title: Experimental evidence for the blue-shifted hydrogen-bonded complexes of CHF3with π-electron donors.
abstract: Blue-shifted hydrogen-bonded complexes of fluoroform (CHF3) with benzene (C6H6) and acetylene (C2H2) have been investigated using matrix isolation infrared spectroscopy and ab initio computations. For CHF3-C6H6complex, calculations performed at the B3LYP and MP2 levels of theory using 6-311++G (d,p) and aug-cc-pVDZ basis sets discerned two minima corresponding to a 1:1 hydrogen-bonded complex. The global minimum correlated to a structure, where the interaction is between the hydrogen of CHF3and the π-electrons of C6H6and a weak local minimum was stabilized through H…F interaction. For the CHF3-C2H2complex, computation performed at MP2/aug-cc-pVDZ level of theory yielded two minima, corresponding to the cyclic C-H…π complex A (global) and a linear C-H…F (n-σ) complex B (local). Experimentally a blue-shift of 32.3cm-1and 7.7cm-1was observed in the ν1C-H stretching mode of CHF3sub-molecule in Ar matrix for the 1:1 C-H…π complexes of CHF3with C6H6and C2H2respectively. Natural bond orbital (NBO), Atoms-in-molecule (AIM) and energy decomposition (EDA) analyses were carried out to explain the blue-shifting and the nature of the interaction in these complexes.
authors.affiliation: Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, India; Homi Bhabha National Institute, Kalpakkam 603102, India.
authors.forename: R
authors.initials: R
authors.lastname: Gopi
authors.affiliation: Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, India.
authors.forename: N
authors.initials: N
authors.lastname: Ramanathan
authors.affiliation: Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, India; Homi Bhabha National Institute, Kalpakkam 603102, India. Electronic address: sundar@igcar.gov.in.
authors.forename: K
authors.initials: K
authors.lastname: Sundararajan
keywords: Ab initio; Acetylene; Benzene; Blue-shifted hydrogen bond; Fluoroform; H…π complex; Infrared; Matrix isolation