Heteroleptic Palladium(II) Complexes with Mixed Thiol- and Sulfide-containing Amino Acids: Self-assembly of Novel Heptanuclear Coordination Oligomers

Abstract

Treatment of a cyclic tripalladium(II) complex, [Pd3(d-pen)3] (d-H2pen: d-penicillamine), with l-methionine (l-Hmet) gave a novel open-chain-type S-bridged heptapalladium(II) complex, [Pd7(d-pen)8(l-met)2]4−, besides a monopalladium(II) complex, [Pd(d-pen)(l-met)]−. A similar reaction using S-methyl-l-cysteine (l-Hsmc) instead of l-Hmet produced an analogous heptapalladium(II) complex, [Pd7(d-pen)8(l-smc)2]4−.

Metal complexes of amino acids and peptides

“…15 Interactions between the cytotoxic hexacationic arene ruthenium assembly and a large range of amino acids (AA) as well as the tripeptide glutathione (GSH) have been monitored in aqueous solution at 37 1C by NMR spectroscopy and ESI MS. 38 In spite of the potential importance, studies on the interactions of niobium and tantalum species with amino acids are surprisingly rare. The reaction rate was found to depend significantly on the type of the amino acid.…”

Chiral Scrambling and Independent Crystallization of d4, l4, and d2l2 Isomers of an AuI4CoIII2 Hexanuclear Complex with Mixed Penicillaminate and Bis(diphenylphosphino)ethane

“…Self-recognition and organization among enantiomers of chiral molecules are essential for the rational synthesis of chiral functional materials, such as chiral separators, asymmetric catalysts, and ferroelectric and nonlinear optical materials, as well as for the understanding of homochirality in nature. , In this context, the control of self-recognition/organization upon chiral molecular assembling and crystallization processes has attracted much attention in synthetic chemistry for many years. − At a molecular level, chiral recognition leads to the selective formation of a pair of enantiomers (racemic isomer) . On the other hand, a racemic mixture of enantiopure crystals (conglomerate crystals) is produced by homochiral recognition in a crystalline level, which is referred to as “spontaneous resolution” upon crystallization .…”

“…On the other hand, a racemic mixture of enantiopure crystals (conglomerate crystals) is produced by homochiral recognition in a crystalline level, which is referred to as “spontaneous resolution” upon crystallization . To date, a great number of reports on the homochiral assembly at either the molecular or crystalline level have appeared in organic, coordination, and supramolecular chemistry . In recent years, interests of researchers in this research field have shifted to explore more complicated recognition systems that are closer to living systems, such as a high degree of chiral recognition that involves a hierarchical chiral-sorting process, partial spontaneous resolution that generates both conglomerate and racemic crystals in a crystallization process, and chiral autocatalysis that leads to a single enantiopure product through a spontaneous symmetry-breaking process .…”