Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) was synthesized and characterized by UV-vis, IR, (1)H NMR, (13)C NMR, (119)Sn NMR, and mass (FAB(+)) spectroscopies and by single-crystal X-ray diffraction, which proved the presence of a nearly linear Sn-Ru-Sn unit. Crystals of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB).3.5C(6)H(6) form in the triclinic space group P&onemacr; in a unit cell of dimensions a = 11.662(6) Å, b = 13.902(3) Å, c = 19.643(2) Å, alpha = 71.24(2) degrees, beta = 86.91(4) degrees, gamma = 77.89(3) degrees, and V = 2946(3) Å(3). One-electron reduction of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) produces the stable radical-anion [Ru(SnPh(3))(2)(CO)(2)(iPr-DAB)](*-) that was characterized by IR, and UV-vis spectroelectrochemistry. Its EPR spectrum shows a signal at g = 1.9960 with well resolved Sn, Ru, and iPr-DAB (H, N) hyperfine couplings. DFT-MO calculations on the model compound Ru(SnH(3))(2)(CO)(2)(H-DAB) reveal that the HOMO is mainly of sigma(Sn-Ru-Sn) character mixed strongly with the lowest pi orbital of the H-DAB ligand. The LUMO (SOMO in the reduced complex) should be viewed as predominantly pi(H-DAB) with an admixture of the sigma(Sn-Ru-Sn) orbital. Accordingly, the lowest-energy absorption band of the neutral species will mainly belong to the sigma(Sn-Ru-Sn)-->pi(iPr-DAB) charge transfer transition. The intrinsic strength of the Ru-Sn bond and the delocalized character of the three-center four-electron Sn-Ru-Sn sigma-bond account for the inherent stability of the radical anion.
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http://dx.doi.org/10.1021/ic960042h | DOI Listing |
Materials (Basel)
November 2024
Institute of Chemistry, Jan Kochanowski University, Uniwersytecka St. 7G, PL-25406 Kielce, Poland.
7,7',8,8'-tetracyanoquinodimethane (TCNQ) is one of the most widely used effective surface electron acceptors in organic electronics and sensors, which opens up a very interesting field in electrochemical applications. In this review article, we outline the historical context of electrochemically stable selective electrode materials based on TCNQ and its derivatives and their development, their electrochemical characteristics, and the experimental aspects of their electrochemical applications. TCNQ-modified electrodes are characterized by long-term stability, reproducibility, and a low detection limit compared to other sensors; thus, their use can increase determination speed and flexibility and reduce investigation costs.
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March 2025
Department of Chemistry, UGC Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143001, Pb., India. Electronic address:
Chem Commun (Camb)
October 2024
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
A stable three coordinate Cu(I)-radical complex with an S donor set having the general formula of [Cu(S-NHCH)(SS-NHCS)] (1) was isolated as dark blue needles. Interestingly, this complex possesses a zwitterionic ligand, S-NHCH, which is coordinated to the central Cu(I) ion its S-atom [S-NHCH C4-thiolate functionalized C2-protonated zwitterionic N-hetero cyclic carbene; SS-NHCS˙ NHC-based dithiolene radical anion]. 1 has been structurally characterized by single-crystal X-ray diffraction, and further characterized by UV-vis, IR, XPS, and EPR spectroscopy.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India.
Mesoionic compounds, with positive and negative charges, are expected to have dual-site highest occupied molecular orbital (HOMO, donor) and lowest unoccupied molecular orbital (LUMO, acceptor) reactivity. Herein, we report a novel class of air-stable mesoionic N-heterocyclic thiones (mNHTs) synthesized from abnormal N-heterocyclic carbenes (aNHCs). DFT studies revealed a highly polarized exocyclic thione moiety and computed Fukui function analysis suggests the dual-site HOMO/LUMO reactivity of mNHTs predicting donor property at the negatively charged 'S' center while acceptor property at the cationic imidazole ring.
View Article and Find Full Text PDFCommun Chem
October 2024
Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany.
In nature, molecular environments in proteins can sterically protect and stabilize reactive species such as organic radicals through non-covalent interactions. Here, we report a near-infrared fluorescent rotaxane in which the stabilization of a chemically labile squaraine fluorophore by the coordination of a tetralactam macrocycle can be controlled chemically and electrochemically. The rotaxane can be switched between two co-conformations in which the wheel either stabilizes or exposes the fluorophore.
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