Synthesis and reactivity of binuclear complexes having the Rh(μ-pz)(μ-SR)Rh framework (pz = pyrazolate, R = Bu t, Ph)

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The formation and properties of the heterobridged complexes [Rh 2(μ-pz)(μ-SPh)(COD) 2] ( I) (COD = 1,5-cyclo-octadiene, pz = pyrazolate) and [Rh 2(μ-pz)(μ-SPh)(CO) 2(PPh 3) 2] ( II) are reported. The related heterobridged compound [Rh 2(μ-pz)(μ-SBu t)(CO) 2{P(OMe) 3} 2] ( III) undergoes stepwise addition of molecular iodine to yield the complexes [Rh 2(μ-pz)(μ-SBu t)I n ,(CO) 2{P(OMe) 3} 2] [ n = 2 ( IV) 4 ( V)]. The formation of the tetracarbonyl derivative [Rh 2(μ-pz)(μ-SBu t)I 2(CO) 4] ( VI) is also reported. Reaction of the dirhodium(II) complex [Rh 2(μ-pz)(μ-SBu t)I 2(CO) 2{P(OMe) 3} 2] with tin(II) chloride gave the trihalostannyl derivative [Rh 2(μ-pz)(μ-SBu t)(SnCl 2I) 2(CO) 2{P(OMe) 3} 2] ( VII). Complex III reacts with mercury(II) chloride in a 1 : 1 molar ratio to give the rhodium(III)-rhodium(I) complex [Rh 2(μ-pz)(μ-SBu t)(μ-HgCl)Cl(CO) 2{P(OMe) 3} 2 ( VIII), resulting from the oxidative addition of HgCl 2 to one metal centre. Interaction of the mixed oxidation state complex VIII with molecular iodine affords the dirhodium(III) compound [Rh 2(μ-pz)(μ-SBu t)(HgCl)(Cl)I 2(CO) 2{P(OMe) 3} 2] ( IX).