Kuyuldar Seher, Burda Clemens, Connick William B
Department of Chemistry, University of Cincinnati 2600 Clifton Ave. Cincinnati OH 44221 USA.
Department of Chemistry, Case Western Reserve University 10900 Euclid Ave. Cleveland OH 44106 USA
RSC Adv. 2019 Aug 15;9(44):25703-25711. doi: 10.1039/c9ra05423e. eCollection 2019 Aug 13.
Palladium(ii) complexes with an NNN type pincer ligand (pipNNN = 2,6-bis(piperdyl-methyl)pyridine) are synthesized and characterized. Electronic and H NMR spectra point to decreasing filled/filled repulsions between the dπ(Pd) orbitals and the halide lone pair orbitals along the Cl < Br < I series. For all complexes, the most downfield α-piperidyl resonance of the pipNNN ligand is sensitive to changes in the coordinated halide while the -pyridyl and benzylic resonances are sensitive to changes in the counter anion. This sensitivity is utilized to study halide association and exchange at the fourth coordination site. Conductivity and H NMR spectroscopy confirm the interaction between the exogenous anion (Cl, Br, BF ) and Pd(pipNNN)X (X = Cl, Br).
合成并表征了具有NNN型钳形配体（pipNNN = 2,6-双（哌啶基甲基）吡啶）的钯（II）配合物。电子光谱和1H NMR光谱表明，沿着Cl < Br < I系列，dπ（Pd）轨道与卤化物孤对轨道之间的满/满排斥作用逐渐减弱。对于所有配合物，pipNNN配体中最向低场移动的α-哌啶基共振对配位卤化物的变化敏感，而吡啶基和苄基共振对抗衡阴离子的变化敏感。利用这种敏感性来研究第四配位位点处的卤化物缔合和交换。电导率和1H NMR光谱证实了外源阴离子（Cl、Br、BF）与Pd（pipNNN）X（X = Cl、Br）之间的相互作用。
