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

Reactions of [Re(NPhF)Cl-3(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)Cl-3(PPh3)(isocyanide)] and cis- or trans-[Re(NPhF)Cl-3(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 F-19 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.

Automated summary

The reactions of [Re(NPhF)Cl-3(PPh3)(2)] with various alkyl and aryl isocyanides were investigated. Different reactivity patterns and products were obtained depending on the steric and electronic properties of the ligands. The stability of the products was correlated with the substitution pattern of the isocyanide ligands. The products were studied using X-ray diffraction, spectroscopic methods, and mass spectrometry, and the reactions were monitored using F-19 NMR.