Dominic Chun-Ming Ng

Syntheses, characterisation and photophysical studies of novel biological labelling reagents derived from luminescent iridium(III) terpyridine complexes

A series of new luminescent iridium(III) terpyridine complexes functionalised with an isothiocyanate group, [Ir(tpy-R)(tpy-C6H4-NCS-p)](PF6)3 [R = H (1), C6H5 (2), C6H4-CH3-p (3), C6H4-Cl-p (4)] has been synthesised, characterised and their photophysical properties studied; the X-ray crystal structure of one of the intermediate complexes, [Ir(tpy-C6H4-Cl-p)(CF3SO3)3] (4b), has also been determined; complex 1 has been used as a luminescent label for proteins.

Luminescent rhenium(I) polypyridine complexes with an isothiocyanate moiety–versatile labelling reagents for biomolecules

The synthesis, characterisation and photophysical properties of a series of new rhenium(I) polypyridine complexes, [Re(N–N)(CO)3(py-3-NCS)]+, are reported; the isothiocyanate moiety enables these complexes to react with primary amine groups of modified oligonucleotides and proteins.

Specific labelling of sulfhydryl-containing biomolecules with redox-active N-(ferrocenyl)iodoacetamide

The synthesis, characterisation, X-ray crystal structure and electrochemical properties of a new redox-active labelling reagent, N-(ferrocenyl)iodoacetamide (Fc-IAA), are reported. This compound exhibits a reversible ferrocenium/ferrocene couple at ca. +0.345 V vs. SCE at a sweep rate of 100 mV s−1 in CH3CN at 298 K, and two irreversible reduction waves at ca. −1.324 and −2.048 V, attributable to the reduction of the iodoacetamide group. Since the iodoacetamide moiety can react specifically with the sulfhydryl group, Fc-IAA has been coupled to various biomolecules including a sulfhydryl-modified oligonucleotide, cysteine, glutathione and sulfhydryl-modified bovine serum albumin. The electrochemical properties of the bioconjugates have also been investigated.