Metallacyclic complexes. Part 3. Reactions of metallathietane 3,3-dioxide complexes of platinum(II) and palladium(II) with alkyl isocyanides; the single crystal X-ray structure of [Pt{CH(COPh)S(O)2C(COPh)CNHBun}(CNBut)-(PPh3)]·CHCl3

Abstract

The reactions of the metallathietane 3,3-dioxide complexes [[graphic omitted]HR}L₂] of platinum(II) and palladium(II) with alkyl isocyanides are dependent on both the mole ratio of isocyanide to metal complex, and on the ring substituent R. Treatment of phenyl-substituted metallathietane 3,3-dioxide complexes with excess of isocyanide results in ligand substitution to afford monosubstituted complexes of the type [[graphic omitted]HPh}(CNBu^t) L]. Similarly, treatment of the benzoyl-substituted complexes [[graphic omitted]H(COPh)}L₂] with 1 equivalent of isocyanide also affords monosubstituted complexes [[graphic omitted]H(COPh)}(CNR)L](M = Pt, L = PPh₃, R = Buⁿ or Bu^t; M = Pd, L = PEt₃, R = Bu^t). On treatment of platinathietane 3,3-dioxide complexes containing benzoyl or methoxycarbonyl ring substituents with excess of isocyanide, ring insertion and hydrogen migration occurs to afford the zwitterionic five-membered ring products [[graphic omitted]NHR′}(CNR′)L] (L = PPh₃ or PMe₂Ph; R = COPh or CO₂Me; R′ = Bu^t or Buⁿ). Treatment of [[graphic omitted]H(COPh)}(PPh₃)(CNBu^t)] with 1 equivalent of BuⁿNC, or [[graphic omitted]H(COPh)}(CNBuⁿ)(PPh₃)] with 1 equivalent of Bu^tNC, affords, in both cases, the n-butyl isocyanide-inserted product [[graphic omitted]NHBuⁿ}(CNBu^t)(PPh₃)] (13), confirmed by a single-crystal X-ray diffraction study carried out on (13)·CHCl₃. Crystals are monoclinic, space group P2₁/n, Z = 4, in a unit cell with lattice parameters a = 28.337(2), b = 9.625(2), c = 16.507(1) Å, and β = 101.71 (5)°. The structure was refined to R 0.0661 (R′ 0.0530) for 4 019 reflections having 7 < 2θ < 54° collected at room temperature.