154795-69-4Relevant academic research and scientific papers
Solution, Solid-State, and Computational Analysis of Agostic Interactions in a Coherent Set of Low-Coordinate Rhodium(III) and Iridium(III) Complexes
Knighton, Richard C.,Emerson-King, Jack,Rourke, Jonathan P.,Ohlin, C. André,Chaplin, Adrian B.
, p. 4927 - 4938 (2018)
A homologous family of low-coordinate complexes of the formulation trans-[M(2,2′-biphenyl)(PR3)2][BArF4] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT 1H and 31P NMR spectroscopy) and solid-state (single crystal X-ray diffraction) data, and analysis in silico (DFT-based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the IrIII compared to RhIII complexes and, with respect to the phosphine ligands, in the order PiBu3>PCy3>PiPr3>PPh3. In addition to these structure–property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2-difluorobenzene vs. CH2Cl2) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M?H?C distances.
Geometrically distorted and redox-active organometallic iridium complexes containing biphenyl-2,2′-diyl
Lu, Zheng,Jun, Chul-Ho,De Gala, Susan R.,Sigalas, Michael P.,Eisenstein, Odile,Crabtree, Robert H.
, p. 1168 - 1175 (2008/10/09)
C-C bond cleavage of biphenylene by an Ir(I) complex via an oxidation addition generates the biph (=biphenyl-2,2′-diyl) ligand. The resulting compound is treated with PPh3 to give [Ir(PPh3)2(biph)Cl], having a 16 e five-coordinate structure lying between Y and T geometries, being closer to a Y, which is rationalized on theoretical grounds. The complex [Ir(PMe3)3-(biph)Cl] can be oxidized quasi-reversibly to an Ir(IV) species. Oxidation with NOBF4 gives the unusual Ir(IV) boryl compound [Ir(PMe3)3(biphBF)Cl]+, which has been isolated and structurally characterized. Extended Hückel (EHT) calculations suggest that the easy oxidation of the {Ir(biph)} system is associated with the presence of a high-lying Ir dyz orbital. The {Ir(biph)} fragment is remarkably stable; only Br2 is able to cleave the Ir-C bonds.
