Preparation and physical properties of early-late heterobimetallic compounds featuring Ir-M bonds (M = Ti, Zr, Hf).
Treatment of Cp*Ir N(t)Bu (1) with the appropriate metallocene equivalent is an effective route for the preparation of the heterobimetallic complexes Cp*Ir(μ-N(t)Bu)MCp(2) (2-M, M = Ti, Zr, Hf). The electronic structures of the isostructural series of compounds, 2-M, are described with reference to single-crystal X-ray, Raman, UV-vis, and cyclic voltammetry data. Density functional theory (DFT) calculations were used to aid in the interpretation of this experimental work. Treatment of the zirconium or hafnium congeners with 2,6-lutidinium triflate leads to protonation of the Ir-M bond, to afford Cp*Ir(μ-N(t)Bu)(μ-H)MCp(2)OTf (3-M, M = Zr, Hf). Compound 3-Zr was characterized by single-crystal X-ray diffraction and independently prepared by the reaction of 1 and Cp(2)Zr(H)Cl in the presence of Me(3)SiOTf. In reactions analogous to those for 2-Zr, 2-Hf reacts with S(8) and aryl azides to insert an S-atom or aryl azide fragment into the metal-metal bond, yielding Cp*Ir(μ-N(t)Bu)(μ-S)HfCp(2) (6-Hf) and Cp*Ir(μ-N(t)Bu)(N(3)Ph)HfCp(2) (4-Hf), respectively. Heating 4-Hf results in N(2) extrusion to form Cp*Ir(μ-N(t)Bu)(NPh)HfCp(2) (5-Hf). The kinetics of the latter reaction were studied to obtain activation parameters and a Hammett trend; these data are compared to those for the analogous reaction involving Ir-Zr heterobimetallics.
Department of Chemistry, University of California, Berkeley, CA 94720, USA.
John J
JJ
Curley
Robert G
RG
Bergman
T Don
TD
Tilley
D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006195:Hafnium / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D008968:Molecular Conformation; D011789:Quantum Theory; D014025:Titanium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
D056831:Coordination Complexes; D007495:Iridium; D015040:Zirconium; D014025:Titanium; D006195:Hafnium