N,N-DIALKYLCARBAMATO COMPLEXES OF CHROMIUM(III) - CRYSTAL AND MOLECULAR-STRUCTURE OF 2 NON-HOMOLEPTIC PRODUCTS OF CHROMIUM(III), CR3(MU-3-O)(O2CNET2)6CL(NHET2)2 AND CR2(O2CNPR(I)2)5CL

The N,N-diethylcarbamato derivative of chromium(III), Cr(O2CNEt2), has been prepared by the procedure involving anhydrous CrCl3, NHEt2 and C O2. The same product was obtained by the redox reaction between Cr2(O2 CNEt2)4(NHEt2)2 and trans-Pd(O2CNEt2)2(NHEt2)2, together with palladiu m metal. A by-product of the reaction between CrCl3, NHEt2 and CO2 is the non homoleptic mu3-oxo compound, Cr3(mu3-O)(O2CNEt2)6Cl(NHEt2)2, w hich was studied by X-ray diffraction methods [crystal data: monoclini c, space group C2/c (No. 15); a = 22.646(6); b = 16.462(2); c = 27.674 (9) angstrom; beta = 91.95(4)-degrees; V = 10311 angstrom3; Z = 8; Dc = 1.353 g cm-3; R = 0.072; R(w) = 0.084] and found to contain an almos t planar Cr3O core with bridging bidentate N,N-diethylcarbamato groups . The distorted pseudo-octahedral geometry of each chromium atom consi sts of four oxygens from the carbamato groups, and one oxygen from the bridging oxide, the sixth coordination position being occupied by an amine nitrogen or a chloride. The reaction of anhydrous CrCl3 with NHi Pr2 and CO2 leads to incomplete chloride substitution even under drast ic conditions: the product of the reaction is Cr2(O2CNiPr2)5Cl, crysta llographically characterized ]crystal data: monoclinic, space group P2 (1)n (No 14); a = 12.356(3); b = 23.748(4); c = 16.725(3) angstrom; be ta = 105.94(2)-degrees; V = 4719 angstrom3; Z = 4; Dc = 1.211 g cm-3; R = 0.046; R(w) = 0.047] as a dimer containing one mu3 bridging and tw o bridging bidentate O2CNiPr2 groups; in this structure the two non-eq uivalent chromium atoms complete their hexacoordination with one termi nal bidentate O2CNiPr2 group each, and one terminal chloride.