The nature of iodine-amine solutions

Schug, John C.; Kogan, Michael J

doi:10.1016/0022-2364(73)90067-x

Cited by 11 publications

(18 citation statements)

References 17 publications

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“…In all cases, the chemical shift moves downfield but the magnitude of the shift is dependent on I − /I 2 concentration. 94,95 These results are consistent with the interaction of sulfur and octylamine, where the amine protons shift as a function of sulfur concentration, which is correlated to the degree of protonation. 101 When I 2 and OAm are left to mix overnight, the downfield shifts increase indicating a higher degree of protonation and a change in the chemical environment due to interaction with I 2 (SI, Figure S30).…”

Section: Resultssupporting

confidence: 76%

“…Thermodynamically favorable formation of 1:1 complexes by the mixture of the dilute solutions of iodine and amine in nonpolar solvents has been known for a long time, and the resulting turbid solutions are indicative of ionic species formation. − When solely considering the interaction between amines and I 2 , the primary amine could be oxidized by I 2 to form iodoamines (RNHI) and in the presence of an excess of amines, could form air-sensitive substituted hydrazine complexes, which can also act as reducing agents. − Control experiments, in which OAm is either mixed or heated under MW reaction conditions with I 2 , do not show evidence for substituted hydrazine formation. Iodine is considered to act as a Lewis acid catalyst in these reactions.…”

Section: Results and Discussionmentioning

confidence: 99%

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Halogen-Induced Crystallinity and Size Tuning of Microwave Synthesized Germanium Nanocrystals

et al. 2019

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The reduction of Ge halides in oleylamine (OAm) provides a simple, yet effective high-yield synthetic route to germanium nanocrystals (NCs). Significant advances based on this approach include size control of Ge NCs, Bi doping of Ge NCs, and synthesis of Ge1–x Sn x alloys. It has been shown that the size of Ge NCs can be controlled by the ratio of Ge2+/Ge4+ in the reaction. Here, we show that finer control of absolute size and crystallinity can be achieved by the addition of molecular iodine (I2) and bromine (Br2) to germanium(II) iodide (GeI2). We also show the presence of a Ge–amine–iodide complex and production of hydrogen and ammonia gases as side products of the reduction reaction. All reactions were carried out by microwave-assisted heating at 250 °C for 30 min. I2 and Br2 are shown to oxidize GeI2 to GeI4 in situ, providing good control over size and crystallinity. The kinetics of Br2 oxidation of GeI2 is slightly different, but both I2 and Br2 provide size control of the Ge NCs. The samples are highly crystalline as indicated by powder X-ray diffraction, selected area electron diffraction, transmission electron microscopy and Raman spectroscopy. Although both I2 and Br2 improve the crystallinity of the Ge NCs, I2 provides overall higher crystallinity in the NCs compared to Br2. Absorption (UV–vis–NIR) spectroscopy is consistent with quantum confinement for Ge NCs. The solutions of I2, GeI2, and colloidal Ge NCs were investigated with Fourier transform infrared and 1H NMR spectroscopies and showed no evidence for imine or nitrile formation. The hydrogen on the amine in OAm is shifted downfield with increasing amounts of I2, consistent with a more acidic ammonium species. Hydrogen and ammonia gases were detected after the reaction by gas chromatography and high-resolution mass spectrometry. The presence of a Ge–amine–iodide complex was also confirmed with no evidence for a hydrazine-like species. These results provide an efficient fine-tuning of size and crystallinity of Ge NCs using halogens in addition to the mixed-valence precursor synthetic protocol previously reported and demonstrate the formation of hydrogen as a reducing agent in OAm.

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Section: Resultssupporting

confidence: 76%

Section: Results and Discussionmentioning

confidence: 99%

Halogen-Induced Crystallinity and Size Tuning of Microwave Synthesized Germanium Nanocrystals

et al. 2019

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“…Upon addition of the substrate benzylamine, the initially purple I 2 solution in 1,2-dichlorobenzene underwent a characteristic color change to yellow, which may be attributed to an amine-induced reduction of iodine to iodide. 55 The activity of I 2 as a catalyst, as well as the key role of dioxygen Open Access Article. Published on 04 September 2020.…”

Section: Mechanistic Insightmentioning

confidence: 99%

Anion–cation synergistic metal-free catalytic oxidative homocoupling of benzylamines by triazolium iodide salts

Byrne

Albrecht

2020

Org. Biomol. Chem.

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“…17 The mechanism leading to alkyl ammonium iodide by reacting amines with iodine has been already hypothesized in the 70s: 18 it was proposed that the reaction goes through an oleylamine-iodide charge transfer complex, followed by a proton-iodine exchange, resulting in alkyliodoamine, hydro iodic acid and triiodide species (Scheme SI1 of the Supporting Information, SI,). 18 Finally, the in situ formed HI reacts with the alkylamine, resulting in the alkylammonium iodide. This last step coincides with the synthesis of alkylammonium halides by reaction of amines with hydrogen halide solutions.…”

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confidence: 98%

Molecular Iodine for a General Synthesis of Binary and Ternary Inorganic and Hybrid Organic–Inorganic Iodide Nanocrystals

et al. 2018

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We report the synthesis of various binary and ternary inorganic and hybrid organic-inorganic iodide nanocrystals starting from molecular iodine (I2). The procedure utilizes a reaction between I2 and oleylamine that yields oleylammonium iodide -the iodide precursor for a subsequent preparation of nanocrystals. The syntheses are facile, carried out under air, in vials heated on a hotplate and deliver nanocrystals with narrow size distributions and, in the case of red and near infrared-emitting lead-based perovskites, with 70-80% photoluminescence quantum yields. The The latter were used to fabricate red and infrared bright light-emitting diodes, with external quantum efficiencies (EQE) exceeding 3%.Metal halide nanocrystals (NCs) have gained increasing attention in past years. [1][2][3] Among these metal halide NCs, the halide perovskite (APbX3 with A = Cs + , methyl ammonium (MA) or formamidinium (FA), B = Pb 2+ or Sn 2+ and X = Cl -, Bror I -) NCs are by far the most studied ones, due to their excellent optical properties and their relatively simple synthesis methods. [1][2]4 The strong interest in these halide perovskite NCs has also motivated the development of synthesis approaches for other colloidal halide based NCs. This interest is mainly driven by the search for lead-free perovskite alternatives to the Pb-based ones for applications in photovoltaics and lighting. This has led for instance to reports on synthesis of ternary Cs2SnI6, Cs3Bi2X9 and Cs3Sb2X9 NCs, and quaternary Cs2AgBiX6 double perovskite NCs. [5][6][7][8][9] Another group of interesting new metal halide NCs emerging from the perovskite NC research are the Cs4PbX6 NCs, as well as simple cesium halide NCs. [10][11]

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The nature of iodine-amine solutions

Cited by 11 publications

References 17 publications

Halogen-Induced Crystallinity and Size Tuning of Microwave Synthesized Germanium Nanocrystals

Halogen-Induced Crystallinity and Size Tuning of Microwave Synthesized Germanium Nanocrystals

Anion–cation synergistic metal-free catalytic oxidative homocoupling of benzylamines by triazolium iodide salts

Molecular Iodine for a General Synthesis of Binary and Ternary Inorganic and Hybrid Organic–Inorganic Iodide Nanocrystals

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