The use of chelating diamide [o-(Me3SiN)2C6H4]2- as a coligand for high-oxidation early
transition metal complexes has been investigated. Reaction of Mo(NPh)2Cl2DME with Li2[o-(Me3SiN)2C6H4] afforded green microcrystals of [Mo(NPh)(μ-NPh)(o-(Me3SiN)2C6H4)]2 (1),
while reaction of Mo(NPh)2Cl2DME with H2[o-(Me3SiN)2C6H4] gave Mo(NPh)Cl2(o-(Me3SiN)2C6H4)(NH2Ph) (2). Two derivatives of 2 are reported, Mo(NPh)Cl2(o-(Me3SiN)2C6H4)(PMe3) (3) and Mo(NPh)Cl2(o-(Me3SiN)2C6H4)(THF) (4). Structural studies of 3 are reported.
Reaction of 3 or 4 with RMgX (X = Cl or Br) gave Mo(NPh)R2(o-(Me3SiN)2C6H4) (R = Me 5,
Ph 6, CH2CMe3
7, CH2Ph 8, CH2SiMe3
9). Reaction of 2 with RMgCl (R = CH2CMe3, CH2SiMe3) gave mixtures of Mo(NPh)R2(o-(Me3SiN)2C6H4) and Mo(NPh)2R2. Both Mo(NPh)2(CH2CMe3)2 (10) and Mo(NPh)2(CH2SiMe3)2 (11) were isolated form the reaction of
Mo(NPh)2Cl2DME and RMgCl (R = CH2CMe3, CH2SiMe3). The alkylidene, Mo(NPh)(C(H)CMe3)(o-(Me3SiN)2C6H4)(PMe3) (13), was isolated from the reaction of 7 and an excess of
PMe3 at 80 °C, while Mo(NPh)(C(H)SiMe3)(o-(Me3SiN)2C6H4)(PMe3) (14) was only observed
by 1H NMR under similar conditions.
Microcrystalline cellulose (MCCI) has been widely used as an excipient for direct compression due to its good flowability, compressibility, and compactibility. In this study, MCCI was obtained from agricultural by-products, such as corn cob, sugar cane bagasse, rice husk, and cotton by pursuing acid hydrolysis, neutralization, clarification, and drying steps. Further, infrared spectroscopy (IR), X-ray diffraction (XRD), optical microscopy, degree of polymerization (DP), and powder and tableting properties were evaluated and compared to those of Avicel PH101, Avicel PH102, and Avicel PH200. Except for the commercial products, all materials showed a DP from 55 to 97. Particles of commercial products and corn cob had an irregular shape, whereas bagasse particles were elongated and thick. Rice and cotton particles exhibited a flake-like and fiber-like shape, respectively. MCCI as obtained from rice husk and cotton was the most densified material, while that produced from corn cob and bagasse was bulky, porous, and more compressible. All products had a moisture content of less than 10% and yields from 7.4% to 60.4%. MCCI as obtained from bagasse was the most porous and compressible material among all materials. This product also showed the best tableting properties along with Avicel products. Likewise, all MCCI products obtained from the above-mentioned sources showed a more rapid disintegration time than that of Avicel products. These materials can be used as a potential source of MCCI in the production of solid dosage forms.
Organic farming and new trends toward the use of safer insecticides for crop protection have created new opportunities for botanical insecticides in the pesticide market. In this study, the botanical insecticide nicotine was formulated as a dispersion (20 vol %) stabilized by sodium caseinate, with nicotine oleate solutions used as the dispersed phase. The formulation showed a phase transition on increasing the nicotine oleate concentration, being an emulsion at 7.5-8.2 wt %, a suspo-emulsion at 8.2-9.7 wt %, and a suspension at 9.7-10.8 wt %. Biological activity, apparent viscosity, dispersion time, and protein surface coverage were dependent on nicotine oleate concentration. The emulsion with 8.2 wt % nicotine oleate and the suspo-emulsion with 8.7 wt % nicotine oleate were found to be the most appropriate formulations for insecticide purposes due to their high bioactivity, low viscosity, and low dispersion time. Nicotine oleate formulations showed good creaming and microbiological stability for at least 4 months without losing their biological activity.
The effect of fatty acid chain length on nicotine carboxylate insecticide emulsions has been studied in terms of particle size, interfacial tension, nicotine encapsulation on emulsion droplets, and bioactivity. The particle size of the nicotine emulsion and the interfacial tension at the nicotine carboxylate oil phase (0.03 M)--Tween 80 aqueous phase (0.001 M) were affected in a similar way by the change in the fatty acid chain length, which was correlated by the packing conformation of Tween 80 and nicotine carboxylate molecules as obtained by AM1 theoretical calculations. The amount of encapsulated nicotine inside the nicotine carboxylate emulsion droplets influenced the insecticide bioactivity of nicotine; this relationship was explained in terms of the acid value of the different fatty acids used to prepare the nicotine formulation.
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