W0006

Structure Determination from Powder Diffraction Data and Structure Validation using Solid State NMR. Manju Rajeswaran,^‡ Thomas N. Blanton,^‡ Nicholas Zumbulyadis,^‡ David J. Giesen,^‡ Carlota Conesa-Moratilla,^§ Scott T. Misture,^† Peter W. Stephens,^# and Ashfia Huq,^{# ‡}Eastman Kodak Company, 1999 Lake Ave., Rochester, NY 14650-2106, ^§Accelrys, 230/250 The Quorum, Barnwell Rd., Cambridge CB5 8RE, ^†New York State College of Ceramics at Alfred Univ., Binns-Merrill Hall, Alfred, NY 14802, ^#SUNY-Stony Brook, Dept. of Physics and Astronomy, Stony Brook, NY 11794-3800.

Feasibility of an integrated approach to the determination and verification of a complete 3D structure for a medium-sized organic molecule will be demonstrated. Our approach uses a combination of powder x-ray diffraction (XRD) data, several computational packages involving Monte Carlo simulations and ab initio quantum mechanical calculations, and experimental solid-state NMR chemical shifts. N-(p-tolyl)-dodecyl sulfonamide (NTDS) has an application as an image-enhancement agent in photographic systems. When working with such compounds, it is important to understand crystallization properties. Issues such as polymorphism, milling parameters, unwanted crystallization in coatings, optical properties, solubility, etc., are influenced by the crystal structure of a material. Structure determination of NTDS was undertaken to use the crystal structure as a starting point in understanding the material properties of this compound. However, repeated attempts to grow single crystals of NTDS were unsuccessful. Therefore, structure elucidation from a polycrystalline sample using powder XRD data was carried out. We were unable to solve the structure using laboratory data and, therefore, collected high-resolution synchrotron XRD data at Brookhaven National Laboratories. Unit cell indexing was achieved utilizing DICVOL. A global optimization algorithm (using PowderSolve by Accelrys), based on Monte Carlo parallel tempering, was used for structure determination. Calculating chemical shifts with ab initio methods and comparing it to experimental ¹³C NMR validated the computed structure.