- Infrared and Raman spectroscopy of 9,9′-spirobifluorene, bis(2,2′-biphenylene)silane, and bis(2,2′-biphenylene)germane. Vibrational assignment by depolarization measurement and HF and density functional theory studies
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The infrared and Raman spectra of 9,9′-spirobifluorene (SBFL), bis(2,2′-biphenylene)silane (BBPS), and bis-(2,2′-biphenylene)germane (BBPG) are measured, and the vibrational frequencies and modes for these molecules are assigned by ab initio Hartree-Fock and Becke 3-Lee-Yang-Parr (B3LYP) density functional theory (DFT) calculations using the 4-31G and 3-21G basis sets for SBFL and for BBPS and BBPG, respectively. Assignment of some of the vibrational modes of SBFL is also confirmed by solution Raman spectroscopy with the depolarization method. Comparison of the calculated and experimental vibrational spectra reveals that the DFT calculations are quite accurate in predicting the vibrational frequencies, intensities, and modes. It is found that the central Si and Ge atoms dominantly enhance some of the IR intensities of the vibrations involving only the M-C4 (M = Si, Ge) antisymmetric stretching motion. The enhancement of some of the infrared intensities is accounted for by the increase of the electric dipole moment involving the M-C4 vibrations due to the presence of the small electronegative Si and Ge atoms in the central position.
- Boo,Park,Yeo,Lee,Park,Kim
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- Spirosilane derivatives as fluoride sensors
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Spirosilane derivatives have been investigated as fluoride sensors. The reactions between these compounds and different fluoride sources, which resulted in structural alterations, have been monitored and quantified by UV and fluorescence spectroscopy. The
- Lenormand, Hugo,Goddard, Jean-Philippe,Fensterbank, Louis
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- Construction method of organic phase electrochemical luminescence system of rigid spiro silole compound
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The invention discloses a construction method of an organic phase electrochemical luminescence system of a rigid spiro silole compound. The method comprises the following steps: dissolving an electrochemical luminescence reagent 5,5'-spiro bis[dibenzo[b,d]silole] and a supporting electrolyte tetrabutyl ammonium hexafluorophosphate in an acetonitrile flushing solution, taking a glassy carbon electrode as a working electrode, taking a platinum electrode and a silver wire electrode as a counter electrode and a reference electrode, immersing into the obtained organic phase, and removing the oxygen in the organic phase to obtain the electrode. According to the invention, the electrochemical luminescence system is easy to construct, the surface of an electrode does not need to be coated with a luminescence agent, the dosage of the used luminescence agent is small, a co-reactant is not needed, generated ECL signals are strong, and the stability and reproducibility are good; and compared with the traditional silole such as hexaphenyl silole, the luminescent molecule has the advantages that the ECL emission of 5,5'-spirobis[dibenzo[b,d]silole] in an acetonitrile solution is enhanced by about 6 times, and the luminous efficiency and the sensitivity are obviously improved.
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Paragraph 0025-0032
(2021/07/28)
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- Method for preparing 9-sila-fluoren derivative
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The invention discloses a method forpreparinga 9-sila-fluoren derivative. The method forpreparingthe 9-sila-fluoren derivative comprises the steps thatsilane shown in a formula II is subjected to intramolecular dehydrocyclization reaction in the presence of a catalyst to obtain the 9-sila-fluoren derivative shown in a formula I; in the formula I and the formula II, R1 represents a substituent at the meta position and/or the para position on a benzene ring and isselected from one or more ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a sulfonyl group, an ester group, and a halogen; R2 is selected from one or more ofthe substituted or unsubstituted alkyl group having the 1 to 10 carbon atoms and an aryl group; and R3 is selected from one or more of the hydrogen, the substituted orunsubstituted alkyl group having the 1 to 10 carbon atoms and the aryl group; and Ar is selected fromone or more of a substituted or unsubstituted phenyl group, a heterocyclic aryl group, and a fused ring aryl group. The method forpreparingthe 9-sila-fluoren derivative has the characteristicsthat the synthesis method iseasy to operate, adopted raw materials are easily obtained, a substrate is wide in applicability, the specific reaction systemis simple and efficient, and good atomic economy andenvironmental friendliness are achieved.
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Paragraph 0082-0085
(2019/10/29)
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- Rhodium-catalyzed asymmetric synthesis of spirosilabifluorene derivatives
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Si goes chiral: Treatment of a bis(biphenyl)silane with a catalytic amount of a rhodium complex gave a spirosilabifluorene bearing a quaternary silicon atom. By using a rhodium catalyst with a chiral phosphine ligand (see scheme), asymmetric dehydrogenative cyclization proceeded to give chiral derivatives in good yields and enantioselectivities. Copyright
- Kuninobu, Yoichiro,Yamauchi, Kanae,Tamura, Naoya,Seiki, Takayuki,Takai, Kazuhiko
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p. 1520 - 1522
(2013/04/24)
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- Structure and chemistry of 1-silafluorenyl dianion, its derivatives, and an organosilicon diradical dianion
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1-Silafluorene dianion was synthesized by potassium reduction of 1,1-dichloro-1-silafluorene in refluxing THF. The X-ray structure of 1,1-dipotassio-1-silafluorene (3b) shows C-C bond length equalization in the five-membered silole ring and C-C bond length alternation in the six-membered benzene rings, indicating aromatic delocalization of electrons in the silole ring. The downfield 29Si chemical shift at 29.0 ppm and theoretical calculations also support electron delocalization in the silole ring of 3b. Dianion salt 3b underwent nucleophilic reactions with Me3SiCl and EtBr to form the corresponding disubstituted products. Benzaldehyde underwent reductive coupling in the presence of 3b. Slow oxidation of 3b yielded 1,1′dipotassio-1,1′-bis(silafluorene) (16). The X-ray structure and 29Si chemical shift (-38.0 ppm) of 16 indicate localized negative charges at the silicon atoms and no aromatic character. Heating a DME/hexane solution of 3b in the presence of 18-crown-6 led to a novel diradical dianion salt.
- Liu,Stringfellow,Ballweg,Guzei,West
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