Comparative Theoretical Study on the Positional Preference for Functionalization of Two OH and SH Groups with (5,5) Armchair SWCNT

Abstract

Covalent sidewall functionalization of (5,5) armchair single-walled carbon nanotube by OH and SH groups has been investigated using density functional theory. Two possibilities for each of 1,2- (adjacent), 1,3- (alternate), and 1,4-additions were considered. Strong intramolecular O–H···O hydrogen bond plays an important role in determining the positions for attachment of two OH groups with SWCNTs and reaction feasibility. The reactions of OH addition(s) are considerably more exothermic than the reactions of SH addition(s). The addition of two OH or SH functional groups prefers to attach at adjacent (1–2 and 1–1′) and 1,4-positions (1–4 and 3–6) rather than at alternate carbon sites (1–3 and 2–6). Owing to the strong intramolecular hydrogen bond, 1,2-addition (1-2-OH) is slightly more favored (by 2.4 kcal/mol) than 1,4-addition (1-4-OH), while 1,4-addition of two SH groups (1-4-SH) is more feasible (by 10 kcal/mol) than 1,2-addition (1-2-SH). Interestingly, the addition reactions of two SH groups at altern...