The Cubane-Type Mo₂Ir₂S₄ Cluster Containing an Organohydrazido(2−) Ligand on the Mo Site

Abstract

Metal-sulfur cubane-type clusters have been attracting significant attention owing to their unique structures and properties. 1 Recent X-ray crystallographic studies on nitrogenase have revealed the structure of the FeMo cofactor cluster, which consists of two incomplete cubane-type units connected by three bridging sulfides {(MoFe 3 S 3 )(µ-S) 3 (Fe 4 S 3 )}. 2 This has spurred on particularly the syntheses of the cuboidal clusters relevant to this active site core, including those with {(MoFe 3 S 4 )(µ-S)(Fe 4 S 4 )} or related Mo/Fe/S chromophores. 3 However, cuboidal metal-sulfides with a N 2 ligand are still unknown, 4 and even those with nitrogenous ligands relevant to N 2 reduction are unexplored except for a few examples having coordinated hydrazines. 3d,5 Our research interest has focused recently on the exploitation of the rational pathways for preparing the metal-sulfido clusters, particularly the cubane-type clusters containing noble metals. 6 Now we have found that a new cubane-type Mo 2 Ir 2 S 4 cluster with a terminal oxo ligand can be obtained from the reaction of a sulfido-bridged dioxo dimolybdenum complex with a hydrosulfido-bridged diiridium complex. Importantly, this cluster has been shown to undergo the condensation reaction with PhMeNNH 2 at its ModO site to afford a novel cluster with a hydrazido(2-) ligand. Although mononuclear hydrazido(2-) complexes of Mo and W with tertiary phosphine coligands have been studied extensively in relevance to the mechanism of biological and industrial N 2 fixation, 7 cubane-type metal-sulfido clusters containing a hydrazido ligand are yet unknown 8 in spite of their potential to give some insight into the biological N 2 -reducing system.

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)

“…Our recent studies toward this direction have revealed that hydrosulfido-bridged dinuclear complexes such as [Cp*MCl-(µ-SH) 2 MCp*Cl] (M ) Ru, Rh, Ir; Cp* ) η 5 -C 5 Me 5 ) and [Cp 2 Ti(µ-SH) 2 RuCp*Cl] (Cp ) η 5 -C 5 H 5 ) serve as versatile precursors for preparing the homo-and heterobimetallic cubane-type clusters such as [(Cp*M) 4 (µ 3 -S) 4 ] (M ) Ru, 7 Rh, Ir 8 ), [(CpTi) 2 (Cp*Ru) 2 (µ 3 -S) 4 ], 9 and [CpTi(Cp*Ru) 3 -(µ 3 -S) 4 ] 10 through a dehydrochlorination-dimerization process (Scheme 1). In addition, it has also been found that the Ir-Mo cluster [(Cp*Ir) 2 {Mo(O)Cl 2 }{MoCl 2 (DMF)}(µ 3 -S) 4 ] can be obtained from [Cp*IrCl(µ-SH) 2 IrCp*Cl] and [MoO-(DMF) 3 (µ-S) 2 MoO(DMF) 3 ] 2+ through condensation and concomitant dehydration, 11 which is also shown in Scheme 1.…”

A Family of Oxo-Chalcogenide Molybdenum and Tungsten Complexes, (n-Bu4N)2[M2O2(μ-Q)2(1,3-dithiole-2-thione-4,5-dithiolate)2] (M = Mo, W; Q = S, Se): New Synthetic Entries, Structure, and Gas-Phase Behavior

“…The action of NaBH 4 or LiBH 4 to ( n -Bu 4 N) 2 [ 2 ] solutions in THF was checked by ESI-MS, and no reaction was detected. Also, the reaction of this [ 2 ] 2- complex with hydrazines, NH 2 NH 2 or PhMeNNH 2 , did not show the formation of the corresponding condensation product, as observed in related oxo-molybdenum or tungsten complexes. − Like compound ( n -Bu 4 N) 2 [ 2 ], the complexes ( n -Bu 4 N) 2 [ 3 − 6 ] do not react with sodium and lithium borohydride, NH 2 NH 2 , and PhMeNNH 2 . ESI-MS monitoring of the reaction between ( n -Bu 4 N) 2 [ 1 ] and sulfur showed the presence of an intact ( n -Bu 4 N) 2 [ 1 ] together with the formation of small amounts of the [Mo 3 S 7 (dmit) 3 ] 2- starting precursor.…”

Coordination behaviour of (diaryl disulfide)-bridged dinuclear thiairidaindan cores: ligand substitution by isocyanides, CO, hydrazines and hydroxylamine, and related reactions

“…10 In connection with this, our group has previously reported the catalytic N-N bond cleavage of hydrazine on thiolato-bridged diruthenium complexes, 11 as well as the synthesis of Mo 2 Ir 2 S 4 cubane-type sulfido clusters having dialkylhydrazido(2Ϫ) ligands. 12 As an extension of these studies, we have investigated the reactivities of the thiairidacycle complexes 1 toward hydrazines. When 1 was reacted with 1 equivalent of anhydrous hydrazine, the bridging mono(hydrazine) complexes…”