Conformational analyses of the isomers of the systems [Co(men)(subscript n)(en)₃₋(subscript n)]³⁺(men =N-methylethane-1,2-diamine, en = ethane-1,2-diamine; n= 1–3)

Atkinson, Ian M., Keene, F. Richard, and Searle, Graeme H. (1991) Conformational analyses of the isomers of the systems [Co(men)(subscript n)(en)₃₋(subscript n)]³⁺(men =N-methylethane-1,2-diamine, en = ethane-1,2-diamine; n= 1–3). Dalton Transactions (1). pp. 45-51.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1039/dt9910000045
6


Abstract

A molecular mechanics study of the configurational/conformational isomers of the system Λ-[Co(men)(en)₂]³⁺(men =N-methylethane-1,2-diamine, en = ethane-1,2-diamine)(16 isomers), and the geometric/configurational/conformational isomers of the systems Λ-[Co(men)₂(en)]³⁺(72 isomers) and Λ-[Co(men)₃]³⁺(88 isomers) has been undertaken using the MM2 force field. Calculated steric energies (adjusted for statistical factors) are used to predict isomer ratios in the three systems, which are compared with experimentally determined themodynamic stabilities. Comparisons are also made between calculated geometries and X-ray molecular structures where these are available. For the Λ-[Co(men)₂(en)]³⁺ system the calculations not only correctly predict the order of stability of the three possible geometric isomers, but also the most stable conformation for each of these cases. For the Λ-[Co(men)₃]³⁺ system the two most stable forms observed experimentally are among the three forms of the molecule (of the 88 possible) calculated to be the most stable. Comparison of the geometric parameters for the two crystal structures and corresponding energy-minimized structures shows that the agreements are very good. The significance of statistical factors in thermodynamic comparisons of this type is discussed.

Item ID: 22757
Item Type: Article (Research - C1)
ISSN: 1477-9234
Keywords: cobalt(III) complexes; electron-transfer; <co(meen)2(en)>3+; <co(meen)3>3+; ligands; cation
Date Deposited: 15 Aug 2012 00:31
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030207 Transition Metal Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page