Cd(Il)-ethylenediamine mono- and bimetallic complexes - Synthesis and characterization by Cd-113 NMR spectroscopy and single crystal X-ray diffraction

摘要

Formation of three Cd(II)-ethylenediamine (en) complexes ([Cd(en)(n)](2+), n = 1-3) in aqueous solution and in DMSO solvent has been established by means of Cd-113 NMR spectroscopy. It is clearly shown that Cd(II)-en complexes form primarily in basic solutions. A correlation between the Cd-113 NMR chemical shifts and the ethylenediamine (en) coordination number has been observed and discussed. Two single crystals with the composition [Cd-2(en)(5)](ClO4)(4) (1) and [Cd(en)(3)](ClO4)(2) (2) were prepared from aqueous solution, and their structures were determined by single crystal X-ray diffraction. Cd(II) ions are coordinated by six atoms in both compounds, I and 2: via five N-donor atoms and one O-donor atom forming a bimetallic complex 1, and via six N-donor atoms forming a distorted octahedral monometallic complex 2. Raman spectra of complexes 1 and 2 also provide additional evidence that the cis-form of the bridging en is present in complex 1. (c) 2005 Elsevier B.V. All rights reserved.