PUB - Publikationen an der Universität Bielefeld

Tetramethylformamidinium trichlorogermanite, [CH(NMe2)(2)][GeCl3], tetramethylformamidinium trichlorostannite, [CH(NMe2)(2)][SnCl3], bis-(tetramethylformamidinium hexaiododigallate, [CH(NMe2)(2)](2)[Ga2I6] and bis-(tetramethylformamidinium hexachlorodiindate, [CH(NMe2)(2)](2)[In2Cl6] have been prepared by the reactions between tetramethylformamidinium chloride, [CH(NMe2)(2)]Cl, and the corresponding low valent halides GeCl2 (as dioxane adduct), SnCl2, "GaI" and InCl. Their crystal structures have been determined by single crystal X-ray diffraction. [CH(NMe2)(2)][GeCl3] aggregates in a centrosymmetric dimeric structure, in which two trigonal pyramidal GeCl3 units are connected together by two weak (GeCl)-Cl-... bonds and each Ge atom is bonded to one cation by a weak (GeN)-N-... contact. Two sets of weak hydrogen bonds C-(HCl)-Cl-... are observed with bond lengths of 2.87(2) Angstrom and 2.85(2) Angstrom. In [CH(NMe2)(2)][SnCl3], the SnCl3- units adopts a (3+3) coordination with three normal Sn-Cl bonds and three weak (SnCl)-Cl-... contacts. [CH(NMe2)(2)](2)[Ga2I6] and [CH(NMe2)(2)](2)[In2Cl6] contain metal-metal bonded anions with distorted staggered ethane-like conformations. The metal-metal bond lengths are 2.423(1) Angstrom (Ga-Ga) and 2.719(1) Angstrom (In-In). Their Raman spectra contain intense bands at 118.7cm(-1) (Ga-Ga) and 174.7 cm(-1) (In-In) associated with metal-metal stretching modes.