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Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Bakir, Mohammed A.; Brown, O.
Author Affiliation, Ana.
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Article Title
Synthesis, and molecular sensing behavior of fac-[Re(CO)3(??2-N,N-dpksc)Cl], dpksc = di-2-pyridyl ketone semicarbazone
Medium Designator
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Connective Phrase
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Journal Title
Journal of Molecular Structure
Translated Title
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Reprint Status
Refereed
Date of Publication
2013
Volume ID
1032
Issue ID
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Page(s)
118-125
Language
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Connective Phrase
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Location/URL
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ISSN
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Notes
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Abstract
When [Re(CO)5Cl] was allowed to react with di-2-pyridyl ketone semicarbazone hydrochloride (dpksc.HCl) in refluxing toluene, fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] was isolated. The identity of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] was elucidated from the results of its elemental analysis and confirmed using a number of spectroscopic measurements. Spectroscopic measurements done on non-aqueous solvents divulged sensitivity of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] to changes in its surroundings. 1H NMR studies revealed significant solvent dependence as manifested by the chemical shift variations; the exchange of the amine protons with solvent deuterium in CDCl3 and d6-acetone; the temperature dependence of the chemical shifts of the amine and amide protons and insignificant temperature dependence of the aromatic proton. The electronic absorption spectra of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] measured on non-aqueous solvents disclosed two high energy intra-ligand charge transfer (ILCT) transitions. Optical measurements performed on protophilic solutions of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] in the presence of bases and acids showed the appearance and disappearance of a low energy ILCT electronic transitions and established reversible inter-conversion between fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] and its conjugate base, fac-[Re(CO)3(kappa2-N,N-dpksc-H)Cl]-. Thermo-optical measurements done on protophilic solutions of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] disclosed the absence of thermal acid-base inter-conversion between fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] and fac-[Re(CO)3(kappa2-N,N-dpksc-H)Cl]- and established reversible electronic transfer between the high energy electronic transitions of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl]. Optosensing measurements done on protophilic solutions of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] showed acids and bases in concentrations as low as 1.00 10-10 M can be detected and determined using protophilic solutions of of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl]. Electrochemical measurements on dmf solutions of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] showed irreversible electrochemical redox process and electrochemically generated product waves pointing to the instability of fac-[Re(CO)3(kappa2-N,N-dpksc)Cl] to redox transformations.....
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Keywords
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