Electronic and thermal transport properties of the metallic antiferromagnet MnSn₂

Abstract

We report the structure, magnetic and electrical/thermal transport properties of the antiferromagnet MnSn2. Importantly, the existence of the two antiferromagnetic states below TN2 (~320 K) is confirmed by the magnetism...

Influence of hydrogen bonds on the reaction of guanine and hydroxyl radical: DFT calculations in C(H+)GC motif

“…Due to the large exchange correlation, the density functional M06-2X developed by Truhlar and Zhao has been demonstrated to describe noncovalent interactions very well [36][37][38][39] and has been successfully utilized to deal with problems corresponding to oxidative damage to DNA. 20,[40][41][42] Vibrational frequency analysis for stationary points was procedurally performed to validate their identity as a minimum or transition at the same theoretical level. The located stationary points without imaginary frequencies are characterized as minima and those with one imaginary frequency are first-order saddle points (transition states, TSs).…”

“…Unlike the reaction in free G, both resulting adduct radicals (G(C4-OH) and G(C5-OH) ) proceed with a facile hydrogen transfer (HT) from N2 to N3 of G with the aid of an ethereal water molecule before OH detachment, that has been reported to facilitate the dehydration of the OH-adduct. 20 The addition of explicit water appears to activate adduct radicals (Int2 and Int9) featuring lower stabilities of Int2w and Int9w, and the slightly elongated N2-H bond, which is 1.01 Å in Int2w and 1.02 Å in Int9w. Int2w and Int9w are deemed to be suitable precursors to furnish the HT through TS2 and TS6 with forward energy barriers of 81.8 and 95.6 kJ mol À1 , respectively.…”

“…17 However, our recent theoretical investigation on the reaction of HO and G in G-quadruplex DNA discerned the tendency for hydrogen abstraction from N2 deriving from the intervention of hydrogen bonding in the Gquadruplex context. 20 Due to the significant difference in the surroundings of G, the potential for H-abstraction by HO from N2 was explored in Tri, where models with and without water were established.…”

“…Indeed, the reactions of HO with free G have been extensively studied using various experimental techniques and theoretical methods (Scheme 1). [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Initially, the reactions were studied by O'Neill and his co-workers using pulse radiolysis, 7 where addition reactions at the C4, C5, and C8 atoms of G were predicted to be the dominant pathway. Afterward, Candeias and Steenken revisited the reactions and proposed that the addition reaction of HO with G at C4 and C5 sites leading to G(C4-OH) and G(C5-OH) dominates (B60-70%) over the addition to its C8 site forming G(C8-OH) (B17%).…”

“…23 A mechanistic study revealed that hydrogen abstraction from N2 leading to a neutral radical favoring G(N2-H) could compete with C8 addition in the G-quartet context, but the addition of HO to C4 and C5 of G was impeded. 20 It is the hydrogen bond (H-bond) that guides the degradation pathway of the reaction, leading to the dramatic difference in final damage products. Thus, elucidating the influence of hydrogen bonding is of great significance to fully understand the reaction between HO and G in the DNA context.…”