New oxorhenium (V) complex with an imidazol [NN] /hydantoin [SN] mixed ligand system, and radiochemical behavior of its oxotechnetium (V) complex analog

Abstract

A [ReO(Imz)(Hyd)(H2O)2OH] complex was suc-cessfully synthesized by the ligand exchange method using oxorhenuim citrate and an imida-zole /Hydanton mixed ligand system. Geometry optimization of complex has been carried out using DFT at the B3LYP/LANL2DZ functional in singlet state. B3LYP predicated infrared spec-trum of the geometrically optimized structure using the same level of the theory and the same base set showed good agreement with experi-mentally observed values. The spin allowed singlet-singlet electronic transition of the [ReO(Imz)(Hyd) (H2O)2OH] complex was calcu-lated with time dependent density function the-ory (TD-DFT) and the UV-Vis spectra has been discussed on this basis. The complex was characterized using microanalysis and IR, UV-Vis, NMR and mass spectroscopic. The techne-tium tracer [99mTcO(Imz)(Hyd) (H2O)2OH] has also been synthesized by two methods using 99mTc-gluconate as a precursor or; by direct re-duction. The radiochemical purity of the com-plex was over 95% as measured by thin layer chromatography. In vitro studies showed that the complex possessed good stability under physiological conditions. The partition coeffi-cient indicated that the complex hydrophilic and the electrophoresis results showed that the complex cationic. Biodistrbution in mice showed that the complex accumulated in heart uptake of 9.53 ± 3.87% ID/gm at 5 min and good retention (6.37 ± 1.21)% ID/gm at 60 min. One hour after the injection, the heart/liver, heart/lung and heart/blood radioactivity ratios were 0.46, 1.04 and 0.56, respectively. These findings indicate that the complex might be