Ephedrine derivatives, extraordinary tools for the study of stereogenic centers in tetra- to heptacoordinated complexes

Syntheses, Structures and Reactivity of New Intramolecularly Coordinated Tin Alkoxides Based on an Enantiopure Ephedrine Derivative

“…The formation of 6·C 7 H 8 from 5 might be catalyzed by traces of bromide in the reaction mixture. This hypothesis is supported by the reaction of 5 with two molar equivalents of Ph 4 PBr that provides compound 3 and bis(tetraphenylphosphonium)hexabromidostannate (7). Compound 6·C 7 H 8 was also obtained from the reaction of 3 with SnBr 4 (Scheme 3).…”

“…The reaction of Sn(O-tBu) 4 with two molar equivalents of the ethanolamine derivative 1 provided the spiro-type compound 3 as colourless crystalline material, which is soluble in common organic solvents such as CH 2 Cl 2 and toluene (Scheme 2). Recrystallization of compound 3 from thf gave single crystals of modification 3a, and recrystallization from toluene gave single crystals of modification 3b that were both suitable for X-ray diffraction analysis.…”

“…[4] To the best of our knowledge, there is only one ephedrine-based tin compound reported in the literature. [5] In the context of our ongoing interest in the tin derivatives of ethanol amines [6] we report here a series of ephedrine-derived derivatives.…”

CH⋯Metal(II) axial interaction in planar complexes (metal = Cu, Pd) and implications for possible environmental effects of alkyl groups at biological copper sites

“…On the other hand, interactions between M and the C-H bond of an alkyl group, known as agostic interactions in electron-deficient transition metal complexes, are currently attracting much attention due their intermediacy in the C-H bond activation by metal complexes as well as the unusual C-H bond coordination [30][31][32][33]. A recent study on the Cu(II) complexes of ephedrine derivatives has revealed an axial contact between Cu(II) and the alkyl C-H moiety with the CuÁ Á ÁH distance of 2.454 Å in the complex with the erythro form of the ligand but not with the threo form for steric reasons [34,35]. The finding, which was originally reported to be an agostic interaction but was later classified [36] as a weak hydrogen bond [37], points to the possibility of MÁ Á ÁH-C interactions involving an alkyl side chain in planar Cu(II) complexes.…”

XPS‐Characterization of Heterometallic Coordination Compounds with Optically Active Ligands

“…In this work, we present the synthesis of the heterotrinuclear compounds [Cu 2 Ni(S,S(+)cpse) 3 [13]. This characterization allowed us to understand structural similarities between homometallic and heterometallic compounds.…”