Bifunctional Single Amino Acid Chelates for Labeling of Biomolecules with the {Tc(CO)3}+ and {Re(CO)3}+ Cores. Crystal and Molecular Structures of [ReBr(CO)3(H2NCH2C5H4N)], [Re(CO)3{(C5H4NCH2)2NH}]Br, [Re(CO)3{(C5H4NCH2)2NCH2CO2H}]Br, [Re(CO)3{X(Y)NCH2CO2CH2CH3}]Br (X = Y = 2-pyridylmethyl; X = 2-pyridylmethyl, Y = 2-(1-methylimidazolyl)methyl; X = Y = 2-(1-methylimidazolyl)methyl), [ReBr(CO)3{(C5H4NCH2)NH(CH2C4H3S)}], and [Re(CO)3{(C5H4NCH2)N(CH2C4H3S)(CH2CO2)}]

Abstract

The reactions of a series of potentially tridentate ligands, derived from single amino acids or amino acid analogues, with [NEt(4)](2)[ReBr(3)(CO)(3)] have been investigated. The model compounds [Re(CO)(3)Br[(2-pyridylmethyl)NH(2)]] (1) and [Re(CO)(3)[(2-pyridylmethyl)(2)NH]]Br (2) were also prepared and structurally characterized. With ligands possessing two pyridyl appendages, (2-pyridylmethyl)(2)NX (X = -CH(2)CO(2)H, -CH(2)CO(2)Et, …