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Abstract. [CuC12(CaH20N20) imposed symmetry but has an approximate molecular C(7N2) mirror plane passing through Cl(1), C1(2), Cu and 0(4).] Experimental. Compound prepared by reaction ofCuC12.2H20 with bis(2-dimethylaminoethyl) ether in boiling ethanol, crystals obtained by cooling of reaction mixture. Blue-green columnar crystal, 1.08 x 0.35 × 0.35 mm, AED2 four-circle diffractometer, graphite-monochromated Cu Ka radiation, cell parameters from 0 values of 128 reflections measured at +o9 (15 < 0 < 17.5°). For data collection, 09--28 scans with o) scan width (0.70+0.347tan0) °, 20max= 120 °, h 0-, 13, k 0--,13, l 0--,20, no significant crystal movement or decay, initial absorption correction using ~, scans, 1872 unique reflections, giving 1668 with F > 6a(F) for structure solution [from a Patterson synthesis (Cu) followed by iterative cycles of leastsquares refinement and difference Fourier synthesis] and refinement [using full-matrix least squares on F

A series of complexes has been prepared with the halides of cobalt(II), nickel(II), copper(II) and 2-,3-,4-ethylpyridine. The compounds were essentially all octahedral with the exception of those formed between 2-ethylpyridine and the cobalt(II) halides. The stereochemical configurations were deduced using spectral and magnetic properties. The decomposition of the complexes was studied by thermogravimetry and differential thermal analysis.This work is a continuation and an extension of previously reported studies [1-9] on the coordination compounds formed between the halides of cobalt(II), nickel(I1) copper(II) and 2-,3-,4-ethylpyridine. The variation of the ethyl constituent in the 2-, 3-and 4-position of the pyridine ring means that both the donor tendency of the N ring atom and the steric influence of the substituted pyridine molecule can be further investigated. The thermal decomposition of the compounds has been studied. Information regarding the stereochemistry of the compounds was obtained using electronic absorption spectra, far infrared spectra and magnetic measurements over the temperature range 300-100 K. ExperimentalThe complexes were prepared by dissolving the appropriate metal halide in hot ethanolic solution and adding an excess of the nitrogen-base dissolved in ethanol. The precipitated complexes were washed with ethanol and air-dried. The complexes prepared by this method are given in Table 1. References are given to previous preparations; where no reference is given it is believed that these are new compounds.Thermal decomposition studies were carried Out in air on a Stanton Redcroft Model TR-O1 Thermobalance with a DTA attachment.Electronic spectra were obtained on a Beckman ACTA M-IV spectrophotometer using 1 cm cells. The solvent used was AR Chloroform dried over molecular sieves. Far infrared spectra were obtained on a Beckman IR 720 M interferometer using a polythene matrix to support the complexes.

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