All-anti Conformation Research Articles

Über polygermane: XVI. Synthese α,ω-dichlorierter polygermane Cl(Ph 2Ge) nCl ( n = 2,3,4) durch germylen-einschub

The germylene Ph 2Ge of Ph 2GeHCl and Net 3 inserts in excess Ph 2GeHCl and forms polygermanes Cl(Ph 2Ge) n H. This one-pot reaction and subsequent chlorination to Cl(Ph 2Ge) n Cl has been optimized. Increasing amounts of NEt 3 step up the yields of higher polygermanes. The 13C NMR phenyl signals for C( ipso) shift to low field with increasing chain length. The crystal structures of Cl(Ph 2Ge) 3,4Cl ( R = 0.072 and 0.087) have been determined. The position of Cl(Ph 2Ge) 4Cl is split off by disorder (main molecule 82%, side molecule 18%). Two crystallographically different molecules of the trigermane are present; the ClGe 3Cl chain contains anti-gauche and gauche-gauche conformation respectively (distances GeGe 241.3–243.7 pm, angles GeGeGe 110.4 and 116.7°). The ClGe 4Cl chain is centrosymmetric and has all-anti conformation (distances GeGe 245.0 and 244.2 and 244.2 pm, angle GeGeGe 116.2°).