Variation in IR and Raman Spectra of CD₃CN upon Solvation of InCl₃in CD₃CN: Distinctive Blue Shifts, Coordination Number, Donor-Acceptor Interaction, and Solvated Species

Abstract

Notable blue shifts of the ν2 C≡N stretching, ν4 C-C stretching and ν8 CCN deformation bands of CD3CN are observed upon solvation of InCl3, resulting from the donor-acceptor interaction. The Raman spectrum in the ν2 region shows further details; at least two new bands emerge on the blue side of the ν2 band of free CD3CN, whose relative intensities vary with concentration, suggesting that there exist at least two different cationic species in the solution. The strong hydrogen bonds formed between the methyl group and InCl4− result in a large band appearing on the red side of the ν1 CD3 symmetric stretching band. The solvation number of InCl3, determined from the Raman intensities of the C≡N stretching bands for free and coordinated CD3CN, increases from ~1.5 to ~1.8 with decreasing concentration.

Power of Infrared and Raman Spectroscopies to Characterize Metal-Organic Frameworks and Investigate Their Interaction with Guest Molecules

“…The C–N stretching modes of the free CD 3 CN molecule are observed at 2263.1 cm –1 . Upon coordination of the nitrile group via the N atom, donation of a nitrogen lone pair from a slightly antibonding orbital occurs.…”

“…The C−N stretching modes of the free CD 3 CN molecule are observed at 2263.1 cm −1 . 605 Upon coordination of the nitrile group via the N atom, donation of a nitrogen lone pair from a slightly antibonding orbital occurs. As a result, the C−N modes of CD 3 CN shift to higher wavenumbers: the higher the frequency, the stronger the bond.…”

Mechanism of Ferric Chloride Facilitating Efficient Lithium Extraction from Magnesium-Rich Brine with Tri-n-butyl Phosphate

“…41,42 The bands at 321, 113, and 94 cm −1 in the Raman spectrum of the In(III)−A336 phase are characteristic for [InCl 4 ] − , as reported at 321, 112, 89 cm −1. 43,44 The band at 291 cm −1 is attributed to [InCl 5 ] 2− , as reported at 293 cm −1 . 45 Although InCl 3 is extracted by Aliquat 336 mainly as [InCl 4 ] − , a small amount of [InCl 5 ] 2− can form, depending on the A336-to-InCl 3 ratio.…”

“…The Raman spectrum of the Fe­(III)–A336 phase shows three bands at 333, 134, and 109 cm –1 , respectively, which match very well with the Raman bands of [FeCl 4 ] − at 334, 132, and 112 cm –1 . , The bands at 321, 113, and 94 cm –1 in the Raman spectrum of the In­(III)–A336 phase are characteristic for [InCl 4 ] − , as reported at 321, 112, 89 cm –1. , The band at 291 cm –1 is attributed to [InCl 5 ] 2– , as reported at 293 cm –1 . Although InCl 3 is extracted by Aliquat 336 mainly as [InCl 4 ] − , a small amount of [InCl 5 ] 2– can form, depending on the A336-to-InCl 3 ratio. , The bands at 308, 231, and 156 cm –1 in the Raman spectrum of the Sn­(IV)–A336 phase can be attributed to [SnCl 6 ] 2– , as reported at 307, 239, and 160 cm –1 .…”

The DFT Quest for Possible Reaction Pathways, Catalytic Species, and Regioselectivity in the InCl3-Catalyzed Cycloaddition of N-Tosyl Formaldimine with Olefins or Allenes

“…As in the case of aluminum­(III) chloride, InCl 3 forms a layer-based crystal structure composed of an indium­(III) central layer and closely packed chloride anions. Cho and co-workers investigated the solution behavior of indium­(III) chloride in acetonitrile using infrared and Raman spectroscopic methods, finding that there is a decomposition of InCl 3 to an [InCl 2 (CH 3 CN) 2–5 ] + cation and an InCl 4 – anion. Furthermore, by DFT calculations and experimental studies, Yu et al also confirmed that, in 1,2-dichloroethane and toluene solution, InCl 2 + can represent the catalytically active species derived from InCl 3 via the following reaction of the dissociation: 2InCl 3 = InCl 2 + + InCl 4 – .…”