Ruthenium(II) bipyridine complexes bearing quinoline-azoimine (NN'N″) tridentate ligands: synthesis, spectral characterization, electrochemical properties and single-crystal X-ray structure analysis

Mousa Al-Noaimi; Obadah S Abdel-Rahman; Ismail I Fasfous; Mohammad El-khateeb; Firas F Awwadi; Ismail Warad

doi:10.1016/j.saa.2014.01.075

Ruthenium(II) bipyridine complexes bearing quinoline-azoimine (NN'N″) tridentate ligands: synthesis, spectral characterization, electrochemical properties and single-crystal X-ray structure analysis

Spectrochim Acta A Mol Biomol Spectrosc. 2014 May 5:125:375-83. doi: 10.1016/j.saa.2014.01.075. Epub 2014 Feb 5.

Authors

Mousa Al-Noaimi¹, Obadah S Abdel-Rahman², Ismail I Fasfous³, Mohammad El-khateeb⁴, Firas F Awwadi⁵, Ismail Warad⁶

Affiliations

¹ Department of Chemistry, Hashemite University, P.O. Box 150459, Zarqa 13115, Jordan. Electronic address: manoaimi@hu.edu.jo.
² Fachbereich Chemie der Universität Konstanz, Universitätstraße 10, D-78457 Konstanz, Germany.
³ Department of Chemistry, Hashemite University, P.O. Box 150459, Zarqa 13115, Jordan.
⁴ Chemistry Department, Faculty of Science and Arts, Jordan University of Science and Technology, Irbid 22110, Jordan.
⁵ Department of Chemistry, The University of Jordan, Amman 11942, Jordan.
⁶ Department of Chemistry, AN-Najah National University, Nablus, Occupied Palestinian Territory.

PMID: 24566116
DOI: 10.1016/j.saa.2014.01.075

Abstract

Four octahedral ruthenium(II) azoimine-quinoline complexes having the general molecular formula [Ru(II)(L-Y)(bpy)Cl](PF6) {L-Y=YC6H4N=NC(COCH3)=NC9H6N, Y=H (1), CH3 (2), Br (3), NO2 (4) and bpy=2,2'-bipyrdine} were synthesized. The azoimine-quinoline based ligands behave as NN'N″ tridentate donors and coordinated to ruthenium via azo-N', imine-N' and quinolone-N″ nitrogen atoms. The composition of the complexes has been established by elemental analysis, spectral methods (FT-IR, electronic, (1)H NMR, UV/Vis and electrochemical (cyclic voltammetry) techniques. The crystal structure of complex 1 is reported. The Ru(II) oxidation state is greatly stabilized by the novel tridentate ligands, showing Ru(III/II) couples ranging from 0.93-1.27 V vs. Cp2Fe/Cp2Fe(+). The absorption spectrum of 1 in dichloromethane was modeled by time-dependent density functional theory (TD-DFT).

Keywords: Azoimine–quinoline ligands; DFT calculation; Electrochemistry; Ruthenium; Spectroelectrochemistry.

MeSH terms

2,2'-Dipyridyl / analogs & derivatives*
2,2'-Dipyridyl / chemical synthesis
2,2'-Dipyridyl / chemistry
Crystallography, X-Ray
Electrochemical Techniques
Electrochemistry*
Electrons
Imines / chemistry*
Ligands
Methylene Chloride / chemistry
Models, Molecular
Molecular Conformation
Organometallic Compounds / chemical synthesis*
Organometallic Compounds / chemistry*
Quantum Theory
Quinolines / chemistry*
Spectrophotometry, Ultraviolet
Thermodynamics

Substances

Imines
Ligands
Organometallic Compounds
Quinolines
bis(bipyridyl)ruthenium(II)
2,2'-Dipyridyl
Methylene Chloride
quinoline