PKa determination of graphene-like materials: Validating chemical functionalization
Tipo
Artigo
Data de publicação
2016
Periódico
Journal of Colloid and Interface Science
Citações (Scopus)
75
Autores
Orth E.S.
Ferreira J.G.L.
Fonsaca J.E.S.
Blaskievicz S.F.
Domingues S.H.
Dasgupta A.
Terrones M.
Zarbin A.J.G.
Ferreira J.G.L.
Fonsaca J.E.S.
Blaskievicz S.F.
Domingues S.H.
Dasgupta A.
Terrones M.
Zarbin A.J.G.
Orientador
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
© 2016 Elsevier Inc.We report a novel pKa determination for different graphene-like samples: graphene oxide (GO), reduced GO (rGO), graphene nanoribbons (GNR), oxidized GNR (GONR), thiol- and imidazole-functionalized GO (GOSH and GOIMZ, respectively) and thiol-functionalized GONR (GONRSH). Using the specialized computational program BEST7 for treating titration curves, pKas for different functional groups were discriminated (confirmed by infrared spectra) and their composition quantified. Overall, three equilibria were distinguished, two relative to carboxylic acids exhibiting different acidic degrees (pKa1~4.0 and pKa2~6.0) and one relative to alcohols (pKa4~10.0). Upon functionalization on carboxylate sites, thiol (pKaGOSH/GONRSH=6.7) and imidazole (pKaGOIMZ=6.6) moieties were discerned, followed by a decrease of their carboxylate percentage (compared to the precursors), thus allowing determining the degree of functionalization (48% and 36% of thiol content for GOSH and GONRSH respectively, and 29% of imidazole for GOIMZ). The proposed method is innovative and simpler when compared to the traditional tools usually employed to quantify chemical functionalization.
Descrição
Palavras-chave
Assuntos Scopus
Chemical functionalization , Computational program , Degree of functionalization , Functionalizations , Graphene nano-ribbon , Graphene nanoribbons (GNR) , Infrared spectrum , PKa determination