@article {48714,
	title = {"Weak" C-H{\textbullet}{\textbullet}{\textbullet}S interaction drives enantioselectivity in cinchona alkaloid complex catalyzed thiocyanation},
	journal = {Chemistry-An Asian Journal},
	volume = {18},
	year = {2023},
	month = {JUL},
	pages = {e202300321},
	type = {Article},
	abstract = {<p>
	The great success of asymmetric organocatalysis has made it one of the most important advancements made in chemistry in the past two decades. A significant achievement in this context is the asymmetric organocatalysis of the thiocyanation reaction. In the current study, computational studies with density functional theory have been done in order to understand an interesting experimental finding: the reversal of enantioselectivity from R to S when the electrophile is changed from beta-keto ester to oxindole for the thiocyanation reaction with the cinchona alkaloid complex catalyst. The calculations reveal an unusual fact - the principal reason for the reversal is the presence of the C-H center dot center dot center dot S noncovalent interaction, which is present only in the major transition states in each of the two nucleophile cases. Only recently has it been realized that the supposedly weak C-H center dot center dot center dot S noncovalent interaction has the properties of a hydrogen bond, and the fact that this interaction is the cause of enantioselectivity has relevance, because of the large number of asymmetric transformations involving the sulphur heteroatom.</p>
},
	keywords = {Density functional calculations, Enantioselectivity, noncovalent interactions, organocatalysis, reaction mechanisms},
	issn = {1861-4728},
	doi = {10.1002/asia.202300321},
	author = {Banerjee, Subhrashis and Vanka, Kumar}
}
@article {49840,
	title = {Pushing the boundaries of pnictogen-bonding organocatalysis: a clash of Sb(III) versus Bi(III)},
	journal = {ChemPhysChem},
	volume = {26},
	year = {2025},
	month = {AUG },
	pages = {e202500265},
	type = {Article},
	abstract = {<p>
	The sigma-hole-mediated noncovalent organocatalysis involving the pnictogen (Pn) elements has thus far been explored mostly from nitrogen to antimony, with antimony identified as the most effective catalyst. Herein, density functional theory calculations have been carried out to demonstrate that tri-aryl (Ar)-substituted bismuth(III) complexes can outperform their antimony counterparts in both anion (Cl-) binding and catalytic activity. Using a range of computational methods, a good correlation between the sigma-hole strength, chloride binding affinity, and the reaction barrier is established. Notably, the findings reveal that dispersion interactions are the dominant force in catalysts with weaker sigma-holes, while electrostatic interactions prevail in catalysts with stronger sigma-holes (for the anion abstraction step). In all cases, Bi(III) catalysts emerge as the winner over the Sb(III) analogues. Additionally, beyond the primary Pn. . .Cl interactions, several secondary interactions such as Cl. . .H/F-C(Ar) and Cl-. . . H-C(Si-TBS) also play a significant role in stabilizing the transition states.</p>
},
	keywords = {Antimony, Bismuth, organocatalysis, pnictogen, sigma (sigma) holes},
	issn = {1439-4235},
	doi = {10.1002/cphc.202500265},
	author = {Sharma, Jyoti and Dash, Soumya Ranjan and Vanka, Kumar}
}
