title: Experimental and database-transferred electron-density analysis and evaluation of electrostatic forces in coumarin-102 dye.
abstract: The electron-density distribution of a new crystal form of coumarin-102, a laser dye, has been investigated using the Hansen-Coppens multipolar atom model. The charge density was refined versus high-resolution X-ray diffraction data collected at 100 K and was also constructed by transferring the charge density from the Experimental Library of Multipolar Atom Model (ELMAM2). The topology of the refined charge density has been analysed within the Bader `Atoms In Molecules' theory framework. Deformation electron-density peak heights and topological features indicate that the chromen-2-one ring system has a delocalized π-electron cloud in resonance with the N (amino) atom. The molecular electrostatic potential was estimated from both experimental and transferred multipolar models; it reveals an asymmetric character of the charge distribution across the molecule. This polarization effect is due to a substantial charge delocalization within the molecule. The molecular dipole moments derived from the experimental and transferred multipolar models are also compared with the liquid and gas-phase dipole moments. The substantial molecular dipole moment enhancements observed in the crystal environment originate from the crystal field and from intermolecular charge transfer induced and controlled by C-H···O and C-H···N intermolecular hydrogen bonds. The atomic forces were integrated over the atomic basins and compared for the two electron-density models.
authors.affiliation: Laboratoire de Cristallographie, Résonance Magnétique et Modélisations (CRM²), CNRS, UMR 7036, Institut Jean Barriol, Faculté des Sciences et Technologies, Université de Lorraine, BP 70239, 54506 Vandoeuvre-lès-Nancy CEDEX, France.
authors.forename: Yvon
authors.initials: Y
authors.lastname: Bibila Mayaya Bisseyou
authors.forename: Nouhza
authors.initials: N
authors.lastname: Bouhmaida
authors.forename: Benoit
authors.initials: B
authors.lastname: Guillot
authors.forename: Claude
authors.initials: C
authors.lastname: Lecomte
authors.forename: Noel
authors.initials: N
authors.lastname: Lugan
authors.forename: Noureddine
authors.initials: N
authors.lastname: Ghermani
authors.forename: Christian
authors.initials: C
authors.lastname: Jelsch
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004583:Electrons; D015394:Molecular Structure; D011789:Quantum Theory; D055672:Static Electricity
chemical_list: D003374:Coumarins; C030123:coumarin