The crystal and molecular structure of the title complex has been determined from single-crystal three-dimensional x-ray data collected by counter methods. Cu(DTDP)·2py·H2O (DTDP = dithiodipropionate) crystallizes as light blue rectangular plates in space group Pna21 (C2v 9, No. 33) with Z = 4; a = 22.268 (15), b = 14.855 (12), c = 5.670 (4) Å; dcalcd = 1.583, dobsd = 1.57 (1) g/cm3. Least-squares refinement of 1077 reflections having F ≥ 2σ gave a conventional R factor of 0.071. The structure contains no discrete molecules; it consists of crystallographically equivalent Cu(II) ions linked by the DTDP ligands to form infinite chains with alternating left- and right-handed disulfide chirality for adjacent DTDP ligands. A trans puckered arrangement of two pyridine nitrogen atoms and two carboxylate oxygen atoms forms the base of the approximately square-pyramidal CUN2O3 ligand set. Cu-N bond lengths (2.02 (1), 2.06 (1) Å) and Cu-O(carboxylate) bond lengths (1.95 (1), 1.95 (1) Å) are appropriate for equatorial ligation. The Cu(II) ion is displaced 0.21 Å from this CUN2O2 plane toward an apically bonded water molecule (Cu-O(H2O) = 2.23 (1) Å). Bonding interactions between the Cu(II) ions and disulfide groups are not implied from the structural data. The title complex was crystallized from pyridine-water mixtures of a dark green precursor with the empirical formula CuIIDTDP·1/2H2O. Electronic spectral and magnetic (μ = 1.40 (5) μb) studies of this latter complex indicated the presence of (~CO2)4Cu2 dimeric units; however, further studies are required to establish whether the crystal contains discrete molecular dimers or is polymeric. Pseudoisotropic ESR spectra (g = 2.08) of the title complex are presented and discussed.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry