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  1. The new compound [(NC)Ru 2 (ap) 4 ] 2 (μ-1,4-C 6 H 4 ) (ap = 2-anilinopyridinate) was prepared to address the open question of whether a 1,4-phenylene bridge can mediate intermetallic electronic coupling. As a manifestation of strong coupling, hole delocalization between the Ru 2 centers on the IR time scale (10 −14 s) was established using spectroelectrochemistry. An orbital mechanism for coupling was elaborated with DFT analysis.
    Free, publicly-accessible full text available May 3, 2023
  2. Reported herein are the two new series of diruthenium aryl compounds: Ru 2 (DiMeOap) 4 (Ar) (1a–6a) (DiMeOap = 2-(3,5-dimethoxyanilino)pyridinate) and Ru 2 ( m - i PrOap) 4 (Ar) (1b–5b) ( m - i PrOap = 2-(3-iso-propoxyanilino)pyridinate), prepared through the lithium-halogen exchange reaction with a variety of aryl halides (Ar = C 6 H 4 -4-NMe 2 (1), C 6 H 4 -4- t Bu (2), C 6 H 4 -4-OMe (3), C 6 H 3 -3,5-(OMe) 2 (4), C 6 H 4 -4-CF 3 (5), C 6 H 5 (6)). The molecular structures of these compounds were established with X-ray diffraction studies. Additionally, these compounds were characterized using electronic absorption and voltammetric techniques. Compounds 1a–6a and 1b–5b are all in the Ru 2 5+ oxidation state, with a ground state configuration of σ 2 π 4 δ 2 (π*δ*) 3 ( S = 3/2). Use of the modified ap ligands (ap′) resulted in moderate increases of product yield when compared to the unsubstituted Ru 2 (ap) 4 (Ar) (ap = 2-anilinopyridinate) series. Comparisons of the electrochemical properties of 1a–6a and 1b–5b against the Ru 2 (ap′)Cl starting material reveals the addition of the aryl ligand cathodically shifted themore »Ru 2 6+/5+ oxidation and Ru 2 5+/4+ reduction potentials. These oxidation and reductions potentials are also strongly dependent on the p -substituent of the axial aryl ligands.« less
    Free, publicly-accessible full text available January 4, 2023
  3. Free, publicly-accessible full text available December 1, 2022
  4. Free, publicly-accessible full text available December 13, 2022
  5. Described herein is the synthesis and characterization of macrocyclic Cr III mono-alkynyl complexes. By using the meso -form of the tetraazamacrocycle HMC (HMC = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane), trans -[Cr(HMC)(C 2 Ph)Cl]OTf ( 1a ), trans -[Cr(HMC)(C 2 Np)Cl]OTf ( 2a ), trans -[Cr(HMC)(C 2 C 6 H 4 t Bu)Cl]OTf ( 3a ), and trans -[Cr(HMC)(C 2 (3,5-Cl 2 C 6 H 3 ))Cl]OTf ( 4a ) complexes have been realized. These complexes were synthesized in high yield through the reaction of trans -[Cr( meso -HMC)(C 2 Ar) 2 ]OTf ( 1b–4b ) with stoichiometric amounts of methanolic HCl. Single crystal X-ray diffraction showed that the trans -stereochemistry and pseudo-octahedral geometry is retained in the desired mono-alkynyl complexes. The absorption spectra of complexes 1a–4a display d–d bands with distinct vibronic progressions that are slightly red shifted from trans -[Cr(HMC)(C 2 Ar) 2 ] + with approximately halved molar extinction coefficients. Time-delayed measurements of the emission spectra for complexes 1a–4a at 77 K revealed phosphorescence with lifetimes ranging between 343 μs ( 4a ) and 397 μs ( 1a ). The phosphorescence spectra of 1a–4a also exhibit more structuring than the bis-alkynyl complexes due to a strengthened vibronic coupling between the Cr IIImore »metal center and alkynyl ligands.« less
  6. Kubarych, Kevin ; Ogilvie, Jennifer (Ed.)
    Photoinduced electron transfer (ET) between electron donor (dimethylaniline) and acceptor (N-isopropyl-1,8-napthalimide) covalently linked by ethyne bridge is investigated by a mid-IR transient absorption spectroscopy and TD-DFT computations. We found that electronic and vibrational properties of the complex, including ET rate, depends strongly on the D-A torsion angle.
  7. Photoinduced electron transfer (ET) between electron donor (dimethylaniline) and acceptor (N-isopropyl-1,8-napthalimide) covalently linked by ethyne bridge is investigated by a mid-IR transient absorption spectroscopy and TD-DFT computations. We found that electronic and vibrational properties of the complex, including ET rate, depends strongly on the D-A torsion angle.