Syntheses and Reactions of Rhenium Carbamoyl Complexes of the Type (CO)4Re(NH2R)(CONHR) (R = Ethyl, Allyl or Isopropyl)

Abstract

Carbamoyl complexes, (CO)4Re(NH2R)(CONHR)(R = ethyl, 1; R = allyl, 2; R = isopropyl, 3) were prepared by reactions of (CO)5ReBr (or (CO)5ReCH2SiMe3) with appropriate amines. Complexes 1, 2 and 3 reacted with CH3CH2COCl to give Re(CO)5(NH2R)+Cl− (R = ethyl, 4; R = allyl, 5; R - isopropyl, 6). Complex 5 undergoes nucleophilic attack by KOMe to give the alkoxycarbonyl complexes (CO)4Re(NH2-Allyl)(COOMe), 7. Complexes 4, 5, 6 and 7 were transformed to the corresponding carbamoyl complexes by reacting with appropriate amines. The reactions between the carbamoyl complexes and R″OH/CHCl3 in air at room temperature gave the proposed products [(CO)4Re(NH2R)]2O (R = allyl, 8; R = isopropyl, 9), respectively. Complex 8 can also be prepared by heating 7 in CDCl3 at 63–68°C for several days. The structure of 1 was confirmed by a X-ray crystallographic study. Crystallographic data: space group P21/c, a = 8.193 (3) Å, b = 19.273 (3) Å, c = 9.348 (8) Å, β = 110.37 (4)°, V = 1383.68 Å3, Z = 4; R(F) = 0.027, Rw(F) = 0.030, based on 1888 reflections with I > 2.5σ(I). The other complexes were characterized by 1H NMR, 13CNMR, IR and mass spectra.