Fully bio-based supramolecular gel based on cellulose nanowhisker gallate by cyclodextrin host-guest chemistry.

Nowadays, supramolecular hydrogels have gained special importance and development of versatile approaches for their preparation as well as their new facile characterization strategies has elicited tremendous scientific interest. Herein, we demonstrate that modified cellulose nanowhisker with gallic acid pendant groups (CNW-GA) could effectively bind with CNW grafted with ß-Cyclodextrin (CNW-g-ß-CD) through HG interaction to form fully biocompatible and low-cost supramolecular hydrogel. Also, we reported an easy and efficient colorimetric characterization method for confirming HG complexation using naked eye. The possibility of this characterization strategy evaluated both experimentally and theoretically using DFT method. Also, phenolphthalein (PP) was used for visual detection of HG complexation. Interestingly, PP undergoes a rearrangement in its structure in presence of CNW-g-ß-CD because of HG complexation that turns the purple molecule into a colorless compound in alkaline condition. Addition of CNW-GA to the resulting colorless solution turned the color to purple again which easily confirmed HG formation.

Influence of donor-acceptor groups on the electrical and optical properties of C50 fullerene.

In this research, the C50 fullerene was employed as the source of the π electrons and the electron donor-acceptor groups were used to enhance its optical properties. Considerable enhancement in its electronic and optical property of C50 as the result of donor and acceptor group presence was observed. For instance, in UV-Visible absorption spectrum, the number of absorption lines significantly increase which may be the relaxation of the electronic transition selection rules. Considerably, the substituted forms of C50, have numbers of absorption bands in near infrared region. The BH2-C50-NCH3Li and NO-C50-NCH3Li molecules have superior improvement in optical properties. Finally, the donor and acceptor groups influence on non-linear optical properties (NLO) of C50 was explored and the considerable improvement in NLO properties of C50 was observed in which the NLO improvements for BH2-C50-NCH3Li and NO-C50-CH2Li cases is higher than others.

Improving the optical properties of [5] circulene with different electron donors and acceptor substitutions (push-pull system).

In this research, the circulene molecule was selected, and the electron donor and acceptor groups were attached to improve its optical properties. Large negative values of enthalpies, Gibbs free energies, and exothermic energies of formation for these molecules, especially for the CN-CIR-NHLi molecule, show that their formation is highly reasonable. It was illustrated that the Eg of the circulene molecule was lowered in the electron donor and acceptor groups' presence, while the CN-CIR-NHLi and CF3-CIR-NHLi molecules have the lowest values of Eg. It was observed that the optical properties of circulene molecules were improved in electron donor and acceptor groups' presence. Between these groups, the -CN and -CF3 as electron acceptors and -NHLi substituents, as electron donor groups, yield higher enhancements on the optical properties of circulene, which is in agreement with the results obtained for Eg values. Graphical abstract.

Design of novel molecules with considerable optical properties based on polymer of BODIPY molecules.

In this research, the BODIPY molecule was selected; and based on its structure, using a different number of BODIPY molecules connected to each other, novel oligomers with significant electrical and optical properties were designed. After structural optimization, the frequency analysis and cohesive energy calculations were done to ensure the oligomers' stability. The electronic properties of the designed oligomers were studied; and it was shown that by increasing the numbers of BODIPY molecules in designed structures, their Eg was narrowed. Finally, it was shown that by increasing the numbers of BODIPY molecules in oligomers, a great improvement in optical properties such as increasing the number of absorption lines and intensity of them was observed. Among the designed oligomers, two di- and tri-BODIPY molecules have substantial optical properties with intense absorption lines in visible and near-infrared regions.

The influence of Sc doping on structural, electronic and optical properties of Be12O12, Mg12O12 and Ca12O12 nanocages: a DFT study.

Density functional theory (DFT) calculations were used to study the effect of scandium doping on the structural, energetic, electronic, linear and nonlinear optical (NLO) properties of Be12O12, Mg12O12 and Ca12O12 nanoclusters. Scandium (Sc) doping on nanoclusters leads to narrowing of their E g, which enhances their conductance greatly. Also, the polarizability (α) and first hyperpolarizability (ß0) of nanoclusters were dramatically increased as Be, Mg or Ca atoms are substituted with a Sc atom. Among all clusters, α and ß0 values for Sc-doped Ca12O12 were the largest. Consequently, the effect of the doping atom, as well as of cluster size, on electronic and optical properties was explored. Time dependent (TD)-DFT calculations were also carried out to confirm the ß0 values; the results show that the higher value of first hyperpolarizability belongs to Sc-doped Ca12O12, which has the smallest transition energy (ΔEgn). The results obtained show that these clusters can be candidates for using in electronic devices and NLO materials in industry.

Effects of the adsorption of alkali metal oxides on the electronic, optical, and thermodynamic properties of the Mg12O12nanocage: a density functional theory study.

The effect of alkali metal oxides M n O (M = Li, Na, K; n = 2, 3, 4) on the geometric, electronic, and linear and nonlinear optical properties of the Mg12O12 nanocage was investigated by density-functional-based methods. According to the computational results, these alkali metal oxides are adsorbed on the Mg12O12 nanocage because this adsorption reduces its energy gap. The static first hyperpolarizability (ß 0) of the nanocage is dramatically increased in the presence of the alkali metal oxides, with the greatest increase seen in the presence of the superalkalis (i.e., M3O; M = Li, Na, and K). The highest first hyperpolarizability (ß 0 ≈ 600,000 a.u.) was calculated for K3O@Mg12O12, which was considerably more than that for Mg12O12. The thermodynamic properties and relative stabilities of these inorganic compounds are discussed. Graphical Abstract Optimized structure and DOS spectrum of K3O(e@Mg12O12).