Dimethyl sulphoxide

CNOs were obtained according to the method proposed by Kuznetsov,^{72 (link)} in which diamond nanoparticles (NDs, Carbodeon µDiamond Molto) with a diameter of 4.2 ± 0.5 nm and a ND content of ≥97 wt% were annealed. All the chemicals and solvents were commercially available and used without further purification: nanodiamond powder (µDiamond®Molto, Carbodeon); 1,2-dicyanobenzene (∼98%, Sigma-Aldrich); ammonia solution (25% pure p.a., Sigma-Aldrich); maleimide (∼99%, Sigma-Aldrich); tetrahydrofuran (pure p.a., Avantor); 2-propanol (pure p.a., Avantor); acetone (99.5% pure p.a., Avantor); 2-mercapto-4-methyl-5-thiazoleacetic acid (∼98%, Sigma-Aldrich); zinc chloride (≥99%, Sigma-Aldrich); nickel(ii) chloride (∼98%, Sigma-Aldrich); copper(ii) chloride (∼97%, Sigma-Aldrich); hydrochloric acid (35–38% pure p.a., Avantor); sulphuric acid (95% pure p.a., Avantor); sodium chloride (pure p.a., Avantor); aluminium powder (∼99.99%, Avantor); sodium (Sigma); 1-octanol (≥95%, Sigma-Aldrich); potassium permanganate (Avantor); dimethyl sulphoxide (DMSO, pure p.a., Avantor); and methanol (99.5% pure p.a., Avantor).