Six-membered cyclopalladated N,N ',N'-triarylguanidines, [{kappa(2)(C,N) Pd}(2)(mu-OAc)(mu-Pz)], [kappa(2)(C,N)Pd(mu-Pz)](2) and a novel [AgNO3 subset of{{kappa(2)(C,N) Pd}(2)(mu-NO3)(mu-Pz)}]: Syntheses, reactivity studies, structural aspects, and solution behavior

摘要

Six-membered cyclopalladated N,N',N ''-triarylguanidines, [{kappa(2)(C,N)Pd}(2)(mu-OAc)(mu-Pz)] (1-4), [kappa(2)(C,N)Pd (mu-Pz)](2) (5-11), and [AgNO3 subset of{{kappa(2)(C,N)Pd}(2)(mu-NO3)(mu-Pz)}] (12) have been isolated in good yields and characterized by micro-analytical, IR, and NMR (H-1, F-19, and C-13) spectroscopic techniques. Molecular structures of ten Complexes were determined by SCXRD, which revealed cisoid in-out (1-4), transoid out-out (5, 6, 8 and 11), transoid in-in (7) and cisoid (12) conformations. VT H-1 NMR spectra of 1 revealed the presence of cisoid in-in as the major species and an equilibrating mixture of cisoid in-out and cisoid out-out as the minor species in solution and this was verified by DFT calculations. In solution, 4-indicated the presence of a mixture of cisoid, and transoid conformers, [kappa(3)(C,N,O)Pd(OAc)], and [kappa(2)(C,N)Pd(kappa O-2,O'-OAc)] (VT H-1 NMR), and a mixture of three conformers of each cisoid and transoid, and [kappa(3)(C,N,O)Pd (Pz)] (VT F-19 NMR). Palladacycles 5 and 10 revealed the presence of a mixture of four and five species, respectively in solution and these species are a mixture of cisoid and transoid conformers as revealed by VT H-1 NMR. Factors that dictate the solid state conformations and number and nature of solution species of the new complexes are outlined. (C) 2016 Elsevier Ltd. All rights reserved.