Photoinduced electron transfer reactions in organic donor-acceptor systems leading to long-lived radical ion pairs (RPs) have attracted broad interest for their potential applications in fields as diverse as solar energy conversion and spintronics. We present the photophysics and spin dynamics of an electron donor - electron acceptor - stable radical system consisting of a meta-phenylenediamine (mPD) donor covalently linked to a 4-aminonaphthalene-1,8-dicarboximide (ANI) electron-accepting chromophore as well as an α,γ-bisdiphenylene-β-phenylallyl (BDPA) stable radical. Selective photoexcitation of ANI produces the BDPA-mPD(+•)-ANI(-•) triradical in which the mPD(+•)-ANI(-•) RP spins are strongly exchange coupled. The presence of BDPA is found to greatly increase the RP intersystem crossing rate from the initially photogenerated BDPA-(1)(mPD(+•)-ANI(-•)) to BDPA-(3)(mPD(+•)-ANI(-•)), resulting in accelerated RP recombination via the triplet channel to produce BDPA-mPD-(3*)ANI as compared to a reference molecule lacking the BDPA radical. The RP recombination rates observed are much faster than those previously reported for weakly coupled triradical systems. Time-resolved EPR spectroscopy shows that this process is also associated with strong spin polarization of the stable radical. Overall, these results show that RP intersystem crossing rates can be strongly influenced by stable radicals nearby strongly coupled RP systems, making it possible to use a third spin to control RP lifetimes down to a picosecond time scale.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.jpca.6b02621 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Treatment of distal femur aseptic nonunion after lateral locking plate fixation: Results of medial custom made plating and free fibula flap transfer using CAD-CAM technology.
J Hand Microsurg
January 2025
Orthopaedics and Traumatology Unit, Cattinara Hospital - ASUGI, Department of Medical, Surgical and Life Sciences, Trieste University, Trieste, Italy.
Background: Aim of the present paper is to report the preliminary results of CAD-CAM (Computer-Aided Design - Computer-Aided Manufacturing) technology application to distal femur nonunion treatment with free fibula flap, custom made medial plating and maintenance of a stable lateral locking plate.
Methods: Two cases of distal femur nonunion that occurred after lateral locking plating were treated and prospectively followed-up. Surgical planning followed the same preoperative protocol adopted for mandibular CAD-CAM reconstruction.
Photochemistry of Microsolvated Nitrous Acid: Observation of the Water-Separated Complex of Nitric Oxide and Hydroxyl Radical.
J Phys Chem Lett
January 2025
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.
The photochemistry of nitrous acid (HONO) plays a crucial role in atmospheric chemistry as it serves as a key source of hydroxyl radicals (OH) in the atmosphere; however, our comprehension of the underlying mechanism for the photochemistry of HONO especially in the presence of water is far from being complete as the transient intermediates in the photoreactions have not been observed. Herein, we report the photochemistry of microsolvated HONO by water in a cryogenic N matrix. Specifically, the 1:1 hydrogen-bonded water complex of HONO was facially prepared in the matrix through stepwise photolytic O oxidation of the water complex of imidogen (NH-HO) via the intermediacy of the elusive water complex of peroxyl isomer HNOO.
View Article and Find Full Text PDFMultimodal treatment combining neoadjuvant therapy, laparoscopic subtotal distal pancreatectomy and adjuvant therapy for pancreatic neck-body cancer: Case series.
World J Gastrointest Surg
January 2025
Department of Hepatobiliary Surgery, Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University), Changsha 410005, Hunan Province, China.
Background: Pancreatic cancer involving the pancreas neck and body often invades the retroperitoneal vessels, making its radical resection challenging. Multimodal treatment strategies, including neoadjuvant therapy, surgery, and postoperative adjuvant therapy, are contributing to a paradigm shift in the treatment of pancreatic cancer. This strategy is also promising in the treatment of pancreatic neck-body cancer.
View Article and Find Full Text PDFEnhancing Electron Donor-Acceptor Complex Photoactivation with a Stable Perylene Diimide Metal-Organic Framework.
J Am Chem Soc
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong 999077, P. R. China.
Electron donor-acceptor complexes are commonly employed to facilitate photoinduced radical-mediated organic reactions. However, achieving these photochemical processes with catalytic amounts of donors or acceptors can be challenging, especially when aiming to reduce catalyst loadings. Herein, we have unveiled a framework-based heterogenization approach that significantly enhances the photoredox activity of perylene diimide species in radical addition reactions with alkyl silicates by promoting faster and more efficient electron donor-acceptor complex formation.
View Article and Find Full Text PDFIntramolecular Redox-driven Synthesis of Mono- and Diradical Iridium(III) Complexes: Insights into Molecular and Electronic Structure, Electrochemistry, and Spin-Communication.
Chemistry
January 2025
Jadavpur University, Chemistry, 188 Raja S. C. Mallick Road, 700032, Kolkata, INDIA.
Two π-radical complexes containing bisazo-aromatic-centered radical anion (1•-) were synthesized through in-situ electron transfer from metal-to-ligand using [IrI] and 2-(2-Pyridylazo)azobenzene (1) in inert hydrocarbon solvent. These are characterized as diradical [IrIII(1•-)2]+[2]+ and monoradical [IrIII(1•-)Cl2(PPh3)] 3. In contrast, a rare metal-mediated hydrolytic cleavage of the C(sp2)-N bond occurred in protic solvent resulting in quaternary radical complex [IrIII(1•-)(1')(PPh3)]+(4)+.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!