Synthesis, structure and substitution reactions of a heterodimetallic tungsten—manganese complex [( η5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 4

Abstract

The room temperature reaction of [( η 5-C 5H 5)W(CO) 3(PPh 2)] with [Mn(CO) 5] in tetrahydrofuran (THF) followed by protonation with H 3PO 4 gives [( η 5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 4] 1 as the major product. Among the identified minor products from this reaction are [Mn 2(CO) 9(PPh 2H)] 2a, [Mn 2(CO) 9(PPh 2PPh 2)] 2b, [Mn 2( μ-H)( μ-PPh 2)(CO) 8] 2c, and [Mn 2( μ-PPh 2) 2(CO) 8] 2d. 13CO reacts with complex 1 substituting both the manganese and tungsten carbonyl groups. In contrast, other two-electron donor ligands, L, only substitute the manganese carbonyl groups to give the substituted products [( η 5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 3L] (L = P(OMe) 3 3a, PMe 2Ph 3b, PMePh 2 3c, PPh 2H 3d), [( η 5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 2L 2] (L = P(OMe) 3 4a or PMe 2Ph 4b). In the case of the photolytic reaction of 1 with the diphosphine, dppm (dppm = Ph 2PCH 2PPh 2), two products are obtained, one in which the ligand is chelated to the manganese centre, [( η 5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 2(dppm)] 5, and the other in which the ligand bridges the tungsten manganese centres, [( η 5-C 5H 5)(OC)W( μ-H)( μ-PPh 2)( μ-dppm)Mn(CO) 3] 6. Conversion of complex 5 to 6 can be achieved by prolonged UV irradiation of 5. A single crystal X-ray diffraction study for [( η 5-C 5H 5)(OC) 2W( μ-H)( μ-PPh 2)Mn(CO) 4] 1 is presented.