81483-61-6Relevant articles and documents
UEBER POLYGERMANE. XV. DARSTELLUNG VON PHENYLIERTEN TRIGERMANEN IN HMPT
Draeger, Martin,Simon, Dietolf
, p. 183 - 192 (2007/10/02)
The optimum conditions for the synthesis of the trigermanes Ge3Ph8 and Ge3Me2Ph6 according to R2GeCl2 + 2 Ph3GeAk (Ak = Li, K) in HMPT have been determined.The main difficulty is to repress a nucleophilic attack of Ph3Ge- at newly formed Ge-Ge bonds.The mass spectrum of Ge3Me2Ph6 shows rearrangements of the GePh3 and Ph/Me groups.The 13C NMR phenyl signals of di-, tri- and tetra-germanes are nearly identical.Ge3Ph8 and Ge4Ph10 transform to the plastically-crystalline state before melting (ΔH 45.3 and 54.9 kJ mol-1).The crystal structure of Ge3Me2Ph6 has been determined.The molecule has C2 symmetry (Ge-Ge 242.9(1) pm, Ge-Ge-Ge 120.3(1) deg).
UEBER POLYGERMANE XIV. POLYGERMANE ALS NEBENPRODUKTE DER GRIGNARD-REAKTION VON PhMgBr MIT GeCl4
Roller, Stefan,Simon, Dietolf,Draeger, Martin
, p. 27 - 40 (2007/10/02)
The synthesis of GePh4 and Ge2Ph6 by Grignard reaction in THF or ether/toluene leads to the by-products Ge3Ph8 (up to 11 percent) and Ge4Ph10 (up to 18 percent) which is dependant on using an excess of Mg.A quantitative analysis of the resulting products by HPLC and a semipreparative separation by column, flash, and HPL chromatography is described.The crystal structures of Ge3Ph8 (R=0.075) and Ge4Ph10*2C6H6 (R=0.054) have been determined.Ge4Ph10 has Ci symmetry and both chain conformations are well staggered (49-70 deg for Ge3Ph8, 53-66 deg for Ge4Ph10).The Ge-Ge distances and Ge-Ge-Ge angles are 244 pm and 121 deg (Ge3Ph8), and 246 pm and 118 deg (Ge4Ph10).
SYNTHESE ET ETUDE SPECTRALE UV DE CHAINES POLYMETALLEES (Ge, Si); ANALYSE THEORIQUE DES EFFETS DE SUBSTITUTION
Castel, A.,Riviere, P.,Saint-Roch, B.,Satge, J.,Malrieu, J. P.
, p. 149 - 160 (2007/10/02)
An UV study of polymetallic chains of Group IVB elements (Ge, Si) was developed.The studied polygermanes and polygermasilanes were mainly synthetized either by reaction of organolithium with organochlorogermanes or by a Wuetz type reaction.An enhanced λmax value for UV absorption of the chromophore Ge-Ge in these polymetallic compounds is observed in alkyl substitution at the metal by phenyl groups or halogen and also when the polymetallic chain is lengthened.A theoretical approach of these phenomena is proposed based on excitonic coupling between phenyl and metallic chain transition moments.
