Publications by authors named "Ozgur A Bozdemir"
Article Synopsis
- - Perylene monoimide diesters and phenyl-linked bichromophores exhibit strong fluorescence in dilute solutions while generating very few triplet states post-excitation, indicating efficient energy relaxation.
- - The monomer in solution tends to form non-emissive face-to-face dimers, which upon illumination create a triplet pair with a yield of 13%, and this triplet has a short lifetime of about 80 ps before it decays.
- - When the concentration increases, self-association happens, especially with the -bridged bichromophore, resulting in reduced triplet formation in solvents like tetrahydrofuran at room temperature.
Article Synopsis
- The mono-BF complex shows weak emission in fluid solution due to radiationless decay caused by an intramolecular hydrogen bond, while cracked symmetry leads to vibronic effects similar to the bis-BF complex (BOPHY).
- In single crystals, the complex exhibits 30% fluorescence quantum yield and 2 ns lifetime, with a significant Stokes shift (5,700 cm) reducing self-absorption.
- The crystal structure consists of head-to-tail molecular pairs that favor excitonic coupling; while standard methods overestimate the coupling strength, improved techniques provide accurate results, and temperature increases slightly shift the emission blue and reduce fluorescence.
A symmetrical molecular array has been synthesized comprising a central zinc(II) 5,10,15,20-tetraphenylporphyrin with identical boron dipyrromethene (BODIPY) units appended at each of the meso sites. Excitation of any subunit causes a cascade of electronic energy-transfer steps, ultimately leading to the BODIPY triplet-excited state in high yield. Coincidentally, the triplet energy levels of the zinc(II) porphyrin and BODIPY appendage are closely balanced such that an equilibrium is established at both 77 K and room temperature.
View Article and Find Full Text PDFThe syntheses and crystal structures of sterically crowded mono- and bichromophoric BODIPY-based dyes are reported. The "monomeric" compound is weakly fluorescent in the liquid phase due to fast internal conversion associated with rotation of aryl rings at the boron atom. The side-by-side "dimer" exhibits weak excitonic coupling between the dipyrrin units and is much more emissive in fluid solution.
View Article and Find Full Text PDFML type complexes of an olefin terminated 5H-dipyrrin ligand can be subjected to twofold ring closing metathesis to give bis(dipyrrinato)copper(ii) and bis(dipyrrinato)zinc(ii) [2]catenates. Demetalation of the copper(ii) [2]catenate with KCN/NH·HO gave the corresponding bis(dipyrrin) [2]catenand. The boron difluoride complex of this bis(dipyrrin) was obtained as the first fluorescent F-BODIPY [2]catenane.
View Article and Find Full Text PDFOrganic charge transfer cocrystals are inexpensive, modular, and solution-processable materials that are able, in some instances, to exhibit properties such as optical nonlinearity, (semi)conductivity, ferroelectricity, and magnetism. Although the properties of these cocrystals have been investigated for decades, the principal challenge that researchers face currently is to devise an efficient approach which allows for the growth of high-quality crystalline materials, in anticipation of a host of different technological applications. The research reported here introduces an innovative design, termed LASO-lock-arm supramolecular ordering-in the form of a modular approach for the development of responsive organic cocrystals.
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