Calculating singlet excited states: comparison with fast time-resolved infrared spectroscopy of coumarins

In contrast to the ground state, the calculation of the infrared (IR) spectroscopy of molecular singlet excited states represents a substantial challenge. Here we use the structural IR fingerprint of the singlet excited states of a range of coumarin dyes to assess the accuracy of density functional theory based methods for the calculation of excited state IR spectroscopy. It is shown that excited state Kohn-Sham density functional theory provides a high level of accuracy and represents an alternative approach to time-dependent density functional theory for simulating the IR spectroscopy of the singlet excited states

Acidic ionic liquids: Promising and cost-effective solvents for processing of lignocellulosic biomass

The efficacy of ionic liquids in pretreatment and production of renewable or platform chemicals from lignocellulosic biomass have been substantiated by many research studies. The search for more efficient, low cost and less toxic ionic liquids is still an active research subject. Acidic ionic liquids (AILs)are a type of IL which has emerged as very attractive pretreatment solvents. This review described the recent developments on biomass processing ability and efficiency of different AILs. Different influential process variables are also look over for their impact on biomass pretreatment, deconstruction and yields of various targeted platform chemicals i.e. 5-hydroxymethylfurfural (5-HMF), levulinic acid (LA)etc., total Reducing Sugars (TRS)and depolymerized products of lignin. The review also highlights the associated problems of ionic liquids i.e. challenges in utilization for the biorefinery, stability, recycling and environmental hazards, that faces in its utilization for biomass processing. The cost is a key factor in any chemical process, therefore, an overview of the cost-effectiveness of AILS have been provided

Development of collagen/PVA composites patches for osteochondral defects using a green processing of ionic liquid

Osteochondral defects are still a big challenge for the surgeons because of good biocompatibility and higher mechanical strength requiring issues of the implants. In this study, different concentrations of collagen (dissolved in ionic liquid) up to 60% were blended with polyvinyl alcohol to prepare hydrogels of good mechanical strength, with the best biocompatibility and excellent fluid uptake ability. Ionic liquid was used as a green solvent for dissolution of collagen at a higher concentration as compared to other normal solvents. The prepared hydrogels were characterized with Fourier transform infrared spectroscopy (FTIR) which showed the characteristic peaks assigned to collagen and PVA. The surface morphology was investigated using scanning electron microscopy (SEM) which revealed homogeneity of the composite patches. Thermal gravimetric analysis (TGA) performed for samples show good thermal stabilities. Fluid uptake ability showed the massive uptake of fluid by the hydrogels. Biocompatibility was tested using hemolysis and MTT assay. Electrodynamic fatigue testing system was used for evaluating the mechanical properties and measured the tensile strength in the range of 2.4 to 8.5 MPa. The prepared osteochondral patches show good biocompatibility and mechanical properties