Discerning Site Selectivity on Graphene Nanoflakes Using Conceptual Density Functional Theory Based Reactivity Descriptors

Abstract

Graphene nanoflakes (GNFs) have more configurational degrees of freedom as compared to Graphene nanoribbons (GNRs) and are viable candidates for future nanodevices. GNFs can be devised with disparate geometries, and their electronic properties can be fine-tuned by genuine chemical functionalization. Hence, it is vital to know specific sites on GNFs where reaction is most feasible for chemical functionalization with donor− acceptor functional groups (nucleophiles/electrophiles). Here, we present spinpolarized and dispersion-corrected density functional theory based relative reactivity descriptor calculations to shed light on the reactivity pattern in smallsized GNFs. To have a clear understanding on the structure−property relationship, we consider GNFs with 24, 42, and 54 carbon atoms having various edges, namely, fully armchair, armchair/zigzag (arm-zig), and fully zigzag. All the edge atoms are saturated by hydrogen atoms. On the basis of the symmetry of the GNFs, susceptibility of assorted reactive sites pertinent to nucleophilic and electrophilic attacks is anticipated using relative reactivity descriptors. Further, we validate these relative reactivity descriptors for nucleophilic attack on armchair-C 24 H 14 and zigzag-C 24 H 12 by explicit adsorption of OH − , NH 2 − , and H 2 O molecules. Our study reveals that the reactivity pattern varies in small-sized GNFs as a function of shape. Importantly, few specific structural isomers have alternate Lewis acid−base pairs. It also manifests how the reactivity of peripheral and interior carbon atoms differ with shape and size of GNFs. With a discernment on site selectivity, GNFs can be functionalized by proper donor−acceptor groups at specific sites and hence can be used as potential candidates for molecular-and nanoelectronics.

Probing the Interaction of Nucleobases and Fluorophore‐Tagged Nucleobases with Graphene Surface: Adsorption and Fluorescence Studies

“…The optimized geometry of C 42 H 16 surface displays near planarity and the −C−C− bond lengths ∼1.42 Å in good agreement with previous reports . We have examined the binding affinity of nucleobases (A, C, G, and T) on to zigzag‐shaped graphene (C 42 H 16 ) surface . We have initially examined the surface of the graphene by MESP and the nucleobases in figure .…”

“…[45][46][47] We have examined the binding affinity of nucleobases (A, C, G, and T) on to zigzag-shaped graphene (C 42 H 16 ) surface. [48] We have initially examined the surface of the graphene by MESP and the nucleobases in figure 1. The MESP depicts the red region as the negative potential and the blue region depicts the positive potential.…”

Dinitrogen Activation on Graphene Anchored Single Atom Catalysts: Local Site Activity or Surface Phenomena

“…A DFT study carried out by Nazrulla et al on different graphene nanoflake sizes reported that, given a spin state and nanoflake size, the armchair isomer is more reactive than the zigzag isomer. 32 An intensive study carried out by Yu et al on graphene sheets to explore the reactive carbon edge responsible for oxygen reduction reaction (ORR) predicted the armchair edge to more active than the zigzag edge. 33 Another work by Owens showed a gradual decrease in the band gap with the increase in chain length of both armchair and zigzag graphene isomers.…”

How reliable is DFT in predicting relative energies of polycyclic aromatic hydrocarbon isomers? comparison of functionals from different rungs of jacob's ladder

“…DFT has been extensively used for modeling reactions involving PAHs and calculating their chemical properties (see, e.g., Refs. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] ). The ability of DFT to predict of the relative energies of PAHs and to accurately describe potential energy surfaces involving PAHs is of central importance to many of these studies.…”