2,2 ': 6 ',2 ''-terpyridine complexes of molybdenum(II) and tungsten(II). X-ray crystal structures of [MoI(CO)(terpy)(eta(2)-PhC2Ph)]I and [WI(terpy)(eta(2)-PhC2Ph)(2)]I center dot CDCl3

Equimolar quantities of [MI2(CO)(3)(NCMe)(2)] (M = Mo or W) and terpy (terp y = 2,2':6',2 "-terpyridine) react in CH2Cl2 at room temperature to give th e cationic complexes [MI(CO)(3)(terpy)]I (1 and 2) in high yield. Treatment of [MoCl(GeCl3)(CO)(3)(NCMe)(PPh3)] with one equivalent of terpy affords [ Mo(GeCl3)(CO)(2)(PPh3)(terpy)]Cl (3) in good yield. Reaction of [MI2(CO)(NC Me)(eta(2)-RC2R)(2)](M = Mo, W; R = fh; for M = W only, R = Me) with an equ imolar quantity of terpy in CH,CI, at room temperature gives the cationic c omplexes [MI(CO)(terpy)(eta(2)-RC2R)]I (4 and 5) or the crystallographicall y characterised cationic complex [WI(terpy)(eta(2)-PhC2Ph2)]I (6). Equimola r quantities of [WI(CO)(terpy)(eta(2)-MeC2Me)]I(5) and Na[BPh4] react to gi ve the anion-exchanged product, [WI(CO)(terpy)(eta(2)-MeC2Me)][BPh4] (7). T he X-ray crystal structure of [MoI(Co)(terpy)(eta(2)-PhC2Ph)]I shows the th ree nitrogen atoms of the terpy bonded in the equatorial plane of an octahe dron together with the carbonyl group. The iodo and diphenylacetylene ligan ds are mutually trans- to each other in the axial positions. The structure of [WI(terpy)(eta(2)-PhC2Ph2)(2)]I . CDCl3 (6) has a distorted octahedral g eometry, with the three nitrogen atoms of the terpy ligand in a mer-configu ration, with two cis-and parallel diphenylacetylene ligands and an iodo gro up occupying the other three mer-sites. (C) 2000 Elsevier Science S.A. All rights reserved.