Raman and DFT study of the vibrational properties of some para‐substituted benzohydroxamic acids: towards an interpretation of SER spectra

Abstract

The vibrational properties of p-chloro-, p-methoxy-and p-nitrobenzohydroxamic acids (BHA) and of the unsubstituted BHA were investigated and the spectra were assigned. The assignment was made on the basis of the experimental information available about the Raman peaks of mono-and disubstituted benzenes and the procedure was greatly facilitated by the data obtained from high-level DFT quantumchemical calculations. In order to support an intended assignment of the SER spectra of BHA on copper, the molecular electrostatic maps and Fukui functions were derived from ab initio calculations. Both quantumchemical descriptors were shown to provide similar information about the possible BHA molecule-copper surface interaction sites.

Adsorption of some benzohydroxamic acid derivatives on copper oxide: assignment and interpretation of SERS spectra

“…The first one is connected with the lack of the vibrational wavenumbers assignment because the current compounds were never investigated by SERS before, and classification of their SERS spectra is not available. Their Raman spectra were previously described by us, 21 but the comparison of that spectra with those given in Fig. 1 shows significant differences.…”

“…we have shown that different p-substituents of BHA influence the maps of electrostatic potentials (MEP) and the Fukui functions (FF) in the region of the hydroxamic group. 21 On the basis of these results, it can be expected that in the case of relatively small molecules, and especially the ones containing aromatic rings with readily moving -electron density, the interaction between the functional and anchoring substituents can be significant. In fact, this change of the electronic structure can be used to improve the adsorption properties of the bonding group and might thus have a positive impact on the surface-molecular bonding.…”

“…On the other hand, it was proved earlier by means of MEP and FF that p-chloro, pmethoxy, and unsubstituted-BHA have a tendency to bind through the hydroxamic group while in the case of p-nitro a bonding by the nitro group cannot be excluded. 21 In view of those results, an investigation of the adsorption geometry of those compounds on Cu 2 O is necessary to correlate their chemical structure with their adsorption behavior.…”

Elucidation of the low coverage chiral adsorption assembly of l-lysine on Cu(110) surface: A theoretical study

“…This property has been used with success in the past to explain the reactivity of molecular [34] and periodic systems [35,36]. The electron density distribution can help us to understand the final geometry of the lysine adlayer.…”

Exploring the reactivity of intraframework vanadium, niobium and tantalum sites in zeolitic materials using the molecular electrostatic potential

“…Their molecular properties were investigated and their reactivity was studied using the Fukui function (f) [14][15][16], a DFT-based reactivity descriptor, known to predict the nucleophilic (f + ) and electrophilic (f À ) character of a molecular system. The Fukui function has been successfully used to solve related problems such as the wettability at a surface [17] or the regioselectivity of a molecule [18][19][20].…”