Trichloropalladate(II) Complexes with Pyridine Ligands – Molecular Structure and Conformational Analysis of [K(18C6)][PdCl₃(py)]

Abstract

K(18C6)] 2 [Pd 2 Cl 6 ] (1) (18C6 ϭ 18-crown-6) was found to react with pyridines in a strictly stoichiometric ratio 1 : 2 in methylene chloride or nitromethane to yield trichloropalladate(II) complexes [K(18C6)][PdCl 3 (py*)] (py* ϭ py, 2a; 4-Bnpy, 2b; 4-tBupy, 2c; Bn ϭ benzyl; tBu ϭ tert-butyl). The reaction of 1 with pyrimidine (pyrm) in a 1 : 1 ratio led to the formation of the pyrimidine-bridged bis(trichloropalladate) complex [K(18C6)] 2 [(PdCl 3 ) 2 -(μ-pyrm)] (3). The identities of the complexes were confirmed by means of NMR spectroscopy ( 1 H, 13 C) and microanalysis. The Xray structure analysis of 2a reveals square-planar coordination of the Pd atom in the [PdCl 3 (py)] Ϫ anion. The pyridine plane forms with the complex plane an angle of 55.8(2)°. In the [K(18C6)] ϩ cation the K ϩ lies outside the mean plane of the crown ether (defined by the 6 O atoms) by 0.816(1) Å . There are tight K···Cl contacts between the cation and the anion (K···Cl1 3.340(2) Å , K···Cl2

Isolation of Stable Organodysprosium(II) Complexes by Chemical Reduction of Dysprosium(III) Precursors

“…Potassium coordination similar to that in 7 had previously been found in palladium and platinum chemistry, e.g. in [(η 2 -cis-pent-2-ene)Pt(μ-Cl) 2 K([18]crown-6)],20a and also in a uranyl complex, [UO 2 (μ-Br) 4 K 2 ([18]crown-6) 2 ] …”

1H, 13C and 15N nuclear magnetic resonance coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with phenylpyridines

“…[13] The deshielding of H (6) [5,6,8 -10] and in the related Ni(II) bromide complex [Ni(2ppy)(2ppy * )Br] − H(6) coord = 0.79 ppm (in benzene-d 6 ). [41] The same phenomenon is predominant for the analogous H(6) atom in Au(III), Pd(II) and Pt(II) chloride complexes with many other 2-aryl pyridine derivatives, although the magnitudes of the H (6) coord parameters are usually smaller than in case of 2ppy (Table 2S, (6) coord = 0.08 ppm, [42] [Au(2-benzoyl-py)Cl 3 ]− H(6) coord = 0.01 ppm, [43] [Au(2-phenoxy-py)Cl 3 ] − H(6) coord = −0.06 ppm and [Au(2-phenylsulfanyl-py)Cl 3 ] − H(6) coord = −0.01 ppm, [44] trans-[Pd(2-benzyl-py) 2 Cl 2 ] − H(6) coord = 0.19 ppm, [45] trans-[Pd(2-(1-phenylethyl)-py) 2 Cl 2 ] − H(6) coord = 0.52 ppm, [46] trans-[Pd(2-(2-naphthyl)-py) 2 Cl 2 ] − H(6) coord = 0.20 ppm, [47] [Pd(2-(8-quinolyl)-py)(P(CH 2 CH 3 ) 3 (2) coord = 0.15 ppm, [37] although not for trans-[Pd(4-phenylpyrimidine) 2 Cl 2 ] (4-phenylpyrimidine being an analogue of 2ppy), where H(2) coord = 0.00 ppm. [49] The above-determined H (6) coord parameters for 2-benzoyl-py, 2-phenoxy-py and 2-phenylsulfanyl-py coordination compounds (relatively small or even negative) are more uncertain as we have compared the complexes in DMSO-d 6 to the free ligands in CDCl 3 .…”

Polymeric Alkylidene-Bridged Platinum Complex [{Pt2(μ-Cl)2{μ-C(OBu)Me}2}n]: Synthesis, Reactivity, and Quantum Chemical Calculations

“…All structures revealed a tilting of the pyridine rings relative to the complex plane (interplanar angle: γ = 62.4(2)−78.8(2)°). This may be the result of steric and electronic interactions (π-type back-donation) . The Pt−N (2.127(4)−2.146(4) Å) and Pt−Cl (2.363(1)−2.368(1) Å) bond distances are longer than those in other platinum(II) complexes having pyridine ligands (median: 2.031 Å, lower/upper quartile: 2.010/2.081 Å, n = 2125, n = number of observations) and chloro ligands (median: 2.314 Å, lower/upper quartile: 2.298/2.355 Å, n = 3734), showing a large trans influence of the alkylidene ligands.…”