resumo
An inclusion compound comprising P-cyclodextrin (P-CD) and diferrocenyldimethylsilane, Fc-SiMe2-Fc [Fc = (eta(5)-C5H5)Fe(eta(5)- C5H4)], has been prepared and characterized in the solid state by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and magic angle spinning (MAS) NMR spectroscopy (C-13, Si-29). Elemental analysis indicated that the host:guest molar ratio in the product was approximately 1.5. Ab initio calculations in vacuo were carried out in order to investigate the possible inclusion modes. The first structure, designated form 2a, was determined assuming a barrel-type conformation, with parallel head-to-head cyclodextrins. A second V-shaped complex (2b) was also found by allowing variation of the angle between the cyclodextrins. Form 2a was assumed to be the best approximation to the real structure, since this geometrical arrangement favors the formation of a channel-type packing motif. (c) 2005 Elsevier B.V. All rights reserved.
palavras-chave
POLY(FERROCENYLSILANE) HIGH POLYMERS; RING-OPENING POLYMERIZATION; TRANSITION-METAL COMPLEXES; HALF-SANDWICH COMPLEXES; C-13 CHEMICAL-SHIFTS; MOLECULAR-MECHANICS; GAMMA-CYCLODEXTRIN; ALPHA-CYCLODEXTRIN; SOLID-STATE; CRYSTAL-STRUCTURE
categoria
Chemistry
autores
Fernandes, JA; Lima, S; Braga, SS; Ribeiro-Claro, P; Rodriguez-Borges, JE; Teixeira, C; Pillinger, M; Teixeira-Dias, JJC; Goncalves, IS
nossos autores
Cátia Teixeira
Bolseiro de pós-Doutoramento
Isabel Maria de Sousa Gonçalves
Professor associado
José Alberto Pires Fernandes
Bolseiro de pós-Doutoramento
José J.C. Teixeira Dias
Professor Catedrático
Martyn Pillinger
Investigador Principal