title: Structural and energetic aspects of a new bupropion hydrochloride polymorph.
abstract: Crystalline bupropion hydrochloride [(±)1-(3-chlorophenyl)-2-[(1,1-dimethylethyl)amino]-1-propanone hydrochloride], recently characterized as form 1, was found to undergo, upon storage at RT within months, a solid-solid conversion to a new polymorphic form, hereafter named form 2, containing a markedly different molecular conformer in the solid state. This new form, available only as a polycrystalline material, has been fully characterized using structural X-ray powder diffraction methods, coupled to thermoanalytical analyses. The relative stability of the two crystalline phases (forms 1 and 2) was compared by quantum mechanics calculations including density functional methods specific for solid state molecular systems. Bupropion hydrochloride form 2 crystallizes in the orthorhombic space group Pbca with Z=8, a=27.2853(5)Å, b=8.7184(3)Å, c=12.0422(3)Å, V=2864.7(1)Å³, as centrosymmetric dimers, thanks to the presence of N-H…Cl interactions, and μ₂-bridging chloride ions, each connected to two protonated amine moieties.
authors: Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, Via Mancinelli 7, I-20131 Milano, Italy. elisabetta.maccaroni@chem.polimi.it
authors: Elisabetta
authors: E
authors: Maccaroni
authors: Luciana
authors: L
authors: Malpezzi
authors: Antonino
authors: A
authors: Famulari
authors: Norberto
authors: N
authors: Masciocchi
mesh_terms: D016642:Bupropion / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning / Q000379:methods / Q000706:statistics & numerical data; D003460:Crystallization; D004355:Drug Stability; D015233:Models, Statistical; D008968:Molecular Conformation; D015394:Molecular Structure; D033362:Powder Diffraction / Q000379:methods / Q000706:statistics & numerical data; D014961:X-Ray Diffraction / Q000379:methods / Q000706:statistics & numerical data
chemical_list: D016642:Bupropion