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Chaughtai Z, Hashmi MA, Yar M, Ayub K. Electronic structure of polypyrrole composited with a low percentage of graphene nanofiller. Phys Chem Chem Phys 2021; 23:8557-8570. [PMID: 33876018 DOI: 10.1039/d0cp03258a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The low concentration of graphene (<5%) in graphene/polypyrrole composites makes it quite challenging to devise a theoretical model for these composites. Thus, herein, we present theoretical calculations to determine the geometric electronic and optical properties of graphene/polypyrrole composites. Ribbon and sheet models of various sizes were considered for graphene. Oligopyrrole of various lengths was deposited in the graphene model in different orientations including π-stacking, tilted and vertical orientations. Theoretical calculations at the M062X/def2-SVP level revealed that π-stacking is the preferred orientation. To model a lower concentration of graphene, sandwich complexes of oligopyrrole were considered with graphene nanoribbons. Interaction energies revealed that sandwich complexes possessed superior additivity. The NCI analysis established that weak van der Waals interactions existed in all composites. Moreover, the HOMO-LUMO gap decreases as the concentration of graphene increases. Thus, the computed optical band gap of the C58H24-based composite is about 1.7 eV, which is consistent with the reported experimental value (2.1-1.81 eV). The computed band gap further decreases to ∼1.6 eV when the proportion of graphene increases to C64H26. Thus, our results for the graphene nanoribbon-based polypyrrole composites are in good agreement with experimental results. The UV/visible spectra revealed that as the concentration of graphene increases, a red shift is observed for all the configurations, which is consistent with experimental results.
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Affiliation(s)
- Zulqarnain Chaughtai
- Department of Chemistry, COMSATS University, Abbottabad Campus, KPK, 22060, Pakistan.
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Zhao X, Cao Y, Duan L, Yang R, Jiang Z, Tian C, Chen S, Duan X, Chen D, Wan Y. Unleash electron transfer in C-H functionalization by mesoporous carbon-supported palladium interstitial catalysts. Natl Sci Rev 2020; 8:nwaa126. [PMID: 34691608 PMCID: PMC8288372 DOI: 10.1093/nsr/nwaa126] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 01/09/2023] Open
Abstract
The functionalization of otherwise unreactive C–H bonds adds a new dimension to synthetic chemistry, yielding useful molecules for a range of applications. Arylation has emerged as an increasingly viable strategy for functionalization of heteroarenes which constitute an important class of structural moieties for organic materials. However, direct bisarylation of heteroarenes to enable aryl-heteroaryl-aryl bond formation remains a formidable challenge, due to the strong coordination between heteroatom of N or S and transitional metals. Here we report Pd interstitial nanocatalysts supported on ordered mesoporous carbon as catalysts for a direct and highly efficient bisarylation method for five-membered heteroarenes that allows for green and mild reaction conditions. Notably, in the absence of any base, ligands and phase transfer agents, high activity (turn-over frequency, TOF, up to 107 h−1) and selectivity (>99%) for the 2,5-bisarylation of five-membered heteroarenes are achieved in water. A combination of characterization reveals that the remarkable catalytic reactivity here is attributable to the parallel adsorption of heteroarene over Pd clusters, which breaks the barrier to electron transfer in traditional homogenous catalysis and creates dual electrophilic sites for aryl radicals and adsorbate at C2 and C5 positions. The d-band filling at Pd sites shows a linear relationship with activation entropy and catalytic activity. The ordered mesopores facilitate the absence of a mass transfer effect. These findings suggest alternative synthesis pathways for the design, synthesis and understanding of a large number of organic chemicals by ordered mesoporous carbon supported palladium catalysts.
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Affiliation(s)
- Xiaorui Zhao
- Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Yueqiang Cao
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Linlin Duan
- Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Ruoou Yang
- Shanghai Synchrotron Radiation Facility, Zhangjiang National Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Zheng Jiang
- Shanghai Synchrotron Radiation Facility, Zhangjiang National Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Chao Tian
- Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Shangjun Chen
- Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Xuezhi Duan
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - De Chen
- Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim N-7491, Norway
| | - Ying Wan
- Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
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Adsorptive recovery and purification of prodigiosin from methanol/water solutions of Serratia marcescens fermentation broth. BIOTECHNOL BIOPROC E 2014. [DOI: 10.1007/s12257-013-0547-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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A theoretical study of structural and electronic properties of pentacene/Al(100) interface. J Mol Graph Model 2012; 38:334-41. [DOI: 10.1016/j.jmgm.2012.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 06/20/2012] [Accepted: 06/22/2012] [Indexed: 11/21/2022]
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