Reactivity of cationic molybdenum(II) complexes. Part 4. Isolation and crystal structure determination of cis-[Mo(CO)2(η-C5Me5)(PPh3)(N3)] and cis-[Mo(CO)2(η-C5Me5)(PPh3)(NCO)]

Abstract

The complex [Mo(CO)₃(η-C₅Me₅)(PPh₃)]BF₄(1) reacts with NaN₃ in methanol solution to give a mixture of cis-[Mo(CO)₂(η-C₅Me₅)(PPh₃)(N₃)](2) and cis-[Mo(CO)₂(η-C₅Me₅)(PPh₃)(NCO)](3), which were separated as pure products by column chromatography. Pure (3) was also obtained by an independent route, i.e. by treating a methanol solution of (1) with cyanate ion. The solid-state structures of complexes (2) and (3) were determined by single-crystal X-ray diffraction: they are isomorphous, space group P2₁/c(no. 14); for (2), a= 8.625(2), b= 18.655(9), c= 17.573(5)Å, β= 92.29(2)°, Z= 4,3 315 independent data [I_o > 2.5σ(I_o)] refined to R= 0.032, R′= 0.034; for (3), a= 8.641 (1), b= 18.547(3), c= 17.52(1)Å, β= 91.15(3)°,Z= 4, 2 045 independent data [I_o > 2.5σ(I_o)] refined to R= 0.044, R′= 0.046. Differences in the co-ordination geometry of the N₃^– and NCO^– ligands are discussed.