Does the recent IUPAC definition on hydrogen bonding lead to new intermolecular interactions?

نویسنده

  • Rajendra Parajuli
چکیده

Hydrogen bonding interaction is one of the most important intermolecular interactions. This interaction has been known almost for a century, but it is popular only after the work of Pauling, who was the first to give a definition of the hydrogen bond. According to Pauling, ‘under certain conditions an atom of hydrogen is attracted by rather strong forces to two atoms, instead of only one, so that it may be considered to be acting as a bond between them. This is called the hydrogen bond’. This interaction may be designated as X–HY. X–H is the hydrogen bond donor in which X and H are covalently bound and Y is the acceptor. Pauling considered both X and Y to be electronegative atoms mainly O, N, F. There are many systems which would not be considered as hydrogen bonds according to Pauling’s definition. One example is the C–HO interaction. This is now accepted as weak hydrogen bond, as the interaction plays an important role in many systems. After the work of Pauling, numerous experimental and theoretical studies on these interactions have been made, from which it is now well established that X can be any atom or a fragment whose overall electronegativity is more than that of hydrogen and Y can be any electron-rich region in a molecule, such as a lone pair,  pair, unpaired and  electrons. A recent report has recognized the diverse nature of hydrogen bond donors and acceptors. The study of hydrogen bonding is of special interest for a variety of reasons. It is one of the most common interactions and is found in many systems. The relatively high boiling point of water is a classic example of hydrogen bonds. Hydrogen bonding interaction is found in biological systems. It plays a role in determining the shapes of folded proteins and in linking base pairs in strands of DNA. According to the new IUPAC definition, the hydrogen bond is an attractive interaction between a hydrogen atom from a molecule or a molecular fragment X–H in which X is more electronegative than H, and an atom or a group of atoms in the same or a different molecule, in which there is evidence of bond formation. From this definition, this interaction may be designated as X–HY–Z. With following criteria given in the IUPAC report this interaction it is now believed to be fully understood. (a) The forces involved in the formation of a hydrogen bond include those of an electrostatic origin, those arising from charge transfer between the donor and acceptor leading to partial covalent bond formation between H and Y, and those originating from dispersion. (b) The atoms X and H are covalently bonded to one another and the X–H bond is polarized, the H–Y bond strength increasing with the increase in electronegativity of X. (c) The X–H—Y angle is usually linear (180), and closer the angle is to 180, stronger is the hydrogen bond and shorter is the HY distance. (d) The length of the X–H bond usually increases on hydrogen bond formation leading to a red shift in the infrared X–H stretching frequency and an increase in the infrared absorption crosssection for the X–H stretching vibration. The greater the lengthening of the X–H bond in X–H—Y, the stronger is the HY bond. Simultaneously, new vibrational modes associated with the formation of the HY bond are generated. (e) The X–H—Y–Z hydrogen bond leads to characteristic NMR signatures that typically include pronounced proton deshielding for H in X–H, through hydrogen bond spin–spin couplings between X and Y, and nuclear Overhauser enhancements. (f) The Gibbs energy of formation for the hydrogen bond should be greater than the thermal energy of the system for the hydrogen bond to be detected experimentally. After the recent definition of hydrogen bonding given by IUPAC, many researchers around the world have studied and characterized different types of intermolecular interactions. According to a Google Scholar search on 18 September 2015, 387 researchers had cited the recent definition of hydrogen bond given by IUPAC till that day. We found that these records were journal articles, thesis and scientific papers in different languages. When same was searched in Web of Science (WoS) on the same date and around the same time, the number of citations recorded was 274. However, in the WoS records we found that only journal articles published in English cited this recent definition. Moreover, the works related with various types of intermolecular interactions also cited this new IUPAC definition of hydrogen bonding. These different of intermolecular interactions are discussed briefly here.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011) or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostati...

متن کامل

Inductive Effect of Bioactive Intermolecular Hydrogen Bonding Complex of 1,2,4,5 –Tetrazine and Inorganic Acid by NMR and QTAIM

In this paper, NMR and QTAIM analysis for three substituted of T2SA complex was investigated in the gas and four solvents at DFT level. Intermolecular O–H…N hydrogen bonds between 1,2,4,5-Tetrazine and Sulphurous acids enhance the stability of complex.1,2,4,5-Tetrazine is a highly reactive diene for [4+2] inverse-Diels–Alder cycloaddition processes and an excellent precursor to attain the pyrid...

متن کامل

Ab Initio Quantum Chemical Studies of 15N and 13C NMR Shielding Tensors in Serine and Complexes of Serine- nH2O: Investigation on Strength of the CαH…O Hydrogen bonding in the Amino Acid Residue.

In this paper, the hydrogen bonding (HB) effects on the NMR chemical shifts of selected atoms in serineand serine-nH2O complexes (from one to ten water molecules) have been investigated with quantummechanical calculations of the 15N and 13C tensors. Interaction with water molecules causes importantchanges in geometry and electronic structure of serine.For the compound studied, the most importan...

متن کامل

Computational study of the intramolecular proton transfer between 6-hydroxypicolinic acid tautomeric forms and intermolecular hydrogen bonding in their dimers

This paper is a density functional theory (DFT) calculation of intramolecular proton transfer (IPT) in 6-hydroxypicolinic acid (6HPA, 6-hydroxypyridine-2-carboxylic acid) tautomeric forms. The transition state for the enol-to-keto transition is reported in the gas phase and in four different solvents. The planar and non-planar dimer forms of 6HPA keto and enol, respectively, were also studied i...

متن کامل

Spectrophotometric Determination of 4-Hydroxy-2-mercapto-6-methylpyrimidine Based on Aggregation of Colloidal Gold Nanoparticles

We report herein the development of a highly sensitive colorimetric method for the detection of 4-hydroxy-2-mercapto-6-methylpyrimidine (MTU) which acts as an anti-thyroid drug utilizing citrate capped gold nanoparticles (Au-NPs). This thiol-containing molecule exhibits intriguing affinity with Au-NPs. The reactivity involves the displacement of the citrate shell by the thiolate shell followed ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2016