Thermal analyses of coordination compounds

Synthesis and Characterization of Dibutyltin Compounds with α-Amino Acids

“…The initial and final temperatures of thermal decomposition process and the thermogravimetric data for the dibutyltin complexes are shown in For the DL-phenylalaninate derivative (IV), a hexacoordinated specie, the thermal degradation starts at 165 o C. Table 5. respectively) it can be concluded that the compound I and III can exist as monomeric species in solid-state while for the compounds II e IV, may be a sign of a certain polymerization degree [15][16][17]20]. This observation is reinforced by minor solubility of the compounds II and IV in relation to the solubility of the compounds I and III, described to get their respective 119m Sn-NMR spectra.…”

“…In the experiments for the synthesis of the dibutyltin compounds described in this work, it was verified that the relative reactivity of the α-amino acids ligands was sensibly lower than the one of α-hydroxycarboxylic acids used in the synthesis of the organotin compounds also previously described by the authors [17][18][19][20].…”

“…Due to its insolubility for compounds II and IV it was not possible to record the NMR spectra. The insolubility of II and IV may be attributed to certain polymerization degree, as observed for diorganotin compounds with α-hydroxycarboxylic acid [17,20].…”

“…The studied compounds I, II and III exist as trigonal bipyramidal tin species while the compound IV exists as slightly distorted trans-octahedral tin specie in solidstate, probably as monomeric or certain polymerization degree structures, as observed for diorganotin compounds with α-hydroxycarboxylic acid [17,20] or α-amino acids [15]. These results are distinct from the ones described for diglycinatotin (II) [1], trimethyltin (IV) glycinate and alaninate [21] and dimethyltin (IV) glycinate and β-alaninate compounds [1] which show polymeric species with bridging α-amino acids, which should link the carboxylic oxygen to the tin and the amino group to the other tin atom [1,21].…”

Síntese e caracterização de um novo composto obtido pela reação entre hidreto de trifenilestanho e ácido (±)-mandélico e avaliação de seu potencial biocida sobre o fungo Fusarium oxysporum f. sp. cubense

“…Essas observações são consideradas evidências para a formação de complexos (BARBIÉRI et al, 1988(BARBIÉRI et al, , 1994(BARBIÉRI et al, , 1995(BARBIÉRI et al, , 2002BOLARD, 1965;LARSEN & HOMEIR, 1972 Também se observa no espectro do composto organometálico, em relação ao respectivo espectro do ácido (±)-mandélico livre, um significativo alargamento da banda cerca de 3400 cm -1 , atribuída à hidroxila alcóolica no ácido, o que evidencia sua participação na coordenação ao estanho (HAMILTON & IBERS, 1968;LARSEN & HOMEIR, 1972;TERRA, 1991). Observa-se ainda no espectro do composto, em relação ao do ácido livre, alterações nas bandas na região 1050-1100 cm -1 , também indicativas da participação da hidroxila alcoólica na coordenação ao estanho (BARBIÉRI, 1978;LARSEN & HOMEIR, 1972).…”