Shapes and Noncovalent Interactions of Oligomers:  The Rotational Spectrum of the Difluoromethane Trimer

Abstract

The trimer of difluoromethane, (CH2F2)3, has been characterized by supersonic jet Fourier transform microwave spectroscopy. The rotational spectrum displays all types (mu(a), mu(b), and mu(c)) of transitions, showing that the adduct does not possess any element of molecular symmetry. The investigation of the three 13C species in natural abundance indicates that the three carbon atoms form a triangle where the C-C distances are 3.648(2), 3.825(8), and 3.942(6) A, respectively. The three subunits are held together by nine CH...F weak hydrogen bonds.

Free jet rotational spectrum of the most stable conformer of 1-(2-fluorophenyl)-1-ethanol

“…More recently, homo-dimers arising from different conformers of glycidol have been revealed [13]. Also induced chiral oligomers, such as the dimer of ethanol [14] and the trimer of difluoromethane [15] have been observed by MW spectroscopy. In all cases the direct determination of the moments of inertia of the various species leaves little doubts about the conformations of the observed species.…”

What are the spectroscopic properties of HFC-32? Answers from DFT

“…[44][45][46][47][48][49]), molecular complexes (e.g., Refs. [50][51][52][53][54][55][56][57]), and conformational energetic and structures of biomolecules (e.g., Refs. [58][59][60][61]), by means of infrared (IR) and microwave (MW) spectroscopy.…”

Reduced bandwidth chirped-pulse microwave spectroscopy for analysis of weakly bound dimers: Rotational spectrum and structural analysis of CH2ClF⋯FHCCH2

“…Weakly bound dimers serve as prototype systems for weak CAHÁ Á ÁX interactions, where the polarity of the CAH bond can be tuned by varying the number and type of electronegative substituents to the carbon atom. While many studies have focused on complexes of CH 3 F [1][2][3], CH 2 F 2 [4][5][6][7][8][9][10][11], and CHF 3 (for example: [2,[12][13][14][15][16][17][18][19]) as the proton donor, more recent investigations have examined a variety of hydrochlorofluorocarbons as CAH donors [20][21][22][23][24][25]. In most of the halogenated methane complexes, cyclic structures have been observed in which a halogen atom also acts as a weak hydrogen bond acceptor.…”