Exploring weak n 8594 960 non covalent interaction gas phase spectroscopy and quantum chemical calculations

Abstract

n 8594 960 non covalent interaction is widely present in biomolecules proteins nucleic acids neurotransmitters etc as well as materials In spite of its immense significance in the structures of various molecular systems this non covalent interaction has been recognized only recently during last two decades by the scientific community due to its counterintuitive and weak strength nature The n 8594 960 interaction is quite analogous to the well known hydrogen bonding interaction in terms of electron delocalization The n 8594 960 interaction involves delocalization of lone pair n electrons on any electronegative atom into the 960 orbital of a nearby carbonyl group or an aromatic ring This non bonding interaction follows the Burgi Dunitz trajectory of approach of a nucleophile towards an electrophile during nucleophilic addition reaction Several Protein Data Bank PDB and Cambridge Structural Database CSD analyses show that the n 8594 960 interaction has a high propensity to occur in bio molecules as well as materials It has been found that the n 8594 960 interaction is most prominent in the protein collagen which is interestingly the most abundant protein in animals Collagen has a repititive sequence of amino acid residues 8211 Pro Hyp Gly and its triple helical structure lacks intrastrand hydrogen bonding interaction It has been found that n 8594 960 interactions between successive carbonyl groups play a significant role in the stability of individual strand of collagen protein Further evidence and understanding of n 8594 960 interaction come from the low temperature NMR spectroscopy studies performed on proline derivatives These studies reveal that n 8594 960 interaction plays an important role in governing the conformational preferences of these molecules Herein we have explored this n 8594 960 interaction in various molecular systems including phenyl formate salicin hydroxyproline derivatives etc in isolated gas phase using UV and IR laser based different spectroscopic techniques combined with quantum chemistry newline newline