Cubane-Type Heterometallic Sulfido Clusters:  Incorporation of Two Metal Fragments into a Dinuclear ReS(μ-S)₂ReS Core Affording Bimetallic M₂Re₂(μ₃-S)₄Clusters (M = Ru, Pt, Cu) or Trimetallic MM‘Re₂(μ₃-S)₄Clusters via Incomplete Cubane-Type MRe₂(μ₃-S)(μ₂-S)₃Intermediates (M = Ru, Rh, Ir; M‘ = Mo, W, Pd, Ru, Rh)

Abstract

Reactions of a dirhenium tetra(sulfido) complex [PPh(4)](2)[ReS(L)(mu-S)(2)ReS(L)] (L = S(2)C(2)(SiMe(3))(2)) with a series of group 8-11 metal complexes in MeCN at room temperature afforded either the cubane-type clusters [M(2)(ReL)(2)(mu(3)-S)(4)] (M = CpRu (2), PtMe(3), Cu(PPh(3)) (4); Cp = eta(5)-C(5)Me(5)) or the incomplete cubane-type clusters [M(ReL)(2)(mu(3)-S)(mu(2)-S)(3)] (M = (eta(6)-C(6)HMe(5))Ru (5), CpRh (6), CpIr (7)), depending on the nature of the metal complexes added. It has also been disclosed that the latter incomplete cubane-type clusters can serve as the good precursors to the trimetallic cubane-type clusters still poorly precedented. Thus, treatment of 5-7 with a range of metal complexes in THF at room temperature resulted in the formation of novel trimetallic cubane-type clusters, including the neutral clusters [[(eta(6)-C(6)HMe(5))Ru][W(CO)(3)](ReL)(2)(mu(3)-S)(4)], [(CpM)[W(CO)(3)](ReL)(2)(mu(3)-S)(4)] (M = Rh, Ir), [(Cp*Ir)[Mo(CO)(3)](ReL)(2)(mu(3)-S)(4)], [[(eta(6)-C(6)HMe(5))Ru][Pd(PPh(3))](ReL)(2)(mu(3)-S)(4)], and [(Cp*Ir)[Pd(PPh(3))](ReL)(2)(mu(3)-S)(4)] (13) along with the cationic clusters [(Cp*Ir)(CpRu)(ReL)(2)(mu(3)-S)(4)][PF(6)] (14) and [(Cp*Ir)[Rh(cod)](ReL)(2)(mu(3)-S)(4)][PF(6)] (cod = 1,5-cyclooctadiene). The X-ray analyses have been carried out for 2, 4, 7, 13, and the SbF(6) analogue of 14 (14') to confirm their bimetallic cubane-type, bimetallic incomplete cubane-type, or trimetallic cubane-type structures. Fluxional behavior of the incomplete cubane-type and trimetallic cubane-type clusters in solutions has been demonstrated by the variable-temperature (1)H NMR studies, which is ascribable to both the metal-metal bond migration in the cluster cores and the pseudorotation of the dithiolene ligand bonded to the square pyramidal Re centers, where the temperatures at which these processes proceed have been found to depend upon the nature of the metal centers included in the cluster cores.

Core Conversion Reactions of the Cubane-Type Metal-Sulfido Clusters: Shape Shift, Contraction, and Expansion of the MM′Re2S4 Cubanes (M = Ir, Rh, Ru; M′ = Pt, Pd)

“…The Rh analogue [(Cp*Rh){Pt(PPh 3 ) 2 }{Re(L)} 2 (μ 3 -S) 4 ] ( 3b ) was obtained from [(Cp*Rh){Re(L)} 2 (μ 3 -S)(μ 2 -S) 3 ] ( 1b ) by analogous treatment, while the reaction of another incomplete cubane-type cluster, [{(Pmb)Ru}{Re(L)} 2 (μ 3 -S)(μ 2 -S) 3 ] ( 4 ; Pmb = η 6 -C 6 Me 5 H), with [Pt(PPh 3 ) 3 ] also afforded a similar raft-type cluster, [{(Pmb)Ru}{Pt(PPh 3 ) 2 }{Re(L)} 2 (μ 3 -S) 4 ] ( 5 ) (eq ). These findings present a sharp contrast to the exclusive formation of cubane-type clusters 2 and [{(Pmb)Ru}{Pd(PPh 3 )}{Re(L)} 2 (μ 3 -S) 4 ] from the reactions of [Pd(PPh 3 ) 4 ] with incomplete cubane-type clusters 1 and 4 , respectively, that was reported previously . Total oxidation numbers of metal centers are +13 for both 2 and 3 .…”

“…Cubane-type or incomplete cubane-type metal sulfido clusters are of particular interest due to their occurrence at the acive sites in metal−sulfur proteins of biological significance, including, e.g., nitrogenases, hydrogenases, and ferredoxins . We reported previously the stepwise syntheses of trimetallic cubane-type MM′Re 2 S 4 clusters (M = Ir, Rh, Ru; M′ = Mo, W, Ru, Rh, Pd), which involve the preparation of bimetallic incomplete cubane-type MRe 2 S 4 clusters from a dirhenium complex [PPh 4 ] 2 [{ReS(L)} 2 (μ-S) 2 ] (L = S 2 C 2 (SiMe 3 ) 2 ) and certain metal M species, followed by the incorporation of the other metal M′ fragment into their void corners . For example, incomplete cubane-type cluster [(Cp*M){Re(L)} 2 (μ 3 -S)(μ 2 -S) 3 ] (M = Ir ( 1a ), Rh ( 1b ); Cp* = η 5 -C 5 Me 5 ), obtained by treatment of the dirhenium complex above with [(Cp*MCl) 2 (μ-Cl) 2 ], reacts readily with [Pd(PPh 3 ) 4 ] to give the cubane-type cluster [(Cp*M){Pd(PPh 3 )}{Re(L)} 2 (μ 3 -S) 4 ] (M = Ir ( 2a ), Rh ( 2b )) (eq ).…”

14 Manganese, technetium and rhenium

“…The new complexes show fluxional behaviour attributed to metal-metal bond rotation and dithiolate rotation. 65 , with coordination by deprotonated sulfur atoms. Conversion of the carboxylic functions to the dianhydride, followed by reaction with amines, including lysine-containing peptides, gave complexes that were considered to have potential for radiopharmaceutical application of 186 Re or 188 Re.…”

Synthesis of a Sulfido-Capped Trinuclear Cluster [{(η5-C5Me5)Ir}2{Mo(CO)3}(μ3-S)2] and Its Reactions at the Molybdenum Site Forming a Series of Ir2MoS2 Clusters

“…This suggests that the metallasulfido moiety “(Cp*IrS) 2 ” in 3 is more electron donating than η 6 -toluene. As for the cubane-type clusters [NEt 4 ] 3 [{Fe(SEt)} 3 {Mo(CO) 3 }(μ 3 -S) 4 ] and [(Cp*Ir)(ReL) 2 {Mo(CO) 3 }(μ 3 -S) 4 ] (L = S 2 C 2 (SiMe 3 ) 2 ), the ν(C⋮O) values are reported to be 1864 and 1750 cm -1 for the former and 2007, 1968, and 1908 cm -1 for the latter. The appearance of four ν(C⋮O) bands is consistent with the presence of two conformers in the solid state as revealed crystallographically.…”