Browsing by Author "Duarte, M. Teresa"
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- An insight into dapsone co-crystals: sulfones as participants in supramolecular interactionsPublication . Martins, Inês; Martins, Marta; Fernandes, Auguste; André, Vânia; Duarte, M. TeresaHerein we disclose a new pathway for the design of dapsone co-crystals exploring the formation of N-H center dot center dot center dot O/N interactions using amide and pyridinic derivatives as potential co-formers. Two new co-crystals of dapsone, a sulfonamide antibiotic, with epsilon-caprolactam and 4,4'-bipyridine have been synthesized preferentially by traditional solution techniques, but mechanochemistry has also been addressed. The full structural characterization of these forms is discussed and shows that: (a) in the co-crystal with epsilon-caprolactam the typical N-NH2 center dot center dot center dot O-SO2 interactions of dapsone molecules and the cages formed between them are disrupted by a new N-NH2 center dot center dot center dot O-CONH interaction, in which epsilon-caprolactam molecules further form amide center dot center dot center dot amide R-2(2)(8) synthons and (b) in the co-crystal with 4,4'-bipyridine, the N-NH2 center dot center dot center dot O-SO2 interactions between dapsone molecules are maintained and additional N-NH2 center dot center dot center dot N-pyridine interactions are responsible for the formation of 4,4'-bipyridine channels between dapsone cages. Moreover, the thermal stability of these co-crystals is also discussed, showing that the co-formers leave the structure and hence the reported melting corresponds to the melting of pure dapsone.
- Synthesis and structural characterization of new Piano-stool Ruthenium(II) complexes bearing 1-Butylimidazole heteroaromatic ligandPublication . Morais, Tânia S.; Garcia, M. Helena; Robalo, Maria Paula; Piedade, M. F. M.; Duarte, M. Teresa; Brito, M. José Villa de; Madeira, Paulo J. AmorimNew cationic ruthenium(II) complexes with the formula [Ru(eta(5)-C5H5)(LL)(1-BuIm)] [Z], with (LL) = 2PPh(3) or DPPE, and Z = CF3SO3-, PF6-, BPh4-, have been synthesized and fully characterized. Spectroscopic and electrochemical studies revealed that the electronic properties of the coordinated 1-butylimidazole were clearly influenced by the nature of the phosphane coligands (LL) and also by the different counter ions. The solid state structures of the six complexes determined by X-ray crystallographic studies, confirmed the expected distorted three-legged piano stool structure. However the geometry of the 1-butylimidazole ligand was found considerably different in all six compounds, being governed by the stereochemistry of the mono and bidentate coligands (PPh3 or DPPE).