Cationic allylnickel(II) complexes bearing labile N,S-donor ligands: Synthesis, characterization and crystal structure

The thienylimine ligands2,6-dimethyl-N-(thiophen-2-ylmethylene)aniline (L1), 2,6-diisoprop yl-N-(thiophen-2-ylmethylene)aniline (12) and 4-methyl-N-(thiophen-2-ylmethylene)aniline (13) were obtained by condensation reactions of 2-formyl thiophene with the corresponding anilines. The reactions of bis(allyl)di-p-bromodinickel with one or two equivalents of the ligands L1, L2 and 1.3, in the presence of the thallium hexafluorophosphate TIPF6, in dichloromethane, always afforded the corresponding complexes [Ni(eta(3)-allyl)L-2][PF6] (L = L1 (1), L2 (2) or L3(3), containing two monodentate thienylimine ligands coordinated to Ni exclusively through the imine nitrogen atoms when the recrystallization was carried out in a non-coordinating solvent system such as dichloromethane/n-hexane. When complex 2 was recrystallized in dichloromethane/diethyl ether, one of the labile thienylimine ligands was substituted by a weekly coordinating diethyl ether solvent molecule giving rise to complex [Ni(eta(3)-allyl)(L2)(O(C2H6)(2))][PF6] (2'). All new complexes 1 [Ni(eta(3)-allyl)(2,6-dimethyl-N-(thiophen-2yl-methylene)aniline)(2) [PF6], 2 [Ni(eta(3)-allyl)(2,6-diisopropyl-N-(thiophen-2-ylmethylene)aniline)21[PF6], 3 [Ni(eta(3)-allyl)(4-methyl-N-(thiophen-2-ylmethylene)aniline)2j[PF6], and 2' [Ni(eta(3)-allyl)(2,6-diisopropylN-(thiophen-2-ylmethylene)aniline)(O(C2F15)(2))][PF6] have been characterized by H-1, C-13,F-19,P-31 NMR and FT-IR spectroscopies and by elemental analysis. The molecular structures in the solid state of complexes 2 and 2' were determined by X-ray diffraction. (C) 2018 Elsevier B.V. All rights reserved.