Synthesis and redox chemistry of octaethylporphyrin complexes of ruthenium(II) and ruthenium(III)

1983 ◽  
Vol 61 (10) ◽  
pp. 2389-2396 ◽  
Author(s):  
Mark Barley ◽  
James Y. Becker ◽  
George Domazetis ◽  
David Dolphin ◽  
Brian R. James
Keyword(s):  
Electron Transfer ◽  
Electrochemical Oxidation ◽  
Ground State ◽  
Ligand Exchange ◽  
Cation Radical ◽  
Electron Transfer Process ◽  
Porphyrin Ligand ◽  
Tertiary Phosphines ◽  
Internal Electron

The syntheses and characterization of some new octaethylporphyrin complexes of ruthenium(II) and ruthenium(III) are described; the complexes are Ru(OEP)(P″Bu3)2, Ru(OEP)(CO)L (L = PPh3, P″Bu3), [Ru(OEP)(P″Bu3)2]Br, and Ru(OEP)(P″Bu3)Br, where OEP is the dianion of octaethylporphyrin. The Ru(OEP)(CO)EtOH complex, 1, which reversibly loses the ethanol ligand in CH2Cl2 solution, undergoes a one-equivalent oxidation at the porphyrin ligand to generate the cation-radical [Ru(OEP)•+(CO)]+; a purple species of 2A2u ground state, produced electrochemically in perchlorate media, can coordinate bromide to generate a green 2A1u ground state species that also results from oxidation of 1 using bromine. Coordination of pyridine to [Ru(OEP)•+(CO)]+ yields the Ru(OEP)•+(CO)py species that can also be formed by electrochemical oxidation of Ru(OEP)(CO)py. Addition of tertiary phosphines (PR3) to the cation-radical carbonyl species can lead to formation of [Ru(OEP)(PR3)2]+, via an internal electron transfer process from Ru(II) to the OEP•+ that appears to be triggered by loss of the CO ligand. A reversible one-electron electrochemical oxidation of Ru(OEP)(P″Bu3)2 at 0.03 V (vs. Ag/AgCl) in CH2Cl2 also gives the ruthenium(III) biphosphine cation, while a further one-electron oxidation at 1.2 V generates [Ru(OEP)•+(P″Bu3)2]2+, a ruthenium(III) π-cation radical characterized by esr. The [Ru(OEP)(P″Bu3)2]Br complex decomposes in the solid state to a mixture of Ru(OEP)(P″Bu3)Br, formed together with free phosphine via an intramolecular ligand exchange, and Ru(OEP)(P″Bu3)2, formed by reduction of the initial ionic ruthenium(III) cation with the phosphine that appears as [P″Bu3Br]Br.

Preparation and Characterization of Glycyrrhizin-Graphene Hybrid Materials

2012 ◽  
Vol 531 ◽  
pp. 145-148
Author(s):  
Zong Hua Wang ◽  
Yan Li Gao ◽  
Jian Fei Xia ◽  
Fei Fei Zhang ◽  
Yan Zhi Xia ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hybrid Materials ◽  
Model Compound ◽  
Carbon Electrode ◽  
The Novel ◽  
Electron Transfer Process ◽  
Efficient Energy ◽  
Sandwich Construction ◽  
Photo Induced Electron Transfer

A glycyrrhizin decorated graphene hybrid materials (GL-G) was synthesized, which is a layer-to-layer sandwich construction. The results of characterization indicate that a photo induced electron transfer process or efficient energy transferring along the GL-G interface. Furthermore, the as-made hybrid material was used as a modifier of the glassy carbon electrode to construct a sensor (GL-G/GCE). Using p-nitrophenol as a model compound, the novel sensor demonstrated a highly enhanced electrochemical activity for it. The peak current of p-nitrophenol was significantly improved at the sensor.

Electron transport via metalloporphyrins

1978 ◽  
Vol 56 (10) ◽  
pp. 1381-1388 ◽  
Author(s):  
Eugene C. Johnson ◽  
Tony Niem ◽  
David Doolphin
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Heme Proteins ◽  
Room Temperature ◽  
Cation Radical ◽  
Cation Radicals ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Internal Electron

The controlled potential electrolysis of Ni(II) meso-tetraphenylporphyrin (Ni(II)TPP) gives at room temperature the corresponding metalloporphyrin π-cation radical [Ni(II)TPP]+ •. Upon freezing a solution of the π-cation radical to 77 K an internal electron transfer occurs to give [Ni(III)TPP]+. A discussion of the routes of electron transport in heme proteins is given, and the roles of metalloporphyrin π-cation radicals in electron transport is evaluated.

Darstellung und spektroskopische Charakterisierung von Nitridophthalocyaninatomangan(V) / Preparation and Spectroscopical Characterization of Nitridophthalocyaninatomanganese(V)

1990 ◽  
Vol 45 (4) ◽  
pp. 483-489 ◽  
Author(s):  
Horst Grunewald ◽  
Heiner Homborg
Keyword(s):  
Electron Transfer ◽  
Raman Spectra ◽  
Electronic Transition ◽  
Resonance Raman ◽  
Cation Radical ◽  
Strong Resonance ◽  
Resonance Enhancement ◽  
Resonance Raman Spectra

Nitridophthalocyaninatomanganese(V), MnNPc(2–), has been prepared by oxidation of [Mn(OH)2,Pc(2–)]- with chlorine in the presence of excess ammonia in dichloromethane as a chemically very stable, diamagnetic microcrystalline blue powder. The band at 1053 cm-1 in the infrared and resonance Raman spectra is assigned to v(Mn=N). The strong resonance enhancement of v(Mn=N) coincides with an electronic transition at 461 nm assigned to (N → Mn) electron transfer. The UV-VIS spectrum in 1-chloronaphthalene is compared with that of the MnNPc(2–)–H2SO4 adduct and the phthalocyanine-π-cation radical [MnNPc(1–)]+.

1,3-Diketonatoboron difluoride sensitized cation radical reactions

1991 ◽  
Vol 69 (8) ◽  
pp. 1331-1336 ◽  
Author(s):  
Y. L. Chow ◽  
Xianen Cheng
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Ground State ◽  
Cation Radical ◽  
Radical Reactions ◽  
Singlet Excited State ◽  
Anti Isomer ◽  
Cation Radicals ◽  
Dibenzoylmethanatoboron Difluoride ◽  
Boron Complexes

Dibenzoylmethanatoboron difluoride (DBMBF2) and allied BF2 complexes interact from their singlet excited state with trans-anethole (t-A), quadricyclene (QC), and norbornadiene (NBD) by electron transfer to generate the corresponding cation radicals, which undergo the reported reactions. By sensitization, t-A undergoes dimerization to form the anti head-to-head and syn head-to-head dimers with retention of stereochemistry. The formation is reversible under sensitization conditions, leading to accumulation of the more stable anti isomer. However, irradiation of the absorption band of the DBMBF2 – t-A ground state complex did not lead to dimerization of t-A. By DBMBF2 sensitization, QC is cleanly converted to NBD while NBD is not affected. The calculation shows QC+• possesses higher energy than NBD+• by 7.5 kcal/mol, hence an irreversible rearrangement. Other sensitizers (e.g., cyanoaromatics and tetrachlorobenzoquinone) also promote these cation radical reactions but not as cleanly as DBMBF2. Key words: photosensitization by boron complexes, cation radical rearrangement, cation radical cycloaddition, electron transfer sensitization, photoreaction of ground state complexes.

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