Reactions of 1,4-diazabicyclo[2,2,2]octane with bis-(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)copper(II) and the crystal structure of the 1 : 1 complex

Abstract

Reaction of (hfac)₂Cu(H₂O)[hfac =(CF₃·CO)₂·CH] with equimolar amounts of N(CH₂·CH₂)₃N (ted), in benzene gave (hfac)₂Cu(ted). A 1 : 2 mixture gave Cu(hfac)₂(ted)₂, which had an i.r. spectrum consistent with cis-octahedral geometry. An attempt to make a tedH⁺ derivative from Cu(hfac)₂(H₂O), hfac, and ted (1 : 1 : 1) gave [Cu(hfac)₂]₂(ted); this composition was confirmed by preliminary X-ray diffraction measurements. A second species lost benzene of crystallisation to give an amorphorus green product characterised by i.r. as probably containing an (hfac)^– anion and the tedH⁺ cation acting as a unidentate ligand to copper in Cu(hfac)₂.

Reaction of (CF₃COCHCOCH₃)₂Cu with ted gave a 1 : 1 complex. A three-dimensional crystal structure analysis on Cu(hfac)₂(ted) was carried out. Full-matrix least-squares refinement on 832 diffractometer observations gave R 0·06. Z= 2 in an orthorhombic unit cell having a= 16·148, b= 8·428, c= 7·743 Å and space group Pnnm. The copper and two β-diketonates lie in a plane of symmetry, the ligands are related by a two-fold axis, giving square-planar co-ordination about copper with Cu–O 1·958 and 1·954 Å. The fifth and sixth axial positions are occupied by nitrogen atoms at 2·566 Å. The ted molecule bridges two copper atoms separated by c, one nitrogen atom being co-ordinated to each copper. As the c axis is a two-fold axis of symmetry the molecules of base are disordered; two sets of sites related by 180° rotation about the c axis are 50% occupied by methylene carbon atoms. Bond lengths and angles in the ligand molecules are as expected.