Preparation and structural characterisation of isocyanide gold(I) nitrates, (Au(NO_3)(CNR))(R=Et, Bu~t or C_6H_3Me_2-2, 6); new auriophilic motifs

摘要

The first examples of isocyanide gold(I) nitrates, [Au(NO_3)(CNR)](R = Et, Bu~t or C_6H_3Me_2-2, 6) have been prepared from the corresponding chlorides and AgNO_3. Full characterisation included crystal structure determinations for each example. The structures of the analogous compounds [AuCl(CNR)](R = Et or C_6H_3Me_2-2, 6) were also determined for comparison. All species show Au...Au interactions in the solid state, but with different modes of aggregation; [AuCl(CNEt)] and [Au(NO_3)(CNBu~t)] have infinite zigzag chains, [AuCl(CNC_6H_3Me_2-2, 6)] has a 'broken' chain of tetrameric units, [Au(NO_3)(CNEt)] has a linked chain of tetrameric units, while [Au(NO_3)(CNC_6H_3Me_2-2, 6)] has a highly compressed chain. In each instance the Au...Au interactions for [Au(NO_3)(CNR)] are shorter than for the analogous [AuCl(CNR)], suggesting NO_3~- enhances these secondary bonds. This is in direct contrast to previous theoretical predictions. The structure of the solvated ionic compound [Au(CNC_6H_3Me_2-2, 6)_2]NO_3 has also been determined.