The Structure of the Other Rotamer of Formic Acid, cis-HCOOH^1,2

Abstract

The very weak microwave spectra of six isotopically substituted species of formic acid in the eis rotamer form (i.e. with the two hydrogen atoms eis to each other) have been studied. From the data on HC 18 OOH, HCO^OH, H^COOH, HCOOD, DCOOH and DCOOD, together with the previously published data for HCOOH, the complete substitution structure of the eis rotamer of formic acid has been derived. The structure is: rs(C-H) = 1.105 (4)

New theoretical insight into the interactions and properties of formic acid: Development of a quantum-based pair potential for formic acid

“…4 More importantly the transition state for the cis-trans rearrangement lies 12.97 kcal/mol above the lower minimum. The calculated structural parameters of the monomer are within the error bars for the gas-phase measurements 41,42 (Table I). The subtle differences between the cis and trans isomers are also well reproduced.…”

Vibrational spectroscopy of cis- and trans-formic acid in solid argon

“…To make the integrals involved in the CC-VSCF calculation more tractable and to reduce the above trans-HCOOH [15]. The optimized MP2/6-311++G(2d,2p) geometrical parameters are given together with the experimental values from [30] in parenthesis. Angles are in degrees and bond length in angstroms.…”

“…This leads to a shortening of the C@O and O-H bond distances and a lengthening of the C-O bond distance, as well as the decrease of the OCO angle in the cis configuration when compared to the trans form [15,30,31]. The structural differences arising from the mesomerism do not have a counterpart on the C-O stretching mode (mC-O) because it is generally a very mixed vibration.…”

Rotational Spectra of cis-HCOOH, trans-HCOOH, and trans-H13COOH

“…and DCOOD together with the previously published data for HCOOH using Kraitchman's equations for a planar molecule (2). The substitution structures of both the cis-and the transrotamer, together with the dipole moment vectors, are shown in Fig.…”

“…1 Present address: Department of Physics, The Ohio State University, Columbus, OH 43210. 2 Present address: Institute for Environmental Management Technology, AIST Tsukuba-West, Onagawa 16-1, Tsukuba 305-8569 Japan. 3 Present address: Institute of Applied Physics, Russian Academy of Science, 46 Ulyanova St., 603600 Nizhny Novgorod, Russia.…”