Nitrosonium tetrafluoroborate

Acetonitrile (CH₃CN) was purchased from Honeywell (Burdick and Jackson, 99.9%) and used as received. The Carbowax^TM employed, polyethyleneglycol bisphenol A epichlorohydrin copolymer (mol wt 15,000–20,000 Da), was purchased from Sigma Aldrich, and was ground by mortar and pestle prior to use to encourage dissolution. Kapton^TM polyimide tape (1″ × 3 m, silicone adhesion) was purchased from McMaster-Carr. Nitrosonium tetrafluoroborate (98%) was purchased from Alfa Aesar and was used as received. Concentrated nitric acid (reagent grade) was purchased from Fisher Scientific and used as received. Titanium(IV) isopropoxide (97%) was purchased from Sigma Aldrich and was used as received. Tetraethylammonium chloride (anhydrous) was prepared by drying tetraethylammonium chloride hydrate (98%, Alfa Products) by literature methods^{41 (link)}.

Indium acetate [In(ac)₃, 99.99%], zinc acetate [Zn(ac)₂, 99.99%], chloroform-d (CDCl₃, 99.8%, contains 0.03% TMS), diisopropyl azodicarboxylate (DIAD, 98%), trioctylamine (TOA, 98%), selenium (Se, 99.99%), sulfur (S, 99.98%), tetrahydrofuran (THF, 99.8%), hydrofluoric acid (HF, 48%), and trichloromethane-d₁ (CDCl₃, 99.9%, contains 0.5 wt% silver foil as stabiliser) were purchased from Sigma-Aldrich. Oleic acid (OA, 99%), trioctylphosphine (PR’₃, 97%), stearic acid (99%), nitrosonium tetrafluoroborate (NOBF₄, 98%), N,N-dimethylformamide (DMF, 99.8%), 1-octadecene (ODE, 99%), and dichloromethand-d₂ (CD₂Cl₂, 99.9%) were purchased from Alfa Aesar. Squalane was purchased from Acros Organics. Tris(trimethylsilyl)phosphine [(TMS)₃P, 99.9%] was purchased from Uniam. All chemicals were used as received.