Mohammed Al-hashimi

Mohammed Al-hashimi
Texas A&M University at Qatar | TAMU Qatar · Department of Chemistry

PhD

About

106
Publications
19,106
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2,179
Citations
Additional affiliations
July 2008 - October 2011
Imperial College London
Position
  • PostDoc Position

Publications

Publications (106)
Article
Full-text available
This paper reports the efficient synthesis of the first class of polyisobutylene(PIB)-supported palladium-PEPPSI precatalyst (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation). The new complexes are employed in Buchwald–Hartwig amination of aryl chlorides and are found to be reasonably active in the titled cross-cou...
Article
We report on the preparation of conjugated polymer nanofibers via template-synthesis. A femtosecond laser machined fused silica template, with a micro-patterned array of high-aspect ratio surface nanopores, was first spin-coated with a polyvinyl alcohol (PVA) solution to form a water-soluble release layer. The PVA-lined template was then coated wit...
Article
Full-text available
The heterocyclic thiazole unit has been extensively used as electron-deficient building block in π-conjugated materials over the last decade. Its incorporation into organic semiconducting materials is particularly interesting due to its structural resemblance to the more commonly used thiophene building block, thus allowing the optoelectronic prope...
Article
Macrocyclic molecules, such as cyclodextrins, possess selective host-guest binding properties and can be incorporated into larger architectures for adsorption or sensing applications. An inverse emulsion approach was developed for the synthesis of crosslinked polymer nanoparticles of cyclodextrins (CD-PNP) without the employment of any additional l...
Article
Textured surfaces are commonly designed to preclude wetting by water. The design of surfaces that are not wetted by alcohols represents a considerable challenge given the low surface tension, viscosity, and density of these liquids. Herein, we present a hierarchically textured plastronic architecture that can suspend alcohol droplets in a metastabl...
Article
Fluorination is a common strategy for improving the electronic properties of π-conjugated materials, and this has shown to be important for applications in organic electronics, especially for the fabrication of...
Article
Synthesis of cycloolefin-based polymers via metathesis-accompanied cyclopolymerization and tandem ring-opening/ring-closing metathesis (RO/RCM) polymerization are undergoing exciting developments and emerging as an area of great interest in the field of polymer synthesis. Among the conventional polymerization techniques, both cyclopolymerization an...
Article
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This article demonstrates a novel synthetic strategy that can be used to tune the interstrand distance between conjugated polymers with unprecedented precision. This control provides an ideal platform for fundamental insight into the solid-state optical properties of NDI polymers. Abstract Conjugated polymers are an important class of chromophores...
Article
Full-text available
Conjugated polymers are an important class of chromophores for optoelectronic devices. Understanding and controlling their excited state properties, in particular, radiative and non‐radiative recombination processes are among the greatest challenges that must be overcome. We report the synthesis and characterization of a molecularly encapsulated na...
Article
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It is urgently desired yet challenging to synthesize porous graphitic carbon (PGC) in a bottom-up manner while circumventing the need for high-temperature pyrolysis. Here we present an effective and scalable strategy to synthesize PGC through acid-mediated aldol triple condensation followed by low-temperature graphitization. The deliberate structur...
Article
Full-text available
Herein, we present two novel organic semiconducting polymers synthesised from an ancient dye. By employing cross-conjugation within the polymer backbone as a synthetic strategy, we are able to engineer optical gaps such that the novel materials absorb over the entire visible spectrum. The cross-conjugated polymers exhibited relatively high n-type c...
Article
The design of earth-abundant electrocatalysts that can facilitate water splitting at low overpotentials, provide high current densities, and enable prolonged operational lifetimes is central to the production of sustainable fuels. The distinctive atomistic and electronic structure characteristics of the edges of MoS2 imbue high reactivity toward th...
Article
Materials possessing simultaneous thermochromism and thermofluorescence are promising in various applications. In order to address the challenges associated with performance, versatility, and feasibility, a direct blending approach is developed to synthesize thermoresponsive polymer composites from indenoquinacridone dye solution and various polyme...
Article
The synthesis, characterisation and photovoltaic performance of an indacenodithiophene (IDT)-based organic dye in DSSCs has been presented. The dye was designed with novel A-D-A system, which combines the advantages of large, π-extended donor core, flanked with double acceptor/anchoring groups. The studies presented herein illustrate the utility of...
Article
An extensive polycyclic π-system with 23 fused rings is synthesized via a highly efficient borylation reaction, in which four B-N covalent bonds and four B←N coordinate bonds are formed in one pot. B←N coordinate bonds not only lock the backbone into a near-coplanar conformation but also decrease the LUMO energy level to around -3.82 eV, demonstrat...
Article
Benzothiadiazole (BT) and its derivatives have been widely used as strong acceptors for enhancing π-stacking and improving the charge carrier transport properties in optoelectronic applications.
Article
Full-text available
The electron-deficient thiazole moiety has high planarity and effective π–π stacking, which leads to the reduction in the energy levels, exhibiting promising charge carrier mobilities.
Article
Imide-functionalized organic monomers and polymers are attractive in organic optoelectronic devices due to the strong electron-withdrawing ability of the carbonyl units. We report the synthesis of diselenophene−pyrrole-2,5-dione and diselenophene−phthalimide based homopolymers P1−P2 and their corresponding copolymers P3−P4. The effect of the chemic...
Article
Full-text available
There a few reports of rhodamine-based fluorescent sensors for selective detection of only Al3+, due to the challenge of identifying a suitable ligand for binding Al3+ ion. The use of fluorophore moieties appended to a polymer backbone for sensing applications is far from mature. Here, we report a new fluorescent probe/monomer 4 and its ROMP derive...
Article
A facile synthetic method is developed to afford cyclodextrin-derived polymer networks that exhibit high selectivity in capturing certain organic compounds in water. The sustainable and scalable synthesis, together with the highly robust adsorption performance enables efficient removal and/or separation of organic molecules from aqueous solution in...
Article
Front Cover: In article number 2000382 Mohammed Al‐Hashimi, Hassan S. Bazzi and co‐workers adapt the organocatalyzed aza‐ and thiol‐Michael addition ‘click’ reaction to polyisobutylene acrylate functionalization. This approach paves the way to a myriad of chain‐end functional polyolefins with a broad range of potential applications.
Article
Functionalization of polyolefins, in particular polyisobutylene, remains a relatively unexplored application for the Michael reaction. This work evaluates the potential of polyisobutylene acrylate (PIBA) chain‐end modification via organocatalyzed thiol‐Michael and aza‐Michael additions. A series of chain‐end functional polyisobutylene oligomers are...
Article
Data-driven approaches have brought about a revolution in manufacturing; however, their application to the deterministic navigation of reaction trajectories to stabilize crystalline solids with precise composition, atomic connectivity, microstructural dimensionality, and surface structure remains much more challenging. The design of synthetic metho...
Article
Tandem metathesis polymerization of terminal alkynes with a small functional ring-size cycloalkene remains a challenge. A series of 1-propargyl-1′-carboxylate ester monomers M1-M4 derived from 3-cyclopentene initiated by ruthenium-alkylidene complexes have been investigated via tandem polymerization. Detailed DFT calculations and end-group analysis...
Article
Silicon circuitry has dominated the semiconductor industry for decades but is constrained in its power efficiency by the Fermi-Dirac distribution of electron energies. Electron-correlated transition metal oxides exhibiting metal-to-insulator transitions (MITs) are excellent candidates for energy-efficient computation, which can further emulate the...
Article
Full-text available
Smart textiles exhibiting optical response to external temperature stimuli are promising functional materials for a wide range of applications. It is critical yet challenging to endow these materials with high‐contrast, vivid, and real‐time optical signals, such as changes in color or fluorescent emission, for the indication of heating and/or cooli...
Article
Polyaniline derivatives represent one of the most widely used classes of conductive polymers. The fundamentally important electronic properties of pernigraniline salts - the fully oxidized and acid-doped derivatives of polyanilines, however, are still not well-understood due to their poor stability and configurational uncertainty. In order to addre...
Article
A series of four donor-acceptor conjugated copolymers P1-P4 with linear and branched side chains based on the ladder type indacenodithiazole (IDTz) moiety containing the electron-deficient thiazole unit was copolymerized with di-2-thienyl-2,1,3-benzothiadiazole (DTBT) and 4,7-di(thien-2-yl)-5,6-difluoro-2,1,3-benzothiadiazole (DTBTff) as the buildi...
Article
Carbon monoxide (CO) is an important biological gasotransmitter in living cells. Precise spatial and temporal control over release of CO is a major requirement for clinical application. To date, the most reported carbon monoxide releasing materials use expensive fabrication methods and require harmful and poorly designed tissue-penetrating UV irrad...
Article
Full-text available
A chief aim in singlet fission research is to develop new materials concepts for more efficient singlet fission. The typical approaches such as tuning π-overlap and charge-transfer interactions, enhancing delocalization, altering diradical character, or extending the conjugation length have profound effects simultaneously on the singlet and triplet...
Article
Full-text available
Ring‐opening metathesis polymerization (ROMP) of thioether‐derived oxanorbornene imide (M1) and its copolymerization with various cycloolefin comonomers such as cyclopentene (M2), cyclopent‐3‐en‐1‐ol (M3), cycloheptene (M4), and cyclooctene (M5) using Hoveyda–Grubbs second generation catalyst has been investigated. Polymerizations were performed at...
Article
The increasing frequency with which organic pollutants can be found in global surface water poses a formidable threat to both our environment and its creatures. While the problem has attracted adequate attention, current water treatment tools such as commercially available active carbon still can’t satisfy the remediating necessity due to its unfav...
Article
A series of 11 novel fluorinated and non-fluorinated di(thiazolyl)benzenes have been synthesized via microwave assisted Stille coupling and characterized using X-ray crystallography. A comparative analysis of nonbonding interactions in bis-heteroaryl-phenylene derivatives depending on the heterocycle structure and degree of fluorination of the cent...
Article
TPEN is an amino chelator of transition metals that is effective at the cellular and whole organism levels. Although TPEN of often used as a selective zinc chelators, it has affinity for copper and iron and has been shown to chelate both biologically. We have previously shown that TPEN selectively kills colon cancer cells based on its ability to ch...
Article
Full-text available
Ethanedithiol-functionalized polyisobutylene was prepared in one step by a photoinitiated thiol-ene “click” reaction starting from ethanedithiol and polyisobutylene (PIB). The functionalized oligomer product was then used as a soluble sequestrant for transition metals. This PIB-bound thioether-thiol ligand is phase selectively soluble in alkanes an...
Article
Directed alignment of polymer chains plays an indispensable role in charge transport properties. We focus not only on a specific method to induce the alignment but also on the design of a liquid crystalline (LC) conjugated polymer to take advantage of an intrinsic self-assembly characteristic. We synthesized a lyotropic LC conjugated polymer, CP1-P...
Article
Full-text available
We report the synthesis and characterization of four novel small bandgap copolymers incorporating the electron-deficient thieno[2,3-d:5,4-d′]bisthiazole and selenopheno[2,3-d:5,4-d′]bisthiazole building blocks with a series of electron-deficient diketopyrrolopyrole units. The four resultant copolymers were synthesized via palladium Stille cross-cou...
Article
Full-text available
Recent advances in flexible and stretchable electronics (FSE), a technology diverging from the conventional rigid silicon technology, have stimulated fundamental scientific and technological research efforts. FSE aims at enabling disruptive applications such as flexible displays, wearable sensors, printed RFID tags on packaging, electronics on skin...
Article
Full-text available
Molybdenum disulfide (MoS2) is a semiconducting transition metal dichalcogenide that is known to be a catalyst for both the hydrogen evolution reaction (HER) as well as for hydro-desulfurization (HDS) of sulfur-rich hydrocarbon fuels. Specifically, the edges of MoS2 nanostructures are known to be far more catalytically active as compared to unmodif...
Article
Composed of alternating electron-rich and electron-deficient repeating units in a fused rigid backbone, donor-acceptor conjugated ladder polymers represent a class of promising material candidates possessing a host of intriguing properties. These polymers are challenging to synthesize because of the typically low reaction efficiency of electron-def...
Conference Paper
Novel low band gap polymers based on pyrrolo[3,2-d:4,5-d′]bisthiazole (PBTz) and thienylenevinylene (TV) For Organic Electronic Applications Dhananjaya Patra?,1 Hassan S. Bazzi,1 Lei Fang¬2 and Mohammed Al-Hashimi1 1Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar 2Department of Chemistry and Department of Materia...
Conference Paper
Conjugated polymers (CPs) are emerging active materials for electronic and optoelectronic devices, such as organic solar cells, thin-film transistors, light-emitting diodes, as well as optical and amperometric sensors. There has been an intensive worldwide research effort on the development of stable, organic semiconductors as potential replacement...
Patent
The organic semiconductor polymers relates to the synthesis of a carbazole-based ladder polymer. The synthesis of the ladder polymer includes forming a precursor conjugated polymer by Suzuki step growth polymerization of 2, 7-dibromocarbazole with 1, 4-dibromo-2, 5-divinylbenzene, followed by end capping with 2-bromostyrene and 2-vinyl-phenylboro...
Article
Herein, this study investigates the impact of branching-point-extended alkyl chains on the charge transport properties of three ultrahigh n-type mobility conjugated polymers. Using grazing incidence wide-angle X-ray scattering, analysis of the crystallinity of the series shows that while π–π interactions are increased for all three polymers as expe...
Article
Full-text available
Fully conjugated ladder polymers (cLPs), in which all the backbone units on the polymer main-chain are π-conjugated and fused, have attracted great interest owing to their intriguing properties, remarkable chemical and thermal stability, and potential suitability as functional organic materials. The synthesis of cLPs can be, in general, achieved by...
Article
The discovery and deployment of earth-abundant electrocatalysts for hydrogen evolution is central to the use of molecular hydrogen as a viable fuel. The edges of molybdenum sulfide are able to mediate proton adsorption and dihydrogen formation at relatively low overpotentials in acidic media. From a practical perspective, an optimal electrocatalyst...
Article
New low band gap copolymers P1-P4, based on thienylenevinylene (TV) and pyrrolo[3,2-d:4,5-d′]bisthiazole (PBTz) unit composed of different alkyl side chains, such as 2-octyldodecyl (OD), n-hexadecyl (HD), 2-ethylhexyl (EH), and 9-heptadecyl (HD) groups, respectively, have been synthesized and characterized. Electrochemical and optical studies of th...
Article
Linear trans-polypentenamers are highly desired materials among synthetic tire additives due to their comparable physical properties to natural rubber. trans-Polypentenamer can be prepared by equilibrium ring-opening metathesis polymerization (ROMP) using well-defined ruthenium catalyst systems. This unique feature of the equilibrium polymerization...
Article
Herein we present the synthesis and characterization of four conjugated polymers containing a novel chro-mophore for organic electronics based on an indigoid structure. These polymers exhibit extremely small band gaps of ~1.2 eV, impressive crystallinity, and extremely high n-type mobility exceeding 3 cm2 Vs-1. The n-type charge carrier mobili-ty c...
Article
The fluorous alkenes H2C[double bond, length as m-dash]CHRfn (Rfn = (CF2)n-1CF3; n = 8, 10) undergo the Mizoroki-Heck reaction with a variety of aromatic monobromides and polybromides such as 1,3- and 1,4-C6H4Br2, 1,3,5-C6H3Br3, 1,3,5-C6H3Br2Cl, 1,4-XC6H4Br (X = CF3, Rf8, COCH3, CN, 1,4-OC6H4Br), 1,2-O2NC6H4Br, 5-bromoisoquinoline, 5-bromopyrimidin...
Article
Molecular doping, under certain circumstances, can be used to improve the charge transport in organic semiconductors through the introduction of excess charge carriers which can in turn negate unwanted trap states often present in organic semiconductors. Here, two Lewis basic indenopyrazine copolymers with large ionization potential (5.78 and 5.82...
Article
Ruthenium catalyzed ring closing metathesis (RCM) and ring opening metathesis polymerization (ROMP) reactions using a supported bis(arylimino)acenaphthene N-heterocyclic carbene (BIAN-NHC) complex have been reported. The BIAN-NHC Ru-complex exhibits excellent catalytic activity and tolerates a wide range of substrates at low catalyst loadings. DFT...
Article
Linear trans-polypentenamers are highly desired materials among the synthetic tire additives due to their comparable physical properties to natural rubber. Trans-polypentenamer can be prepared by equilibrium ring-opening metathesis polymerization (ROMP) using well-defined ruthenium catalyst systems. This unique feature of the equilibrium polymeriza...
Article
We report the synthesis of a novel naphthalene diimide (NDI) monomer containing two (tributylstannyl)vinyl groups. The utility of this building block is demonstrated by its copolymerization with five different electron-rich comonomers under Stille conditions. The resulting high molecular weight polymers show red-shifted optical absorptions in compa...
Article
Molybdenum disulfide (MoS2) is a promising earth-abundant and low-cost electrocatalyst for the hydrogen evolution reaction (HER). In this study, we describe a stepwise synthetic approach comprising vapor transport, reduction, and topochemical sulfidation for creating 3D arrays of MoS2 nanosheets directly integrated onto carbon fiber paper (CFP) sub...
Article
In the past decade, numerous examples of chemical technologies based on olefin metathesis have been developed to make olefin metathesis increasingly dominant in several sustainable and green chemical processes. In spite of the wide application profile, conjugated olefin metathesis, especially conjugated polyene metathesis, is an area of great inter...