Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.



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

Author affiliations

Abstract

This report explores the synthesis and spectral, structural, thermal, electrochemical, linear and nonlinear (NLO) properties of unsymmetrically-substituted N2O2 tetradentate Schiff base proligand and related bi and trimetallic PdII complexes. The diprotic proligand Fc-C([double bond, length as m-dash]O)CH[double bond, length as m-dash]C(4-C6H4OH)NH-CH2CH2N[double bond, length as m-dash]CH-(2-OH,4-CO2H-C6H3) (2, Fc = ferrocenyl = (η5-C5H5)Fe(η5-C5H4))), is synthetized by condensation of the 4-hydroxyphenyl-appended ferrocenylenaminone 1 with 4-formyl-3-hydroxybenzoic acid. The related Pd(II) complexes, neutral bimetallic 3 and ionic trimetallic 4, were both prepared via a three-component one-pot template reaction involving the half unit 1, palladium acetate, the CO2H-functionalized salicylaldehyde and the organometallic salicylaldehyde [Cp*Ru(η6-2-OH-C6H4CHO)]PF6, respectively (Cp* = η5-C5Me5). Compounds 2–4 were isolated as colored air and thermally stable solids in 74–86% yields. They were thoroughly characterized using various physicochemical tools, such as CHN analyses, IR, UV-vis, 1H and 13C NMR spectroscopy, TGA and cyclic voltammetry. The molecular structures of 3 and 4 were authenticated by single-crystal X-ray diffraction methods. In both 3 and 4, the four-coordinate palladium atom adopts a square planar geometry with two nitrogen and two oxygen atoms as donors occupying cis positions. Additionally in 4, the ferrocenyl and Cp*Ru+ moieties exhibit an anti-conformation with respect to the [Pd(N2O2] Schiff base platform. The electrochemical behavior of the two Pd(II) complexes was investigated by cyclic voltammetry, showing in both cases a reversible redox process ascribed to the Fe(II)/Fe(III) couple of the dangling donor ferrocene. Compared to that for 3, the oxidation wave for 4 is anodically shifted by 30 mV, evidencing a greater electron accepting ability of Cp*Ru+ vs. –CO2H. The second-order NLO responses of the push–pull derivatives 2–4 have been determined by harmonic light scattering measurements in N,N-dimethylformamide solutions at 1.91 μm incident wavelength, and rather good quadratic hyperpolarisability β values ranging from 120–160 × 10−30 esu were determined.

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

Back to tab navigation

Supplementary files

Article information


Submitted
20 Apr 2020
Accepted
13 May 2020
First published
13 May 2020

New J. Chem., 2020, Advance Article
Article type
Paper

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

S. Celedón, T. Roisnel, V. Artigas, M. Fuentealba, D. Carrillo, I. Ledoux-Rak, J. Hamon and C. Manzur, New J. Chem., 2020, Advance Article , DOI: 10.1039/D0NJ01982H

Social activity

Search articles by author

Spotlight

Advertisements