Phosphate ester cleavage by a positively charged porous silica adorned with lanthanum (III)

Vargas, Carlos Alberto Amaya; Santos, Joel I. dos; Nascentes, Clésia C.; Denadai, Ângelo Márcio Leite; Araújo, Maria Helena; Brandão, Tiago A. S.

doi:10.1016/j.micromeso.2018.04.022

Cited by 9 publications

(4 citation statements)

References 76 publications

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“…In contrast, when the hydroxylated MCM-41 is dried and reused, hydrolysis exhibits a new induction period that suggests that the siloxane to silanol interconversion exhibits reversibility. Such an observation is fully supported by IR and Raman spectroscopic data previously reported by Warring et al Similar behaviors were also observed for organosilicas, but the role of hydration for the existence and extent of the induction period was unclear. , …”

Section: Resultssupporting

confidence: 83%

Efficient Catalysis of Phosphate Ester Hydrolysis by Bare Silica

et al. 2020

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This work reports the catalysis of bare silica materials (MCM-41, SBA-15, and silica gel) for the complete hydrolyses of bis(2,4-nitrophenyl)phosphate (BDNPP) and bis(4nitrophenyl)phosphate (BNPP), which share the same phosphate diester chemical core with important biological molecules, DNA and RNA, and toxic substances like EA2192 and anatoxin-a(s). Catalytic effects above 7000-fold were observed for the hydrolysis of BNPP, which were consistent with a concerted S N 2(P) mechanism under the action of siloxide and silanol groups that provide water activation by general base catalysis and leavinggroup departure stabilization by general acid catalysis, respectively. We also observed that product formation follows a sigmoidal behavior as a result of catalytic effect enhancement following an induction period. This effect is discussed considering cooperative effects caused by silica hydration, which is unchanged upon material reuse affording strong catalytic effects for phosphate diester hydrolyses and no induction periods.

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Section: Resultssupporting

confidence: 83%

Efficient Catalysis of Phosphate Ester Hydrolysis by Bare Silica

et al. 2020

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“…The catalytic capacity of the fibers was evaluated for the hydrolysis of BDNPP (Scheme ), a typical activated surrogate of poorly reactive phosphate diesters (e.g., phospholipids, RNA, and DNA). − Hydrolysis was followed at pH 8.1 and 25 °C using UV–vis spectroscopy and a flow system containing the fibers (10 mg) PCL, PCL–La, and PCL–LaMC before and after visible light irradiation. Figure a depicts the kinetic data obtained at wavelengths of 360 and 502 nm, which were chosen depending on the absorption of DNP and LaMC.…”

Section: Resultsmentioning

confidence: 99%

Structural and Electronic Characterization of a Photoresponsive Lanthanum(III) Complex Incorporated into Electrospun Fibers for Phosphate Ester Catalysis

Reis

Miguez

Vargas

et al. 2020

ACS Appl. Mater. Interfaces

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Herein, we present the light-induced synthesis and characterization of a La 3+ /spiropyran derivative complex (LaMC) and its application as a catalyst when incorporated into electrospun polycaprolactone (PCL) fibers. In addition to experimental methods, computational calculations were also essential to better understand the structure and electronic characteristics of LaMC. The LaMC complex was identified as a 10-coordinated structure with the La 3+ ion coordinated by four oxygens from the phenolate and the carbonyl of the carboxyl acid group from both MC ligands and by six oxygens from three nitrate ligands. In addition, LaMC was capable of getting reversibly isomerized by UV or visible light cycling. All PCL fibers were successively obtained, and their morphologies, surface properties, and catalytic behavior were studied. Results showed that PCL/LaMC fibers were capable of catalyzing bis(2,4-dinitrophenyl)phosphate degradation efficiently. Complete hydrolysis was accomplished in only 1.5 days relative to the half-life time of 35 days for the uncatalyzed hydrolysis at pH 8.1 and 25 °C.

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“…Except the above‐discussed functionalities, the other functional groups such as glycidyloxy, azido, isocyanate, cyano, vinyl, pyridyl substituted thioether, pyridyl, carboxylic acid, and phosphonate groups are grafted on silica through the condensation with the corresponding organosilanes. J. T. Sarmiento et al.…”

Section: Conventional Fss: Types and Their Chemical Modificationsmentioning

confidence: 99%

“…Silica grafted with isocyanate groups is subjected to diurea formation through the reaction with o‐phenylene diamine in boiling toluene . In the other report, isocyanate groups on silica are sequentially reacted with hydrogen peroxide and sulfuric acid, and eventually converted to ammonia cations (NH 3 + ) . Recently, cyano FS has undergone the acid catalysed hydrolysis and peroxidation for the chemical conversion of cyano groups to peroxo groups (−COOOH) …”

Section: Conventional Fss: Types and Their Chemical Modificationsmentioning

confidence: 99%

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

Antony

Marimuthu

Yang

et al. 2019

The Chemical Record

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Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs. Having certain functional groups in structure, FSs can act as the useful catalysts for few organic reactions even without the need of metal active sites which are termed as the covetous reusable organocatalysts. Magnetic FSs have laid the platform where the effortless recovery of catalysts is realized just using an external magnet, resulting in the simplified reaction procedure. Using FSs of multiple functional groups, we can envisage the shortened reaction pathway and, reduced chemical uses and chemical wastes. Unstable bio‐molecules like enzymes have been stabilized when they get chemically anchored on FSs. The resultant solid bio‐catalysts exhibited very good reusability in many catalytic reactions. Getting provoked from the green chemistry aspects and benefits of FS‐based catalysts, we confer the recent literature and progress focusing on the significance of FSs in heterogeneous catalysis. This review covers the preparative methods, types and catalytic applications of FSs. A special emphasis is given to the metal‐free FS catalysts, multiple FS‐based catalysts and magnetic FSs. Through this review, we presume that the contribution of FSs to green chemistry can be well understood. The future perspective of FSs and the improvements still required for implementing FS‐based catalysts in practical applications have been narrated at the end of this review.

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Phosphate ester cleavage by a positively charged porous silica adorned with lanthanum (III)

Cited by 9 publications

References 76 publications

Efficient Catalysis of Phosphate Ester Hydrolysis by Bare Silica

Efficient Catalysis of Phosphate Ester Hydrolysis by Bare Silica

Structural and Electronic Characterization of a Photoresponsive Lanthanum(III) Complex Incorporated into Electrospun Fibers for Phosphate Ester Catalysis

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

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