SYNTHESIS AND MOLECULAR-STRUCTURE OF THE TRINUCLEAR MIXED-METAL COMPLEX [((ME2NCH2CH2CH2)2CR(MU-CL)2)2MG] AND OF THE TETRANUCLEAR GRIGNARD-REAGENT [(ME2NCH2CH2CH2)MG2CL3(THF)2]2

CrCl3.3THF reacts with [(Me2NCH2CH2-CH2)Mg2Cl3(THF)2]2 (1) in THF at room temperature to form the complex [{(Me2NCH2CH2CH2)2Cr(mu-Cl)2}2Mg[ (2). The solid-state structures of 1 and 2 have been determined by X-ray crystal analysis. 1 is triclinic, space group P1BAR (No. 2), with a = 10.035(8) angstrom, b = 10.393(8) angstrom, c = 10.707(8) angstrom, alpha = 75.59(6)-degrees, beta = 68.61(6)-degrees, gamma = 75.28(7)-degrees, and Z = 1 (the asymmetric unit is half of the molecule); the structure was refined to a conventional R factor of 0.079. In this tetranuclear Grignard reagent 1 Mg and Cl atoms form a system of five four-membered bridging units, where the Mg atoms exhibit five and six coordination and are connected by doubly (mu) or triply (mu3) bridging chloro ligands. 2 is triclinic, space group P1BAR (No. 2), with a = 8.514(8) angstrom, b = 12.471(9) angstrom, c = 14.976(9) angstrom, alpha = 81.54(5)-degrees, beta = 92.52(6)-degrees, gamma = 95.32(6)-degrees, and Z = 2; the structure was refined to R = 0.064. 2 is a trinuclear complex with two (Me2NCH2CH2CH2)2Cr(mu-Cl)2 fragments attached either side of a central Mg atom through four Cr-Cl-Mg bridges.