Gold(I) Complexes of Open-chain and Cyclic Di-secondary Amines

Z. Naturforsch. 52 b, 209-213 (1997); received December 4, 1996 Gold(I) Coordination, Amine Complexes, Secondary Amines, Ammonium Complexes Treatment of N,N'-diisopropyl-ethylenediamine or 1,4-piperazine with two equivalents of [(Ph^P)Au]+ BF4leads to binuclear complexes of the diamines: {[(Ph3P)Au]HN('Pro)NCH2-}22+ 2 BF4~ (1) and {[(Ph3P)Au]HNCH2CH2}22+ 2 BF4~ (2), respectively. In the products each quaternary ammonium center bears one gold ligand, one hydrogen atom and two alkyl substituents. The crystal structures of both compounds have been determined. Compound 1 contains discrete ion-triples. The ethylene bridge in the dications is in an unfolded conformation, with a crystallographic center of inversion, and allows for weak hydrogen bonding N-H--F [2.085 A; N-H--F 169.2°] between the NH functions and the counterions. The existing distant contacts F-A u [3.599 A] are probably less significant for the aggregation of the ion triples, but will contribute through Coulomb forces. Compound 2 crystallizes with two solvent molecules CH2CI2. The dication has a crystallographic center of inversion with the piperazine ring in a chair conformation and the gold atoms in equatorial positions. There are hydrogen bonds N-H--F [2.076 and 2.457 A] between the dication and the anions which lead to the formation of ion-triples, with further contacts between the BF4~ anions and the solvent molecules [C-H--F 2.340 and 2.446 A].