Palladium(ii) complexes of tetradentate donor–acceptor Schiff base ligands: synthesis and spectral, structural, thermal and NLO properties

Abstract

Structural and NLO behavior of push–pull palladium(ii) complexes of metallocenyl-containing asymmetric Schiff base ligands.

Ferrocene functionalized enantiomerically pure Schiff bases and their Zn(ii) and Pd(ii) complexes: a spectroscopic, crystallographic, electrochemical and computational investigation

“…Moreover, in 6, the carboxylic acid substituent is identified by the n(CQO) vibration seen at 1680 cm À1 . 39 The 1 H NMR spectra of the four compounds 3-6, recorded in DMSO-d 6 at 298 K, displayed the expected resonance patterns consistent with the proposed structures (see Experimental section for complete assignments and Fig. 1, and Fig.…”

“…[23][24][25] Schiff bases, characterized by an imine (4CQN-) or an azomethine (-CHQN-) group, 26,27 form an outstanding class of proligands that play a key role in the development of coordination chemistry due to their facile synthesis, structural flexibility, easily tunable electronic properties, selectivity and sensitivity towards the coordinated metal ion and their ability to form stable complexes under various coordination geometries and oxidation states. 22,[28][29][30] Transition-metal complexes of Schiff base ligands have been widely investigated because of their applications in various branches of science such as in catalysis, [31][32][33] sensing, [34][35][36] as NLO molecular materials, 23,[37][38][39] and in biochemistry, [40][41][42] among others. Ferrocene substituted asymmetric N 2 O 2 -tetradentate Schiff bases are generally obtained upon condensation of salicylaldehyde or its derivatives with a preformed tridentate organometallic precursor bearing a free amino group.…”

“…Ferrocene substituted asymmetric N 2 O 2 -tetradentate Schiff bases are generally obtained upon condensation of salicylaldehyde or its derivatives with a preformed tridentate organometallic precursor bearing a free amino group. 22,39 These latter tridentate proligands featuring O,N,N-donor sets, so-called half-units, 43 result from a monocondensation of ferrocenoyl-ketones of the type Fc-C(O)CH 2 C(O)R (R = CH 3 , 4-C 6 H 4 OH) with either 1,2-diaminoethane or 1,2-phenylenediamine. [44][45][46] Interestingly, introduction of two asymmetric carbon atoms of a chiral diamine, such as 1,2-diphenylethylenediamine or 1,2diaminocyclohexane, has been developed to force the crystallization of Schiff base complexes into a noncentrosymmetric space group, a prerequisite to observe second-harmonic generation.…”

Pentacoordinated isothiocyanate iron(III) complexes supported by asymmetric tetradentate donor and acceptor Schiff base ligands: Spectral, Structural and Hirshfeld Surface Analyses

“…Transition metal complexes of Schiff base ligands have been widely investigated because they can be formed as stable complexes under various coordination geometries and oxidation states [1][2][3][4][5]. They have found a plethora of applications in various branches of science [6], such as, for instance, in catalysis [7,8], molecular magnetism [9,10], as nonlinear optics (NLO) molecular materials [11][12][13], and for their remarkable bioactivity [14][15][16]. Schiff base complexes have also been used as molecular building blocks in the development of multimetalic and new materials [17,18].…”

Nickel(II)-Based Building Blocks with Schiff Base Derivatives: Experimental Insights and DFT Calculations

“…Schiff bases usually coordinate to a metallic ion through the imine nitrogen atom and are able to complex most metals in the periodic table with distinct oxidation states, coordination numbers and geometries [4][5][6][7], thus finding a plethora of applications within numerous scientific areas [8,9]. Their diverse applications, associated with their structural flexibility, made them essential compounds that have extensively been used in homogenous and heterogeneous catalysis [10][11][12][13][14], chemical sensing [15][16][17][18], nonlinear optics (NLO) [19][20][21][22], beside remarkable pharmacological and biological activities [23][24][25][26][27][28], to name a few.…”