02499nas a2200241   4500008004100000022001400041245010600055210006900161260000900230300001100239490000800250520167900258653001101937653000801948653004201956653002301998653002102021100002402042700003002066700002602096700001702122856011802139       2022                        eng d  a0014-305700aStructure-property insights into chiral thiophene copolymers by direct heteroarylation polymerization0 aStructureproperty insights into chiral thiophene copolymers by d  cDEC   a1116760 v1813 a<p>
	Chiral thiophene copolymers with fluorene as co monomer are designed having N-Boc-L-glutamic acid-1-tert-butyl ester as a chiral substituent located either on the thiophene unit or the fluorene unit with varying spacer length. The atom-economic direct heteroarylation polymerization (DHAP) method is utilized for the polymerization. Gibb's free energy (delta G) for polymerization determined using DFT calculations indicate difficulty in achieving high molar mass when the bulky chiral substituents are attached through short spacer to the backbone. The experimental observations are in agreement with the theoretical calculations with no polymer-ization or very low molar mass sticky compounds obtained for reactions with predicted + &amp; UDelta;G values. Structure -property relationship are compared for two chiral polymers -P4 and P5 having the chiral substitution on thiophene and fluorene units respectively. No CD signal is observed in THF-a good solvent where the polymers are molecularly dissolved. Intense bisignated CD signal is observed for both polymers upon addition of methanol - a poor solvent, to their THF solution. The bisignate CD signal with maxima at lower wavelength and inflection point associated with the pi-pi* absorption band is characteristic of exciton coupling between polymer chains in a left handed helical orientation. Small differences are observed in the intensity of the CD signal for the polymers P4 and P5 highlighting the impact of steric hindrance of bulky pendant groups on polymer conformation. DHAP is an atom economic polymerization procedure that can be gainfully utilized for developing chiral conjugated polymers.</p>
10achiral10aDFT10aDirect heteroarylation polymerization10aGibb?s free energy10aSteric Hindrance1 aNikam, Shrikant, B.1 aSingh, Chandrodai, Pratap1 aKrishnamurty, Sailaja1 aAsha, S., K.  uhttps://library.ncl.res.in/content/structure-property-insights-chiral-thiophene-copolymers-direct-heteroarylation02182nas a2200229   4500008004100000022001400041245012100055210006900176260000800245300001200253490000700265520138100272653002501653653002101678653000801699653002201707653001501729100002401744700003001768700002601798856012801824       2023                        eng d  a0892-702200aUnderstanding the thermal stability of a 3d, 4d, and 5d element doped aluminium nanocluster through BOMD simulations0 aUnderstanding the thermal stability of a 3d 4d and 5d element do  cFEB  a245-2500 v493 a<p>
	Endohedrally doped atomic clusters have generated considerable interest among computational chemists on account of their tunable chemical properties that mimic a super atom. Such endohedrally doped clusters have also been experimentally realised in the more recent past. The present work explores the practical existence of 3d, 4d and 5d doped aluminium clusters, more specifically doped Al13 cluster, by evaluating systematically their structural stability through the first principle molecular dynamical simulations. Born-Oppenheimer Molecular Dynamics (BOMD) simulations have been carried out on Al12X atomic clusters where X = Ti, V, Fe, Co, Ni, Cu, Zn, Y, Mo, Ru, Rh and W are in endohedral position. The thermal stability of such endohedrally doped clusters is quantified through parameters such as delta(rms), MSD and is an element of(pro). Electronic structure calculations reveal that endohedral doping of only Rh, Cu and Zn is preferred in the Al-13 cluster. Other dopants prefer to remain on the surface positions. However, finite temperature calculations reveal that the Al12Zn cluster undergoes surface modifications from 300K leading to a distorted icosahedral structure. Al12Cu cluster in quartet spin state is the only thermally stable cluster with Cu remaining in the endohedral position and structure retaining icosahedral confirmation till 700K.</p>
10aAl-13 atomic cluster10aBOMD simulations10aDFT10aEndohedral doping10asuper atom1 aSamudre, Nikhil, S.1 aSingh, Chandrodai, Pratap1 aKrishnamurty, Sailaja  uhttps://library.ncl.res.in/content/understanding-thermal-stability-3d-4d-and-5d-element-doped-aluminium-nanocluster-through