Matrix-isolation infrared studies of 1:1 molecular complexes containing chloroform (CHCl3) and Lewis bases: seamless transition from blue-shifted to red-shifted hydrogen bonds.
The infrared spectra of molecular complexes containing chloroform (CHCl(3)) and Lewis bases (N(2), CO, H(2)O, and CH(3)CN) have been observed in an Ar matrix, and vibrational peaks for the 1:1 complexes have been assigned. The C-H stretching band of chloroform in the complexes showed a seamless transition from a blue shift (for N(2) and CO) to a red shift (H(2)O and CH(3)CN), in accord with the proton affinity of the base molecules. Density functional calculations predicted that the C-H··(σ-type lone pair) isomer is the most stable, which is consistent with the observed vibrational peak shift upon complex formation. The underlying mechanisms of the C-H hydrogen bond were explored using the topological properties of the electronic charge density and natural orbital analyses.
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba-West, Onogawa 16-1, Tsukuba, Ibaraki 305-8569, Japan. f-ito@aist.go.jp
Fumiyuki
F
Ito
D000097:Acetonitriles / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry; D002725:Chloroform / Q000737:chemistry*; D003116:Color; D006860:Hydrogen Bonding; D058115:Lewis Bases / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D014867:Water / Q000737:chemistry
D000097:Acetonitriles; D058115:Lewis Bases; D014867:Water; D002248:Carbon Monoxide; D002725:Chloroform; D009584:Nitrogen; C032159:acetonitrile