Syntheses, characterization and properties of silver, copper and palladium complexes from bis(oxazoline)-containing ligands

The reactions of 2,6-di(2-oxazolyl)pyridine (L-1) and 2,6-bis[(S)-4-phenyl-2-oxazolyl]pyridine (L-2) with silver, copper and palladium salts to yield six new complexes: {[Ags(L-1)(5)](BF4)(5)}(n) (1), {[Ag(L-1)](SbF6)}(n) (2), [Cu4I4(L-1)(2)] (3), [Cu6I6(L-1)(2)] (4), [Pd(L'(1))(OAc)] (5), [Pd(L'(2))CI] (6), which were fully characterized by single-crystal and powder X-ray diffraction, IR, elemental and thermogravimetric analyses. 1 and 2 are a pair of Ag-oxazoline helical chain structure complexes. The spiral directions of chains are opposite in I, while identical in 2; the measurement of CD spectra can further confirm their meso and chiral structures. Complexes 3 and 4 show eight-nuclear and twelve-nuclear iodine-cuprous cluster structure. Their structural diversity is induced by different molar ratios of CuI:L-1. Complexes 5 and 6 are discrete mononuclear palladium complexes. In situ oxazolyi-ring-opening reactions take place in the syntheses of them and the L-1 and the L-2 were transformed to their oxazolyl-ring opened derivatives L'(1) and L'(2). Moreover, fluorescence, non-linear optical properties, and ferroelectric properties have been investigated. (C) 2015 Elsevier Inc. All rights reserved.