@article {50161,
	title = {From brittle to elastic: substituent effects on mechanical flexibility in aromatic amide crystals},
	journal = {Chemistry-An Asian Journal},
	volume = {21},
	year = {2026},
	month = {MAY},
	pages = {e70795},
	type = {Article},
	abstract = {<p>
	Mechanical flexibility in molecular crystalline materials represents a compelling paradigm shift from the long-held perception of crystals as inherently brittle solids. Herein, we demonstrate a brittle-to-elastic transition by subtle molecular modification in a pair of structurally analogous aromatic amides; N-[(4-methoxyphenyl)methyl]formamide (N4MFA, Crystal 1) and N-benzylformamide (NBFA, Crystal 2). Despite their close structural similarity, Crystal 1 exhibits brittle fracture under minimal stress, whereas Crystal 2 shows 1D elastic flexibility with reversible bending. Structural, computational, and mechanical analyses reveal that this contrast arises from substituent-controlled supramolecular packing. In Crystal 1, the methoxy (-OCH3) group promotes dense, anisotropic packing, leading to rigidity and fracture under stress. Removing the substituent in Crystal 2 enhances isotropy, pi-pi stacking, and interlocked packing, enabling reversible strain during elastic bending. Nanoindentation, energy framework, and elastic tensor analyses confirm this transition: Crystal 2 shows near-isotropic stiffness (E max/E min = 1.65) and interconnected energy networks, whereas Crystal 1 exhibits pronounced anisotropy (E max/E min = 3.95) and 1D cohesion. Hirshfeld surface analysis supports more balanced contacts in the elastic crystal. This work establishes a direct structure-mechanical correlation, showing that minor chemical modifications can tune flexibility and provide insights to guide the development of adaptive crystalline materials.</p>
},
	keywords = {crystal engineering, Elasticity, Mechanical property, nanoindentation, responsive crystals},
	issn = {1861-4728},
	doi = {10.1002/asia.70795},
	author = {Bhowmik, Aritra and Das, Nirmal and Saxena, Ashish Kumar and Mishra, Kamini and Barsu, Nagaraju and Mishra, Manish Kumar}
}
@article {50108,
	title = {Phosphine radical cation catalysis for Markovnikov hydroamination of unactivated alkenes},
	journal = {Journal of Chemical Sciences},
	volume = {138},
	year = {2026},
	month = {APR },
	pages = {51},
	type = {News Item},
	abstract = {<p>
	Markovnikov-selective hydroamination of unactivated terminal alkenes has long remained a challenging transformation in C-N bond formation. Fan and co-workers1 addressed this using a metal-free phosphine photoredox system that operates via an unprecedented phosphine radical cation (P(IV)) mechanism, enabling alkene activation toward azole addition. This work highlights a powerful new strategy for C(sp3)-N bond construction beyond traditional transition-metal catalysis.Graphical abstractMetal-free phosphine photoredox catalysis enables Markovnikov-selective hydroamination of unactivated terminalalkenes via a novel phosphine radical cation mechanism, off ering a new strategy for C(sp3)-N bond formation.</p>
},
	keywords = {azoles, hydroamination, Markovnikov selectivity, Phosphine catalysis, photoredox, radical cation},
	issn = {0974-3626},
	doi = {10.1007/s12039-026-02522-x},
	author = {Das, Nirmal and Barsu, Nagaraju}
}
