The Stability of Tetrabutylammonium Tetrachloroiodide¹

From Square‐Planar [ICl4]− to Novel Chloroiodates(III)? A Systematic Experimental and Theoretical Investigation of Their Ionic Liquids

“…Generally,t wo modes of decomposition were considered:t he decomplexation reaction to yield [ICl 4 ] À and I 2 Cl 6 and alternatively the elimination of dichlorine to yield compounds comprising iodine in the oxidation state + I, which is analogoust ot he reported behaviour [10,28] for the [ICl 4 ] À anion.T os hed some light on these questions, we have performed extensive quantum-chemical calculations form onoanions containing up to three iodinea toms in either the oxidation state + Io r+ III. Generally,t wo modes of decomposition were considered:t he decomplexation reaction to yield [ICl 4 ] À and I 2 Cl 6 and alternatively the elimination of dichlorine to yield compounds comprising iodine in the oxidation state + I, which is analogoust ot he reported behaviour [10,28] for the [ICl 4 ] À anion.T os hed some light on these questions, we have performed extensive quantum-chemical calculations form onoanions containing up to three iodinea toms in either the oxidation state + Io r+ III.…”

“…However,t he Ramans pectra of the obtainedm ixtures were inconclusive. [10] The melting behaviour of [ 4 ], only the last transition to form orange liquids, with simultaneous evolution of gas, was observed at (62 AE 5) 8Ca nd (85 AE 5) 8C, respectively. The results indicated al ower than expected chlorine content with deviations of 30 %f rom the expected ratio of I À to Cl À .T he final procedure, applied to all reactions sketched in Figure 4, was therefore modified.…”

“…10 8C) and [BMP] 2 [Br 20 ]( m.p. 137-139 8C), [10] which can be considered to be an adduct of ICl 3 and Cl À .I Ls of triatomic anionso ft he general type [XY 2 ] À have already been studied as reagents in organic synthesis [11] and as electrolytes for dye sensitised solar cells. [7] By combining more than one kind of halogen, for example dihalogens X 2 or interhalogens XY n with halidesZ À ,agreat variety of polyinterhalogenm onoanions is accessible.…”

“…Inorganic salts of the tetrachloroiodate anion werep ublished as early as 1839; [22] its molecular structure was later determined by single-crystal X-Ray Diffraction (scXRD), [23,24] and furthera nalysed by UV/Vis, [10] vibrational [25,26] and nuclear quadrupole resonance( NQR) spectroscopy. [27] The relative instabilityo ft etrachloroiodate salts in respect to the elimination of elemental dichlorine to yield the [ICl 2 ] À anion,w as investigated on experimental grounds both fort he decomposition in solution [10] and in the solid state.…”

“…[28] Buckles andM ills noted that the evolution of dichlorine from the tetramethylammonium salts was faster than for the tetrabutylammoniums alts, and that, upon irradiation, the chlorination of the butyl residue combined with the evolution of HClt ookp lace. [10] Like many others after them [29] ,t hey also studied the reactivity of organic tetrachloroiodate salts towards double bond containing organic substances. If compared to reactions with elementald ichlorine, they found as imilar, but more controlledr eaction under the influenceo ft hese salts.…”