Design and synthesis of heterobimetallic donor-acceptor chemodosimetric ensembles for the detection of sulfhydryl-containing amino acids and peptides

摘要

A competitive indicator displacement assay has been successfully developed for the ratiometric determination of sulfhydryl-containing amino acids and peptides using heterobimetallic donor-acceptor complexes as chemodosimetric ensembles.Chromotropic cis-[ML_2(CN)_2] (M=Fe~(II),Ru~(II),Os~(II);L=diimine) are used as signaling indicators and Pt~(II)(DMSO)Cl_2 acceptor moiety is used as the receptor for the sulfhydryl-containing analytes.A series of three heterobimetallic donor-acceptor complexes:cis-Fe~(II)(bpy)_2[CN-Pt~(II)(DMSO)Cl_2]_2 (1),cis-Ru~(II)(bpy)_2[CN-Pt~(II)(DMSO)Cl_2]_2 (2) and cis-Os~(II)(bpy)_2[CN-Pt~(II)(DMSO)Cl_2]_2 (3) are synthesized and characterized by X-ray crystallography.All the three ensembles are able to produce specific colorimetric/fluorimetric responses to sulfhydryl-containing amino acids (cysteine,homocysteine and methionine) as well as the sulfhydryl-containing small peptide glutathione.The mechanism of the competitive displacement assay is evaluated by examining the thermodynamics of formation of the donor-acceptor linkage and adducts between the acceptor metal and the sulfhydryl-containing analytes as well as by systematic variation of the donor and acceptor metals in the chemodosimetric ensembles.