Computational Investigation of Multifaceted Cationic Rearrangement and Stereo- and Regioselectivity in the Formation of Dysideanone's Analogues.

Mechanistic studies of regiodivergent arylations of cycloalkanols to furnish enantioenriched dysideanone's analogues are performed by employing density functional theory (DFT) calculations (B3LYP-D3(SMD)/6-311++G**//B3LYP-D3/6-31+G** level of theory). On the basis of our calculations, remote γ'-C-H arylation is preferred for unsubstituted carbinol 1, an outcome from combined factors like carbocationic stability, less steric hindrance during C-C coupling, and facile dearomatization. Meanwhile, in the presence of dimethyl substituent 1Me, regioselective γ-arylation is favored by 3.4 kcal/mol, and both findings are in agreement with the reported experimental observations. Most importantly, we concur that the barrier associated with the formation of carbocation 6 and its substituted analogues correlates with the C-H arylation outcomes. Furthermore, the ß-arylation route remains unlikely for all the reaction pathways explored in this study.

"Visualizing" the partially reversible conversion of gold nanoclusters via the Au23(S-c-C6H11)17 intermediate.

Transformation chemistry of atomically precise metal nanoclusters has emerged as a novel strategy for fundamental research on the structure-property correlations of nanomaterials. However, a thorough understanding of the transformation mechanism is indeed necessary to understand the structural growth patterns and corresponding property evolutions in nanoclusters. Herein, we present the ligand-exchange-induced transformation of the [Au23(SR)16]- (8e-) nanocluster to the [Au25(SR')18]- (8e-) nanocluster, through the Au23(SR)17 (6e-) intermediate species. Identification of this key intermediate through a partially reversible transformation helped in a detailed investigation into the transformation mechanism with atomic precision. Moreover, photophysical studies carried out on this Au23(SR)17 species, which only differs by a single ligand from that of the [Au23(SR)16]- nanocluster reveal the property evolutions at the slightest change in the nanocluster structure.

Energy level alignments between organic and inorganic layers in 2D layered perovskites: conjugation vs. substituent.

2D layered hybrid perovskites have attracted huge attention due to their interesting optoelectronic properties and chemical flexibility. Depending upon their electronic structures and properties, these materials can be utilised in various optoelectronic devices like photovoltaics, LEDs and so on. In this context, study of the excited energy levels of the organic spacers can help us to align the excited energy levels of the organic unit with the excitonic level of the inorganic unit according to the requirement of a particular optoelectronic device. We have explored the role of 3-phenyl-2-propenammonium on the electronic structure of a perovskite containing this cation as a spacer. Our results clearly demonstrate the active participation of conjugated ammonium spacers in the electronic structure of a perovskite. Also, we have considered a variety of amines to identify the best alignment with common inorganic units and studied the role of substituents and conjugation on the energy level alignment. Placing the triplet excited level of an organic spacer below the lowest excitonic level of the inorganic unit can induce energy transfer from the inorganic to organic unit, finally resulting in phosphorescence emission. We have shown that the triplet energy level of 3-anthracene-2-propeneamine/3-pyrene-2-propeneamine can be tuned in such a way that there can be an excitonic energy transfer from the Pb2I7/PbI4 inorganic unit-based perovskites. Therefore, perovskite material with such combinations of organic spacer cations will be very useful for light emission applications.