N/B/BN doping in graphene enhances adsorption of boranes.

Two series of oxo-bridged Co(III) complexes of the type Co(4)O(4)(O(2)CC(6)H(4)-X)(4)(py)(4) (1) and Co(4)O(4)(O(2)CC(6)H(4)-X)(4)(4-Mepy)(4) (2), where X = H (a), Me (b), MeO (c), Cl (d), NO(2) (e), have been synthesized and characterized in detail. The molecular structures of the complexes consist of a cubelike Co(4)(mu(3)-O)(4) core having Co and O atoms at alternate vertices with carboxylato ligands bridging the Co(3+) ions along four face diagonals of the approximate cube. Nitrogen atoms from pyridyl ligands complete the distorted-octahedral coordination around each Co(III). These neutral Co(III) complexes undergo a nearly reversible one-electron oxidation involving the redox couple [Co(4)(III)(mu(3)-O)(4)](4+) <--> [Co(3)(III)Co(IV)(mu(3)-O)(4)](5+) at potentials (approximately 0.7-1.0 V) that linearly depend on the electronic influence of X. The cobalt(III) clusters of types 1 and 2 have been found to effectively promote the TBHP oxidation of benzylic alcohols under homogeneous conditions to produce the corresponding carbonyl compounds.

The study presents a quantitative estimation of B-H b Á Á Áπ interaction in diboranelocalized-π half sandwiches and sandwiches. DFT-D3 method is used for geometry optimization and estimating the stability of the complexes (in terms of stabilization energies). The diborane molecule is the source of bridging hydrogen and O 2 , C 2 H 4 , and C 2 H 2 molecules are considered as the localized π-systems. MP2 and CCSD(T) calculations are also performed to measure the stability of the chosen complexes. Results indicate that the complexes are feebly stable in gas phase with stabilization energies <5.0 kcal mol −1 . Compared to DFT-D3 functionals, MP2 calculations are found to be more suitable in predicting the stability of the complexes. Dispersive interaction is the primary mode of interaction in stabilizing the complexes. Presence of substituents either on diborane or on the considered π-systems play key role in stabilizing the complexes. Thermochemical analysis demonstrates the exothermic nature of complexation. 1 H and 13 B NMR analysis are also performed. K E Y W O R D S B-H b Á Á Áπ interaction, CCSD(T), DFT-D3, dispersion interaction, MP2, sandwich

Effect of doping B and/or N on the reactivity, aromaticity and absorption spectra of graphene and functionalized (–OH and –COOH) carbon cluster mimicking graphene is studied using DFT, DFRT and TD-DFT.

Density functional theory calculation on BAH b :X interaction (X5 N, O, P, S, F, Cl, Br) is performed. HOMO energy predicts the feasibility of such complexation. Steric and electronic effects play significant role on geometry of the complexes. Interaction energy suggests that the interaction is moderately strong (< 5.00 kcal mol 21 ) in nature and the complexes are stable in both gas and solvent phase. Electron donating group on: X facilitates the interaction whereas electron withdrawing group impedes the same. MP2 and CCSD(T) calculations further confirm the suitability of xB97X-D and M06-2X functional for studying such interactions. Dispersive interaction is the primary mode of interaction in stabilizing the complexes. 1 H NMR and IR study are also performed.Thermochemical analysis advocates exothermic nature of complexation.B2H b :X interaction, CCSD(T), DFT, MP2, stabilization energy, thermochemical analysis 1 | I N TR ODU C TI ON Noncovalent interactions such as hydrogen bonding, stacking, dispersion interaction, hydrophobic interaction, interaction with p systems (anionÁÁÁp, CAHÁÁÁp, OAHÁÁÁp, NAHÁÁÁp, SAHÁÁÁp, cationÁÁÁp) and halogen bonding have drawn attention owing to their potential application in different fields [1][2][3][4] and play significant role in controlling different physical, chemical, and biological phenomena in crystal engineering, drug designing, protein folding, molecular recognition process, and supramolecular chemistry. [2,[5][6][7][8][9][10][11][12][13][14] These interactions are classified depending on their origin, nature, and strength. [8] Hydrogen bonding is one of the most versatile and extensively studied noncovalent interaction [15][16][17] that plays an essential role in the function, dynamics, and structure of biological and chemical systems. Hydrogen bonding interactions can be either conventional or nonconventional. [18] In conventional hydrogen bonding, DAHÁÁÁA, both D (donor) and A (acceptor) atoms are highly electronegative (usually N, O, F) whereas in nonconventional case D and A may both be less electronegative.A relatively new and less known nonconventional interaction is the BAHÁÁÁp interaction in which both terminal (H t ) and bridging (H b ) hydrogens of boranes interact with interaction in which both terminal (H t ) and bridging (H b ) hydrogens of boranes interact with electron rich p systems. [19,20] However, partially negative H t (H d-) of borane is reluctant to form stable BAH t ÁÁÁp interactions. In contrast, H b is partially positive (H d1 ) due to its involvement in the formation of two electron-three center (2eA3c) bond and thereby results a stable BAH b ÁÁÁp interaction. [20] Recently, new type of noncovalent interaction involving lone pairs (nonbonded pairs) has also been explored. [8] Lone pair of electrons not only control the geometry but also play a decisive role in the chemistry of the species. Amongst the interactions involving lone pair, lone pairÁÁÁp interaction is widely studied [4,18] and was first identified in the structure of Z-DNA. [21] How...

Sandwich and multidecker complexes via organic π–inorganic π interaction.

Adsorption of seven 5-membered N-heterocycles on B/N/BN-doped graphene (with coronene as a model system) has been studied using density functional theory (DFT). The geometry of the complexes validated the involvement of both π···π stacking and N–H···π interaction in the adsorption process. The stability of the complexes is measured in terms of stabilization energy, and the results suggested that the complexes are stable enough (stabilization energies are in the range of 7.61–14.77 kcal mol –1 ). Studies confirmed the stability of complexes in the solvent phase too irrespective of the dielectric of the solvent. Dispersive force is the major mode of interaction in stabilizing the complexes. Natural bond orbital analysis indicated a small contribution from electrostatic and covalent interactions. Thermochemical analysis revealed that the complexation is exothermic in nature and favorable at a lower temperature. Adsorption of N-heterocycles exerts a nominal impact on the electronic properties of the undoped/doped graphene. The study presents a simple approach to introduce an arbitrary functionality to undoped/doped graphene by preserving its electronic properties.

No abstract