Optically active co-ordination compounds. Part XXXV. Configurations, preparations, and reactivities of some complexes of amino-acids

Abstract

A comparison of c.d. spectra in solution and solid phases has been made for various complexes of α-amino-acidates. Such comparisons are found to be unreliable as guides to the configurations of [Cu(L-aa)]₂ complexes. Some unexpected effects are observed for the chiroptical d–d spectra of the insoluble isomers ‖Λ-(+)-β-[Co(L-aa)₃](where aa = the anion of L-ala, L-val, L-leu, L-pro, and L-thr), of their isomorphous chromium(III) and rhodium(III) analogues, and of Δ-(–)-β-[Co(L-leu)₃]. Reasons are advanced for the observed c.d. spectra. Full details of preparation and separation are given for isomers of [Co(L-thr)₃], [CO(L-lys)₃], [Cr(aa)₃](where aa = the anions of gly and L-ala), and of some novel dimeric complexes of cobalt(III). Geometric and optical configurations are assigned to many of the new isomers. A number of isomerisations, carried out in water above 100°, are reported and discussed, and experimental details are given for some reactions of [M(aa)_n] and related compounds. Useful lines of further work are indicated.