Renewable polymeric materials derived from biomass with built-in phototriggers were synthesized and evaluated for degradation under irradiation of UV light. Complete decomposition of the polymeric materials was observed with recovery of the monomer that was used to resynthesize the polymers.

Vibrational spectroscopy techniques can be applied to identify a susceptibility-to-adenocarcinoma biochemical signature. A sevenfold difference in incidence of prostate adenocarcinoma (CaP) remains apparent amongst populations of low- (e.g. India) compared with high-risk (e.g. UK) regions, with migrant studies implicating environmental and/or lifestyle/dietary causative factors. This study set out to determine the biospectroscopy-derived spectral differences between risk-associated cohorts to CaP. Benign prostate tissues were obtained using transurethral resection from high-risk (n = 11, UK) and low-risk (n = 14, India) cohorts. Samples were analysed using attenuated total reflection Fourier-transform infrared (FTIR) spectroscopy, FTIR microspectroscopy and Raman microspectroscopy. Spectra were subsequently processed within the biochemical cell region (1,800(-1)-500 cm(-1)) employing principal component analysis (PCA) and linear discriminant analysis (LDA) to determine whether wavenumber-absorbance/intensity relationships might reveal biochemical differences associated with region-specific susceptibility to CaP. PCA-LDA scores and corresponding cluster vector plots identified pivotal segregating biomarkers as 1,582 cm(-1) (Amide I/II trough); 1,551 cm(-1) (Amide II); 1,667 cm(-1) (Amide I); 1,080 cm(-1) (DNA/RNA); 1,541 cm(-1) (Amide II); 1,468 cm(-1) (protein); 1,232 cm(-1) (DNA); 1,003 cm(-1) (phenylalanine); 1,632 cm(-1) [right-hand side (RHS) Amide I] for glandular epithelium (P < 0.0001) and 1,663 cm(-1) (Amide I); 1,624 cm(-1) (RHS Amide I); 1,126 cm(-1) (RNA); 1,761, 1,782, 1,497 cm(-1) (RHS Amide II); 1,003 cm(-1) (phenylalanine); and 1,624 cm(-1) (RHS Amide I) for adjacent stroma (P < 0.0001). Primarily protein secondary structure variations were biomolecular markers responsible for cohort segregation with DNA alterations exclusively located in the glandular epithelial layers. These biochemical differences may lend vital insights into the aetiology of CaP.

Complexation of N-alkyl derivatives of PMDI with β-CD is probed using a variety of techniques. Although MALDI-TOF and CV experiments suggested complex formation, it is very evident from UV−vis and NMR experiments that these complexes are different from regular inclusion complexes. A clear understanding of the structure of the binary complex PMDI@β-CD could be obtained using ICD and NMR ROESY experiments. ICD signals were negative which suggest that the PMDI moiety is placed outside of the cavity. ROESY experiments provide support for this contention. When the alkyl group is tbutyl or 2-propyl, the CH 3 protons exist very close to the inner protons of β-CD, but the aromatic proton of PMDI is clearly outside the β-CD cavity. Based on these results we proposed a structure for PMDI@β-CD with the PMDI moiety placed at the narrow rim of β-CD and the N-alkyl group projecting into the cavity and designated these as "rim-binding" complexes. Additional experiments showed that β-CD can accommodate a PMDI moiety at the narrow rim and an adamantane moiety in its cavity simultaneously, resulting in the formation of ternary complexes PMDI⊃β-CD⊂ADA. Structure of the ternary complex was also probed by ROESY. The ternary complex formation can be utilized for the design of higher order functional materials such as CDbased hydrogels.

A detailed understanding of the photoluminescence (PL) from silicon nanocrystals (SiNCs) is convoluted by the complexity of the decay mechanism, including a stretched-exponential relaxation and the presence of both nanosecond and microsecond time scales. In this publication, we analyze the microsecond PL decay of size-resolved SiNC fractions in both full-spectrum (FS) and spectrally resolved (SR) configurations, where the stretching exponent and lifetime are used to deduce a probability distribution function (PDF) of decay rates. For the PL decay measured at peak emission, we find a systematic shift and narrowing of the PDF in comparison to the FS measurements. In a similar fashion, we resolve the PL lifetime of the ‘blue’, ‘peak’, and ‘red’ regions of the spectrum and map PL decays of different photon energy onto their corresponding location in the PDF. A general trend is observed where higher and lower photon energies are correlated with shorter and longer lifetimes, respectively, which we relate to the PL line width and electron-phonon coupling.

Room‐temperature phosphorescence of metal and heavy atom‐free organic molecules has emerged as an area of great potential in recent years. A rational design played a critical role in controlling the molecular ordering to impart efficient intersystem crossing and stabilize the triplet state to achieve room‐temperature ultralong phosphorescence. However, in most cases, the strategies to strengthen phosphorescence efficiency have resulted in a reduced lifetime, and the available nearly degenerate singlet‐triplet energy levels impart a natural competition between delayed fluorescence and phosphorescence, with the former one having the advantage. Herein, an organic helical assembly supports the exhibition of an ultralong phosphorescence lifetime. In contrary to other molecules, 3,6‐phenylmethanone functionalized 9‐hexylcarbazole exhibits a remarkable improvement in phosphorescence lifetime (>4.1 s) and quantum yield (11 %) owing to an efficient molecular packing in the crystal state. A right‐handed helical molecular array act as a trap and exhibits triplet exciton migration to support the exceptionally longer phosphorescence lifetime.

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A novel ambient pressure process for the continuous gas-phase, synthesis of Si-QDs by pyrolysis of cyclohexasilane (Si6H12), a liquid hydrosilane.

Selective ESIPT photocycloaddition of 3-hydroxyflavones with trans, trans-1,4-diphenyl-1,3-butadiene is described. Using this methodology, total syntheses of the natural products (±)-foveoglin A and (±)-perviridisin B have been accomplished. Enantioselective ESIPT photocycloaddition using TADDOLs as chiral hydrogen-bonding additives provided access to (+)-foveoglin A. Mechanistic studies have revealed the possibility for a photoinduced electron transfer (PET) pathway.