Heterofunctionalized phosphines derived from (2-formylphenyl)diphenylphosphine and their reactions with oxorhenium(V) complexes

Phenylimido complexes of rhenium: fluorine substituents provide protection, reactivity, and solubility

Reactions of [Re(NPhF)Cl₃(PPh₃)₂] ({NPhF}^2- = p-fluorophenylimide) with a variety of alkyl and aryl isocyanides have been studied. Different reactivity patterns and products have been obtained depending on the steric and electronic properties of the individual ligands. This involves the formation of 1 : 1 and 1 : 2 exchange products of Re(V) with the general formulae mer-[Re(NPhF)Cl₃(PPh₃)(isocyanide)] and cis- or trans-[Re(NPhF)Cl₃(isocyanide)₂]. The stability of the obtained products is correlated with the substitution pattern of the isocyanide ligands. The products have been studied by single-crystal X-ray diffraction and spectroscopic methods, including IR and multinuclear NMR spectroscopy as well as mass spectrometry. The use of partially fluorinated starting materials and ligands allows the modulation of the solubilities of the starting materials and the products as well as the monitoring of the reactions by means of ¹⁹F NMR. The attachment of the CF₃ or F substituent on the isocyanides gives control over the steric bulk and the electronic properties of the ligands and, thus, their reactivity.

Rhenium(V)-oxo complexes [ReOX2(N∩O)(EPh3)] (X=Cl, Br, I; E=P, As) – synthesis, structure, spectroscopy, and catalytic properties

The present review aims to give a comprehensive survey about the chemistry of rhenium(V)-oxo complexes of general formula [ReOX2(N∩O)(EPh3)], where X=Cl, Br, I, E=P, As, and N∩O stands for uninegative chelating N∩O-ligand, carried out within the last four decades. In addition to the synthesis aspects, the available structural data as well as the results issued from techniques such as infrared and ultraviolet-visible spectroscopies are collected and discussed. Furthermore, a brief description of the applications of these compounds in catalysis is included.

A new bifunctional chelator enables facile biocoupling and radiolabeling as the basis for a bioconjugation kit

A new tridentate bifunctional chelator, N-(-2-picolyl)(-4-hydroxy)(-3-amino)benzoic acid (PHAB), was designed to efficiently coordinate the [(99m)Tc(CO)3](+) core and facilitate coupling reactions to biomolecules. The chelator can be procured in the form of the corresponding benzotriazole ester (PHAB-OBT), which can be stored and used as a bioconjugation kit. PHAB-OBT reacts with modified carbohydrates with high selectivity and efficiency in a single step in both aqueous and organic media. As is desirable for a kit, no complicated chemical bench work is required. Glycoconjugate postlabeling resulted in neutral radiolabeled glycans with high radiochemical yields. Prelabeling approaches were assessed by successive reaction of PHAB-OBT with the [(99m)Tc(CO)3](+) core and a modified galactose model. The radiolabeled galactose was obtained in 84% yield as defined by HPLC analysis. Biodistribution of the radioactive (99m)Tc-labeled chelator, as well as the glycoconjugates, were examined in mice. Noticeably different biodistribution patterns were observed that reflect trends in the uptake of carbohydrate analogues by various organs.