02501nas a2200193   4500008004100000022001400041245024300055210006900298260011000367300001200477490000700489520158500496100002702081700001602108700001602124700002002140700002102160856012602181       2015                        eng d  a1463-907600aSpectroscopic and ab initio investigation of 2,6-difluorophenylacetylene-amine complexes: coexistence of C-H center dot center dot center dot N and lone-pair center dot center dot center dot pi complexes and intermolecular coulombic decay0 aSpectroscopic and ab initio investigation of 26difluorophenylace  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT  a434-4430 v173 a<p>Binary complexes of 2,6-difluorophenylacetylene with methylamine, dimethylamine, trimethylamine and triethylamine were investigated using one colour resonant two photon ionization and infrared-optical double resonance spectroscopic techniques combined with high level ab initio calculations. All four amines form C-Ac-H center dot center dot center dot N hydrogen-bonded complexes. Additionally trimethylamine and triethylamine form complexes characterized by Lp center dot center dot center dot pi interactions, due to the electron deficient nature of the phenyl ring of 2,6-difluorophenylacetylene. The Lp center dot center dot center dot pi interacting structure of the 2,6-difluorophenylacetylenetrimethylamine complex is about 1.5 kJ mol(-1) higher in energy than the C-Ac-H center dot center dot center dot N hydrogen-bonded structure, which is the global minimum. Energy decomposition analysis indicates that the electrostatics and dispersion interactions favour the formation of C-Ac-H center dot center dot center dot N and Lp center dot center dot center dot pi complexes, respectively. Interestingly the C-Ac-H center dot center dot center dot N hydrogen-bonded complex of 2,6-difluorophenylacetylene-triethylamine showed a smaller shift in the acetylenic C-H stretching frequency than the 2,6-difluorophenylacetylene-trimethylamine complex. The observed fragmentation of the binary complexes of 2,6-difluorophenylacetylene with the four amines following resonant two-photon ionization can be explained on the basis of the intermolecular coulombic decay process.</p>1 aMondal, Sohidul, Islam1 aDey, Arghya1 aSen, Saumik1 aPatwari, Naresh1 aGhosh, Debashree  uhttps://library.ncl.res.in/content/spectroscopic-and-ab-initio-investigation-26-difluorophenylacetylene-amine-complexes-0