Open bond orders analysis

So far, we have encountered the spin density as a variable both in the description of electronic structures of open-shell character and in the analysis of local quantities such as local spins or bond orders. For an accurate treatment of open-shell molecules, spin-spin interactions and chemical bonding, reliable spin densities are thus mandatory. However, the determination of rehable spin density distributions can be a difficult task in quantum chemistry [199, 200]. Examples of such difficult cases are iron nitrosyl complexes containing salen or porphyrin ligands for which DFT spin densities considerably depend on the approximate exchange-correlation functional [87,199]. 

More recently, Fujiwara has investigated the racemization of anhydrous salts of the type [Co(phen)3 n(en)n]X3 where n = 0, 1 or 2 and X- = Cl-, Br- or I-.29 All compounds exhibit anion effects. For [Co(phen)3]3+ the rates varied Cl- > Br-, whereas for [Co(phen)2(en)]3+ and [Co(phen)(en)2]3+ the sequence I- > Br- > Cl- was observed. The anion effects were interpreted in terms of the chemical interactions due to the donicity and hydrogen bonding ability of the anions. However, the kinetic analysis is open to criticism because a first-order rate law was assumed. 

In a study presented by Jinno et al. [124], packed column capillary electrochromatography, open-tubular CEC, and microcolumn liquid chromatography using a cholesteryl silica bonded phase have been studied to compare the retention behavior for benzodiazepines. The results indicated that CEC was a promising method, as it yielded better resolution and faster analysis than microcolumn LC for benzodiazepines. Similar selectivity to HPLC was noted, except for a few solutes that were charged under the separation conditions. Columns packed with the ODS and cholesteryl phases were compared and showed totally different migration orders of the analytes. The retention on the cholesteryl silica sta-... 

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