The nature of close Pd...Pd and Pd...H(-C) contacts The crystal structures of R-aminohexahydroazepine-dichloropalladium(II), and N-ethyl-R-aminohexahydroazepine-dichloropalladium(II) and a molecular mechanics analysis of the close contacts

摘要

The preparations and crystal structures of [PdCl_2(R-ahaz)] (ahaz=3-aminohexahydroazepine) and [PdCl_2(R-etahaz)] (etahaz=N-ethyl-3-aminohexahydroazepine) are described. Both complexes crystallise with two independent molecules stacked in "dimeric" pairs with short Pd...Pd contacts. In [PdCl_2(R-ahaz)] the Pd...Pd separation is 3.361(1) A and in [PdCl_2(R-etahaz)] it is 3.415(1) A. Hydrogen bonds between the N-H groups of one complex and the chloro ligands of the other link the dimers. There are also Pd...H contacts in the range 2.60 A to 2.75 A between the ligand backbone and the metal. Molecular mechanics models indicate that the hydrogen bonds are the major contributor to dimer formation.