Crystal structure of di-μ-chlorido-bis[1-(2-(4-nitrophenyl)amidoethyl)-3-(2,4,6-trimethylphenyl)imidazol-2-ylidene-κC]di(dichlorido)dipalladium(II)) (Pd–Pd) dichloro methane solvate, C43H46Cl6N8O6Pd2
Zeitschrift für Kristallographie - New Crystal Structures
C 43 H 46 Cl 6 N 8 O 6 Pd 2 ,triclinic, P1 (no. 2), a =12.4700(4) Å, b =12.4810(3) Å, c =18.0322(5) Å, a =71.609(1)°, b =76.951(1)°, g =71.537(1)°, V =2501.3 Å 3 , Z =2, R gt (F) =0.0332, wR ref (F 2 ) =0.0867, T =100 K. Source of material To ad ichloromethane solution of [1-(2-(4-nitrophenyl)amidoethyl)-3-(2,4,6-trimethylphenyl)imidazol-2-ylidene]chloridosilver(I) ( 78 mg, 0.15 mmol) was added 1e quivalent of dichloridobis(acetonitrile)palladium(II) (35 mg). The resulting orange suspension
... orange suspension wasfiltered over apad of celite, after which the solvent was allowed to evaporate slowly, yielding yellow crystals (94% yield). Experimental details The structure contains solvent accessible voids (153 Å 3 /unit cell), filled with disordered solvent molecules. Their contribution to thestructure factors(43 electrons/unit cell)was securedbyback-Fourier transformation with the SQUEEZE routine of the PLATON software  . Discussion In the course of our research in N-heterocyclic carbene (NHC) chemistry, we developed anew ligand scaffold, bearing an amide-moiety, for use in rhodium-mediated iodomethane oxidative addition .Aside from rhodium(NHC)complexes, we were interested in the coordination chemistry of these ligands with palladium . It was shown thatakinetically stable trans-isomer was obtained when two equivalents of NHC were coordinated to palladium  .When only one equivalent is used, the dinuclear species is formed preferentially over thee xpectedm ononuclear species in which the ligand coordinates bidentate    . However, theamide does play arole, in contrast to earlier reports  . It stabilizesthe solidstate structure by engaging in intramolecular hydrogen bonding with the terminal chlorido ligands of the core (H···Cl: 2.63(4) and 2.75(4) Å). Further hydrogen bond stabilization occurs intermolecularly between the oxygen atomso ft he -NO 2 group and the hydrogen atomso nt he NHC backbones. These hydrogen bonds create athree-dimensional network. The coordination sphere around the palladium centers is square planar, slightly distorted by the dinuclear character of the complex. All other values such as the NHC-Pd bond lengths and the Pd-Pd distance are within literature values  .