Probing the Low-Barrier Hydrogen Bond in Hydrogen Maleate in the Gas Phase:  A Photoelectron Spectroscopy and ab Initio Study

Abstract

The strength of the low-barrier hydrogen bond in hydrogen maleate in the gas phase was investigated by low-temperature photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of maleic and fumaric acid monoanions (cis-/trans-HO(2)CCH=CHCO(2)(-)) were obtained at low temperatures and at 193 nm photon energy. Vibrational structure was observed for trans-HO(2)CCH=CHCO(2)(-) due to the OCO bending modes; however, cis-HO(2)CCH=CHCO(2)(-) yielded a broad and featureless spectrum. The electron binding energy of cis-HO(2)CCH=CHCO(2)(-) is about 1 eV blue-shifted relative to trans-HO(2)CCH=CHCO(2)(-) due to the formation of intramolecular hydrogen bond in the cis-isomer. Theoretical calculations (CCSD(T)/ aug-cc-pVTZ and B3LYP/aug-cc-pVTZ) were carried out to estimate the strength of the intramolecular hydrogen bond in cis-HO(2)CCH=CHCO(2)(-). Combining experimental and theoretical calculations yields an estimate of 21.5 +/- 2.0 kcal/mol for the intramolecular hydrogen bond strength in hydrogen maleate.

Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

“…This advance not only allowed high-resolution PES data to be obtained by eliminating vibrational hot bands [42][43][44][45] but has also allowed temperature-dependent phenomena to be studied. [46][47][48][49][50] The first PES experiments performed using this newly built apparatus were the observation of C-H· · ·O hydrogen bonding in long-chain alkane carboxylate anions at low temperatures 46 and the vibrationally resolved PE spectra of C 60 − , allowing the electron affinity (EA) of C 60 to be measured with an accuracy of ±8 meV (2.683 ± 0.008 eV). 42 The largest anion that was completely vibrationally cooled using this instrument was the fullerene dimer oxide dianion, [C 60 OC 60 ] 2− with 121 atoms, for which vibrationally resolved PE spectra were obtained at low temperatures.…”

“…Despite some initial skepticism, it has proven to perform quite well by completely eliminating vibrational hot bands in PES [41][42][43][44][45] and observation of temperature-dependent effects. [46][47][48][49][50] Recent high-resolution experiments showed that rotational temperatures can reach down to 20-35 K (see Section VII C), while the trap is operated at 4.4 K. The biggest advantage of the 3D Paul trap is its ease of operation and its suitability for extracting ions for subsequent time-of-flight mass analyses. A number of cryogenic Paul traps have been built recently to conduct spectroscopy on cold ions, [71][72][73][74] in particular, Johnson and co-workers have developed it into a powerful cryogenic ion spectroscopy technique via H 2 tagging.…”

“…[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] Issendorff and coworkers have also coupled a cryogenic 12-pole linear ion trap with a magnetic-bottle PES analyzer for the study of atomic clusters. 114 The moderate resolution of the magneticbottle analyzer is sufficient for MCAs, for which no slow electrons are possible due to the RCB.…”

A multi-agent quantum Monte Carlo model for charge transport: Application to organic field-effect transistors

“…Despite some initial skepticism, it has proven to perform quite well by completely eliminating vibrational hot bands in PES [41][42][43][44][45] and observation of temperature-dependent effects. [46][47][48][49][50] Recent high-resolution experiments showed that rotational temperatures can reach down to 20-35 K (see Section VII C), while the trap is operated at 4.4 K. The biggest advantage of the 3D Paul trap is its ease of operation and its suitability for extracting ions for subsequent time-of-flight mass analyses. A number of cryogenic Paul traps have been built recently to conduct spectroscopy on cold ions, [71][72][73][74] in particular, Johnson and co-workers have developed it into a powerful cryogenic ion spectroscopy technique via H 2 tagging.…”

“…[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] Issendorff and coworkers have also coupled a cryogenic 12-pole linear ion trap with a magnetic-bottle PES analyzer for the study of atomic clusters. 114 The moderate resolution of the magneticbottle analyzer is sufficient for MCAs, for which no slow electrons are possible due to the RCB.…”