Preparation and X-ray crystal and molecular structure of di-µ-diphenylphosphido-bis(triphenylphosphinecarbonyliridium)

Abstract

Sum~naryIn the title compound, obtained from two nitrogen for 3 h, a brown diamagnetic compound (C) which is insoluble in all common solvents separates. The i.r. spectrum of (C) in Nujol shows no Ir-H band and shows CO stretching bands a t 1920s and 1870sh cm-l. Since the lack of solubility prevents a molecular weight WHEN solutions of Ir(CO)H(PPh,), (A),1 or IrH,(PPh,), determination and makes it impossible to record n.m.r.(B) ,2 in dimethylformamide (DMF) are refluxed under spectra, a crystallographic analysis was undertaken to different iridium hydrides in boiling DMF, the two metal atoms are connected by a formal double bond 2-551(1) A long, and are bridged by two diphenylphosphido-ligands.

Chemistry of group 9 dimetallaborane analogues of octaborane(12)

“…The bridging hydride atoms and the hydrogens of [B(OH) 4 ] − unit could not be located in the X-ray study whereas their presence are inferred by 1 H NMR data. The Ir-Ir bond length (2.459(2) Å) in 7 is significantly shorter than those previously reported for the formal Ir-Ir double bonds found in the carbonyl-bridged analogues [Cp* 2 Ir 2 (μ-CO) 2 ] (2.554(1) Å), 23 [Ir 2 (μ-PPh 2 ) 2 (CO) 2 (PPh 3 ) 2 ] (2.551(1) Å) 24 and [Cp* 2 Ir 2 (μ-H) 2 -(μ 2 -η 1 ,η 1 -N 2 C 3 H 3 )] (2.663(1) Å). 25…”

Reactions of Laser-Ablated Iridium Atoms with O2. Infrared Spectra and DFT Calculations for Iridium Dioxide and Peroxo Iridium(VI) Dioxide in Solid Argon

“…The calculated metal-metal bond length is comparable to the value of 2.55 Å determined for the diphenylphosphido-bridged dimer (Ph 3 P)(CO)Ir(µ-PPh 2 ) 2 Ir(CO)-(PPh 3 ) in which the metal-metal bond was interpreted as having a formal bond order of 2. 33,34 The NBO analysis for Ir 2 O shows the molecule to be composed of two single Ir-O bonds and an Ir-Ir double bond, supporting the earlier bonding analysis for the bridged dimer complex. 33,34 The oxygen orbitals in the Ir-O bonds are sp 2 hybridized with the O(2p) contribution greater than 90%, and these bonds may be designated as σ bonds that are polarized toward oxygen.…”

Transfer of Ketyls from Alkali Metals to Transition Metals. Formation and Diverse Reactivities of d-Block Transition-Metal Ketyls

“…An X-ray analysis has established that 8 is a dihydride-bridged binuclear iridium(II) complex which possesses a crystallographic inversion center at the center of the molecule (Figure , Table ). The length of the Ir(1)−Ir(1‘) bond in 8 (2.4157(6) Å) is much shorter than those previously reported for the formal Ir−Ir triple bonds found in the cationic complexes [(C 5 Me 5 ) 2 Ir 2 (μ-H) 3 ] + [BF 4 ] - (2.458(6) Å), [Ir 2 (μ-H) 3 H 2 (PPh 3 ) 4 ] + [PF 6 ] - (2.518 Å), and [Ir 2 H 5 (dppp) 2 ] + [BF 4 ] - (2.514(1) Å) (dppp = 1,3-bis(diphenylphosphino)propane) and those for the formal Ir−Ir double bonds found in [(C 5 Me 5 )Ir(μ-CO)] 2 (2.554(1) Å) and [Ir(μ-PPh 2 )(CO)(PPh 3 )] 2 (2.551(1) Å) . To the best of our knowledge, the Ir(1)−Ir(1‘) bond distance in 8 is the shortest ever reported for a bonding interaction between iridium atoms.…”

“…The length of the Ir(1)-Ir(1′) bond in 8 (2.4157(6) Å) is much shorter than those previously reported for the formal Ir-Ir triple bonds found in the cationic complexes [(C 5 Me 5 ) 2 Ir 2 (µ-H) 3 ] + [BF 4 ] -(2.458(6) Å), 25 [Ir 2 (µ-H) 3 H 2 -(PPh 3 ) 4 ] + [PF 6 ] -(2.518 Å), 26 and [Ir 2 H 5 (dppp) 2 ] + [BF 4 ] -(2.514(1) Å) (dppp ) 1,3-bis(diphenylphosphino)propane) 27 and those for the formal Ir-Ir double bonds found in [(C 5 Me 5 )Ir(µ-CO)] 2 (2.554(1) Å) 28 and [Ir(µ-PPh 2 )(CO)(PPh 3 )] 2 (2.551(1) Å). 29 To the best of our knowledge, the Ir(1)-Ir(1′) bond distance in 8 is the shortest ever reported for a bonding interaction between iridium atoms. Although this unusually short Ir-Ir bond distance and the 18-electron rule may suggest that 8 should possess an Ir-Ir triple bond, an examination of the molecular orbitals has shown that only a single metal-metal bond may be formed between the two Ir atoms, which is similar to the situation of the isoelectronic tetrahydride-bridged Ru complex (C 5 Me 5 )Ru(µ-H) 4 Ru(C 5 Me 5 ).…”