Siloxy Group-Induced Highly Efficient Room Temperature Phosphorescence with Long Lifetime

The design and development of organic phosphors that exhibit efficient emission at room temperature but do not contain precious metals such as iridium and platinum have attracted increasing attention. We report herein highly efficient green phosphorescence-emitting 1,4-dibenzoyl-2,5-bis­(siloxy)­benzene crystals in air at room temperature. Remarkable luminescence quantum yields of 0.46 to 0.64 and long lifetimes ranging from 76.0 to 98.3 ms were observed. X-ray diffraction analysis of the single crystals revealed that there were several intermolecular interactions causing suppression of intramolecular motion, thereby minimizing nonradiative decay of the triplet excited state. Comparison with the corresponding 2,5-bis­(dimethylphenylsilylmethyl) and 2,5-bis­(trimethylsilyl) derivatives revealed that the siloxy groups are essential for efficient room temperature phosphorescence. Density functional calculations suggested that σ–n conjugation was operative in the siloxy moieties. Electron spin resonance measurement indicated that the radiative process included generation of the triplet diradical species, whose electron distribution was very similar to that of naphthalene. The present study largely expands the possibilities for the molecular design of precious metal- and halogen-free organic phosphors exhibiting efficient room temperature phosphorescence

Quantitative Analyses of Schizophrenia-Associated Metabolites in Serum: Serum D-Lactate Levels Are Negatively Correlated with Gamma-Glutamylcysteine in Medicated Schizophrenia Patients

<div><p>The serum levels of several metabolites are significantly altered in schizophrenia patients. In this study, we performed a targeted analysis of 34 candidate metabolites in schizophrenia patients (<i>n</i> = 25) and compared them with those in age- and gender-matched healthy subjects (<i>n</i> = 27). Orthogonal partial least square-discriminant analysis revealed that complete separation between controls and patients was achieved based on these metabolites. We found that the levels of γ-glutamylcysteine (γ-GluCys), linoleic acid, arachidonic acid, D-serine, 3-hydroxybutyrate, glutathione (GSH), 5-hydroxytryptamine, threonine, and tyrosine were significantly lower, while D-lactate, tryptophan, kynurenine, and glutamate levels were significantly higher in schizophrenia patients compared to controls. Using receiver operating characteristics (ROC) curve analysis, the sensitivity, specificity, and the area under curve of γ-GluCys, a precursor of GSH, and D-lactate, a terminal metabolite of methylglyoxal, were 88.00%, 81.48%, and 0.8874, and 88.00%, 77.78%, and 0.8415, respectively. In addition, serum levels of D-lactate were negatively correlated with γ-GluCys levels in patients, but not in controls. The present results suggest that oxidative stress-induced damage may be involved in the pathogenesis of schizophrenia.</p></div

Correlations between serum levels of metabolites and CP equivalent (mg) or duration of illness (months).

<p>Correlations between serum levels of metabolites and CP equivalent (mg) or duration of illness (months).</p

Serum levels of metabolites (µmol/L) that were differentially expressed between controls and schizophrenia patients.

<p>Only <i>p</i> values below 0.05 are included in this table.</p><p>*Non-parametric Mann-Whitney <i>U</i>-test.</p>a<p>Significantly different following Bonferroni correction (<0.05/34).</p

Receiver operating characteristic (ROC) curve analyses of γ-GluCys (a), lenoleic acid (b), and D-lactate (c).

<p>Receiver operating characteristic (ROC) curve analyses of γ-GluCys (a), lenoleic acid (b), and D-lactate (c).</p

Characteristics of subjects.

<p>The comparison between 2 groups was performed using the χ² test for gender difference and smoking, and the Student’s <i>t</i>-test for age and body mass index (BMI).</p

Correlation plots of D-lactate and γ-GluCys serum levels in controls (a) and in patients with schizophrenia (b), and between GSH and γ-GluCys in controls (c) and in patients with schizophrenia (d).

<p>Correlation plots of D-lactate and γ-GluCys serum levels in controls (a) and in patients with schizophrenia (b), and between GSH and γ-GluCys in controls (c) and in patients with schizophrenia (d).</p