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9‐Br‐closo‐1,2‐C2B10H11 has been prepared and its gas‐phase structure has been examined by means of gas electron diffraction. The structure of the carbaborane core is similar to the structure of the parent compound, which is of C2v symmetry. A DFT‐based search for the corresponding reaction pathway of the bromination of closo‐1,2‐C2B10H12 revealed that the catalytic amount of aluminum reduces the barrier of the initial attack of the bromination agent toward the negatively charged part of the icosahedral carbaborane, i. e., the first transition state, from about 40 to about 27 kcalmol‐1. The Br−Br bond is weakened by an intermediate binding to the large π‐hole on the aluminum atom of AlBr3, which is the driving force for the AlBr3‐catalyzed bromination. [ABSTRACT FROM AUTHOR]

The thermally unstable α-fluoroalcohol undecafluorocyclohexanol (c-C6F11OH) was prepared by addition of hydrogen fluoride to the corresponding ketone. c-C6F10(CF3)OH was obtained by protonation of its alkoxide [NMe4]+[C7F13O]−. Decafluorocyclohexane-1,1-diol (c-C6F10(OH)2) was prepared by acidic workup of the corresponding alkoxide [NMe4]+[C6F11O]− with sulfuric acid, which yielded (c-C6F10(OH)2) and fluorosulfonic acid. The structures of c-C6F10(CF3)OH·2H2O and of (c-C6F10(OH)2) were elucidated by single-crystal X-ray and gas-phase electron-diffraction studies. [ABSTRACT FROM AUTHOR]

Abstract: Disulfuryl dichloride ClSO2OSO2Cl was characterized by vibrational spectroscopy in the gaseous and liquid phase as well as in the Ar‐matrix. By varying the temperature, certain bands could be assigned to several conformers. Gas‐phase electron diffraction revealed a dominance of the anti‐conformer at ambient temperature. The same conformation was found in the solid state. Via the in situ technique for crystallization, not less than four different modifications were identified. Among these different modifications, the structural parameters of the molecules remain relatively constant, but the aggregation pattern changes. Although the molecules aggregate by chlorine⋅⋅⋅oxygen contacts in each modification, the geometrical parameters of these interaction show significant differences and were evaluated and are in part inconsistent with the halogen bonding concept. [ABSTRACT FROM AUTHOR]

Fluoromethyl triflate (superfluoromethyl, SFM, FCH2OSO2CF3) and fluoromethyl fluorosulfonate (magic fluoromethyl, MFM, FCH2OSO2F) are two easily synthesized, highly effective and non-ozone depleting fluoromethylation reagents. They are analogous to the well-known and widely used methylation re-agents CH3OSO2CF3 and CH3OSO2F. Both SFM and MFM have been fully characterized by multinuclear NMR spectroscopy (1H, 13C, 17O, 19F, 33S). Their structures have been determined in the solid state on in situ grown crystals by X-ray diff-raction and in the gas phase by electron diffraction. The fluoromethylation efficiency of SFM and MFM was shown by reaction with chalcogen nucleophiles of differing nucleophilicity. All fluoromethylated products were isolated as pure com-pounds and charac-terized by NMR and vibrational spec-troscopy, as well as in some cases by single crystal X-ray diffraction., (© 2024 Wiley‐VCH GmbH.)

The reactivity of the frustrated Lewis pair (FLP) (F 5 C 2 ) 3 SnCH 2 P(tBu) 2 (1) was investigated with respect to the activation of elemental hydrogen. The reaction of 1 at elevated hydrogen pressure afforded the intramolecular phosphonium stannate(II) (F 5 C 2 ) 2 SnCH 2 PH(tBu) 2 (3). It was characterized by means of multinuclear NMR spectroscopy and single crystal X-ray diffraction. NMR experiments with the two isotopologues H 2 and D 2 showed it to be formed via an H 2 adduct (F 5 C 2 ) 3 HSnCH 2 PH(tBu) 2 (2) and the subsequent formal reductive elimination of pentafluoroethane; this is supported by DFT calculations. Parahydrogen-induced polarization experiments revealed the formation of a second product of the reaction of 1 with H 2 , [HP(tBu) 2 Me][Sn(C 2 F 5 ) 3 ] (4), in 1 H NMR spectra, whereas 2 was not detected due to its transient nature., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

9-Br-closo-1,2-C 2 B 10 H 11 has been prepared and its gas-phase structure has been examined by means of gas electron diffraction. The structure of the carbaborane core is similar to the structure of the parent compound, which is of C 2v symmetry. A DFT-based search for the corresponding reaction pathway of the bromination of closo-1,2-C 2 B 10 H 12 revealed that the catalytic amount of aluminum reduces the barrier of the initial attack of the bromination agent toward the negatively charged part of the icosahedral carbaborane, i. e., the first transition state, from about 40 to about 27 kcalmol -1 . The Br-Br bond is weakened by an intermediate binding to the large π-hole on the aluminum atom of AlBr 3 , which is the driving force for the AlBr 3 -catalyzed bromination., (© 2020 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

Three 1,2-diaryltetramethyldisilanes X 5 C 6 -(SiMe 2 ) 2 -C 6 X 5 with two C 6 H 5 , C 6 F 5 , or C 6 Cl 5 groups were studied concerning the importance of London dispersion driven interactions between their aryl groups. They were prepared from 1,2-dichlorotetramethyldisilane by salt elimination. Their structures were determined in the solid state by X-ray diffraction and for free molecules by gas electron-diffraction. The solid-state structures of the fluorinated and chlorinated derivatives are dominated by aryl-aryl interactions. Unexpectedly, Cl 5 C 6 -(SiMe 2 ) 2 -C 6 Cl 5 exists exclusively as an eclipsed syn-conformer in the gas phase with strongly distorted Si-C 6 Cl 5 units due to strong intramolecular interactions. In contrast, F 5 C 6 -(SiMe 2 ) 2 -C 6 F 5 reveals weaker interactions. The contributions to the total interaction energy were analyzed by SAPT calculations., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

An improved synthesis of the simplest nitric acid ester, methyl nitrate, and a new synthesis of fluoromethyl nitrate use the metathesis of the corresponding iodomethanes with silver nitrate. Both compounds were identified by spectroscopy and the structures determined for in situ grown crystals by X-ray diffraction as well as in the gas phase by electron diffraction. Fluorination leads to structures with shorter C-O and N-O bonds, has an energetically destabilizing effect and increases friction sensitivity, but decreases detonation performance., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

The structures of the three para-substituted halotetrafluoropyridines with chlorine, bromine, and iodine have been determined in the solid state (X-ray diffraction). The structures of these compounds and that of pentafluoropyridine were also determined in the gas phase (electron diffraction). Structures in the solid state of the bromine and iodine derivatives exhibit halogen bonding as a structure-determining motif. On the way to an investigation of halogen bond formation of halotetrafluoropyridines in the solid state with the stronger Lewis base pyridine, co-crystals of benzene adducts were investigated to gain an understanding of the influence of aryl-aryl interactions. These co-crystals showed halogen bonding only for the two heavier halotetrafluoropyridines. In the pyridine co-crystals halogen bonding was observed for all three para-halotetrafluoropyridines. The formation of homodimers and heterodimers with pyridine is also supported by quantum-chemical calculations of electron density topologies and natural bond orbitals., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermally unstable α-fluoroalcohol undecafluorocyclohexanol (c-C6F11OH) was prepared by addition of hydrogen fluoride to the corresponding ketone. c-C6F10(CF3)OH was obtained by protonation of its alkoxide [NMe4]+[C7F13O]-. Decafluorocyclohexane-1,1-diol (c-C6F10(OH)2) was prepared by acidic workup of the corresponding alkoxide [NMe4]+[C6F11O]- with sulfuric acid, which yielded (c-C6F10(OH)2) and fluorosulfonic acid. The structures of c-C6F10(CF3)OH·2H2O and of (c-C6F10(OH)2) were elucidated by single-crystal X-ray and gas-phase electron-diffraction studies.