The crystal structure of the complex of 1,4,7,10-tetraoxacyclododecane with copper(II) chloride

Abstract

The crystal structure of C8H1604. CuCI2, the complex of 1,4,7,10-tetraoxacyclododecane with copper(II) chloride has been determined by a single-crystal X-ray diffraction study. The compound crystallizes in the space group P21212~ with a= 7-062 (3), b= 13.661 (8), and c= 12.337 (7) ,~ (Z= 4). The intensities of 1565 unique reflections were measured on a Picker automatic diffractometer (Mo Kct radiation) and the structure was solved by Patterson and Fourier methods. All hydrogen atoms were located. Fullmatrix least-squares refinement of atom positions, hydrogen isotropic temperature factors and anisotropic thermal parameters for all other atoms converged at a final RI = 3"4 % for the 1038 reflections above background. The Cu(II) ion is hexacoordinate and its coordination geometry can be pictured as an elongated and distorted octahedron, where two cis sites are taken by chlorine atoms and the remaining vertices are occupied by the four oxygens of the macrocycle. The equatorial plane of the coordination polyhedron coincides with a non-crystallographic mirror plane and contains the copper atom, two chlorines and two oxygens in a square-planar pattern. The Cu-Cl bond lengths are 2-214 (2) and 2.228 (2) A and the Cu-O distances are 2.128 (3) and 2.113 (3)/~. The apical Cu-O bonds are much longer, 2-343 (4) and 2.403 (3) A respectively, and the angle between them is only 135.2 ° compared with 180 ° in an ideal octahedron.

Study of Copper(II) Polyazamacrocyclic Complexes by Electronic Absorption Spectrophotometry and EPR Spectroscopy

“…[25,28,29] Although the formation of binuclear complexes (M 2 L) has been observed in some cases in the solid state, [23] it appears to be negligible in solution. [20][21][22] Most of the Cu II tri-and tetraazamacrocyclic complexes present in aqueous solution are thus mononuclear and fiveor six-coordinate, with the metal ion probably bound to all the nitrogen atoms of the macrocyclic ring and to two or three carboxylate oxygens of its pendant arms. These Cu II complexes often display strong tetragonal distortions that normally result in a lengthening of the axial metal-ligand bonds and an associated compression of the four equatorial ones.…”

“…Furthermore, even though there is a reported EPR study on the Cu II /DOTA system, [8] the effect of the pH on the EPR pattern of these macrocyclic complexes in aqueous solution was never investigated. The solid-state structures of Cu II complexes with NOTA, [9] NOTP, [10] DOTA, [11] and analogous tetraazamacrocyclic ligands, [12][13][14][15][16][17][18][19][20] have been obtained by X-ray diffractrometry.…”

Tetrahedral and octahedral cobalt(II) in hexaaquacobalt tetrachlorocobaltate–18-crown-6–acetone

“…H20 (Kn6chel, Kopf, Oehler & Rudolph, 1978) where octahedral Mn is coordinated to five water molecules and one nitrate ion, and CuC12. 12-crown-4 where the metal is directly bound to the polyether O atoms (van Remoortere, Boer & Steiner, 1975). We have determined the structures of a series of transition-metal complexes with crown ethers to examine the structural consequences of change of ring size and metal ion (part II: Vance, Holt, Varie & Holt, 1980;Vance, 1978).…”

Nitrato(1,4,7,10-tetraazacyclododecane)copper(II) nitrate

“…cycles (Anichini, Fabbrizzi, Paoletti & Clay, 1978), but a Cu H complex of the tetraoxa analogue of (I) is cisoctahedral (van Remoortere, Boer & Steiner, 1975).…”