Coordination behavior of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) towards first-row transition metals. X-ray structure of [Cu(bddn)(H 2O)](BF 4) 2

Abstract

The synthesis and characterization of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) and its coordination compounds, viz. [M(L)(X) 2] where M is Co 2+, Zn 2+; X is Cl −, Br −, NCS −, and [Cu(L)(H 2O)](BF 4) 2 are described. The X-ray structure of [Cu(bddn)(H 2O)](BF 4) 2 has been determined. The compound crystallizes from ethanol in the monoclinic space group P2 1/ c with unit-cell parameters a=18.508(5), b=9.253(3), c=15.743(5) Å, β=107.91(3)°, V=2565.5 Å 3, D calc=1.57 g/cm 3 for Z=4. The structure was refined to R=0.099 and R w=0.116 for 1841 unique reflections with I>σ( I). The copper(II) ion is coordinated by two pyrazole nitrogen donors, two thioether donors and a water molecule in a trigonal bipyramidal environment, with the two pyrazoles in an unusual cis position. The donor atoms at the axial positions area nitrogen and a sulfur, the equatorial plane donors are nitrogen, sulfur and the oxygen atom. From the ligand field spectra, the infrared patterns and the X-ray powder patterns it was concluded that the structures of the cobalt(II)- and zinc(II)-containing compounds are structurally similar to Zn(bddo)(NCS) 2, a previously reported chain like structure with an MN 2N′ 2 chromophore, in which the ligand S atoms do not bind to the metal ion.