The crystal structure of di-μ-hydroxo-bis(N,N,N',N'-tetramethylethylenediamine)dicopper(II) bromide

Abstract

Crystals of [Cu2{(CH3)2NCH2CH2N(CH3)2}2(OH)2]Br2 are orthorhombic, space group Fddd, with eight formula units in a unit cell of dimensions a= 17.072, b= 18.482 and c= 12-825, all + 0.005 A. The structure was determined by three-dimensional Patterson syntheses from data taken with Nifiltered Cu K0c radiation using the equi-inclination, multiple-film Weissenberg technique. The formula unit was found to have a dimeric structure with a Cu-Cu distance of 3.000 A. Anisotropic refinement was carried out by the method of block-diagonal least-squares to obtain a final R index of 0.082.

The crystal and molecular structure of di-μ-hydroxobis[di(1,10-phenanthroline)chromium(III)] chloride hexahydrate

“…The Cr-O-Cr-O bridging unit is roughly planar, with all atoms lying within 0.015 A of the least-squares plane through the four atoms; the least-squares planes were calculated using Doedens' program PLANET. The Cr-Cr separation is 3.008 (3)A, which is slightly longer than the value of 2.974 (2)/k in [Cr(gly)zOH]2 and is very similar to the value of 3.000 (4)A for the Cu-Cu separation in [Cu(tmen)2OH] 2+ (Mitchell et al, 1970). This increase in the Cr-Cr distance relative to the glycinato complex is brought about by an increase in the Cr-O-Cr bridging angles; the values of 102-2 (3) and 103.1 (3) ° here are considerably larger than the angle of 98.2 (2) ° found in [Cr(gly)2OH]2.…”

“…Hatfield Jeter, Lewis, Hempel, Hodgson & Hatfield, 1972) and similar studies on the analogous systems [Cu(bipy)OH] 2+, where bipy is 2,2'-bipyridine (Casey, Hoskins & Whillans, 1970;Majeste & Meyers, 1970;Barnes, Hodgson & Hatfield, 1972) and [Cu(tmen)OH] 2+, where tmen = tetramethylethylenediamine (Mitchell, Bernard & Wasson, 1970;Cole & Brumage, 1970) we were able to deduce that the value of 2J, the singlet-triplet energy separation, decreases as the Cu-O-Cu bridging angle ~0 increases, and that 2J changes from positive to negative in the region 97 to 99 ° .…”

Structure of a new type of copper carboxylate complex: [Cu(C14H8O3)(C10H8N2)]2.C3H7N.H2O

“…Cu202 core has not been seen in copper(II) carboxylate complexes before, but a similar core was found in [Cu2(OH)2L,] type complexes (Casey, Hoskins & Whillans, 1970;Majeste & Meyers, 1970;Mitchell, Bernard & Wasson, 1970;Lewis, Hatfield & Hodgson, 1972). It is worth noting that there is no H atom in both a-hydroxyl groups for the title compound, while there are still OH ligands in the Cu2(OH)2Ln complexes.…”

Dinitrato(N,N,N',N'-tetramethylethylenediamine)copper(II)

“…We are investigating this feature and have previously reported our findings for [Cu(tmen)(OH)]2(C104) 2 as a four-coordinate dimer (Arcus, Fivizzani & Pavkovic, 1977), and also for [Cu(tmen)SO4(H20)2]H20 as a hydrated fivecoordinate monomer (Balvich, Fivizzani, Pavkovic & Brown, 1976). The conformation of the diamine ligand in these two complexes is significantly less twisted about the ethylene C atoms than found in other tmen complexes of known structure (Mitchell, Bernard & Wasson, 1970;Estes, Estes, Hatfield & Hodgson, 1975;Luukkonen & Pajunen, 1973). In the search for additional examples containing this reduced-twist conformation, the structure determination of the anhydrous complex Cu(tmen)(NO3)2 was undertaken.…”