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  • 1.
    El Nahhas, Amal
    et al.
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Shameem, Muhammad Anwar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Chabera, Pavel
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Uhlig, Jens
    Lund Univ, Dept Chem Phys, Lund, Sweden..
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes2017Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, nr 24, s. 5673-5677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of new materials for solar-to-energy conversion should consider stability, ease of fabrication, and beneficial photophysical properties. In this context, a set of novel -conjugated building blocks, with phospha- and arsaalkenes possessing a unique dithienyl annulated heterofulvenoid core, have been prepared as air- and moisture-stable sensitizers. These compounds unify electron-donor and -acceptor moieties, making them potential candidates for light-harvesting applications. Optical characterization of these systems was performed by steady-state and time-resolved absorption spectroscopy, supported by time-dependent DFT calculations. Tuning of the optical properties of these systems can be achieved by varying the pnictogen element at the bridgehead position, giving a bathochromic shift of approximate to 40nm and coordinating the phosphaalkene towards gold Au-I centers. The latter results in a approximate to 2000-fold extension of the approximate to 10ps lifetime of uncoordinated systems well into the ns regime.

  • 2.
    Shameem, Muhammad A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Esfandiarfard, Keyhan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Öberg, Elisabet
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes2016Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, nr 30, s. 10614-10619Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The first direct alkynylation of C,C-dibromophosphaalkenes by a reaction with sulfonylacetylenes is reported. Alkynylation proceeds selectively in the trans position relative to the P substituent to afford bromoethynylphosphaalkenes. Owing to the absence of transition metals in the procedure, the previously observed conversion of dibromophosphaalkenes into phosphaalkynes through the phosphorus analog of the Fritsch-Buttenberg-Wiechell rearrangement is thus suppressed. The bromoethynylphosphaalkenes can subsequently be converted to C,C-diacetylenic, cross-conjugated phosphaalkenes by following a Sonogashira coupling protocol in good overall yields. By using the newly described method, full control over the stereochemistry at the P=C double bond is achieved. The substrate scope of this reaction is demonstrated for different dibromophosphaalkenes as well as different sulfonylacetylenes.

  • 3.
    Shameem, Muhammad Anwar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Syntetisk molekylär kemi.
    Low-Coordinate Organopnictogens: Synthesis and Optoelectronic properties2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis work is based on the development of novel organopnictogen compounds and the exploration of their potential applications in organic electronics. In particular, incorporation of phosphorus and arsenic into π-conjugated systems is known to modify the optoelectronic properties.

    The first chapter of this thesis is fully devoted to the development of a metal-free synthetic route that allows direct, sequential and stereoselective alkynylation of C,C-dibromophosphaalkenes. The subsequent unusual reactivity of thus synthesized C-mono and C,C-diacetylenicphosphaalkenes with terminal acetylenes afforded highly substituted 1-phoshpha-1,3-butadienes heavier analogue of all carbon 1,3-butadiene motifs. Optimization of the reaction condition favored exclusively the formation of 1-phospha-1,3-butadienes. Unveiling the unique cyclization of the 3-yne 1-phospha-1,3-butadiene gave highly substituted phosphole derivatives. Further, it has been experimentally shown that the P=C unit is essential for this rare cyclization and rearrangement to give π-conjugated phosphole derivatives.

    The second chapter of this thesis work deals with incorporation of P/As in the form of phosphinidene and or arsinidene units as an exocyclic substituent at the bridge of the fused rigid cyclpentadithiophenes (p-CPDT) core. Furthermore, it demonstrates how this chemical modification at the bridgehead position selectively lowers the LUMO level. At a later stage, substitutions at α and α` positions of the central CPDT core was used to modify the HOMO level without further affecting the LUMO level. We also performed DFT calculations on these phosphinide/arsinidene p-CPDT derivatives to theoretical evaluate the impact of P and or As incorporation. The phosphinidene/arsinidene p-CPDT derivatives were fully characterized using electrochemical and optical spectroscopic techniques including transient absorption spectroscopy. Additionally, the arsinidene-p-CPDT were electrochemically polymerized, and the resultant polymer film was characterized by means of SEM and EDX.

    The last chapter of this research work is dealing with the exploration and functionalization of open-ended small fragments of fullerene-C60 such as sumanene and truxene. Functionalisation of these motifs was achieved via the introduction of pnictogens (P/As), either in the form of phosphinidene/arsinidene or as heteroles. The optoelectronic spectra of the unprecedented pnictinidenotruxene exhibited significantly redshift absorption and three fully reversible reduction events upon electrochemical reduction.

    Delarbeten
    1. Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes
    Öppna denna publikation i ny flik eller fönster >>Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes
    Visa övriga...
    2016 (Engelska)Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, nr 30, s. 10614-10619Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The first direct alkynylation of C,C-dibromophosphaalkenes by a reaction with sulfonylacetylenes is reported. Alkynylation proceeds selectively in the trans position relative to the P substituent to afford bromoethynylphosphaalkenes. Owing to the absence of transition metals in the procedure, the previously observed conversion of dibromophosphaalkenes into phosphaalkynes through the phosphorus analog of the Fritsch-Buttenberg-Wiechell rearrangement is thus suppressed. The bromoethynylphosphaalkenes can subsequently be converted to C,C-diacetylenic, cross-conjugated phosphaalkenes by following a Sonogashira coupling protocol in good overall yields. By using the newly described method, full control over the stereochemistry at the P=C double bond is achieved. The substrate scope of this reaction is demonstrated for different dibromophosphaalkenes as well as different sulfonylacetylenes.

    Nyckelord
    alkynylation, cross-conjugation, phosphaalkenes, Sonogashira coupling, sulfonyl coupling
    Nationell ämneskategori
    Oorganisk kemi
    Identifikatorer
    urn:nbn:se:uu:diva-302705 (URN)10.1002/chem.201601955 (DOI)000380273300043 ()27310813 (PubMedID)
    Externt samarbete:
    Forskningsfinansiär
    VetenskapsrådetCarl Tryggers stiftelse för vetenskaplig forskning
    Tillgänglig från: 2016-09-08 Skapad: 2016-09-08 Senast uppdaterad: 2019-01-18Bibliografiskt granskad
    2. Highly branched 2,3-diyne-1-phospha-1,3-butadiene motifs via Pd/Cu mediated alkynyl addition
    Öppna denna publikation i ny flik eller fönster >>Highly branched 2,3-diyne-1-phospha-1,3-butadiene motifs via Pd/Cu mediated alkynyl addition
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-373905 (URN)
    Tillgänglig från: 2019-01-17 Skapad: 2019-01-17 Senast uppdaterad: 2019-01-18
    3. Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes
    Öppna denna publikation i ny flik eller fönster >>Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes
    Visa övriga...
    2017 (Engelska)Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, nr 24, s. 5673-5677Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The development of new materials for solar-to-energy conversion should consider stability, ease of fabrication, and beneficial photophysical properties. In this context, a set of novel -conjugated building blocks, with phospha- and arsaalkenes possessing a unique dithienyl annulated heterofulvenoid core, have been prepared as air- and moisture-stable sensitizers. These compounds unify electron-donor and -acceptor moieties, making them potential candidates for light-harvesting applications. Optical characterization of these systems was performed by steady-state and time-resolved absorption spectroscopy, supported by time-dependent DFT calculations. Tuning of the optical properties of these systems can be achieved by varying the pnictogen element at the bridgehead position, giving a bathochromic shift of approximate to 40nm and coordinating the phosphaalkene towards gold Au-I centers. The latter results in a approximate to 2000-fold extension of the approximate to 10ps lifetime of uncoordinated systems well into the ns regime.

    Ort, förlag, år, upplaga, sidor
    WILEY-V C H VERLAG GMBH, 2017
    Nyckelord
    arsaalkene, electrochemistry, main group elements, phosphaalkene, pnictogens, time-resolved spectroscopy
    Nationell ämneskategori
    Kemi
    Identifikatorer
    urn:nbn:se:uu:diva-322721 (URN)10.1002/chem.201700917 (DOI)000400044400006 ()28248442 (PubMedID)
    Forskningsfinansiär
    Vetenskapsrådet, 2013-4763Knut och Alice Wallenbergs StiftelseÅForsk (Ångpanneföreningens Forskningsstiftelse)
    Tillgänglig från: 2017-05-29 Skapad: 2017-05-29 Senast uppdaterad: 2019-01-18Bibliografiskt granskad
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  • 4.
    Shameem, Muhammad Anwar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Organophosphorus Compounds in Organic Electronics2016Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, nr 31, s. 10718-10735Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This Minireview describes recent advances of organophosphorus compounds as opto-electronic materials in the field of organic electronics. The progress of (hetero-) phospholes, unsaturated phosphanes, and trivalent and pentavalent phosphanes since 2010 is covered. The described applications of organophosphorus materials range from single molecule sensors, field effect transistors, organic light emitting diodes, to polymeric materials for organic photovoltaic applications.

1 - 4 av 4
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