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Selective Recognition of Copper(II) by a Water‐Soluble, Emitter‐Receptor Conjugate Containing a Ruthenium Chromophore, a Lysine Bridge, and a Cyclen Unit
Author(s) -
Geißer Bernd,
König Burkhard,
Alsfasser Ralf
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200106)2001:6<1543::aid-ejic1543>3.0.co;2-z
Subject(s) - chemistry , cyclen , ruthenium , chromophore , protonation , ligand (biochemistry) , aqueous solution , amide , metal ions in aqueous solution , hydrolysis , copper , stereochemistry , combinatorial chemistry , inorganic chemistry , medicinal chemistry , photochemistry , metal , ion , organic chemistry , catalysis , receptor , biochemistry
The amino acid derivative [H‐Lys{Ru(bipy) 2 m}‐cyclenH 2 ](PF 6 ) 5 ( 7 ; Lys = lysine, bipy = 2,2′‐bipyridyl, m = 4‐carbonyl‐4′‐methyl‐2,2′‐bipyridyl, cyclen = 1,4,7,10‐tetraazacyclododecane) has been synthesized. A modular approach was taken which involves only standard amide‐coupling methods well‐known from peptide synthesis. Compound 7 is readily soluble in water. It contains a luminescent ruthenium chromophore and a cyclen ligand which serves as a binding site for metal ions. The emission of 7 is pH‐independent but efficiently quenched by Cu 2+ ions in a pH range of 6−7. Copper(II) binding is reversible upon protonation of the ligand at pH values below 6. In contrast, no significant spectral changes are observed with Zn 2+ and Ni 2+ , respectively. Thus, 7 selectively recognizes copper(II) in aqueous solution under slightly acidic to neutral conditions. Unfortunately, applications at higher pH values are limited by metal‐promoted hydrolysis of 7 under mildly basic conditions.