Crystal structure of bis(diaqua-dicinnamatocopper(II)), C36H36CU2O12

Abstract

C36H36Cu2O12, orthorhombic, Pbca (No. 61), a = 10.992(1) A, b = 7.706(1) A, c = 41.770(5) A, V = 3538.0 A, Z = 4, Rgt(F) = 0.109, wRref(F) = 0.269, T = 293 K. Source of material All reagents and solvents were used as obtained without further purification. An aqua-ammonium solution (10 ml) of Cu2O (71 mg, 0.5 mmol) and cinnamatic acid (147 mg, 1.0 mmol) were stood still for 1 week to vapor most of the ammonium gas, large blue slab crystals of the title complex were deposited and collected by filtration, washed with water and dried in a vacuum desiccator over silica gel (yield 67%). Elemental analysis: found – C, 54.66%; H, 4.66%; calc. for C36H36Cu2O12 – C, 54.89%; H, 4.61%. Experimental details All the hydrogen atoms are geometrically fixed excepting those attached to the water molecules which are located using the program HYDROGEN [1] and freely refined. We refined these hydrogen atoms to confirm that these are really water molecules and not OH or O atoms. Discussion Metal complexes with carboxylates are among the most investigated compounds in the field of coordination chemistry. Nevertheless, the crystal structures of metal complexes with cinnamate ligands have rarely been reported. Previously, we reported the structure and properties of a silver(I) comples [Ag( -hmt)(cin)] · 2H2O (hmt = hexamethylenetetramine, cin = cinnamate) [2], with this organic carboxylic acid. The title complex is a discrete electronically neutral dinuclear copper(II) unit, [Cu(cinH)2(H2O)2]2, where cinH is cinnamatic acid. The two copper(II) atoms in each dinuclear unit are equivalent, each of which is ligated by four oxygen atoms from two cinnamate anions and two coordinated water molecules, respectively. The four coordination atoms around the central metal are coplanar, constituting a square-planar geometry around the copper(II) atom with plane deviation of 0.0384(4) A, and the copper atom is deviated from the square-plane by 0.0123(4) A. All the cinnamate anions are unidentate ligands, and the average Cu-O(cinnamate) bond length (2.001(6) A) is in the normal range for the complexes with aromatic carboxylates. The two diagonal angles in the CuO4 square plane are respectively 175.8(3)° and 178.0(2)°, indicating a slightly distorted square-planar geometry of Cu(1). The Cu square plane is at the angles of 73.7(2)° and 123.4(2)° with the two kinds of aromatic rings. All the CuO4 planes in the complex are parallel one another. Weak interactions play an important role in the crystal structure of the title complex. The shortest distance between the CuO4 planes is 3.528(6) A, and a great deal of hydrogen bonds between the adjacent O atoms join the two monomers to form a dinuclear copper(II) unit. Z. Kristallogr. NCS 218 (2003) 261–262 261 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: blue slab, size 0.06 × 0.24 × 0.38 mm Wavelength: Mo K radiation (0.71073 A) : 12.65 cm Diffractometer, scan mode: Siemens SMART CCD, 2 max: 56.6° N(hkl)measured, N(hkl)unique: 20956, 4397 Criterion for Iobs, N(hkl)gt: Iobs > 2 (Iobs), 2212 N(param)refined: 242 Programs: SHELXTL [3], SHELXTL-plus [4] Table 1. Data collection and handling. H(1) 8c –0.0137 0.9659 0.1160 0.057 H(2) 8c –0.0383 0.8838 0.1683 0.078 H(3) 8c 0.1206 0.7573 0.1960 0.065 H(4) 8c 0.3001 0.7099 0.1705 0.060 H(5) 8c 0.3330 0.8065 0.1194 0.047 H(7) 8c 0.1043 0.9792 0.0674 0.034 H(8) 8c 0.3519 0.9345 0.0716 0.033 H(10) 8c 0.4710 0.8780 0.1946 0.068 H(11) 8c 0.4746 0.9165 0.2493 0.073 H(12) 8c 0.6345 1.0631 0.2727 0.072 H(13) 8c 0.7882 1.1667 0.2419 0.084 H(14) 8c 0.7803 1.1317 0.1865 0.070 H(16) 8c 0.5333 0.9393 0.1426 0.066 H(17) 8c 0.7683 1.0099 0.1368 0.078 H(1W1) 8c 0.50(2) 1.21(2) 0.048(4) 0.13(6) H(1W2) 8c 0.509(8) 0.67(1) 0.027(2) 0.02(2) H(2W1) 8c 0.628(9) 1.31(1) 0.016(2) 0.05(3) H(2W2) 8c 0.619(8) 0.67(1) 0.056(2) 0.05(3) Table 2. Atomic coordinates and displacement parameters (in A). Atom Site x y z Uiso