combustion analysis. Their variable temperature 1H- and 31P-NMR spectra are in accordance with fast ring inversion processes and inversion of configuration at the E atoms (E=P, As), suggesting the presence of different diastereomeric forms in solution. The structures of the main diastereomeric form of 1a (triclinic, P1̄) and of the isotypic derivatives 1c and 1d (monoclinic, P21/c), respectively, were
最初的1-metalla-2,4-diphospha-3-silacyclobutanes [(dppe)M(PH)2 Si t -Bu(Is)] 1a(M = Ni,Is = 2,4,6-
三异丙基苯基)的合成,dppe = 1,2-双(
二苯基膦基)
乙烷),1c(M = Pd),1d(M = Pt)和类似的1-nickela-2,4-diarsa-3-silacyclobutane [(dppe)Ni(AsH )2 Si t -Bu(Is)](1b),这是通过t -Bu(Is)Si(EHLi)2(2a,E = P; 2b,E = As)与各自的
金属
氯化物[(dppe)MCl 2]在-70°C下的
甲苯中。通过多核NMR光谱,质谱和燃烧分析对它们进行了表征。它们的可变温度1 H-和31 P-NMR光谱与快速环反转过程和E原子处构型的反转有关(E = P,As),表明溶液中存在不同的非对映异构体