Cyclization Dynamics and Competitive Processes of Photochromic Perfluorocyclopentene Dithienylethylene in Solution.

Time-resolved absorption spectroscopy measurements were performed to study the dynamics of photochromic 1,2-Bis(2,4-dimethylthiophene-3-yl)perfluoro-cyclopentene (DMTPF) in chloroform, including antiparallel conformer ring-closure reaction and parallel conformer photophysics. All characteristic times are given, discussed and compared to a previous publication concerning the close molecule substituted with phenyl rings. (Hamdi et al., PCCP, 2016). Apart from the expected photocyclization process, condensed ring by-product formation is observed and hypotheses concerning the origin of this by-product are presented.

Understanding the properties of dithienylethenes functionalized for supramolecular self-assembly: a molecular modeling study.

A dithienylethene (DTE) photochromic compound functionalized by ureidopyrimidinone (UPy) quadruple hydrogen bonding blocks was synthesized by Takeshita and coworkers [Takeshita et al., Chem. Commun., 2005, 761] in order to form a light-responsive supramolecular self-assembling system. In solution, the formation of supramolecular assemblies was only observed for one DTE isomer, namely the closed-form isomer. To rationalize this experimental finding, with the help of Molecular Dynamics (MD) and (time-dependent) DFT calculations, the behaviour of open-form and closed-form monomers, dimers, hexamers and π-stacked dimers in solution is investigated. Our simulations show that, for the open-form oligomers, the progression of the supramolecular assembly is hindered due to (i) the possible formation of a very stable cyclic dimer for the open-form parallel isomer, (ii) the relative flexibility of the open-form oligomers compared to their closed-form counterparts, and (iii) the possible existence of π-stacked dimers that constitute bottlenecks blocking the progression of the supramolecular self-assembly.

Unraveling ultrafast dynamics of the photoswitchable bridged dithienylethenes under structural constraints.

The excited state dynamics of constrained photochromic benzodithienylethenes were addressed by considering the bridging with polyether chains (from x = 4 to 6 units) at the ortho and meta positions of the aryl group, named DTE-ox and DTE-mx, via time-resolved absorption spectroscopy supported with (TD)-DFT calculations. The photochromic parameters and geometrical structures of these series are discussed. A novel photocyclization pathway via a triplet state, evidenced recently (Hamdi et al., Phys. Chem. Chem. Phys., 2016, 18, 28091-28100), is largely dependent on the length and the position of the polyether chain. For the first time, by comparing the two series, we revealed, for the DTE-ox series, an interconversion not only in the ground state but also between the triplet states of the anti-parallel and parallel open form conformers.

Acute intoxication cases admitted to the emergency department of a university hospital / 世界急诊医学杂志（英文）

@#BACKGROUND: This study aimed to describe the clinical and socio-demographic aspects of acute poisoning in 2010 in Duzce City, Northwest Anatolian Region of Turkey. METHODS: Acute poisoning was due to the intentional ingestion of drugs in young and adult people (≥16), who were treated at the Emergency Service of Duzce University Medical Hospital, Turkey from January 1, 2010 to December 31, 2010. In this retrospective and descriptive study, 95 patients were diagnosed with intoxications and 30 of them intentionally ingested drugs to commit suicide. Records of the patients diagnosed with intoxication were obtained from the Clinical Archive of the hospital. Their diagnoses were established according to the International Statistical Classification of Diseases and Related Health Problems. Codes X60-X84 of this classification were used to classify self-infringed drug injuries and drug poisoning. RESULTS: In this series, 35 (36.8％) patients were male and 60 patients (63.2％) female. The male/female ratio was 1.0/1.7. The mean age of the patients was 33.1±14.2 years; 17 (17.9％) patients were below 20 years old and 9 (9.5％) were older than 50 years. Of these patients, 29 (30.5％) were single, 7 (7.4％) divorced or separated, and 59 (62.1％) married. Their mean time for admission to the emergency service after the incident was 208±180 (15–660) minutes. The mean time for admission to the emergency service for patients with food intoxication after the incident was 142±160 minutes, for those with drug intoxication 173±161 minutes, for those with carbon monoxide (CO) intoxication 315±209 minutes, and for those with undefined intoxication 289±166 minutes (P=0.005). Most of the intoxication cases occurred in winter (41.1％, 39 of 95 patients). Admissions to the emergency service were most common in December and April (21 and 16 of 95 patients, respectively). Sixty-five (68.4％) cases were involved in non-deliberate poisoning, whereas 30 (31.6％) were involved in deliberate poisoning. Twenty-six of the 95 patients with acute poisonings had mortality risk at admission, however only one died from CO intoxication in the emergency service (1.1％). Suicide attempts were more common in females than in males (21 of 30 patients, 70％, P<0.05). CONCLUSION: In Duzce City of Turkey, most intoxication cases occurred in winter, especially in December. They had non-deliberate poisoning, but deliberate poisoning in suicide attempts was more common in females than in males.

The photochemistry of inverse dithienylethene switches understood.

The photophysical properties of a series of dithienylethenes, free or blocked in an ideal photoactive conformation by an alkyl bridge, have been investigated by stationary, ultrafast spectroscopy and state-of-the-art time-dependent density functional theory calculations. Thanks to the clear ultrafast transient signatures corroborating NMR results, we bring strong evidence that the unreactive parallel open form conformer has been efficiently removed by the chain. For the first time, the photophysics of this species, namely an internal conversion of 120 ps is highlighted. In contradiction to the main ideas in the literature, the photocyclization mechanism is rationalized by a direct photocyclization mechanism from the Franck-Condon region passing directly through a conical intersection within ≈100 fs (not few picoseconds) while a competitive mechanism occurs through the relaxed S1 state. Relaxation processes (fluorescence and internal conversion) originating from this relaxed state are sensitive to the length of the blocking chain. Both concomitant pathways are necessary to rationalize: (i) the inverse relationship between emission and cyclization quantum yields and (ii) the non-unity value of the latter for bridged compounds.