Transient Absorption Spectroscopic Investigation of the Photocyclization-Deprotection Reaction of 3',5'-Dimethoxybenzoin Fluoride.

The 3',5'-dimethoxybenzoin (DMB) system has been widely investigated as a photoremovable protecting group (PRPG) for the elimination of various functional groups and has been applied in many fields. The photolysis of DMB fluoride leads to a highly efficient photocyclization-deprotection reaction, resulting in a high yield of 3',5'-dimethoxybenzofuran (DMBF) in a MeCN solution, while there is a competitive reaction that produces DMB in an aqueous solution. The yield of DMB increased as the volume ratio of water increased.

Time-Resolved Spectroscopic Study of a Photoinduced Intramolecular Chloride Exchange Reaction of 3',5'-Dimethoxybenzoin Chloride.

Photoremovable protecting groups are of great importance due to their remote control over the liberation of diverse reactive species temporally and spatially, including biologically active compounds and functional groups. Here, an in-depth investigation on the heterolysis-solvolysis reaction mechanisms of a photoremovable protecting group, 3',5'-dimethoxybenzoin (DMB) chloride, has been accomplished. With the aid of transient absorption and time-resolved resonance Raman spectroscopies, the features of the intermediates that emerged from the photolysis process were directly observed.

Revealing the Photophysical Dynamics of Selected Rigid Donor-Acceptor Systems: From Ligands to Ruthenium(II) Complexes.

Newly designed push-pull ligands ( and ) with bithiophene () as a donor and phenazine () or quinoxalino[2,3-]quinoxaline () as acceptors were synthesized and also incorporated with a bipyridyl Ru(II) complex to give and , respectively. The ultrafast photophysical dynamics of the ligand and their respective Ru(II) complexes were well-characterized using time-resolved spectroscopies and quantum chemical calculations. Photoinduced charger transfer (CT) and intersystem crossing (ISC) processes were directly observed for and .

Synthesis of Pyrazinopyrazine-Fused Azaacenes through Direct Condensation Reactions between Quinoxalinediamine and Diketones.

We report the synthesis of a new type of pyrazinopyrazine-fused azaacene molecules by a simple and versatile procedure. 6,9-Dihexyldithieno[3,2-f:2',3'-h]quinoxaline-2,3-diamine was synthesized through the condensation between 2,7-dihexylbenzo[1,2-b:6,5-b']dithiophene-4,5-diamine and bis(2,2,2-trifluoroethyl) oximidate. A series of derivatized molecules with extended two-dimensional aromatic fused-ring structures could be obtained by simple condensation reactions between the quinoxalinediamine intermediate and various diketones.

Control of Electron Flow Direction in Photoexcited Cycloplatinated Complex Containing Conjugated Polymer-Single-Walled Carbon Nanotube Hybrids.

Conjugated polymers incorporated with cycloplatinated complexes (P1-Pt and P2-Pt) were used as dispersants for single-walled carbon nanotubes (SWCNTs). Significant changes in the UV-vis absorption spectra were observed after the formation of the polymer/SWCNT hybrids. Molecular dynamics (MD) simulations revealed the presence of a strong interaction between the cycloplatinated complex moieties and the SWCNT surface.

Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids.

Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs.

A new route to the synthesis of near-infrared absorbing pyrazinopyrazine bridged dyes with intramolecular charge transfer character.

A simple and versatile procedure was developed for the synthesis of pyrazino[2,3-b]thieno[3,4-e]pyrazine derivatives with intramolecular charge transfer character. The compounds obtained exhibited a narrower band gap compared to those with one pyrazine bridge.