Stepwise construction of a 4-hydroxyphenyl functionalized O,N,N-tridentate ferrocene-containing enaminone: Spectral, analytical and structural studies

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

A combination of X-ray diffraction, IR, UV-vis and NMR spectroscopy together with computational methods was used to characterize and study the properties of the title compounds.

Novel Ferrocene-Appended β-Ketoimines and Related BF2 Derivatives with Significant Aggregation-Induced Emission and Second-Order Nonlinear Optical Properties

A series of new β-ketoimines containing a ferrocene moiety and their BF₂ complexes have been synthesized and structurally characterized. The solvatochromism of the β-ketoimines was studied, putting in evidence a redshift with increasing solvent polarity. This positive solvatochromism can be attributed to a more polarized excited state compared with the ground state, due to intramolecular charge transfer (ICT) transitions. The β-ketoimines exhibited weak emission, attributable to the excited-state intramolecular proton transfer (ESIPT) phenomenon. This ESIPT effect is suppressed upon restriction of the keto-enamine tautomerism, induced upon addition of BF₃ ⋅OEt₂ , which afforded the related BF₂ complexes, characterized by an enhancement of the fluorescence through the ICT effect. Both the β-ketoimines and BF₂ complexes exhibited significant aggregation-induced emission behavior in mixtures of CH₃ CN/H₂ O, due to restriction of intramolecular rotation in the aggregated state. The frontier molecular orbital levels, ground- and excited-state dipole moments (μ_g and μ_e ), and the origin of electronic absorption spectra were studied by time-dependent DFT calculations. The second-order nonlinear optical (NLO) properties were determined by the electric-field-induced second-harmonic generation technique. The μβ₁₉₀₇ values of the β-ketoimines increased upon the formation of the related BF₂ complexes, mainly due to an enhancement of the ground-state dipole moment. The results presented here reveal that some of these novel compounds are excellent multifunctional candidates for NLO and luminescence applications.

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

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

A β-ketoiminato palladium(II) complex for palladium deposition

The ¦-ketoiminato complex [Pd(OAc)L] (3) can be synthesized by the reaction of bis(benzoylacetone)diethylenetriamine (1, = LH) with [Pd(OAc)2] (2). The structure of 3 in the solid state has been determined by single X-ray diffraction analysis. Complex 3 crystallizes as a dimer (3 2), which is formed by hydrogen bonds between NH and OOAc functionalities of two adjacent ligands. Each of the Pd atoms is complexed by one ON2 donor unit of the polydentate ligand L − and an acetate group. Pd–Pd interactions and hydrogen bond formation between a NH and the C=O acetate moiety lead to a [4 + 2] coordination at Pd. The non-coordinated part of L exists in its ¦-keto-enamine form. The thermal decomposition behavior of 3 2 was studied by TG (thermogravimetry) and TG-MS showing that 3 2 decomposes between 200 and 500°C independent of the applied atmosphere. Under oxygen PdO is produced, while under argon Pd is formed as confirmed by PXRD measurements. Complex 3 2 was applied as a spin-coating precursor (conc. 0.1 mol L−1, volume 1.5 mL, 3000 rpm, deposition time 6 min, heating rate 50 K min−1, holding time 60 min (Ar) and 120 min (air) at T = 800°C). The as-obtained samples are characterized by granulated particles of Pd/PdO on the substrate surface. EDX (energy-dispersive X-ray spectroscopy) and XPS (X-ray photoelectron spectroscopy) measurements confirmed the formation of Pd (Ar) or PdO (O2) with up to 12 mol% C impurity.

Synthesis, structures, electrochemical and quantum chemical investigations of Ni(ii) and Cu(ii) complexes with a tetradentate Schiff base derived from 1-(2-thienyl)-1,3-butanedione

Electrochemical oxidation of four-coordinate square planar Schiff-base Ni(ii) and Cu(ii) complexes leads to the formation of oligomers at the electrode.

Efficient preparation of multimetallic ONO-based Schiff base complexes of nickel(ii) and copper(ii)

Spectroscopy, structures, electrochemical behavior and magnetic properties of a series of readily prepared [(R-ONO)M(μ-4,4′-bipy)M(R-ONO)] complexes (R = anisyl or ferrocenyl; M = Ni, Cu) have been explored.

Four-coordinate nickel(ii) and copper(ii) complex based ONO tridentate Schiff base ligands: synthesis, molecular structure, electrochemical, linear and nonlinear properties, and computational study

The properties of NLO active ternary Ni(ii)- and Cu(ii)-unsymmetrical Schiff base complexes were explored in concert with DFT calculations.