Phosphorus-31 NMR studies on molybdic and tungstic heteropolyanions. Correlation between structure and chemical shift

Massart, R.; Contant, Roland; Fruchart, J.M.; Ciabrini, Jean Pierre.; Fournier, Michel

doi:10.1021/ic50177a049

Cited by 340 publications

(128 citation statements)

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“…1) O 40 were observed at the similar frequency (Ϫ14.7 ppm 26) and Ϫ14.5 ppm 27) respectively), it would be supported that phosphotungstate in PWAA maintained the heteropoly acidic structure such as the Keggin type (PW 12 O 40 3Ϫ ). 28,29) A scanning electron microscope (SEM) of PWAA was also investigated (Fig.…”

mentioning

confidence: 70%

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Yamada

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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IntroductionDevelopment of immobilized and insoluble metal catalysts is of great interest in recent organic chemistry. [1][2][3][4][5][6][7][8][9] The simple recovery of catalysts by filtration and their reuses resulted in enhancing the economical evaluation of the reaction. At the same time, there is a prospect that the environmental pollution caused by residual metals in the waste fluid will be decreased. Although a great deal of effort has been made to carry out such ideal reactions using immobilized metal catalysts, what seems to be lacking is the efficiency of the catalytic systems. It is obvious that the heterogeneous catalytic systems exhibit generally lower activity than the homogeneous ones. Besides, it is expected that the activity of the catalysts decreases gradually in the recycled systems because the metal species leaches away from their supports. Taking these into consideration, we decided to concentrate on developing insoluble metal catalysts which are highly active and stable. We designed that they were still effective in the use of ppm mol eq, and in the recycled use of many times in any reaction media. To achieve the challenging theme, we have focused on the amphiphilic insoluble catalysts based on a novel concept (Chart 1).Over the past few decades, a considerable numbers of study have been made on solid-phase catalysts which were immobilized with cross-linked polystyrene resins, silica gels or metals. These catalytic systems, however, generally resulted in lower catalytic activity compared with their soluble counterparts, and were often obliged to use hazardous chlorohydrocarbon solvents. [10][11][12][13][14][15] Besides, reuse of these catalysts was often difficult owing to the gradual decline of the catalytic activity. These problems made them less practical.In traditional triphase catalysts, as I have mentioned before, a catalytic species was anchored to a linker that was immobilized to a polymer resin or silica gel (Chart 1, above). In July 2005Chem. Pharm. Bull. 53(7) 723-739 (2005)

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confidence: 70%

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Yamada

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…A,PNagPW9034. 17H20 a Ct C prCparCe suivant la mtthode dkcrite (12) pour la forme protonee. Ce cornposC n'est pas recristallisable, la prkcipitation est brutale et il est possible que dans certains Cchantillons une partie de la forme protonee en tquilibre soit entrainee.…”

Section: Prkparations Et Analysesunclassified

Relations entre les tungstophosphates apparentés à l'anion PW₁₂O₄₀³⁻. Synthèse et propriétés d'un nouveau polyoxotungstophosphate lacunaire K₁₀P₂W₂₀O₇₀•24H₂O

Contant¹

1987

Can. J. Chem.

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Chem. 65, 568 (1987). Les relations entre toutes les especes apparentCes aux anions PW120403-et P2W210716-ont Ct C Ctablies. Un nouveau composC KIOP2W20070 a Ct C synthCtisC et caractCrisC par spectroscopie infra-rouge et Raman. L'ensemble de ses proprittks et plus particulierement les spectres de resonance magnktique nuclCaire ( 3 1~ et Is3w) permettent d'en proposer la structure. C'est une esp2ce lacunaire qui rCagit sur le cobalt(I1) pour donner deux complexes 1 -1, probablement des isomeres de coordination. En solution, en prksence de co2+, 1'isomCrisation A-PW9 + B-PW9 se fait en plusieurs Ctapes qui ont t t t prCcisCes. Les isomkres p des tungstophosphates sont moins stables que les tungstosilicates ou germanates correspondant et P-PWI2 n'a Ct C identifit que sous forme rCduite. ROLAND CONTANT. Can. J. Chem. 65,568 (1987). The relationship between all the polyoxotungstophosphates related to P w~~~~~~-and P 2~2 1 0 7 1 6 -anions was established. A new compound K10P2W20070 was synthesized and characterized by infrared and Raman spectroscopy. These properties, and especially the 31P and Is3w nuclear magnetic resonance spectra, allowed us to propose the structure. It is a lacunary species that reacts with Co(I1) to give two 1-1 complexes, probably coordination isomers. In the presence of Co(I1) the A-type + B-type PW9 isornerization occurs in several steps, which are specified. The tungstophosphate P isomers are less stable than the corresponding tungstosilicates or germanates, and P-PWI2 was only identified as a reduced species PW120404-.

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“…The catalysts used were HPW, KPWV 1 and KPWV 3 . The reaction products were analyzed using a Shimadzu UV-1800 UV/Vis spectropho-tometer and the total reducing sugar content (%TRS) was quantified by dinitrosalicylic acid method (DNS) [22] at 540 nm. Analyses by high performance liquid chromatography (HPLC) were conducted on a Shimadzu Prominence chromatograph equipped with a RID-10A detector, a LC-20AT pump and a Shim-pack AminoNa column (6 mm × 100 mm; 5 mm particle size) maintained at 80 °C.…”

Section: Hydrolysis Reactionsmentioning

confidence: 99%

Hydrolysis of cellulose using heteropoly salts derivatives from H3PW12O40 with different redox properties as catalysts

et al. 2017

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Heteropoly salts containing different numbers of vanadium atoms (K 4 [PVW 11 O 40 (HPW), and used as catalysts in hydrolysis of cellulose reactions in order to change the redox properties and verify whether the cluster of catalysts are involved in mechanism reaction. The hydrolysis reactions following a full 23 factorial design with the variables: mass ratio (catalyst/substrate), reaction time and temperature. The variables evaluated were significant at a 90% confidence level including second and third order interactions. According to the conducted experiments, the catalysts were all active in hydrolysis. The best results occurred when HPW was used suggesting that the redox properties did not have much influence in depolymerization of cellulose and the hydrolysis mechanism are assigned to acidic properties of the medium. The main products obtained from the reactions were glucose and HMF, which are products of great interest in the chemical industry.

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Phosphorus-31 NMR studies on molybdic and tungstic heteropolyanions. Correlation between structure and chemical shift

Cited by 340 publications

References 1 publication

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Relations entre les tungstophosphates apparentés à l'anion PW₁₂O₄₀³⁻. Synthèse et propriétés d'un nouveau polyoxotungstophosphate lacunaire K₁₀P₂W₂₀O₇₀•24H₂O

Hydrolysis of cellulose using heteropoly salts derivatives from H3PW12O40 with different redox properties as catalysts

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Phosphorus-31 NMR studies on molybdic and tungstic heteropolyanions. Correlation between structure and chemical shift

Cited by 340 publications

References 1 publication

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Self-Assembled Complexes of Non-cross-linked Amphiphilic Polymeric Ligands with Inorganic Species: Highly Active and Reusable Solid-Phase Polymeric Catalysts

Relations entre les tungstophosphates apparentés à l'anion PW12O403−. Synthèse et propriétés d'un nouveau polyoxotungstophosphate lacunaire K10P2W20O70•24H2O

Hydrolysis of cellulose using heteropoly salts derivatives from H3PW12O40 with different redox properties as catalysts

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Relations entre les tungstophosphates apparentés à l'anion PW₁₂O₄₀³⁻. Synthèse et propriétés d'un nouveau polyoxotungstophosphate lacunaire K₁₀P₂W₂₀O₇₀•24H₂O