Step 1.1: Add 1.09 g of 2,6-diaminopyridine, 3.42 mL of 3-tert-butyl-2-hydroxybenzaldehyde and 50.00 mL of methanol to the reaction vessel, heat the reaction for about 5 hours, filter after the orange-yellow solid precipitates, and purify to obtain ligand L1 with a yield of 80%.

[0034] Step 1.2: Dissolve 500.00 mg of ligand L1 in 50.00 mL of methanol, then add 132.19 mg of NaBH4, and react at room temperature for 12 hours; add 50.00 mL of deionized water to the solution, extract three times with dichloromethane, dry the organic phase with anhydrous Na2SO4, remove the solvent under reduced pressure, and then wash the white solid with n-pentane and diethyl ether to obtain ligand L2 [C 27 H 35 [N3O2], its molecular structure is as follows: like Figure 1 As shown, the yield was 63%. Elemental analysis of ligand L2: calculated values: C 76.37; H 8.20; N 8.76. Measured values: C 76.96; H 8.311; N 8.54.

[0035] like Figures 2-4 As shown, 1H NMR (400 MHz, DMSO, 25℃) δ 9.81 (s, 1H, O H ), 7.11-7.05 (m, 5H, Ar) H ), 6.72-6.68 (m, 4H, Ar) H ), 5.65 (d, J = 7.9 Hz, 2H, ArCH2N H ), 4.35 (d, J = 6.4 Hz, 4H, ArC H 2), 1.35 (s, 18H, ArC(C) H 3)3). 13 C NMR (400 MHz, DMSO, 25℃) δ 157.28, 153.93, 139.15, 136.98, 127.49, 125.21, 118.91, 94.71, 41.24, 34.48, 29.74. LC-MS: Calculated m / z: 433.27 (100%), 434.28 (29.7%), 435.28 (4.7%), 434.27 (1.1%); Measured m / z [L2+H + ]: 434.2 (100%), 435.2 (32.59%), 436.25 (5.03%), 437.2 (1.54%); [L2+ACN+ H + 475.3 (1.54%).

[0036] Step 1.3: 500.00 mg of ligand L2, 716.96 mg of tris[N,N-bis(trimethylsilyl)amide]cerium(III) and 230.21 mg of [N,N-bis(trimethylsilyl)amide]potassium were dissolved in 10.00 mL of tetrahydrofuran under an argon atmosphere and reacted at room temperature for approximately 12 hours. After removing the tetrahydrofuran, the mixture was purified to obtain the yellow cerium potassium complex [CeKC]. 62 H 80 [N6O6], such as Figure 5 As shown, the yield was 73%. 30 mg of the cerium-potassium complex was dissolved in 2 mL of toluene, filtered through a filter membrane, and then crystallized with 5 mL of n-pentane at -35 °C using a layer-by-layer diffusion method to obtain a pale yellow crystalline product [CeKC]. 62 H 80 [N6O6·1.5Tol]. Pale yellow crystalline product [CeKC] 62 H 80The product [N6O6·1.5Tol] was dried under reduced pressure and then elemental analyzed using a Vario MICRO cube analyzer: Calculated values: C 65.83; H 7.01; N 6.35. Measured values: C 66.32; H 7.28; N 6.71. Crystallographic data: The crystal belongs to the monoclinic system, space group [missing information]. C 2 / c, crystallographic parameters: a=22.4143(3)Å, b=12.5984(14)Å, c=26.3708(3)Å, α=90°, γ=90°, β=113.4619(14)°, Z=8, V=6831.07(15).

[0037] Step 2: Add 200.00 mg of cerium potassium complex and 39.14 mg of germanium(II) dioxane adduct, along with 10.00 mL of tetrahydrofuran, to the reaction vessel. React at room temperature for 12 hours. Remove the solvent, then wash the pale yellow solid with n-pentane. After removing the solvent, obtain cerium germanium complex A[CeGeC]. 54 H 65 [N6O4], such as Figure 6 As shown, the yield was 89%. 30 mg of cerium-germanium complex A was dissolved in 2 mL of tetrahydrofuran, filtered through a filter membrane, and then crystallized with 5 mL of n-pentane at -35 °C using a layer-by-layer diffusion method to obtain a pale yellow crystalline product [CeGeC]. 54 H 65 [N6O4·2THF]. Pale yellow crystalline product [CeGeC]. 54 H 65 [N6O4·2THF] was dried under reduced pressure and then elemental analyzed using a Vario MICRO cube elemental analyzer: Calculated values: C 61.08; H 6.7; N 6.89. Measured values: C 61.506; H 7.27; N 6.89. Crystallographic data: The crystal belongs to the monoclinic system, space group [missing information]. P 21. Crystallographic parameters: a = 12.9087(13) Å, b = 39.6670(3) Å, c = 13.9101(13) Å, α = 90°, γ = 90°, β = 112.0191(11)°, Z = 2, V = 6603.18(12).

[0038] Example 2 A method for preparing a cerium-germanium complex B includes the following steps: 200.00 mg of the cerium-germanium complex A from Example 1 and 30.17 mg of potassium graphite, along with 10.00 mL of tetrahydrofuran, were added to a reaction vessel. The mixture was reacted at room temperature for 3 hours. The solvent was removed, and the brownish-yellow solid was washed with n-pentane. After removing the solvent, cerium-germanium complex B [CeGeKC] was obtained. 54 H 64[N6O4], such as Figure 7 As shown, the yield was 71%. 30 mg of cerium-germanium complex B was dissolved in 2 mL of tetrahydrofuran, filtered through a filter membrane, and then crystallized with 5 mL of n-pentane at -35 °C using a layer-by-layer diffusion method to obtain a yellow crystalline product [CeGeKC]. 54 H 64 N6O4·THF]. Yellow crystalline product [CeGeKC] 54 H 64 [N6O4·THF] was dried under reduced pressure and then elemental analyzed using a Vario MICRO cube elemental analyzer: Calculated values: C 58.78; H 6.41; N 7.09. Measured values: C 58.678; H 6.514; N 6.594. Crystallographic data: The crystal belongs to the monoclinic system, space group [missing information]. P 21 / c, crystallographic parameters: a=12.6345(2)Å, b=25.2160(3)Å, c=18.7542(3)Å, α=90°, γ=90°, β=105.887(2)°, Z=4, V=5746.71(16).

[0039] Example 3 A method for preparing a cerium-germanium complex C includes the following steps: 200.00 mg of cerium-germanium complex B and 67.64 mg of 2,2,2-cryptoether, along with 10.00 mL of tetrahydrofuran, were added to a reaction vessel. The mixture was reacted at room temperature for 12 hours. After removing the solvent, the pale yellow solid was washed with n-pentane, and the solvent was removed under reduced pressure to obtain cerium-germanium complex C[CeGe2KC]. 72 H 100 N8O 11 ],like Figure 8 As shown, the yield was 75%. 30 mg of the cerium-germanium complex C was dissolved in 2 mL of toluene, filtered through a filter membrane, and then crystallized with 5 mL of n-pentane at -35 °C using a layer-by-layer diffusion method to obtain a pale yellow crystalline product [CeGe2KC]. 72 H 100 N8O 11 • 1.5Tol]. Pale yellow crystalline product [CeGe2KC] 72 H 100 N8O 11 [1.5Tol] After vacuum drying, elemental analysis was performed using a Vario MICRO cube elemental analyzer: calculated values: C 58.61; H 6.63; N 6.39. Measured values: C 58.438; H 6.323; N 6.344. Crystallographic data: the crystal belongs to the triclinic system, space group [missing value]. P-1, crystallographic parameters: a=13.9521(2)Å, b=16.9413(3)Å, c=17.4375(3)Å, α=89.234(1)°, γ=86.977(1)°, β=88.171(1)°, Z=2, V=4113.53(12).

[0040] Application Example 1 UV-Vis absorption spectroscopy measurements were performed on a Shimadzu 2600 spectrometer. The cerium-germanium complexes A, B, and C in the test examples were tested in a glove box filled with high-purity argon (H). O 0.1ppm, O Prepared in 0.1 ppm solution using anhydrous tetrahydrofuran as solvent. The solution was transferred and sealed in a quartz cuvette with a PTFE valve cap, specifically designed for air-sensitive samples, and then rapidly transferred to the spectrometer. Figure 9 As shown, cerium-germanium complex A, cerium-germanium complex B, and cerium-germanium complex C were successfully coordinated.

[0041] Application Example 2 Cerium-germanium complex A was used as an activator to activate styrene: 50.00 mg of cerium-germanium complex A from Example 1, 5.34 μL of styrene, and 10.00 mL of tetrahydrofuran were added to a reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. This solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 10 As shown in the figure, UV-Vis spectroscopy reveals that after the cerium-germanium complex A interacts with styrene, its peak at 254 nm exhibits a blue shift, and its peak at 319 nm exhibits a red shift. This phenomenon is consistent with the electronic perturbation expected by the bimetallic synergistic polarization mechanism. Based on the decrease in absorbance at 254 nm, approximately 69% of the cerium-germanium complex A interacted with styrene within 8 hours.

[0042] Application Example 3 Cerium-germanium complex A acts as an activator to activate phenylacetylene: 50.00 mg of the cerium-germanium complex A from Example 1, 5.12 μL of phenylacetylene, and 10.00 mL of tetrahydrofuran were added to the reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. The solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 10 As shown in the figure, UV-Vis spectroscopy reveals that after the cerium-germanium complex A interacts with phenylacetylene, its peaks at 254 nm and 319 nm exhibit a significant red shift, and its characteristic absorption valley near 292 nm becomes noticeably shallower and broader, with a red shift at the valley bottom. This phenomenon is consistent with the electronic perturbation expected by the bimetallic synergistic polarization mechanism. Based on the decrease in absorbance at 254 nm, approximately 74% of the cerium-germanium complex A interacted with phenylacetylene within 8 hours.

[0043] Application Example 4 Cerium-germanium complex B was used as an activator to activate styrene: 50.00 mg of cerium-germanium complex B from Example 2, 5.16 μL of styrene, and 10.00 mL of tetrahydrofuran were added to a reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. This solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 11 As shown in the figure, UV-Vis spectroscopy reveals that after the cerium-germanium complex B interacts with styrene, its peak at 250 nm undergoes a blue shift, and the sharp characteristic absorption peak at 295 nm is significantly weakened, transforming into a broad absorption band in the 274-305 nm range. This spectral change indicates that electronic interactions occurred between the complex and the substrate, leading to a change in the previously defined electronic structure. This phenomenon is entirely consistent with the mechanism proposed in this invention, which involves the synergistic electronic polarization of unsaturated bonds through hard-soft acid-base interactions. Based on the decrease in absorbance at 250 nm, approximately 67% of the cerium-germanium complex B interacted with styrene within 8 hours.

[0044] Application Example 5 Cerium-germanium complex B acts as an activator for activating phenylacetylene: 50.00 mg of the cerium-germanium complex B from Example 2, 4.94 μL of phenylacetylene, and 10.00 mL of tetrahydrofuran were added to the reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. This solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 11 As shown in the figure, UV-Vis spectroscopy reveals that after the cerium-germanium complex B interacts with phenylacetylene, its peak at 250 nm exhibits a blue shift, and the sharp characteristic absorption peak at 295 nm is significantly weakened, transforming into a broad absorption band in the 272-312 nm range. This spectral change indicates that electronic interactions occurred between the complex and the substrate, leading to a change in the previously defined electronic structure. This phenomenon is entirely consistent with the mechanism proposed in this invention, which involves the synergistic electronic polarization of unsaturated bonds through hard-soft acid-base interactions. Based on the decrease in absorbance at 250 nm, approximately 74% of the cerium-germanium complex B interacted with phenylacetylene within 8 hours.

[0045] Application Example 6 Cerium-germanium complex C was used as an activator to activate styrene: 50.00 mg of cerium-germanium complex C from Example 3, 3.64 μL of styrene, and 10.00 mL of tetrahydrofuran were added to a reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. This solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 12 As shown in the figure, UV-Vis spectroscopy reveals that after the cerium-germanium complex C interacts with styrene, its peak at 301 nm exhibits a blue shift, and the characteristic absorption peak at 254 nm broadens significantly along with the blue shift. This change is consistent with the synergistic activation mechanism of the unsaturated bonds by the cerium(III) and germanium(II) centers. Based on the decrease in absorbance at 254 nm, approximately 71% of the cerium-germanium complex C interacted with styrene within 8 hours.

[0046] Application Example 7 Cerium-germanium complex C is used as an activator to activate phenylacetylene: 50.00 mg of the cerium-germanium complex C from Example 3, 3.48 μL of phenylacetylene, and 10.00 mL of tetrahydrofuran were added to the reaction vessel. After reacting at room temperature for 8 hours, a yellow solution was obtained. This solution was filtered through a 0.22 μm needle filter, and an appropriate amount of solution was diluted and injected into a dried and sealed quartz cuvette, which was immediately sealed. A Shimadzu UV-2600 spectrometer was used, with tetrahydrofuran as a reference, to scan in the 200-800 nm range. The obtained spectrum is shown below. Figure 12 As shown in the figure, UV-Vis spectroscopy reveals a significant blue shift in the peaks at 254 nm and 301 nm of the cerium-germanium complex C after interaction with phenylacetylene. This change is consistent with the synergistic activation mechanism of the unsaturated bonds by the cerium(III) and germanium(II) centers. Based on the decrease in absorbance at 254 nm, approximately 75% of the cerium-germanium complex C interacted with phenylacetylene within 8 hours.

[0047] In summary, in Application Examples 2-7, the reactions between cerium-germanium complexes A, B, and C and styrene and phenylacetylene are essentially non-covalent, strongly oriented electronic interactions between the unsaturated carbon atoms of the substrates (styrene and phenylacetylene) and the cerium and germanium atoms of cerium-germanium complexes A, B, and C. This interaction does not lead to the formation of new covalent bonds (such as CH bonds), but it pushes the unsaturated bonds from the "ground state" to the "activated state" through electron cloud rearrangement, making them more susceptible to subsequent transformations (such as hydrogenation and hydrosilylation). Specifically, the cerium (III) centers in cerium-germanium complexes A, B, and C, acting as hard Lewis acids, tend to attract the relatively electron-rich π-electron regions of the unsaturated bonds; simultaneously, the germanium (II) centers, acting as soft Lewis bases, synergistically act on the relatively electron-deficient regions of the same unsaturated bond. This synergistic "pull-push" effect causes an asymmetric shift in the substrate's π-electron cloud, significantly polarizing, weakening, and lengthening the C=C or C≡C bonds. This allows the substrate to transition from a stable state to an activated, high-energy intermediate state, readily facilitating subsequent transformations. Simultaneously, the rigid spatial structure of the complex predetermines a specific geometric configuration for this activated molecule, spatially guiding the attack direction of subsequent reagents. The core of this process lies in creating a highly oriented and activated molecular platform for the subsequent selective functionalization of carbon-carbon unsaturated bonds.

[0048] The cerium-germanium complexes A, B, and C, with their unique mechanism of "hard Lewis acid-soft Lewis base" synergistic polarization of unsaturated bonds, can serve as bimetallic synergistic activators, demonstrating great potential in the synthesis of fine chemicals and polymer materials. Through the electronic properties of the cerium(III) and germanium(II) centers, they act simultaneously on both ends of the unsaturated bond, forming directional electronic synergy, thereby achieving inherent control over regio and stereoselectivity. This is expected to be directly used in the synthesis of high-purity pharmaceutical intermediates, trans-fatty acid-free food additives, structurally regular polymer monomers, and highly selective silicone oils, significantly simplifying production processes and reducing energy consumption and separation costs while improving product quality.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A heteronuclear cerium germanium complex, characterized in that, The molecular structure of the heteronuclear cerium-germanium complex is as follows: , denoted as cerium germanate complex A.

2. A heteronuclear cerium germanium complex characterized in that, The heteronuclear cerium-germanium complex of claim 1 is used as a precursor and reacted with potassium graphite to obtain the following molecular structure: , denoted as cerium germanate complex B.

3. A heteronuclear cerium germanium complex characterized by, The heteronuclear cerium-germanium complex of claim 2 is used as a precursor and reacted with 2,2,2-caecinyl ether to obtain the following molecular structure: , denoted as cerium germanium complex C.

4. The heteronuclear cerium-germanium complex according to claim 1, characterized in that, The cerium germanium complex A is monoclinic, and the space group is P 21, the cell parameters are a = 12.9087(13) Å, b = 39.6670(3) Å, c = 13.9101(13) Å, α = 90°, γ = 90°, β = 112.0191(11)°, Z = 2, V = 6603.18(12).

5. The heteronuclear cerium-germanium complex according to claim 2, characterized in that, The cerium germanium complex B is monoclinic, space group P 21 / c, with cell parameters a = 12.6345(2) Å, b = 25.2160(3) Å, c = 18.7542(3) Å, a = 90°, y = 90°, β = 105.887(2)°, Z = 4, V = 5746.71(16).

6. The heteronuclear cerium-germanium complex according to claim 3, characterized in that, The cerium germanium complex C is of triclinic system, space group P -1 with cell parameters a = 13.9521(2) Å, b = 16.9413(3) Å, c = 17.4375(3) Å, a = 89.234(1) °, g = 86.977(1) °, b = 88.171(1) °, Z = 2, V = 4113.53(12).

7. The method for preparing the heteronuclear cerium-germanium complex according to claim 1, characterized in that, Includes the following steps: Step 1: Under an argon atmosphere, ligand L2, tris[N,N-bis(trimethylsilyl)amide]cerium(III) and [N,N-bis(trimethylsilyl)amide]potassium are dissolved in tetrahydrofuran for reaction. The solvent is removed and the mixture is purified to obtain the cerium-potassium complex. Step 2: Under an argon atmosphere, the cerium-potassium complex and germanium dioxane adduct are inserted into germanium via a salt elimination reaction to obtain cerium-germanium complex A.

8. The method for preparing the heteronuclear cerium-germanium complex according to claim 7, characterized in that, The molecular structure of the ligand L2 is as follows: .

9. The heteronuclear cerium-germanium complex as described in any one of claims 1 to 3, as a bimetallic synergistic activator in the synthesis of high-purity pharmaceutical intermediates, food additives that eliminate trans fatty acids, polymer monomers, and highly selective silicone oils.

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