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Abstract Reactions of the Ir^Vhydride [^MeBDI^Dipp]IrH₄{BDI=(Dipp)NC(Me)CH(Me)CN(Dipp); Dipp=2,6‐iPr₂C₆H₃} with E[N(SiMe₃)₂]₂(E=Sn, Pb) afforded the unusual dimeric dimetallotetrylenes ([^MeBDI^Dipp]IrH)₂(μ₂‐E)₂in good yields. Moreover, ([^MeBDI^Dipp]IrH)₂(μ₂‐Ge)₂was formed in situ from thermal decomposition of [^MeBDI^Dipp]Ir(H)₂Ge[N(SiMe₃)₂]₂. These reactions are accompanied by liberation of HN(SiMe₃)₂and H₂through the apparent cleavage of an E−N(SiMe₃)₂bond by Ir−H. In a reversal of this process, ([^MeBDI^Dipp]IrH)₂(μ₂‐E)₂reacted with excess H₂to regenerate [^MeBDI^Dipp]IrH₄. Varying the concentrations of reactants led to formation of the trimeric ([^MeBDI^Dipp]IrH₂)₃(μ₂‐E)₃. The further scope of this synthetic route was investigated with group 15 amides, and ([^MeBDI^Dipp]IrH)₂(μ₂‐Bi)₂was prepared by the reaction of [^MeBDI^Dipp]IrH₄with Bi(NMe₂)₃or Bi(OtBu)₃to afford the first example of a “naked” two‐coordinate Bi atom bound exclusively to transition metals. A viable mechanism that accounts for the formation of these products is proposed. Computational investigations of the Ir₂E₂(E=Sn, Pb) compounds characterized them as open‐shell singlets with confined nonbonding lone pairs at the E centers. In contrast, Ir₂Bi₂is characterized as having a closed‐shell singlet ground state. 

Abstract The dialkyl malonate derived 1,3‐diphosphines R₂C(CH₂PPh₂)₂(R=a, Me;b, Et;c,n‐Bu;d,n‐Dec;e, Bn;f,p‐tolCH₂) are combined with (p‐tol₃P)₂PtCl₂ortrans‐(p‐tol₃P)₂Pt((C≡C)₂H)₂to give the chelatescis‐(R₂C(CH₂PPh₂)₂)PtCl₂(2 a–f, 94–69 %) orcis‐(R₂C(CH₂PPh₂)₂)Pt((C≡C)₂H)₂(3 a–f, 97–54 %). Complexes3 a–dare also available from2 a–dand excess 1,3‐butadiyne in the presence of CuI (cat.) and excess HNEt₂(87–65 %). Under similar conditions,2and3react to give the title compounds [(R₂C(CH₂PPh₂)₂)[Pt(C≡C)₂]₄(4 a–f; 89–14 % (64 % avg)), from which ammonium salts such as the co‐product [H₂NEt₂]⁺Cl⁻are challenging to remove. Crystal structures of4 a,bshow skew rhombus as opposed to square Pt₄geometries. The NMR and IR properties of4 a–fare similar to those of mono‐ or diplatinum model compounds. However, cyclic voltammetry gives only irreversible oxidations. As compared to mono‐platinum or Pt(C≡C)₂Pt species, the UV‐visible spectra show much more intense and red‐shifted bands. Time dependent DFT calculations define the transitions and principal orbitals involved. Electrostatic potential surface maps reveal strongly negative Pt₄C₁₆cores that likely facilitate ammonium cation binding. Analogous electronic properties of Pt₃C₁₂and Pt₅C₂₀homologs and selected equilibria are explored computationally.