COORDINATION-COMPOUNDS OF THE CHELATING TRIDENTATE PYRAZOLE-CONTAINING LIGAND BIS[2-(3,5-DIMETHYL-1-PYRAZOLYL)ETHYL]AMINE (DDAH) - CRYSTAL AND MOLECULAR-STRUCTURES OF [CU(DDAH)CL](2)(CUCL4), [CO(DDAH)CL](2)(COCL4), [CU(DDAH)CL](BF4), AND [CO(DDAH)CL](BF4)

The synthesis, spectroscopy, and structure of transition-metal coordin ation compounds of the ligand bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]am ine (abbreviated ddaH) are described. The ligand acts as a tridentate Ns-donor Ligand in the compounds [M(ddaH)Cl](2)(MCl(4)) with M = CU2+, Co2+, and Zn2+, and in the compounds [M(ddaH)-Cl](BF4) with M = CU2and Co2+ as shown spectroscopically and - in a selected number of case s - proven by X-ray diffraction. The compound [Cu(ddaH)Cl](2)(CuCl4) c rystallizes in the monoclinic space group C2/c (Z = 4). The cell dimen sions are a = 23.207(9) Angstrom, b = 11.614(5) Angstrom, c = 14.408(4 ) Angstrom, beta = 90.26(4)degrees, V = 3883(2) Angstrom(3), D-x = 1.5 84 g/cm(3), and R = 0.056 (R(W) = 0.058) for 1765 significant reflecti ons. The copper(II) ion in the cationic part is surrounded by two pyra zole nitrogens (Cu-N distances are 1.999(8) and 1.980(7) Angstrom) and an amine nitrogen (Cu-N distance is 2.022(7) Angstrom) from the ligan d and by one chloride anion (Cu-Cl distance is 2.232(3) Angstrom) in a distorted tetrahedral coordination geometry. The compound [Co(ddaH)Cl ](2)(CoCl4) crystallizes in the monoclinic space group C2/c (Z = 4). T he cell dimensions are a = 20.810(7) Angstrom, b = 13.429(3) Angstrom, c = 14.284(2) Angstrom, beta = 92.53(2)degrees, V = 3988(2) Angstrom( 3), D-x = 1.519 g/cm(3), and R = 0.040 (R(W) = 0.052) for 2825 signifi cant reflections. The cobalt(II) ton in the cationic part is surrounde d by two pyrazole nitrogens (Co-N distances are 2.004(3) Angstrom and 1.982(3) Angstrom) and an amine nitrogen (Co-N distance is 2.068(3) An gstrom) from the ligand and by one chloride anion (Co-Cl distance is 2 .216(1) Angstrom) in a distorted tetrahedral coordination geometry. Th e anionic part of both compounds consists of a distorted tetrahedral t etrachlorometalate(II) with a Cu-Cl distance of 2.215-2.282 Angstrom, a Co-Cl distance of 2.255-2.289 Angstrom, a Cl-Cu-Cl bond angle of 100 .8-137.0 degrees, and a Cl-Co-Cl bond angle of 104.1-116.4 degrees. Th ere is a moderately strong hydrogen bridge between the (MCl(4))(2-) an ion and the amine nitrogen of the ligand ddaH. The shortest distances from the (MCl(4))(2-) anion to the M(2+) in the cation are 4.26 Angstr om and 3.673 Angstrom for respectively Co2+ and Cu2+. The compound [Cu (ddaH)Cl](BF4) crystallizes in the orthorombic space group Pbca (Z = 8 ). The cell dimensions are a 10.163(2) Angstrom, b = 19.542(3) Angstro m, c = 19.647(3) Angstrom, V = 3898(2) Angstrom(3), D-X = 1.524 g/cm(3 ), and R = 0.056 (R(W) = 0.032) for 1134 significant reflections. The Cu2+ ion in [Cu(ddaH)Cl](+) is surrounded by two pyrazole nitrogens (C u-N distances are 1.977(8) and 1.962(9) Angstrom) and an amine nitroge n (Cu-N distance is 2.038(9) Angstrom) from the ligand and by one chlo ride anion (Cu-Cl distance is 2.247(3) Angstrom) in a distorted tetrah edral coordination geometry. The compound [Co(ddaH)Cl](BF4) crystalliz es in the monoclinic space group P2(1)/c (Z = 4). The cell dimensions are a = 12.372(1) Angstrom, b = 14.297(1) Angstrom, c = 12.753(1), bet a = 117.55(1)degrees, V = 2000(1) Angstrom(3), D-x 1.470 g/cm(3), and R = 0.046 (R(W) = 0.035) for 2198 significant reflections. The Co2+ io n in [Co(ddaH)Cl](+) is surrounded by two pyrazole nitrogens (Co-N dis tances are 1.977(3) and 1. 985(5) Angstrom) and an amine nitrogen (Co- N distance is 2.057(5) Angstrom) from the ligand and by one chloride a nion (Cu-Cl distance is 2.207(2) Angstrom) in a distorted tetrahedral coordination geometry. In all compounds, the tetrafluoroborate anions are weakly hydrogen bridged to the amine nitrogen of the ligand. The c ompound [Zn(ddaH)Cl](2)(ZnCl4) is IR isomorphous with the correspondin g copper(II) and cobalt(II) compounds.