Insertion of 2,6-dimethylphenyl isocyanide into the U-N bond of [U(?-C5H5)3(NEt2)]. Crystal structure of [U(?-C5H5)3{C(NEt2)=NC 6H3Me2-2,6}]

Insertion of CNC6H3Me2-2,6 into the U-N bonds of [U(?-C5H5)2(NEt2)2] and [U(?-C5H5)3(NEt2)] has been observed, leading to the formation of iminocarbamoyl derivatives. The structure of one of the resulting complexes [U(?-C5H5)3{C(NEt2)=NC 6H3Me2-2,6}] has been determined by X-ray analysis; this shows that the [C(NEt2)=NC6H3Me2-2,6]- anion is ?2-co-ordinated and the C=N double bond lies perpendicular to the U-M axis (where M is the midpoint of the C=N bond). 1H N.m.r. shows that the C5H5 protons are magnetically inequivalent. Some evidence of the insertion of CNC6H3Me2-2,6 into the U-P bond of [U(?-C5H5)3(PPh2)] is also reported.