Synthesis, structure, lipophilicity and protonation behaviour of mixed ligand rhenium chelates functionalized by amine groups

A series of systematically altered neutral oxorhenium complexes of the general formula ReO[Et2NCH2CH2N(CH2CH2S)2][p-X–C6H4–S] where X=NH2 (1), OMe (2), Me (3), t-Bu (4), H (5), Cl (6), Br (7), I (8), NO2 (9) was prepared by simultaneous action of (CH3CH2)2NCH2CH2N(CH2CH2SH)2 and p-XC6H4SH on [ReOCl3(PPh3)2].The molecular structure of complex 6 (where X=Cl) was determined by X-ray crystallography, revealing a trigonal bipyramidal geometry. PHPLC/pH profiles and pKa values were determined by HPLC.