The reaction of the group 9 bis(hydrosulfido) complexes [Cp*M(SH)2(PMe3)] (M = Rh, Ir; Cp* = η5-C5Me5) with the group 6 nitrosyl complexes [Cp*M′Cl2(NO)] (M′ = Mo, W) in the presence of NEt3 affords a series of bis(sulfido)-bridged early−late heterobimetallic (ELHB) complexes [Cp*M(PMe3)(μ-S)2M′(NO)Cp*] (2a, M = Rh, M′ = Mo; 2b, M = Rh, M′ = W; 3a, M = Ir, M′ = Mo; 3b, M = Ir, M′ = W). Similar reactions of the group 10 bis(hydrosulfido) complexes [M(SH)2(dppe)] (M = Pd, Pt; dppe = Ph2P(CH2)2PPh2), [Pt(SH)2(dppp)] (dppp = Ph2P(CH2)3PPh2), and [M(SH)2(dpmb)] (dpmb = o-C6H4(CH2PPh2)2) give the group 10−group 6 ELHB complexes [(dppe)M(μ-S)2M′(NO)Cp*] (M = Pd, Pt; M′ = Mo, W), [(dppp)Pt(μ-S)2M′(NO)Cp*] (6a, M′ = Mo; 6b, M′ = W), and [(dpmb)M(μ-S)2M′(NO)Cp*] (M = Pd, Pt; M′ = Mo, W), respectively. Cyclic voltammetric measurements reveal that these ELHB complexes undergo reversible one-electron oxidation at the group 6 metal center, which is consistent with isolation of the single-electron oxidation products [Cp*M(PMe3)(μ-S)2M′(NO)Cp*][PF6] (M = Rh, Ir; M′ = Mo, W). Upon treatment of 2b and 3b with ROTf (R = Me, Et; OTf = OSO2CF3), the O atom of the terminal nitrosyl ligand is readily alkylated to form the alkoxyimido complexes such as [Cp*Rh(PMe3)(μ-S)2W(NOMe)Cp*][OTf]. In contrast, methylation of the Rh−, Ir−, and Pt−Mo complexes 2a, 3a, and 6a results in S-methylation, giving the methanethiolato complexes [Cp*M(PMe3)(μ-SMe)(μ-S)Mo(NO)Cp*][BPh4] (M = Rh, Ir) and [(dppp)Pt(μ-SMe)(μ-S)Mo(NO)Cp*][OTf], respectively. The Pt−W complex 6b undergoes either S- or O-methylation to form a mixture of [(dppp)Pt(μ-SMe)(μ-S)W(NO)Cp*][OTf] and [(dppp)Pt(μ-S)2W(NOMe)Cp*][OTf]. These observations indicate that O-alkylation and one-electron oxidation of the dinuclear nitrosyl complexes are facilitated by a common effect, i.e., donation of electrons from the group 9 or 10 metal center, where the group 9 metals behave as the more effective electron donor.

The reaction of the mono(hydrosulfido) iridium complex [Cp∗IrH(SH)(PPh3)] (1, Cp∗ = η5-C5Me5) with [Cp∗MCl2(NO)] (2, M = Mo, W) afforded the mono(sulfido)-bridged Ir–Mo and Ir–W heterodinuclear complexes [Cp∗IrH(PPh3)(μ-S)MCl(NO)Cp∗] (3a and 3a′, M = Mo; 3b and 3b′, M = W) as a 2:1 mixture of diastereomers. Abstraction of the hydrido ligand in both 3a and 3a′ with [Ph3C][BF4] in CH2Cl2–MeCN underwent stereoselectively to give the RIr,RMo/SIr,SMo pair of the cationic acetonitrile complex [Cp∗Ir(NCMe)(PPh3)(μ-S)MoCl(NO)Cp∗][BF4] (4). The stereochemical course for the formation of 4 from the major isomer 3a was confirmed to be inversion at the iridium center by X-ray crystallographic studies. Ligand substitution experiment of 4 with CD3CN revealed that the stereochemistry of 4 is controlled thermodynamically.Mono(sulfido)-bridged heterodinuclear complexes [Cp∗IrH(PPh3)(μ-S)MCl(NO)Cp∗] (M = Mo, W) are obtained by the reaction of the hydrido–hydrosulfido complex [Cp∗IrH(SH)(PPh3)] with [Cp∗MCl2(NO)]. Treatment of the Ir–Mo complex with [Ph3C][BF4] in CH2Cl2–MeCN gives the acetonitrile complex [Cp∗Ir(NCMe)(PPh3)(μ-S)MoCl(NO)Cp∗][BF4] with high diastereoselectivity, where the stereochemical course of the reaction has been revealed by X-ray analysis.

The tetraruthenium complex [Cp*RuCl]4 (Cp* = η5-C5Me5) reacts with Na2NCN to afford the anionic bis(cyanamido)-capped triruthenium complex [(Cp*Ru)3(µ3-NCN)2]− (2−), which undergoes single electron oxidation to form [(Cp*Ru)3(µ3-NCN)2] upon workup with 1 equiv. of [Cp2Fe](PF6) (Cp = η5-C5H5). Treatment of 2− with 1 equiv. of HCl at room temperature leads to the protonation of one of the Ru–Ru edges to give the hydrido-bridged complex [(Cp*Ru)3(µ-H)(µ-NCN)2], while the cationic side-on NCNH2 complex [(Cp*Ru)3(µ-Cl)(µ3-NCN)(µ3-NCNH2-1κC,N:2κC:3κN)]Cl (5) is obtained by the reaction of 2− with an excess amount of HCl at −78 °C. On the other hand, the reaction of 2− with BR3 (R = Et, Ph) results in the ligation of two BR3 molecules to the terminal nitrogen atoms of the cyanamido ligands to yield the bis(borane) adduct (PPN)[(Cp*Ru)3{(µ4-NCN)(BR3)}2] (6, PPN = Ph3PNPPPh3). 6b (R = Et) slowly liberates one BEt3 molecule in acetone to give the mono(borane) adduct (PPN)[(Cp*Ru)3(µ3-NCN){(µ4-NCN)(BEt3)}] (7). 2− is also shown to react with [AuCl(PPh3)] or PhCOCl to afford the tetranuclear heterometallic complex [(Cp*Ru)3(µ3-NCN){(µ4-NCN)(AuPPh3)}] (8) or the benzoylcyanamido complex [(Cp*Ru)3(µ3-NCN)(µ3-NCNCOPh)] in which the Au(PPh3)+ or benzoyl fragment is bound to the terminal nitrogen atom of a cyanamido ligand. The molecular structures of PPN+2−, 5·C6H6, 7 and 8·C6H6 have been determined by single-crystal X-ray analyses.