Crystal and molecular structure of catena-µ-acetato-[di-(3-aminopropyl)amine]copper(II) perchlorate

Abstract

The X-ray structural analysis of the title compound [orthorhombic, space group Pna2₁ or Pnam, a= 8·53(1), b= 18·50(2), c= 8·74(1)Å, Z= 4] reveals a polymeric complex cation in which copper has primary squareplanar co-ordination with the three amino-nitrogen atoms and one oxygen atom of the acetate ion [Cu–N(1) 1·92(2), Cu–N(2)(secondary) 2·05(2), Cu–N(3) 2·02(2), and Cu–O(2) 2·02(1)Å]. The second oxygen atom of this acetate bonds more weakly in a tetragonal site of a second copper atom [Cu′–O(1) 2·29(1)Å] completing square-pyramidal co-ordination. This same oxygen is also involved in a still weaker interaction with the initial copper atom in a direction displaced ca. 40° from the tetragonal axis so that a distorted octahedral co-ordination geometry is present at a tertiary level [Cu–O(1) 2·74(1)Å]. The acetate group thus functions as a bridging asymmetric bidentate ligand. The amine adopts a conformation with the six-membered chelate ring including N(2) and N(3) in a chair, and the ring including N(1) and N(2) in a distorted-boat conformation. The bond angles N(1)–Cu–N(2) 83·9(9) and N(2)–Cu–N(3) 98·9(8)° are unusually divergent from the value ca. 92° observed for other complexes with saturated six-membered chelate rings.

The structure was solved from 1350 photographic data and refined by block-diagonal least-squares methods to R 0·100.