trans-Aquachloro[(1S,4S,7S,8R,11R,14R)-5,5,7e,12,12,14e-hexamethyl-1,4,8,11-tetraazacyclotetradecane]chromium(III) nitrate, [CrCl(H2O)(C16H36N4)](NO3)2

Crystal structure of cis-aqua-chlorido-(rac-5,5,7,12,12,14-hexa-methyl-1,4,8,11-tetra-aza-cyclo-tetra-decane-κ(4) N)chromium(III) tetra-chlorido-zincate trihydrate from synchrotron data

The structure of the title compound, cis-[CrCl(cycb)(H2O)][ZnCl4]·3H2O (cycb is rac-5,5,7,12,12,14-hexa-methyl-1,4,8,11-tetra-aza-cyclo-tetra-decane; C16H36N4), has been determined from synchrotron data. In the complex cation, the Cr(III) ion is bound by four N atoms from the tetra-dentate cycb ligand, a chloride ion and one water mol-ecule in a cis arrangement, displaying a distorted octa-hedral coordination geometry. The distorted tetra-hedral [ZnCl4](2-) anion and three additional water mol-ecules remain outside the coordination sphere. The Cr-N(cycb) bond lengths are in the range of 2.0837 (14) to 2.1399 (12) Å while the Cr-Cl and Cr-(OH2) bond lengths are 2.2940 (8) and 2.0082 (13) Å, respectively. The crystal packing is stabilized by hydrogen-bonding inter-actions between the N-H groups of the macrocyclic ligand, the O-H groups of the water mol-ecules and the Cl atoms of the tetra-chlorido-zincate anion, leading to the formation of a three-dimensional network.

Three transition-metal complexes with the macrocyclic ligandmeso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (L): [Cu(ClO4)2(L)], [Zn(NO3)2(L)] and [CuCl(L)(H2O)]Cl

The three transition-metal complexes, (meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-κ4N)bis(perchlorato-κO)copper(II), [Cu(ClO4)2(C18H40N4)], (I), (meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-κ4N)bis(nitrato-κO)zinc(II), [Zn(NO3)2(C18H40N4)], (II), and aquachlorido(meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-κ4N)copper(II) chloride, [CuCl(C18H40N4)(H2O)]Cl, (III), are described. The molecules display a very similarly distorted 4+2 octahedral environment for the cation [located at an inversion centre in (I) and (II)], defined by the macrocycle N4group in the equatorial sites and two further ligands intrans-axial positions [two O–ClO3ligands in (I), two O–NO2ligands in (II) and one chloride and one aqua ligand in (III)]. The most significant difference in molecular shape resides in these axial ligands, the effect of which on the intra- and intermolecular hydrogen bonding is discussed. In the case of (I), all strong hydrogen-bond donors are saturated in intramolecular interactions, while weak intermolecular C—H...O contacts result in a three-dimensional network. In (II) and (III), instead, there are N—H and O—H donors left over for intermolecular interactions, giving rise to the formation of strongly linked but weakly interacting chains.