Reactions of Mo(II)-tetraphosphine complex [MoCl2{meso-o-C6H4(PPhCH2CH2PPh2)2}] with a series of small molecules

Abstract Reactions of Mo(II)-tetraphosphine complex [MoCl 2 (κ 4 - P4 )] ( 2 ; P4  =  meso - o -C 6 H 4 (PPhCH 2 CH 2 PPh 2 ) 2 ) with a series of small molecules have been investigated. Thus, treatment of 2 with alkynes RC CR′ (R = Ph, R′ = H; R =  p -tolyl, R′ = H; R = Me, R′ = Ph) in benzene or toluene gave neutral mono(alkyne) complexes [MoCl 2 (RC CR′)(κ 3 - P4 )] containing tridentate P4 ligand, which were converted to cationic complexes [MoCl(RC CR′)(κ 4 - P4 )]Cl having tetradentate P4 ligand upon dissolution into CDCl 3 or CD 2 Cl 2 . The latter complexes were available directly from the reactions of 2 with the alkynes in CH 2 Cl 2 . On the other hand, treatment of 2 with 1 equiv. of XyNC (Xy = 2,6-Me 2 C 6 H 3 ) afforded a seven-coordinate mono(isocyanide) complex [MoCl 2 (XyNC)(κ 4 - P4 )] ( 7 ), which reacted further with XyNC to give a cationic bis(isocyanide) complex [MoCl(XyNC) 2 (κ 4 - P4 )]Cl ( 8 ). From the reaction of 2 with CO, a mono(carbonyl) complex [MoCl 2 (CO)(κ 4 - P4 )] ( 9 ) was obtained as a sole isolable product. Reaction of 9 with XyNC afforded [MoCl(CO)(XyNC)(κ 4 - P4 )]Cl ( 10a ) having a pentagonal–bipyramidal geometry with axial CO and XyNC ligands, whereas that of 7 with CO resulted in the formation of a mixture of 10a and its isomer 10b containing axial CO and Cl ligands. Structures of 7 and 9 as well as [MoCl(XyNC) 2 (κ 4 - P4 )][PF 6 ]( 8 ′) and [MoCl(CO)(XyNC)(κ 4 - P4 )][PF 6 ] ( 10a ′) derived by the anion metathesis from 8 and 10a , respectively, were determined in detail by the X-ray crystallography.