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The current research aims to present a straightforward synthesis of binuclear palladated triphenylphosphine derivative by the reaction of the phosphonium salt [(PhCH 2 )P(Ph) 2 (Ph-4-CH 3 )]Br with palladium(II) chloride and to afford the dimeric palladated complex {Pd[P(Ph)(CH 2 Ph)(Ph-4-CH 3 )]((μ-Br)Br)} 2 . Moreover, elemental analysis (CHN), FT-IR, 1H, 31P, 13C NMR and X-ray crystallography led to the characterization of the obtained compound. Finally, This compound was found to be an efficient catalyst in C–C bond formation between various aryl halides with phenylboronic acid (Suzuki–Miyaura reaction) and aryl halides with n -butyl acrylate (Heck–Mizoroki reaction). [ABSTRACT FROM AUTHOR]

The objective of this work was to use a statistical tool to study and evaluate the main parameters in the preparation of organo-montmorillonite (O-Mt) by using different compounds and reactional routes (aqueous, semi-solid and supercritical CO 2 medium) aiming a better relationship between efficiency and environmental impact. For this, ammonium-modified montmorillonite (AmMt) and phosphonium-modified montmorillonite (PhMt) were prepared according to design of experiments. The samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and contact angle. XRD and TGA analysis showed that the compounds were incorporated in the montmorillonite providing an efficient modification by all the reactional routes employed. The clay interlayer spacing was expanded and AmMt showed the largest d 001 while PhMt showed better thermal stability. Statistical analysis indicated that the process parameters had low or no significance in the organo-montmorillonite characteristics. XRD, TGA and FTIR showed that the d 001 , yield and chemical environment of the O-Mt changed with the amount of organic compound and washing process. The contact angle test showed that the surface tension of montmorillonite was reduced with organophilization. It was concluded that semi-solid method could be a good, efficient and environmentally friendly alternative to prepare O-Mt. [ABSTRACT FROM AUTHOR]

The use of biodegradable polymers to produce nanocomposites with mineral fillers leads to the production of new materials with low cost and reduced environmental impact, combined with improvements in mechanical and thermal properties. Nanocomposites based on poly(butylene adipate-co-terephthalate) and starch blend (Ecobras) and vermiculite (VMT) modified with hexadecyltributylphosphonium bromide (P-VMT) were prepared by melt intercalation in a mixing chamber at 140 °C, keeping the amount of clay at 4%wt. The intercalation of P-VMT in Ecobras was characterized by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). VMT organophilization was confirmed by the appearance of FTIR bands characteristic of the long alkyl chain of the phosphonium salt used and also by displacement of the basal peak towards lower 2θ values in the diffractogram compared to pure vermiculite. The thermal properties of Ecobras and its compositions were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of VMT and P-VMT in Ecobras increased the crystallization temperature (Tc ) and crystalline melting temperature (Tm), as observed by DSC analysis. The result of the thermogravimetric analysis showed that the addition of P-VMT in Ecobras improved thermal stability of the nanocomposite. The Young's modulus of the composite with 4 wt% of P-VMT indicated an increase in stiffness compared to the pure matrix. [ABSTRACT FROM AUTHOR]

The use of light to control the course of a chemical/biochemical reaction is an attractive idea because of its ease of administration with high precision and fine spatial resolution. Staudinger ligation is one of the commonly adopted conjugation processes that involve a spontaneous reaction between azides and arylphosphines to form iminophosphoranes, which further hydrolyze to give stable amides. We designed an anthracenylmethyl diphenylphosphinothioester ( 1) that showed promising Staudinger ligation reactivity upon photo-excitation. Broadband photolysis at 360-400 nm in aqueous organic solvents induced heterolytic cleavage of its anthracenylmethyl-phosphorus bond, releasing a diphenylphosphinothioester ( 2) as an efficient traceless Staudinger-Bertozzi ligation reagent. The quantum yield of such a photo-induced heterolytic bond-cleavage at the optimal wavelength of photolysis (376 nm) at room temperature is ≥0.07. This work demonstrated the feasibility of photocaging arylphosphines to realize the photo-triggering of the Staudinger ligation reaction. [ABSTRACT FROM AUTHOR]

Photopolymer networks containing a phosphonium polyelectrolyte were used as scaffolds for the synthesis of gold nanoparticles (AuNPs). Chloride anions electrostatically bound to the phosphonium salt were exchanged with AuCl4− and then reduced with NaBH4 to form AuNPs. The stiffness of the photopolymer matrix had a pronounced effect on the concentration of AuNPs formed within the material, where softer, more swellable networks provided greater anion-exchange sites and therefore more AuNP formation. Numerous loading/reduction cycles with AuCl4− and NaBH4 increased the concentration of AuNPs upon each cycling step without significantly changing AuNP size, thus providing a means to control AuNP concentration within the material. SEM and TEM analysis revealed particles sizes ranging from 10 to 30 nm with significant microscale heterogeneity likely arising from phase separation of the phosphonium polyelectrolyte from the photopolymer matrix followed by AuNP synthesis within those regions. We also demonstrate how this methodology can be applied to patterned photopolymer networks, providing the means to explore this approach for photolithographic applications. [ABSTRACT FROM AUTHOR]

The treatment of tri( p -tolyl)phosphine with 1,2-bis(bromomethyl)benzene results in (2-bromomethylbenzyl)tri( p -tolyl)phosphonium bromide. The resulted phosphonium salt reacts with palladium acetate(II) in a molar ratio of 1.5:1, respectively, to give [(CH 3 C 6 H 4 ) 3 PCH 2 C 6 H 4 CH 2 OC(O)CH 3 ] 2 [Pd 2 Br 6 ], bis[(2-methylacetatobenzyl)tri( p -tolyl)phosphonium]hexabromodipalladate(II), as a dark brown powder. Characterization of the obtained compound was performed by elemental analysis (CHN), IR, 1 H, 31 P, 13 C NMR and X-ray crystallography techniques. This compound was found to be an efficient catalyst for the amination of aryl halides using aqueous ammonia to produce primary amines and for Stille cross-coupling reaction to produce biphenyl and its derivatives as well. Describe catalyst showed satisfactory results and could be recovered and reused without significant loss of its catalytic activity in both reactions. [ABSTRACT FROM AUTHOR]

Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH) was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1) was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect) forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F 1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei , bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial F o F 1 ATPase. [ABSTRACT FROM AUTHOR]

In this study palladium(II) acetate reacts with a phosphonium salt, [Ph 3 PCH 2 C 6 H 4 CH 2 Br]Br, to give [Ph 3 PCH 2 C 6 H 4 CH 2 OC(O)CH 3 ] 2 [Pd 2 Br 6 ]. Characterization of the obtained compound was performed by elemental analysis, IR, 1 H, 31 P, 13 C NMR and X-ray crystallography. It was found that this compound can act as an efficient catalyst for amination of aryl halides to afford primary amines and satisfactory results were obtained. It has also been successfully employed in the catalytic Stille cross-coupling reaction. The catalyst is easily recoverable and reusable without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

The title hydrated salt, C26H32O3P+.Cl-.H2O, contains four different substituents (H, alkyl, aryl, and biaryl) on the P atom. The P--H hydrogen atom of the phosphonium ion was located in a difference Fourier map and refined without imposing additional restraints. In the crystal, the Cl- ions and water molecules are linked by pairs of Owater--H···Cl- hydrogen bonds and further linked to the phosphonium cation by P--H+···Cl- and CAr/OMe--H···Owater hydrogen bonds to form an infinite one-dimensional chain along the [010] direction. [ABSTRACT FROM AUTHOR]

1,3,5-triaza-7-phosphaadamantane (PTA) was shown to form phosphonium alkanoate zwitterions with unsaturated dicarboxylic acids in water in the absence of strong acids. Solid-state structures of the phosphonium salt ( 1) derived from maleic or fumaric acids and that of the zwitterionic product ( 2) of the reaction of PTA with citraconic and mesaconic acids were determined by single-crystal X-ray diffraction. DFT calculations gave insight into the mechanism of the reaction, including the relative reactivity of the four dicarboxylic acids, and revealed the reasons for the lack of phosphonium salt formation by PTA in strongly acidic aqueous solutions. [ABSTRACT FROM AUTHOR]