Synthesis and Characterization of Neutral Cyano-Bridged Dicobaloximes. (Alkyl)cobaloxime-μ-cyano-(ligand)cobaloxime

Published

Journal Article

The reaction of an alkylaquocobaloxime, Co(dmgH) 2 (R)(H 2 O), with a cyano(ligand)cobaloxime, Co(dmgH) 2 (CN)(B), has been found to produce a series of cyano-bridged dicobaloximes of the general formula R-Co(dmgH) 2 -NC-Co(dmgH) 2 -B (I). A series of 30 such cyano-bridged dicobaloximes where R = CF 3 , CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 , or C 6 H 11 and B = py, py-4-NH 2 , py-3-Cl, NH 3 , or pip have been synthesized and isolated as crystalline solids. The complexes are characterized as dicobaloximes by means of elemental analysis and molecular weight data for selected compounds. Evidence for formulation as dicobaloximes containing a cyano ligand bridge is obtained from infrared data which show a 28-51-cm -1 increase in vex upon formation of the dicobaloxime from the corresponding terminal cyanocobaloxime Co(dmgH) 2 (CN)(B). Characterization of I as the exclusive linkage isomer formed in all 30 compounds is based on electronic spectra of selected compounds and regular variations in vCN with variations in the ligands R and B. Further characterization of the bonding in the cyano-bridged dicobaloximes described here is obtained from 1 H NMR data. The relative stabilities of the cyano-bridged dicobaloximes with respect to dissociation were found to vary with the σelectron donating ability of the ligands R and B; the most stable cyano-bridged compounds are formed when R and B have a relatively small electron donating ability, as measured by the pK b and σ * values for the free ligand. © 1976, American Chemical Society. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Gaus, PL; Crumbliss, AL

Published Date

  • September 1, 1976

Published In

Volume / Issue

  • 15 / 9

Start / End Page

  • 2080 - 2086

Electronic International Standard Serial Number (EISSN)

  • 1520-510X

International Standard Serial Number (ISSN)

  • 0020-1669

Digital Object Identifier (DOI)

  • 10.1021/ic50163a013

Citation Source

  • Scopus