Preparation and characterization of µ-amido-µ-acetato and µ-amido-µ-formato binuclear ammine complexes of cobalt(III) and related kinetic studies

Abstract

which subsequently decomposes, as reported el~ewhere.~ Plots of log (ODt -OD,) against time were linear to only ca. 10% reaction, values of OD, being calculated on the assumption that the p-amido-p-hydroxo-complex is formed. Rate constants k, (Table 5), obtained from these plots, are seen to fit a dependence of the form (2). -At 50 "C, a = K, = a + b[H+] (5-9 f 1.7) x lO-'s-landb = (9-4 & 1.2) x 10-71mol-1s-1, (2) [2/440 Received, 28th February, 19721 Alternative p.ocedure.

Structure of μ-amido-μ-formato-bis[tetraamminecobalt(III)] tetrachloride tetrahydrate, [Co2NH2(CHO2)(NH3)8]Cl4.4H2O

“…The bridging formate ligand has Co-O 1.912 (2) A, C-O 1.248 (3)/k, not significantly different from the essentially symmetrical bridging acetate ligand reported by Schaefer (1983). A symmetrical carboxylate bridge is expected in these complexes, not only because of the presumed equivalence of the metal atoms, but also on the basis of infrared spectroscopy (Scott & Sykes, 1972). The unsymmetrical bridging acetate reported by Mandel, Marsh, Schaefer, Mandel & Wang (1977) * Lists of structure factors, anisotropic thermal parameters and H-atom parameters have been deposited with the British Library Lending Division as Supplementary Publication No.…”

“…We report here the structure of a complex with a strictly symmetrical formate bridge. The preparation has already been described (Scott & Sykes, 1972).…”

“…A symmetrical carboxylate bridge is expected in these complexes, not only because of the presumed equivalence of the metal atoms, but also on the basis of infrared spectroscopy (Scott & Sykes, 1972 (Clegg, 1983, unpublished). Whether this is an intrinsic property of Table 1.…”