Copper coordination compounds of the ligand 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh). X-ray structures of [Cu(bddh)] 2(BF 4) 2, [Cu(bddh)Cl] 2CuCl 4 and [Cu(bddh)(3,5-dimethylpyrazole)](BF 4) 2

Abstract

The new ligand 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh) rendered the following coordination compounds with copper(I) and copper(II) salts: Cu(bddh)(NO 3) 2, [Cu(bddh)(H 2O)](BF 4) 2, [Cu(bddh)Cl] 2CuCl 4, [Cu(bddh)(Hdmpz)](BF 4) 2 (Hdmpz=3,5-dimethylpyrazole), [Cu(bddh)Cl]BF 4, [Cu(bddh)] 2(BF 4) 2, Cu(bddh)Cl and Cu(bddh)Br. The compound [Cu(bddh)Cl] 2CuCl 4 crystallizes from ethanol in the monoclinic space group Cc, with a=19.018(4), b=14.840(3), c=14.963(3) Å, β=100.24(2), V=4158 Å p3, Z=4 and D calc=1.63 g cm −3. The refinement using 5145 measured and 1826 observed ( F>2σ( F)) reflections resulted in the R values 0.062 ( R) and 0.068 ( R w). The asymmetric unit consists of two [Cu(bddh)Cl] + cations and a CuCl 4 2− anion. The copper(II) atom in [Cu(bddh)Cl] + cation is coordinated by two pyrazole nitrogen atoms in trans position (1.991(9) and 1.98(1) Å), two thioether atoms in cis position (2.422(3) and 2.480(3) Å) and one chloride atom (2.249(4) Å) in a distorted trigonal bipyramid with the nitrogen donors on axial positions and the two sulfurs and chloride in the equatorial plane. The tetrahedral CuCl 4 2− anion lies in disorder. The compound [Cu(bddh)(Hdmpz)](BF 4) 2 crystallizes from ethanol in the monoclinic space group P2 1/ c, with a=18.360(3), b=9.419(3), c=16.068(2) Å, β= 100.29(1), V=2734 Å 3, Z=4 and D calc=1.55 g cm −3. The refinement using 6883 measured and 2326 observed ( F>2σ( F)) reflections resulted in the R values 0.055 ( R) and 0.061 ( R w). The asymmetric unit consists of a [Cu(bddh)(Hdmpz)] 2+ cation and two tetrafluoroborate anions. The copper(II) atom is coordinated by three pyrazole nitrogen atoms (1.987(6) and 1.962(6) Å; Hdmpz: 1.977(6) Å) and two sulfur atoms (2.478(2) and 2.404(3) Å) in a distorted trigonal bipyramid, with the ligand pyrazole groups on axial positions. The copper(I) compound [Cu(bddh)] 2(BF 4) 2 crystallizes from ethanol in the monoclinic space group C2/ c, with a=22.679(2), b=12.766(2), c=14.213(2) Å, β=106.69(1), V=3942 Å 3, Z=8 and D calc=1.55 g cm −3. The refinement using 1495 observed ( F>2.5σ( F)) reflections resulted in the R values 0.049 ( R) and 0.082 ( R w). The cationic part of the compound is dinuclear with C 2 symmetry. The copper(I) ions are 4.603(3) Å apart. Each copper(I) ion is coordinated by a pyrazole nitrogen atom at 2.067(6) Å and two thioether atoms at 2.426(2) and 2.333(3) Å from one ligand and by a pyrazole nitrogen at 1.980(8) Å of another ligand in a strongly distorted tetrahedral fashion. Spectroscopic results strongly suggest that the compounds [Cu(bddh)(H 2O)](BF 4) 2 and [Cu(bddh)Cl]BF 4 contain the trigonal bipyramidal [Cu(bddh)A] unit (A=anion), as present in [Cu(bddh)Cl] 2CuCl 4 and [Cu(bddh)(Hdmpz)](BF 4) 2. The compounds Cu(bddh)Cl and Cu(bddh)Br are IR and X-ray isomorphous.