New azaheterocyclic aromatic diphosphonates for hybrid materials for fuel cell applications

Teixeira, Fátima C.; Rangel, C. M.; Teixeira, António P. S.

doi:10.1039/c3nj00585b

Cited by 10 publications

(7 citation statements)

References 43 publications

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“…The reduction of 2 with NaBH 4 or by an alternative method using NaBH 4 /CoCl 2 ·6H 2 O (catalytic amount) gave 1,2‐diamine 3 in moderated yield . Cyclization of 1,2‐diamine 3 to 4,7‐dibromobenzimidazole 4 was performed by the reaction with trimethylorthoformate in acid conditions, using (±)‐camphorsulfonic acid .…”

Section: Resultsmentioning

confidence: 99%

“…2,1,3‐Benzothiadiazole 1 is commercially available (Aldrich, 2710‐901 Sintra, Portugal). 4,7‐Dibromo‐1 H ‐benzimidazole 4 was synthesized in a three‐step synthesis by modifying the synthetic procedures reported . 4,7‐Dibromo‐1 H ‐benzotriazole 5 and tetraethyl ethenylidenebisphosphonate were prepared according to literature procedures.…”

Section: Methodsmentioning

confidence: 99%

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Synthesis of New Azole Phosphonate Precursors for Fuel Cells Proton Exchange Membranes

2015

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INTRODUCTIONIn an energy scenario that increasingly demands cleaner and more efficient energy sources, fuel cells are considered promising electrochemical devices since they can provide electric energy with high efficiency and low environmental impact, converting the energy stored in fuels with zero pollution levels. The proton exchange membrane fuel cells (PEMFC) are considered one of the most promising sources among the various kinds of existing fuel cells due to their high power density and high power-to-weight ratio. One of the drawbacks of current cells is related to the electrolytes currently in use, limiting their use to temperatures below 100°C when operating under water-assisted proton conduction.The temperature operation above 100°C could increase the performance of PEMFC due to a faster electrode reaction without CO poisoning of the Pt electrocatalyst, easier heating, and high energy efficiency [1][2][3][4][5][6][7][8].The proton exchange membrane is a key component for the operation of PEMFC. During recent years, the study of membrane materials have been focused in obtaining high proton conductivity, low electrical conductivity, low permeability to fuel and oxidant, good chemical and thermal stabilities, good mechanical properties, and low cost [1][2][3][4][5][6][7][8]. 236

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Synthesis of New Azole Phosphonate Precursors for Fuel Cells Proton Exchange Membranes

2015

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“…As indicated, this is a challenging research endeavor, and quite frequently, the yields of the applied procedures are moderate or even low [ 2 , 3 , 4 , 5 ]. Therefore, it is not surprising that the number of papers devoted to the elaboration of methods to prepare these compounds has increased in recent years [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. The most commonly used method for the introduction of a phosphonate moiety to an sp 2 hybridized aromatic carbon atom is a palladium-catalyzed reaction [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

One-Pot Phosphonylation of Heteroaromatic Lithium Reagents: The Scope and Limitations of Its Use for the Synthesis of Heteroaromatic Phosphonates

et al. 2023

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A one-pot lithiation–phosphonylation procedure was elaborated as a method to prepare heteroaromatic phosphonic acids. It relied on the direct lithiation of heteroaromatics followed by phosphonylation with diethyl chlorophosphite and then oxidation with hydrogen peroxide. This protocol provided the desired phosphonates with satisfactory yields. This procedure also had some limitations in its dependence on the accessibility and stability of the lithiated heterocyclic compounds. The same procedure could be applied to phosphonylation of aromatic compounds, which do not undergo direct lithiation and thus require the use of their bromides as substrates. The obtained compounds showed weak antiproliferative activity when tested on three cancer cell lines.

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“…2,1,3-Benzothiadiazole (BTD)i so ne of the most important nuclei in heteroaromatic chemistry,b ecause of its convenient synthesis and attractivep otential applicationsi nd ifferent areas. [1][2][3][4][5][6][7][8][9][10][11] Because of the favorable chemical stabilityo ft his compound, [12] only af ew reports (Scheme 1A)h ave suggested that a1 ,2-benzenediamine compound could be obtainedb y reductives ulfur extrusion from BTD and subsequently transformed into synthetically useful quinoxaline [13][14][15][16] and benzimidazole (BID) [17,18] derivatives, whicha re hard to obtain by traditional direct cross-coupling reactions.…”

Section: Introductionmentioning

confidence: 99%

Direct Conversion of Benzothiadiazole to Benzimidazole: New Benzimidazole‐Derived Metal–Organic Frameworks with Adjustable Honeycomb‐Like Cavities

Zhao

Han

et al. 2019

Chemistry A European J

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Up to now, the direct conversion of the thiadiazole ring to other heterocyclic rings has been a very challenging task. Herein, a CdII‐mediated alcohol‐substitution strategy for direct conversion from benzothiadiazole to benzimidazole is reported. Experimental and molecular modeling studies on the role of the chelated metal ion in this in situ alcohol‐substitution reaction revealed that it serves as an all‐rounder that is involved in the insertion of alcohol, activation of the thiadiazole ring by coordinative interaction, and the sulfur‐extrusion process. Interestingly, the insertion of alcohol occurs much earlier than the sulfur‐extrusion process, supported by a water‐mediated proton‐transfer process. This strategy also is suitable for constructing new benzimidazole‐derived MOFs [Cd2(HMBIDC2−)2]⋅4 H2O (Cd‐BID‐MOF‐1, HMBIDC2−=2‐methyl‐1H‐benzimidazole‐4,7‐dicarboxylate) and [Cd2(HPBIDC2−)2]⋅1/3 H2O (Cd‐BID‐MOF‐2, HPBIDC2−=2‐(3‐hydroxypropyl)‐2H‐benzimidazole‐4,7‐dicarboxylate). Because the terminal hydroxyl group on the imidazole ring protrudes into the circular channel in rhombohedral Cd‐BID‐MOF‐2, the cavity is closer to hydrophilic than the honeycomb‐like cavity in Cd‐BID‐MOF‐1 with similar 3D structure. This rare observation will provide a new strategy to develop in situ ligand‐reaction synthesis of functional MOFs and useful chelation‐assisted catalytic reactions in heteroaromatic chemistry.

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New azaheterocyclic aromatic diphosphonates for hybrid materials for fuel cell applications

Cited by 10 publications

References 43 publications

Synthesis of New Azole Phosphonate Precursors for Fuel Cells Proton Exchange Membranes

Synthesis of New Azole Phosphonate Precursors for Fuel Cells Proton Exchange Membranes

One-Pot Phosphonylation of Heteroaromatic Lithium Reagents: The Scope and Limitations of Its Use for the Synthesis of Heteroaromatic Phosphonates

Direct Conversion of Benzothiadiazole to Benzimidazole: New Benzimidazole‐Derived Metal–Organic Frameworks with Adjustable Honeycomb‐Like Cavities

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