Insights into electronic and structural properties of novel Pd(II) salen-type complexes

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Joana Fonseca (Author) Other; Javier Martinez (Author) Other; Luis Cunha Silva (Author) Other; Alexandre L Magalhaes (Author) FCUP; Teresa Duarte, MT (Author) Other; Cristina Freire (Author) FCUP

Journal

Title: Inorganica Chimica Acta

Vol. 363

Pages: 4096-4107

ISSN: 0020-1693

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 19 Citations

Scopus - 23 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-0WR

DOI: 10.1016/j.ica.2010.08.023

Abstract (EN): Novel palladium(II) complexes with salen-type ligands based on 3-methylsalicyladehyde and a set of aliphatic diamines (C1 to C4) have been synthesised and characterized by spectroscopic techniques (UV-Vis and FTIR), Density Functional Theory (DFT) calculations and single-crystal X-ray diffraction for C1 and C4. X-ray diffraction analysis of these complexes was focused on coordination sphere and supramolecular arrangements. In the two compounds, the molecules form dimers, being the most relevant intermolecular interactions the hydrogen bonds of the type C-H center dot center dot center dot O, C-H center dot center dot center dot pi and pi center dot center dot center dot pi stacking interactions between the six-membered metallocycles. Electronic spectra of all Pd(II) complexes are dominated by charge transfer and intraligand bands at lambda < 400 nm. DFT calculations showed that the HOMO is ligand-dominated, with the metal contribution being similar to 18% for all complexes. This suggests that the structural/electronic differences between the ligands do not influence significantly the participation of metal orbitals in HOMO. All the complexes exhibit dipole moments with the same direction, from the aldehyde moiety towards the imine bridge with C2 and C3 showing quite similar values, mu(C2) = 5.49 and mu(C3) = 5.54 D, whereas complexes C1 and C4 show slightly higher values: mu(C1) = 5.79 and mu(C4) = 6.17 D. The magnitude of bond lengths and angles predicted by DFT calculations are comparable to those determined by X-ray crystallography. The experimental vibrational frequencies of the Pd(II) complexes were correlated with the values estimated by DFT calculations. The good agreement between the experimental and theoretical vibrational data allowed the assignment of relevant IR bands to molecular vibration modes.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12