Preparation and physical properties of early-late heterobimetallic compounds featuring Ir–M bonds (M = Ti, Zr, Hf)

Abstract

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.

Complete Series of {FeNO}8, {FeNO}7, and {FeNO}6 Complexes Stabilized by a Tetracarbene Macrocycle

“…Chemicals were purchased from commercial sources and used as received. Complex 1, 19 [ NHC LFe II (MeCN) 2 ](OTf) 2 22 as well as 1,5-bis(dimethyl)-piperidinium tetrafluoroborate, 54 1,5-dimethylpyridinium triflate 53 and thianthrenium tetrafluoroborate 55 were prepared according to literature procedures. Nitric oxide gas was purchased from Linde and passed through a column with Ascarite II and a cooling trap (−78 °C) before being added to the reaction mixture.…”

Radical Rebound Hydroxylation Versus H-Atom Transfer in Non-Heme Iron(III)-Hydroxo Complexes: Reactivity and Structural Differentiation

“…Diphenylhydrazine (Sigma-Aldrich) was recrystallized from a mixture of diethyl ether and hexanes at −35 °C. Fe­(OTf) 2 (MeCN) 2, LuHOTf, and Gomberg’s dimer were prepared according to modified literature procedures. Ligand precursors 6-bromo-2-acetylpyridine and 2-bromo-6-(1,3-dioxylane)­pyridine were synthesized according to literature procedures and identified by their 1 H NMR spectra.…”

A Terminally Bound Niobium Methylidyne

“…1 H NMR (400 MHz, Benzene-d 6 , 300 K): δ 7.30 (m, 3H, Ar-CH), 7.23 (br, 1H, Ar-CH),7.20 -7.10 (overlapped with C 6 D 5 H, 2H, Ar-CH),7.01 (t,3 J HH = 7.5 Hz, 1H, OAr-CH),6.87 (dd,3 J HH = 6.2, 3 J PH = 17.1 Hz, 1H, Ar-CH), 6.82 (overlapped dd,3 J HH = 7.4, 3 J PH = 20.4 Hz, 1H, Ar-CH), 6.02 (br, 1H, NbCH), 5.50 -3.00 (br, 2H, OArCH(CH 3 ) 2 ), 2.37 (m, 1H, PCH(CH 3 ) 2 ), 2.30 (m, 1H, PCH(CH 3 ) 2 ), 2.18 (s, 3H, ArCH 3 ), 2.09 (s, 3H, ArCH 3 ), 2.20 -2.11 (m, 1H, PCH(CH 3 ) 2 ), 1.97 (m, 1H, PCH(CH 3 ) 2 ), 1.75 -0.89 (overlapped m, PCH(CH 3 ) 2 and OArCH(CH 3 ) 2 ). 13 C{ 1 H} NMR (126 MHz, Benzene-d 6 , 300 K) δ.…”

“…ArCH 3 ), 2.20 -1.90 (overlapped m, 3H, PCH(CH 3 ) 2 ), 1.67 (dd, 1 J HH = 7.2 Hz,3 J PH = 17.2 Hz, 3H, PCH(CH 3 ) 2 ), 1.59 (dd, 1 J HH = 6.8 Hz, 3 J PH = 16.0 Hz, 3H, PCH(CH 3 ) 2 ), 1.36 S11 (br, 12H, OArCH(CH 3 ) 2 ), 1.15 -0.84 (overlapped m, 15H, PCH(CH 3 ) 2 ), 1.59 (dd, 1 J HH = 6.8 Hz, 3 J PH = 16.8 Hz, 3H, PCH(CH 3 ) 2 ). 13 C{ 1 H} NMR (126 MHz, Benzene-d 6 , 300 K) δ.…”