Metal complexes of the three sparteine diastereoisomers. Properties and reactivities of the copper(II) derivatives

Crystal structure, spectroscopy and ferromagnetostructural behavior of the complex [CuII(L)(Cl)(L´)]•H2O (L = 2-aminomethylbenzimidazole, L´= L-isoleucinate)

“…In addition, the chloro apical ligand shows a deviation of its perpendicularity to the square pyramidal base, which establish an interaction between electronic density of the chloro ligand and some of the atomic orbitals d xz and d yz , promoting a minimum differentiation (Figure 2 a, (a) and (b) bands) between both d atomic orbitals (Figure 2b). [24][25][26] [28][29][30][31] These IR data are in full agreement with the functional groups present in the structure.…”

Bispidine Coordination Chemistry

“…Figure 12. Plots of the complex cations of various isomers of bispidine-copper(I) complexes, determined by X-ray crystallography (hydrogen atoms omitted; the structural data and references are given in Table VII; (a) [Cu (14) (22) …”

“…Although the landscape around these three local minima has been studied to some extent, and some possibilities to stabilize-destabilize specific structures have been identified (199), unambiguous rules have not yet been defined. The striking structural difference between [Cu (14)Cl] þ and [Cu (35)Cl] þ , and the difference in redox potential (ÁE ¼ 300 mV) and aziridination efficiency (see above) (168) indicate that a thorough understanding of these systems in a wider context might lead to complexes and catalysts with the possibility to switch between various structures and properties (redox potential, catalytic efficiency) with a variation of the temperature or other external parameters.…”

“…The coordination chemistry of sparteine is not extensively explored, but recent reports have described the synthesis, spectroscopic properties and structures of a row of its transition metal complexes (9)(10)(11)(12)(13)(14)(15). One possible reason for the poorly studied coordination chemistry of sparteine is the fact that differently substituted and enantiomerically pure derivatives of sparteine require some effort and are expensive to synthesize (16,17), which limits their application to a few small-scale experiments.…”

“…Hole size curve of ligand 14 (lowest energy curve, no metal-donor interaction terms included), and hole size curves of the two isomers of [Co(14)] 2þ with the cobalt-bispidine interaction terms included. The arrows are averaged sums of observed MÀ ÀL bond distances(189).…”