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The crystallization of 3‐chloroisonicotinic acid (3‐CINA) can lead to three crystal forms (I, II and III), but 3‐CINA in each form has different conformation. The three crystal forms have different lattice energies. The intermolecular interactions in the molecular pairs involving the conformer in each crystal were evaluated, it is found that the sum of these intermolecular interaction energies in each crystal has a linear relationship with the corresponding lattice energy. QTAIM analyses for the intermolecular interactions of molecular pairs correspond to Hirshfeld surface analyses for the crystal form, illustrating that the stability of the crystal is closely associated with the intermolecular interactions involving the conformer in the asymmetric unit of the crystal. 3‐chloroisonicotinic acid (3‐CINA) has three crystal forms (I, II and III), first principles investigation and Hirshfeld surface analysis have been employed to explore them. [ABSTRACT FROM AUTHOR]

To uncover the correlation between the bond length change and the corresponding stretching frequency shift of the proton donor D-H upon hydrogen bond formation, a series of hydrogen-bonded complexes involving HF and HCl which exhibit the characteristics of red-shifted hydrogen bond were investigated at the MP2/aug-cc-pVTZ, M062X/aug-cc-pVTZ, and B3LYP/aug-cc-pVTZ(GD3) levels of theory with CP optimizations. A statistical analysis of these complexes leads to the quantitative illustrations of the relations between bond length and stretching vibrational frequency, between bond length and bond force constant, between stretching vibrational frequency and bond force constant, between bond length and bond order for hydrohalides in a mathematical way, which would provide valuable insights into the explanation of the geometrical and spectroscopic behaviors during hydrogen bond formation. [ABSTRACT FROM AUTHOR]

• The mechanisms for organocatalytic synthesis of chiral allene by racemic propargylic alcohol and 3-phenylindole were proposed. • Eight possible reaction pathways were found after the dehydration process. • The intermolecular interactions including HBs and π-π interactions play crucial roles in determining the enantioselectivity. Organocatalytic synthesis of chiral allene can be successfully achieved through the reaction between propargylic alcohol and 3-phenylindole catalyzed by chiral phosphoric acid with high yield and high enantioselectivity. The detailed reaction mechanism and origin of enantioselectivity were uncovered by quantum mechanical calculations. The results indicate that the reactions undergo the dehydration process, the C–C bonding reaction, the hydrogen abstraction and the regeneration of catalyst. Eight possible pathways were found and the most favorable reaction paths leading to the major and minor products were evaluated which were consistent with the experimental results. The distortion/interaction analyses of the transition states in enantioselectivity-determining steps confirm the most favorable pathway in leading the major product. QTAIM and IGM analyses are used to illustrate the role of intermolecular interactions. EDA analysis is also employed to understand the origin of selectivity. This work would provide insightful viewpoints on the asymmetric organocatalytic reaction by chiral phosphoric acid. [Display omitted] [ABSTRACT FROM AUTHOR]

The high-energetic and low-sensitive explosive material of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) was theoretically investigated by first principles calculations and Hirshfeld surface analysis. The experimental and partly optimized LLM-105 crystals were compared which indicated that it is important to correct the hydrogen positions. Hirshfeld surface analyses of the experimental and partly optimized LLM-105 crystals were also compared, which showed that the intermolecular H⋯O interactions significantly contribute to the stability of the LLM-105 crystal, while the contributions of other intermolecular interactions in the experimental and partly optimized LLM-105 crystals are quite different. The geometrical and electronic structures of LLM-105 molecules in the experimental and partly optimized crystals as well as that in the gas phase were compared. QTAIM analysis was employed to illustrate the existences of intermolecular interactions in the molecular pairs taken from partly optimized LLM-105 crystal, and the types of intermolecular interactions from QTAIM analysis are in agreement with the results of Hirshfeld surface analysis. The reason why the LLM-105 molecule in the partly optimized crystal adopts a non-coplanar structure in which the NO 2 and NH 2 groups is not coplanar with the six-membered ring is elaborated. The existence of cooperativity among different intermolecular interactions were verified by analysing the trimeric complexes formed among three LLM-105 molecules in the partly optimized crystal. The non-coplanar of the NO 2 and NH 2 groups with the six-membered ring in LLM-105 molecule is favorable in forming more intermolecular interactions which cooperate and stabilize the crystal. [Display omitted] • The explosive material of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) crystal was investigated theoretically. • The single LLM-105 molecule, the dimeric and trimeric complexes were analyzed. • The non-coplanar LLM-105 molecule favors the formation of more intermolecular interactions which stabilize the crystal. • The cooperativity among the intermolecular interactions was verified. [ABSTRACT FROM AUTHOR]

The rich π-electrons region of graphene enables it to be a good material which can interact with many organic molecules. As a low-sensitivity and high-energy explosive, 1,1-diamino-2,2-dinitroethene and its dimer possess unique characters including hydrogen bonds and π bond which can adsorb on graphene through physisorption. The results suggest that the adsorption energies have a very small difference on the different adsorption sites. Due to the physisorption, the geometrical and electronic properties of 1,1-diamino-2,2-dinitroethene and its dimer vary significantly. The intramolecular as well as intermolecular hydrogen bond strengths are considerably affected due to the π···π interaction of 1,1-diamino-2,2-dinitroethene or its dimer with graphene. The cooperativity between intermolecular hydrogen bonds and π···π interactions is observed which causes wax of intermolecular hydrogen bonds and wane of π···π interactions. The physisorption of 1,1-diamino-2,2-dinitroethene or its dimer also leads to the variation of electronic property of graphene. The physisorptions of 1,1-diamino-2,2-dinitroethene and its dimer on graphene have been investigated theoretically. Image 1 • The physisorptions of 1,1-diamino-2,2-dinitroethene and its dimer on graphene have been investigated theoretically. • The geometrical and electronic properties of 1,1-diamino-2,2-dinitroethene and its dimer vary significantly. • The cooperativity between intermolecular hydrogen bonds and π···π interactions is observed. • The physisorption of 1,1-diamino-2,2-dinitroethene or its dimer modulates the electronic property of graphene. [ABSTRACT FROM AUTHOR]