Nitrosyl derivatives of the unsaturated dihydrides [Mn2(μ-H)2(CO)6(μ-L2)] (L2 = Ph2PCH2PPh2, (EtO)2POP(OEt)2)

Abstract The title dimanganese complexes react with NO (5% in N 2 ) at room temperature to give as major products the corresponding hexanitrosyl derivatives [Mn 2 (NO) 6 (μ-L 2 )] in moderate yields, and they react rapidly with NO 2 to give the corresponding hydride derivatives [Mn 2 (μ-H)(μ-NO 2 )(CO) 6 (μ-L 2 )], these having a nitrite ligand bridging the dimetal centre through the N and O atoms. The dppm-bridged dihydride also reacts selectively at 273 K with (PPN)NO 2 to give first the nitro derivative (PPN)[Mn 2 (μ-H)(H)(NO 2 )(CO) 6 (μ-dppm)], which then transforms into the nitrosyl complex (PPN)[Mn 2 (μ-CO)(CO) 5 (NO)(μ-dppm)] at room temperature or above (dppm = Ph 2 PCH 2 PPh 2 ; PPN +  = [N(PPh 3 ) 2 ] + ). The latter anion reacts with (NH 4 )PF 6 to give the hydride-bridged nitrosyl complex [Mn 2 (μ-H)(μ-NO)(CO) 6 (μ-dppm)] and with [AuCl(PPh 3 )] to give the trinuclear cluster [AuMn 2 (μ-NO)(CO) 6 (μ-dppm)(PPh 3 )] (Mn–Au = ca. 2.68 A; Mn–Mn = 2.879(2) A). Both products are derived from the addition of the added electrophile at the intermetallic bond and rearrangement of the nitrosyl ligand into a bridging position. In contrast, methylation of the anion with CF 3 SO 3 Me takes place at the nitrosyl ligand to yield the unstable methoxylimide derivative [Mn 2 (μ-NOMe)(CO) 6 (μ-dppm)]. Analogous reactions at the nitrosyl ligand take place upon the addition of HBF 4 ·OEt 2 to the nitrosyl-bridged hydrides [Mn 2 (μ-H)(μ-NO)(CO) n (μ-dppm) m ] (n = 6, m = 1; n = 4, m = 2) to give the corresponding hydroxylimide derivatives [Mn 2 (μ-H)(μ-NOH)(CO) n (μ-dppm) m ]BF 4 , which were also thermally unstable and could not be isolated nor fully characterized.