2 aminothiophenol

Starting 1H-indole-3-carboxaldehyde (purity 97%), furfural (99%), 2-thiophenecarboxaldehyde (98%), 4-pyridinecarboxaldehyde (97%), cyclohexanecarbaldehyde (97%), 1,2-phenylenediamine (99.5%), 2-aminothiophenol (99%), benzoyl chloride (99%), iodomethane (99%), benzyl bromide (98%), and n-butyllithium solutions (2.5 M in hexanes) were purchased from Sigma-Aldrich (St. Louis, MO, USA). The reagents for the analysis of the antimicrobial activity were as follows: cefazolin—MP Biomedicals (Illkirch, France); cefotaxime—PROMED (Saransk, Russia); amikacin sulfate—Sigma-Aldrich (St. Louis, MO, USA); rifampicin—GERBU (Gaiberg, Germany); fluconazole—Sigma-Aldrich (St. Louis, MO, USA); isoniazid—Sigma (St. Louis, MO, USA); LB broth—VWR (Radnor, PA, USA); and LB agar—Sigma (St. Louis, MO, USA).

Acetic acid (99.8%), chitosan (MW = 45 kDa, degree of acetylation >75.0%), hydrogen tetrachloroaurate III trihydrate (HAuCl₄·3H₂O, 99.9%), and N-(2-Hydroxyethyl) piperazyne-N’-(2-ethanesulfonic acid) (HEPES), ammonia solution, glutaraldehyde solution, pyrocatechol, 2-aminothiophenol (≥99.0%), bisphenol-A (≥99.0%), 2-nitrophenol (98.0%), 4-aminothiophenol (97.0%), and 4-tert-butylcatechol (≥99.0%) were purchased from Sigma Aldrich. Phosphate buffered saline (PBS; pH 7.4, 0.1 M) was prepared with Na₂HPO₄, NaH₂PO₄ and NaCl salt also obtained from Sigma Aldrich (Darmstadt, Germany). Tri-sodium citrate dihydrate (99.0%) was obtained from Alfa Aesar (Kandel, Germany). Acetone, ethanol (98%), sulfuric acid (95%), hydrogen peroxide (30.0% in water), and 4-nitrophenol (≥99.5%) were purchased from Fluka (München, Germany).
Aqueous solutions were prepared using Milli Q water (resistivity 18.2 MΩ∙cm).
Boron-doped diamond electrodes were provided by NEOCOAT company (La Chaux-de-Fonds, Switzerland). 300 nm thick polycrystalline boron-doped diamond with boron concentration higher than 7000–8000 ppm was grown by MPECVD on a highly doped silicon substrate.

Iron(III) chloride hexahydrate 98%, iron(II) chloride tetrahydrate 99%, tetraethylortosilicate (TEOS), 98%,hexadecyltrimethylammonium bromide (CTAB), 2-hydroxybenzoic acid, triphenyl phosphite (TPP), tetrabutylammonium bromide (TBAB), 2-aminothiophenol, sodium hydroxide (NaOH), pyridine, 3-isocyanatopropyltriethoxysilane (ICTES), 3-iodopropyltrimethoxysilane (IPTMS), magnesium sulfate, and the nitrate salts of metal cations for fluorescence measurements, that is, Na⁺, K⁺, Ag⁺, Ca²⁺, Mg²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Ba²⁺, Hg²⁺, Pb²⁺, and Al³⁺, were purchased from Sigma Aldrich (Tres Cantos, Spain) and were used as received. Iron(III) nitrate nonahydrate, extra pure sodium acetate anhydrous, sodium hydrogen carbonate, ascorbic acid, and ethylene glycol were purchased from Scharlau (Móstoles, Spain) and were used as received, without further purification. Triethylamine (Et₃N) redistilled 99% was purchased from Fluka (Tres Cantos, Spain) and was used as supplied. Organic solvents such as THF and acetone were purchased from Carlo Erba (Sabadell, Spain) and were distilled and dried over appropriate drying agents. Ethanol was purchased from VWR (Barcelona, Spain) and Milli-Q (Merck-Millipore, Barlington, MA, USA) quality water was used in the experiments.