Halogenated Gold(III) Complexes Containing 4-Cyanopyridine: Synthesis, Characterization, and Crystal Structure

Supramolecular Aggregation of Perfluoroorganyl Iodane Reagents in the Solid State and in Solution

“…In both acid adducts of 4, the acidic proton is unambiguously located at the iodane oxygen atom, as verified by X-ray structural analysis (see below). Additionally, the two products could be characterized thoroughly by 1 H, 19 F, and 13 C NMR spectroscopy. For [4-H]NTf 2 in dry CDCl 3 , a sharp 1 H NMR signal at δ = 6.76 ppm was observed for the acidic proton, whereas a similar signal was not visible for [(4) 2 H]BArF.…”

“…The compounds are highly soluble in acetonitrile, chloroform, and dichloromethane. The new derivatives 6-9 were characterized by 1 H, 13 C, and 19 F NMR spectroscopy as well as elemental analysis (C, H) and high-resolution mass spectrometry. The crystalline H[SbF 6 ] adduct of acid reagent 1, that is, [1-H][SbF 6 ]·H 2 O, was accidentally obtained through the hydrolysis of NO[SbF 6 ] in a mixture with reagent 1 in CH 2 Cl 2 (Scheme 3a).…”

“…For [4-H]NTf 2 in dry CDCl 3 , a sharp 1 H NMR signal at δ = 6.76 ppm was observed for the acidic proton, whereas a similar signal was not visible for [(4) 2 H]BArF. The latter compound displays only one set of 1 H, 19 F, and 13 C NMR signals; therefore, the acidic proton seems to undergo rapid dynamic exchange between the two iodane moieties. The 19 F NMR signal is drastically downfield-shifted compared with that of 4 (δ = -40.1 ppm), and the shift is remarkably similar for both compounds {δ = -22.9 pm for [4-H]NTf 2 and -22.6 ppm for [(4) 2 H]BArF}.…”

“…Thereby, a square‐planar coordination of the iodine atom is highly favored and can be compared with the coordination geometries of structurally related metal compounds such as gold(III) complexes. In the latter, the Au atom displays square‐planar coordination with four ligands, but the fifth and sixth coordination site are additionally readily occupied in the crystalline state through secondary bonding interactions with free donor moieties (Scheme a) . For this reason, we wondered if similar additional bonding interactions are relevant for trivalent iodine to result in formal penta‐ or hexacoordination.…”

“…In the latter, the Au atom displays square-planar coordination with four ligands, but the fifth and sixth coordination site are additionally readily occupied in the crystalline state through secondary bonding interactions with free donor moieties (Scheme 2a). [18][19][20] For this reason, we wondered if similar additional bonding interactions are relevant for trivalent iodine to result in formal penta-or hexacoordination. Thus, it would be meaningful to distinguish between "secondary" (i.e., the occupancy of the fourth coordination site leading to square-planar coordination) and "tertiary" bonding interactions (i.e., the occupancy of further coordination sites through even weaker iodine-donor contacts, Scheme 2b).…”