Total surface areas of Group IVA organometallic compounds: Predictors of toxicity to algae and bacteria

There is a high correlation between molecular surface area (TSA) of triorganotin and triorganolead compounds and their toxicity towards a bacterium (Escherichia coli) and an alga (Selenastrum capricornutum). Parallel attempts to correlate other Group IVA organometals incorporating silicon or germanium were unsuccessful. It was further demonstrated, however, that a high correlation was obtainable between certain series of compounds with the same organic substituent but different metal centers involving all Group IVA elements. In both instances, the inability to obtain a quantitative structure-activity relationship (QSAR) for all systems studied appears to be a function of the solubility of the compounds. While organotin TSA values have been found to correlate well with their toxicities toward various organisms, this study clearly suggests that this type of QSAR can be readily extended to include other organometal systems, provided that there is no solubility problem and the toxicity is a function of the hydrophobicity of the organometal compounds.     

β-羧基乙基锗倍半氧化物及其衍生物

本文综述了β-羧基乙基锗倍半氧化物及其衍生物的生物活性、合成方法以及该领域最新研究动向。     

New organogermanium cations [RGe(OCH2CH2NME2)2]+ with intramolecular N→Ge coordination bonds

New organohalogermanes RGe(OCH₂CH₂NMe₂)₂X (R = Ph, X = I (5); R = Me, X = Cl (6) or I (7)) with an intramolecular N→Ge coordination bond were synthesized. According to the ¹H and ¹³C NMR spectroscopic data, iodides 5 and 7 exist in solution as ionic compounds with the pentacoordinated germanium atom. In solution of compound 4 (R = Ph, X = Cl), there is an equilibrium between the ionic and covalent forms. The equilibrium shifts toward the ionic form with increasing solvent polarity or temperature. In solution, chloride 6 is a covalent compound. The structures and relative stabilities of different isomers of compounds 4–7 were studied by quantum chemical calculations at the density functional level of theory. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 892–900, May, 2007.     

Modular and Selective Arylation of Aryl Germanes (C−GeEt3) over C−Bpin,C−SiR3 and Halogens Enabled by Light-Activated Gold Catalysis

Selective C –C couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd⁰/Pd^II catalysis) in the presence of the valuable functionalities C−BPin, C−SiMe₃, C−I, C−Br, C−Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C−Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N₂⁺, which were specialized in Ar–N₂⁺ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N₂⁺ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N₂⁺, which requires an alternative photo-redox approach to enable productive couplings.     

Synthesis of 1-triphenylgermylpropiono-4-substituted semicarbazides,thiosemicarbazides and their heterocyclic derivatives

Twenty-one new organogermanium compounds with the formulae Ph₃GeCHR¹CH₂CONHNHC(X)NHR² (1) (R¹=H, Ph; = Ph, p-CH₃Ph, O -CH₃Ph, p-ClPh, COPh, X = S, O) and (R¹ = H, Ph; R² = Ph, p-CH₃Ph, o-CH₃Ph, p-ClPh; X=S, O) were synthesized and characterized by elemental analysis, ¹H NMR, IR, MS and X-ray diffraction techniques. Compounds l were prepared by the reactions of Ph₃GeCHR¹CH₂CONHNH₂ with R²NCX in chloroform in 77-94% yields, and 2 were obtained by refluxing l with sodium hydroxide (8%) with yields of 55-94%.     

A facile route to germanium(IV) binaphthoxide complexes: crystal structure of a chiral resolved germanium(IV) binaphthoxide

A method for the facile synthesis of chiral germanium(IV) binaphthoxide complexes from the corresponding binaphthols and an organogermanium trichloride has been developed, which allows these unusual types of compounds to be synthesized in high yields. The crystal structure of one such complex, (S)-[Ge{O2C20H10(SiMe3)2-3,3'}{Cl}{Ph}], has been determined.     

氨基酸及杂环胺酰乙基锗倍半氧化物合成及对癌细胞的作用

β-羧乙基锗倍半氧化物(即Gc-132)是具广谱药理活性的水溶性有机锗化合物,但因其在体内代谢速度太快而影响药物利用度。因此,对它的各种衍生物的合成和生物活性研究受到重视。为提高Ge-132的亲脂性,增强药物活性,我们在分子中引入具有生物活性的氨基酸或杂环胺,合成了8种新型酰胺衍生物。合成路线如下:     

有机锗测定方法的研究

在总结有机锗已有分析方法基础上,介绍了一种分光光度法,它可用于有机锗产品的相态和含量分析。     

Synthesis of a calix[4]crown modified with germanium‐containing side chains

A germacalix‐crown, 25,27‐bis[1‐(3‐trimethylgermylpropyl)oxy]calix[4]arene‐crown‐6, 1,3‐alternate ( 1a ), and its carbon analog, 25,27‐bis‐[1‐(4,4‐dimethylpentyl)oxy]calix[4]arene‐crown‐6, 1,3‐alternate ( 1b ), were prepared and their structures were confirmed by elemental analysis and ¹H and ¹³C NMR spectroscopy. A cation transport test indicated that both compounds exhibited much the same cation transport ability, so that the role of the germanium moiety in capturing and transporting counteranions is not yet clear. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis of tri-and tetraalkynylgermanes

A straightforward synthesis of tetra-and trialkynylgermanes by reactions of compounds containing Ge-N or Ge-Cl bonds with alk-1-ynes was proposed. Reactions of appropriate amino-or halogermanes with alk-1-ynes were effective only in the presence of an equivalent amount of zinc dihalide. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1377–1379, August, 2006.