Wednesday, 6 December 2017

Persulfurated Coronene: A New Generation of “Sulflower”

STR1
STR1

2073844-77-4
C24 S12, 673.04
Coroneno[1,​12-​cd:2,​3-​c'd':4,​5-​c''d'':6,​7-​c'''d''':8,​9-​c''''d'''':10,​11-​c'''''d''''']​hexakis[1,​2]​dithiole
A persulfurated coronene, a molecule dubbed a “sulflower” for its resemblance to a sunflower, bloomed this year. It’s the first fully sulfur-substituted polycyclic aromatic hydrocarbon and only the second member of a new class of circular heterocyclic carbon sulfide compounds, after the synthesis of octathio[8]circulene a decade ago.
Chemists hope to create other class members, including the simplest one, persulfurated benzene, for use in battery cathodes and other electronic materials.
A team led by Xinliang Feng of Dresden University of Technology and Klaus Müllen of the Max Planck Institute for Polymer Research created the sulflower (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.6b12630).

STR1


STR1
Synthesis of persulfuratedcoronene (5, PSC)
5 (82 mg) as dark red solid in 61% yield. HR-MS (HR-MALDI-TOF) m/z: Calcd. for C24S12: 671.6629; Found 671.6648 [M]+; Elem. Anal. calcd. for C24S12: C, 42.83; S, 57.17. Found: C, 42.87; S, 57.13.
STR1

Persulfurated Coronene: A New Generation of “Sulflower”

 Department of Chemistry and Food Chemistry, Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
§ Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
 Institute for Materials Science, Max Bergmann Center of Biomaterials, and Center for Advancing Electronics Dresden, TU Dresden, 01069 Dresden, Germany
 Dipartimento di Chimica, Materiali ed Ingegneria Chimica ‘G. Natta’, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
J. Am. Chem. Soc.2017139 (6), pp 2168–2171
DOI: 10.1021/jacs.6b12630
Publication Date (Web): January 27, 2017
Copyright © 2017 American Chemical Society
Abstract Image
We report the first synthesis of a persulfurated polycyclic aromatic hydrocarbon (PAH) as a next-generation “sulflower.” In this novel PAH, disulfide units establish an all-sulfur periphery around a coronene core. The structure, electronic properties, and redox behavior were investigated by microscopic, spectroscopic and electrochemical methods and supported by density functional theory. The sulfur-rich character of persulfurated coronene renders it a promising cathode material for lithium–sulfur batteries, displaying a high capacity of 520 mAh g–1 after 120 cycles at 0.6 C with a high-capacity retention of 90%

Renhao Dong

Image result for Renhao Dong DRESDEN
Research Group Leader
Renhao received his PhD in Physical Chemistry from Shandong University in 2013. Since 01/2017, he is a research group leader at the Chair for Molecular Functional Materials in TUD. His current research interest focuses on synthesis of organic 2D crystals (2D polymers/COFs/MOFs) and their applications in electronics and energy technology.

Contact

Phone: +49 – 351 / 463-40401 or -34932
Email: renhao.dong@tu-dresden.de
Prof. Xinliang Feng

Prof. Xinliang Feng

Work Biography:

This is a professorship in the context of the cluster of excellence cfaed.

Xinliang Feng received his Bachelor’s degree in analytic chemistry in 2001 and Master’s degree in organic chemistry in 2004. Then he joined Prof. Klaus Müllen's group at the Max Planck Institute for Polymer Research for PhD thesis, where he obtained his PhD degree in April 2008. In December 2007 he was appointed as a group leader at the Max-Planck Institute for Polymer Research and in 2012 he became a distinguished group leader at the Max-Planck Institute for Polymer Research.
His current scientific interests include graphene, two-dimensional nanomaterials, organic conjugated materials, and carbon-rich molecules and materials for electronic and energy-related applications. He has published more than 370 research articles which have attracted more than 25000 citations with H-index of 75.
He has been awarded several prestigious prizes such as IUPAC Prize for Young Chemists (2009), Finalist of 3rd European Young Chemist Award, European Research Council (ERC) Starting Grant Award (2012), Journal of Materials Chemistry Lectureship Award (2013), ChemComm Emerging Investigator Lectureship (2014), Highly Cited Researcher (Thomson Reuters, 2014, 2015 and 2016), Fellow of the Royal Society of Chemistry (FRSC, 2014). He is an Advisory Board Member for Advanced Materials, Journal of Materials Chemistry A, ChemNanoMat, Energy Storage Materials, Small Methods and Chemistry -An Asian Journal. He is also one of the Deputy Leaders for European communitys pilot project Graphene Flagship, Head of ESF Young Research Group "Graphene Center Dresden", and Working Package Leader of WP Functional Foams & Coatings of GRAPHENE FLAGSHIP.

Academic Employment

  • 12/2007-12/2012: Group Leader, Max Planck Institute for Polymer Research in Mainz, Germany
  • 06/2010: Director of the Institute of Advanced Organic Materials, Shanghai Jiao Tong University
  • 03/2011: Distinguished Adjunct Professorship in Shanghai Jiao Tong University, Chin
  • 12/2012-07/2014: Distinguished Group Leader, Max Planck Institute for Polymer Research in Mainz, Germany
  • 08/2014: W3 Chair Professor, Technische Universität Dresden, Germany

Honors and Duties

  • Marie Currie Fellowship (2005-2006)
  • Chinese Government Award for Outstanding Self-financed Students (2008)
  • IUPAC Prize for Young Chemists (2009)
  • Finalist of 3rd European Young Chemist Award (2010)
  • ISE (International Society of Electrochemistry) Young Investigator Award (2011)
  • Adjunct Professorship, China University of Geosciences (Wuhan) (2011)
  • Deputy Leader of one of the ten European representatives of the European community’s pilot project GRAPHENE FLAGSHIP (2012)
  • EU FET Young Explorer (2012)
  • ERC Starting Grant Award (2012)
  • Advisory Board Member for Advanced Materials (2013)
  • Journal of Materials Chemistry Lectureship Award (2013)
  • Advisory Board Member for Journal of Materials Chemistry A (2014)
  • Editorial Board Member of Chemistry - An Asian Journal (2014)
  • ChemComm Emerging Investigator Lectureship (2014)
  • Highly Cited Researcher (Thomson Reuters, 2014)
  • Fellow of the Royal Society of Chemistry (2014)
  • Highly Cited Researcher (Chemistry and Materials Science) (2015)
  • International Advisory Board of Energy Storage Materials (2015)
  • International Advisory Board of ChemNanoMat (2015)
  • Highly Cited Researcher (Chemistry and Materials Science, Thomson Reuters) (2016)
  • Head of ESF Young Research Group “Graphene Center Dresden” (2016)
  • Working Package Leader of WP Functional Foams & Coatings of GRAPHENE FLAGSHIP (2016)
  • International Advisory Board of Small Methods (2016)
  • Path Leader of 2.5D path within the cluster of excellence CFAED (2016)
  • ERC Proof-of-Concept Project Award (2017)
  • Small Young Innovator Award (2017)
  • Hamburg Science Award (2017)

Referee for:

Nature, Science, Nature Materials, Nature Nanotechnology, Nature Chemistry, Journal of the American Chemical Society, Angewandte Chemie International Edition, Nano Letters, Advanced Materials, Chemical Society Reviews, ACS Nano, Small, Chemical Communications, Chemistry of Materials, Organic Letters, Journal of the Organic Chemistry, Chemistry - A European Journal, ChemSusChem, ChemPhysChem, Macromolecular Rapid Communications, Journal of Material Chemistry, New Journal of Chemistry, Chemistry - An Asian Journal, ACS Applied Materials & Interfaces, Energy & Environmental Science, Organic Electronics and so on
Referee for research grants in NSF, US Department of Energy, ESF, ISF and Fondazione Cariparo and Fondazione CariModena.

Publications

Contact (Secretariat)

Phone: +49 351 / 463-43251
Fax: +49 351 / 463-43268
Email: sabine.strecker@tu-dresden.de




Klaus Müllen
Max-Planck-Institute for Polymer Research, Mainz, 55128, Germany
vyrez_DSC_3783.JPG
Research into energy technologies and electronic devices is strongly governed by the available materials. We introduce a synthetic route to graphenes which is based upon the cyclodehydrogenation (“graphitization”) of well-defined dendritic (3D) polyphenylene precursors. This approach is superior to physical methods of graphene formation such as chemical vapour deposition or exfoliation in terms of its (i) size and shape control, (ii) structural perfection, and (iii) processability (solution, melt, and even gas phase). The most convincing case is the synthesis of graphene nanoribbons under surface immobilization and in-situ control by scanning tunnelling microscopy.
Columnar superstructures assembled from these nanographene discs serve as charge transport channels in electronic devices. Field-effect transistors (FETs), solar cells, and sensors are described as examples.
Upon pyrolysis in confining geometries or “carbomesophases”, the above carbon-rich 2D- and 3D- macromolecules transform into unprecedented carbon materials and their carbon-metal nanocomposites. Exciting applications are shown for energy technologies such as battery cells and fuel cells. In the latter case, nitrogen-containing graphenes serve as catalysts for oxygen reduction whose efficiency is superior to that of platinum.
Müllen, K., Rabe, J.R., Acc. Chem. Res. 2008, 41, (4), 511-520;
Wang, X., Zhi, L., Müllen, K. Nano. Lett. 2008, 8, 323-327;
Feng, X.; Chandrasekhar, N.; Su, H. B.; Müllen, K., Nano. Lett. 2008, 8, 4259.;
Pang, S.; Tsao, H. N.; Feng, X.; Müllen, K., Adv. Mater. 2009, 31, 3488;
Feng, X., Marcon, V., Pisula, W., Hansen, M.R., Kirkpatrick, I., Müllen, K., Nature Mater. 2009, 8, 421;
Cai, J., Ruffieux, P., Jaafar, R., Bieri, M., Braun, T., Blankenburg, S., Muoth, M., Seitsonen, A. P., Saleh, M., Feng, X., Müllen, K., Fasel, R., Nature 2010, 466, 470-473;
Yang, S., Feng, X., Zhi, L., Cao, Q., Maier, J., Müllen, K., Adv. Mater. 2010, 22, 838; Liu, R., Wu, D., Feng, X., Müllen, K., Angew. Chem. Int. Ed. 2010, 49, 2565;
Käfer, D., Bashir, A., Dou, X., Witte, G., Müllen, K., Wöll, C., Adv. Mater. 2010, 22, 384;
Diez-Perez, I., Li, Z., Hihath, J., Li, J., Zhang, C., X., Zang, L., Dai, Y., Heng, X., Müllen, K., Tao, N. J. Nature Commun. 2010, DOI: 10.1038.
Prof. Dr. Klaus Müllen
joined the Max-Planck-Society in 1989 as one of the directors of the Max-Planck Institute for Polymer Research. He obtained a Diplom-Chemiker degree at the University of Cologne in 1969 after work with Professor E. Vogel. His Ph.D. degree was granted by the University of Basel, Switzerland, in 1972 where he undertook research with Professor F. Gerson on twisted pi-systems and EPR spectroscopic properties of the corresponding radical anions. In 1972 he joined the group of Professor J.F.M. Oth at the Swiss Federal Institute of Technology in Zürich where he worked in the field of dynamic NMR spectroscopy and electrochemistry. He received his habilitation from the ETH Zürich in 1977 and was appointed Privatdozent. In 1979 he became a Professor in the Department of Organic Chemistry, University of Cologne, and accepted an offer of a chair in Organic Chemistry at the University of Mainz in 1983. He received a call to the University of Göttingen in 1988.
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S1Sc6c8c1c9SSc%10c2SSc%13c2c%11c4c3c%13SSc3c%12SSc7c%12c4c(c5c7SSc56)c8c%11c9%10

Persulfurated Coronene: A New Generation of “Sulflower”

STR1
STR1

2073844-77-4
C24 S12, 673.04
Coroneno[1,​12-​cd:2,​3-​c'd':4,​5-​c''d'':6,​7-​c'''d''':8,​9-​c''''d'''':10,​11-​c'''''d''''']​hexakis[1,​2]​dithiole
A persulfurated coronene, a molecule dubbed a “sulflower” for its resemblance to a sunflower, bloomed this year. It’s the first fully sulfur-substituted polycyclic aromatic hydrocarbon and only the second member of a new class of circular heterocyclic carbon sulfide compounds, after the synthesis of octathio[8]circulene a decade ago.
Chemists hope to create other class members, including the simplest one, persulfurated benzene, for use in battery cathodes and other electronic materials.
A team led by Xinliang Feng of Dresden University of Technology and Klaus Müllen of the Max Planck Institute for Polymer Research created the sulflower (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.6b12630).

STR1


STR1
Synthesis of persulfuratedcoronene (5, PSC)
5 (82 mg) as dark red solid in 61% yield. HR-MS (HR-MALDI-TOF) m/z: Calcd. for C24S12: 671.6629; Found 671.6648 [M]+; Elem. Anal. calcd. for C24S12: C, 42.83; S, 57.17. Found: C, 42.87; S, 57.13.
STR1

Persulfurated Coronene: A New Generation of “Sulflower”

 Department of Chemistry and Food Chemistry, Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
§ Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
 Institute for Materials Science, Max Bergmann Center of Biomaterials, and Center for Advancing Electronics Dresden, TU Dresden, 01069 Dresden, Germany
 Dipartimento di Chimica, Materiali ed Ingegneria Chimica ‘G. Natta’, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
J. Am. Chem. Soc.2017139 (6), pp 2168–2171
DOI: 10.1021/jacs.6b12630
Publication Date (Web): January 27, 2017
Copyright © 2017 American Chemical Society
Abstract Image
We report the first synthesis of a persulfurated polycyclic aromatic hydrocarbon (PAH) as a next-generation “sulflower.” In this novel PAH, disulfide units establish an all-sulfur periphery around a coronene core. The structure, electronic properties, and redox behavior were investigated by microscopic, spectroscopic and electrochemical methods and supported by density functional theory. The sulfur-rich character of persulfurated coronene renders it a promising cathode material for lithium–sulfur batteries, displaying a high capacity of 520 mAh g–1 after 120 cycles at 0.6 C with a high-capacity retention of 90%

Renhao Dong

Image result for Renhao Dong DRESDEN
Research Group Leader
Renhao received his PhD in Physical Chemistry from Shandong University in 2013. Since 01/2017, he is a research group leader at the Chair for Molecular Functional Materials in TUD. His current research interest focuses on synthesis of organic 2D crystals (2D polymers/COFs/MOFs) and their applications in electronics and energy technology.

Contact

Phone: +49 – 351 / 463-40401 or -34932
Email: renhao.dong@tu-dresden.de
Prof. Xinliang Feng

Prof. Xinliang Feng

Work Biography:

This is a professorship in the context of the cluster of excellence cfaed.

Xinliang Feng received his Bachelor’s degree in analytic chemistry in 2001 and Master’s degree in organic chemistry in 2004. Then he joined Prof. Klaus Müllen's group at the Max Planck Institute for Polymer Research for PhD thesis, where he obtained his PhD degree in April 2008. In December 2007 he was appointed as a group leader at the Max-Planck Institute for Polymer Research and in 2012 he became a distinguished group leader at the Max-Planck Institute for Polymer Research.
His current scientific interests include graphene, two-dimensional nanomaterials, organic conjugated materials, and carbon-rich molecules and materials for electronic and energy-related applications. He has published more than 370 research articles which have attracted more than 25000 citations with H-index of 75.
He has been awarded several prestigious prizes such as IUPAC Prize for Young Chemists (2009), Finalist of 3rd European Young Chemist Award, European Research Council (ERC) Starting Grant Award (2012), Journal of Materials Chemistry Lectureship Award (2013), ChemComm Emerging Investigator Lectureship (2014), Highly Cited Researcher (Thomson Reuters, 2014, 2015 and 2016), Fellow of the Royal Society of Chemistry (FRSC, 2014). He is an Advisory Board Member for Advanced Materials, Journal of Materials Chemistry A, ChemNanoMat, Energy Storage Materials, Small Methods and Chemistry -An Asian Journal. He is also one of the Deputy Leaders for European communitys pilot project Graphene Flagship, Head of ESF Young Research Group "Graphene Center Dresden", and Working Package Leader of WP Functional Foams & Coatings of GRAPHENE FLAGSHIP.

Academic Employment

  • 12/2007-12/2012: Group Leader, Max Planck Institute for Polymer Research in Mainz, Germany
  • 06/2010: Director of the Institute of Advanced Organic Materials, Shanghai Jiao Tong University
  • 03/2011: Distinguished Adjunct Professorship in Shanghai Jiao Tong University, Chin
  • 12/2012-07/2014: Distinguished Group Leader, Max Planck Institute for Polymer Research in Mainz, Germany
  • 08/2014: W3 Chair Professor, Technische Universität Dresden, Germany

Honors and Duties

  • Marie Currie Fellowship (2005-2006)
  • Chinese Government Award for Outstanding Self-financed Students (2008)
  • IUPAC Prize for Young Chemists (2009)
  • Finalist of 3rd European Young Chemist Award (2010)
  • ISE (International Society of Electrochemistry) Young Investigator Award (2011)
  • Adjunct Professorship, China University of Geosciences (Wuhan) (2011)
  • Deputy Leader of one of the ten European representatives of the European community’s pilot project GRAPHENE FLAGSHIP (2012)
  • EU FET Young Explorer (2012)
  • ERC Starting Grant Award (2012)
  • Advisory Board Member for Advanced Materials (2013)
  • Journal of Materials Chemistry Lectureship Award (2013)
  • Advisory Board Member for Journal of Materials Chemistry A (2014)
  • Editorial Board Member of Chemistry - An Asian Journal (2014)
  • ChemComm Emerging Investigator Lectureship (2014)
  • Highly Cited Researcher (Thomson Reuters, 2014)
  • Fellow of the Royal Society of Chemistry (2014)
  • Highly Cited Researcher (Chemistry and Materials Science) (2015)
  • International Advisory Board of Energy Storage Materials (2015)
  • International Advisory Board of ChemNanoMat (2015)
  • Highly Cited Researcher (Chemistry and Materials Science, Thomson Reuters) (2016)
  • Head of ESF Young Research Group “Graphene Center Dresden” (2016)
  • Working Package Leader of WP Functional Foams & Coatings of GRAPHENE FLAGSHIP (2016)
  • International Advisory Board of Small Methods (2016)
  • Path Leader of 2.5D path within the cluster of excellence CFAED (2016)
  • ERC Proof-of-Concept Project Award (2017)
  • Small Young Innovator Award (2017)
  • Hamburg Science Award (2017)

Referee for:

Nature, Science, Nature Materials, Nature Nanotechnology, Nature Chemistry, Journal of the American Chemical Society, Angewandte Chemie International Edition, Nano Letters, Advanced Materials, Chemical Society Reviews, ACS Nano, Small, Chemical Communications, Chemistry of Materials, Organic Letters, Journal of the Organic Chemistry, Chemistry - A European Journal, ChemSusChem, ChemPhysChem, Macromolecular Rapid Communications, Journal of Material Chemistry, New Journal of Chemistry, Chemistry - An Asian Journal, ACS Applied Materials & Interfaces, Energy & Environmental Science, Organic Electronics and so on
Referee for research grants in NSF, US Department of Energy, ESF, ISF and Fondazione Cariparo and Fondazione CariModena.

Publications

Contact (Secretariat)

Phone: +49 351 / 463-43251
Fax: +49 351 / 463-43268
Email: sabine.strecker@tu-dresden.de




Klaus Müllen
Max-Planck-Institute for Polymer Research, Mainz, 55128, Germany
vyrez_DSC_3783.JPG
Research into energy technologies and electronic devices is strongly governed by the available materials. We introduce a synthetic route to graphenes which is based upon the cyclodehydrogenation (“graphitization”) of well-defined dendritic (3D) polyphenylene precursors. This approach is superior to physical methods of graphene formation such as chemical vapour deposition or exfoliation in terms of its (i) size and shape control, (ii) structural perfection, and (iii) processability (solution, melt, and even gas phase). The most convincing case is the synthesis of graphene nanoribbons under surface immobilization and in-situ control by scanning tunnelling microscopy.
Columnar superstructures assembled from these nanographene discs serve as charge transport channels in electronic devices. Field-effect transistors (FETs), solar cells, and sensors are described as examples.
Upon pyrolysis in confining geometries or “carbomesophases”, the above carbon-rich 2D- and 3D- macromolecules transform into unprecedented carbon materials and their carbon-metal nanocomposites. Exciting applications are shown for energy technologies such as battery cells and fuel cells. In the latter case, nitrogen-containing graphenes serve as catalysts for oxygen reduction whose efficiency is superior to that of platinum.
Müllen, K., Rabe, J.R., Acc. Chem. Res. 2008, 41, (4), 511-520;
Wang, X., Zhi, L., Müllen, K. Nano. Lett. 2008, 8, 323-327;
Feng, X.; Chandrasekhar, N.; Su, H. B.; Müllen, K., Nano. Lett. 2008, 8, 4259.;
Pang, S.; Tsao, H. N.; Feng, X.; Müllen, K., Adv. Mater. 2009, 31, 3488;
Feng, X., Marcon, V., Pisula, W., Hansen, M.R., Kirkpatrick, I., Müllen, K., Nature Mater. 2009, 8, 421;
Cai, J., Ruffieux, P., Jaafar, R., Bieri, M., Braun, T., Blankenburg, S., Muoth, M., Seitsonen, A. P., Saleh, M., Feng, X., Müllen, K., Fasel, R., Nature 2010, 466, 470-473;
Yang, S., Feng, X., Zhi, L., Cao, Q., Maier, J., Müllen, K., Adv. Mater. 2010, 22, 838; Liu, R., Wu, D., Feng, X., Müllen, K., Angew. Chem. Int. Ed. 2010, 49, 2565;
Käfer, D., Bashir, A., Dou, X., Witte, G., Müllen, K., Wöll, C., Adv. Mater. 2010, 22, 384;
Diez-Perez, I., Li, Z., Hihath, J., Li, J., Zhang, C., X., Zang, L., Dai, Y., Heng, X., Müllen, K., Tao, N. J. Nature Commun. 2010, DOI: 10.1038.
Prof. Dr. Klaus Müllen
joined the Max-Planck-Society in 1989 as one of the directors of the Max-Planck Institute for Polymer Research. He obtained a Diplom-Chemiker degree at the University of Cologne in 1969 after work with Professor E. Vogel. His Ph.D. degree was granted by the University of Basel, Switzerland, in 1972 where he undertook research with Professor F. Gerson on twisted pi-systems and EPR spectroscopic properties of the corresponding radical anions. In 1972 he joined the group of Professor J.F.M. Oth at the Swiss Federal Institute of Technology in Zürich where he worked in the field of dynamic NMR spectroscopy and electrochemistry. He received his habilitation from the ETH Zürich in 1977 and was appointed Privatdozent. In 1979 he became a Professor in the Department of Organic Chemistry, University of Cologne, and accepted an offer of a chair in Organic Chemistry at the University of Mainz in 1983. He received a call to the University of Göttingen in 1988.
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S1Sc6c8c1c9SSc%10c2SSc%13c2c%11c4c3c%13SSc3c%12SSc7c%12c4c(c5c7SSc56)c8c%11c9%10

Thursday, 23 November 2017

Catalytic C-H amination at its limits: challenges and solutions



Catalytic C-H amination at its limits: challenges and solutions
Org. Chem. Front., 2017, 4,2500-2521
DOI: 10.1039/C7QO00547D, Review Article
Damien Hazelard, Pierre-Antoine Nocquet, Philippe Compain
Pushing C-H amination to its limits fosters innovative synthetic solutions and offers a deeper understanding of the reaction mechanism and scope.

Catalytic C–H amination at its limits: challenges and solutions

 

Abstract

Catalytic C–H amination reactions enable direct functionalization of non-activated C(sp3)–H bonds with high levels of regio-, chemo- and stereoselectivity. As a powerful tool to unlock the potential of inert C–H bonds, C–H amination chemistry has been applied to the preparation of synthetically challenging targets since major simplification of synthetic sequences are expected from this approach. Pushing C–H amination to its limits has led to a deeper understanding of the reaction mechanism and scope. In this review, we present a description of the specific challenges facing catalytic C–H amination in the synthesis of natural products and related compounds, as well as innovative tactics created to overcome them. By identifying and discussing the major insights gained and strategies designed, we hope that this review will stimulate further progress in C–H amination chemistry and beyond.
Conclusion Since the seminal works of Du Bois in the early 2000s, the pace of discovery in the field of metal-catalysed C–H amination has been breath-taking. Not surprisingly, this synthetic tool has been applied to the total synthesis of many compounds of interest, given the high prevalence of the amino group in natural products and synthetic pharmaceuticals.67 Chemist’s confidence in the high potential of the C–H amination methodology to unlock inert C–H bonds has been demonstrated by its application to more and more challenging substrates. This has been a powerful drive for progress in the field. New valuable insights have been gained allowing, for example, a better regiochemical control via stereoelectronic and/or conformational effects. Innovative strategies have been discovered to direct the insertion event in substrates bearing a large degree of attendant functionality. Solutions have spanned from the elegant exploitation of kinetic isotope effects to the tactical use of protecting groups with different sizes or electronic characteristics. Systematic exploration of different catalytic systems has been also performed leading to the opening of new possibilities in C–H amination technology. Manganese-based catalysts have thus given rise to nitrenoids that overcome the low reactivity of primary aliphatic C–H bonds without interfering with weaker secondary/tertiary C–H bonds. Despite these impressive achievements, much remains to be done. Counterintuitive selectivity and unexplained reactivity should serve as a reminder that further studies are highly needed to understand in depth catalytic C–H amination chemistry. Many challenges remain on the way, from basic to applied research. A clear mechanistic view based on definitive evidence concerning the details of the C–N bond forming process would undoubtedly facilitate the rational design of efficient catalytic systems leading to higher regio-, chemio- and stereoselectivity. In particular, the quest for site-selective C–H amination through catalyst control has to be pursued.10d,e In this context, the development of efficient intermolecular C–H amination process still represents a major challenge and upcoming advancements are expected to increase the impact of this technology in organic synthesis. Future progress made in the field of catalytic C–H amination chemistry might also lead to industrial-scale applications in the next decade. It is likely that total synthesis of synthetically challenging targets related to natural products will continue to be a powerful driving force towards this goal.
STR1 STR2
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“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

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Tuesday, 21 November 2017

Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

Graphical abstract: Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

 

Abstract

Iridium complexes generated from Ir(I) precursors and PIB oligomer functionalized bpy ligands efficiently catalyzed the reactions of arenes with bis(pinacolato)diboron under mild conditions to produce a variety of arylboronate compounds. The activity of this PIB bound homogeneous catalyst is similar to that of an original non-recyclable catalyst which allows it to be used under milder conditions than other reported recyclable catalysts. This oligomer-supported Ir catalyst was successfully recovered through biphasic extraction and reused for eight cycles without a loss of activity. Biphasic separation after the initial use of the catalyst led to an insignificant amount of iridium leaching from the catalyst to the product, and no iridium leaching from the catalyst was observed in the subsequent recycling runs. Arylboronate products obtained after extraction are sufficiently pure as observed by 1H and 13C-NMR spectroscopy that they do not require further purification.
Hind MAMLOUK, PhD

Hind MAMLOUK, PhD

R&D in Organic Materials Chemistry Looking for a New Challenge
Texas A&M University
 
3-Chloro-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)anisole (5). Transparent oil. Yield: 87%.
 
1H NMR (600 MHz, CDCl3) δ 7.37 (s, 1H), 7.22 – 7.16 (m, 1H), 6.99 (s, 1H), 3.82 (s, 3H), 1.34 (s, 12H);
 
13C NMR (101 MHz, CDCl3) δ 159.88, 134.57, 126.84, 117.71, 117.43, 84.15, 55.52, 24.82.
 
GCMS: RT=14.55 min, M+ = 268.1 vs MW= 268.54 g.mol-1 .
 
 STR1 STR2
 
 
Image result for Sherzod T. Madrahimov Texas A&M University at Qatar

Sherzod Madrahimov

Asst. Prof.

Research experience

  • Aug 2015–present
    Asst. Prof.
    Texas A&M University at Qatar · Chemistry
    Qatar · Doha
  • Jul 2012–Jul 2015
    PostDoc Position
    Northwestern University · Department of Chemistry
    United States · Evanston
  • Aug 2007–Jul 2012
    Graduate student
    University of Illinois, Urbana-Champaign · Department of Chemistry
    United States · Urbana
Image result for Texas A&M University at Qatar
Texas A&M University at Qatar

A headshot
David Bergbreiter
Professor
Contact
Department of Chemistry
Texas A&M University
College Station, TX 77843-3255
P: 979-845-3437
F: 979-845-4719
bergbreiter@chem.tamu.edu

Current Activities

Our group explores new chemistry related to catalysis and polymer functionalization using the tools and precepts of synthetic organic chemistry to prepare functional oligomers or polymers that in turn are used to either effect catalysis in a greener, more environmentally benign way or to more efficiently functionalize polymers. Often this involves creatively combining the physiochemical properties of a polymer with the reactivity of a low molecular weight compound to form new materials with new functions. These green chemistry projects involve undamental research both in synthesis and catalysis but has practical aspects because of its relevance to practical problems.
A common theme in our catalysis studies is exploring how soluble polymers can facilitate homogeneous catalysis. Homogeneous catalysts are ubiquitously used to prepare polymers, chemical intermediates, basic chemicals and pharmaceuticals. Such catalysts often use expensive or precious metals or expensive ligands or are used at relatively high catalyst loadings. The products often contain traces of these catalysts or ligands - traces that are undesirable for esthetic reasons or because of the potential toxicity of these impurities. Both the cost of these catalysts of these issues require catalyst/product separation - separations that often are inefficient and lead to chemical waste. These processes also use volatile organic solvents - solvents that have to be recovered and separated. Projects underway in our lab explore how soluble polymers can address each of these problems. Examples of past schemes that achieve this goal in a general way as highlighted in the Figure below.
We also use functional polymers to modify existing polymers. Ongoing projects involve molecular design of additives that can more efficiently modify polymers' physical properties. We also use functional polymers in covalent layer-by-layer assembly to surface polymers' surface chemistry. An example of this work is our use of 'smart' polymers that reversibly change from being water soluble cold to being insoluble and hydrophobic on heating. Such polymers' have been used by us to prepare 'smart' catalysts, 'smart' surfaces and membranes, and to probe fundamental chemistry underlying temperature and salt-dependent protein solvation.
Jakkrit Suriboot

Jakkrit Suriboot

Research Assistant at Texas A&M University
 
Image result for Praveen Kumar Manyam TEXAS

Dr. Praveen Kumar

Title: Research Assistant Professor
Education: M.S., I.I.T. Roorkee
Ph.D., Panjab University Chandigarh (2008)
Visiting Fellow (w/ Prof. G. G. Balint-Kurti), Bristol University, UK
Postdoctoral Research Associate (w/ Prof. Svetlana Malinovskaya), Stevens Institute of Technology, Hoboken, NJ
Senior Postdoctoral Research Associate (w/ Prof. Seogjoo Jang), Queens College of CUNY, NY
Office: Chemistry 010
Phone: 806-742-3124
Email: praveen.kumar@ttu.edu





“ORG SYN INT” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent
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Thursday, 16 November 2017

Synthesis with Catalysts

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Axay Parmar

Axay Parmar

Founder at Synthesis with Catalysts Pvt. Ltd

 

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Synthesis with Catalysts Pt. Ltd. is a company started with an aim to produce chiral and achiral precious metal based catalysts on commercial scale in line with “Clean and Green India” and “Make in India” vision of Government of India. These catalysts have been developed to promote efficient, economical and environmentally benign processes for the target compounds being produced in aroma, fine chemicals and pharmaceutical industries. These catalysts and their intermediates are also extensively used in academic and industrial R&D centres across globe. In India these catalysts are currently imported at a very prohibitive cost, due to which their use is limited for want of funds. In this direction Synthesis with Catalysts Pvt. Ltd. is striving to make these products available to indigenously available at a very competitive price at small and bulk scale. We are also doing in-house research to optimize process parameters ofvarious organic transformations particularly asymmetric hydrogenation and isomerization reactionsfor customers as and when required.
For the list of our products please visit our wesitewww.synthesiswithcatalysts.com
ABOUT US
  • Our vision is to be the most respected catalyst manufacturing company in the country
  • Our goal is to help our customers:
  • to further improve their production methodologies
  • increase productivity,
  • develop new products with the intervention of catalysts to make the process green and clean
  • Highly selective catalysts for intended application
  • Competitive pricing with short delivery lead times
  • Custom product and process development
Activities:A
Manufacture of Homogeneous catalysts using metal ions viz. Rh, Pt, Ir, Pd, Ru, Co, and Mn
Manufacture of ligands and intermediates
Pharmaceutical, bulk drugs, API, aroma chemical, essential oil industries served
Focus on chiral chemistries
Gram to kilogram quantities
ASYMMETR

Some of the representative reactions are:

ASYMMETRIC/ CHEMOSELECTIVE HYDROGENATION CATALYSTS
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Statements
  • Catalysts are chiral metal complexes derived from a precious metal ion and chiral ligands
  • Ru used most frequently, Rh used in some cases to enhance chemo- and enantio- selectivity
  • Chiral ligands can be selected from variety of simple and substituted BINAP alone or in combination with chiral/achiral diamines
  • Suggested catalysts:
    • RuCl2[(S)-BINAP](dmf)n
    • RuCl2[(S)- tolBINAP][(S,S)-dpen]
    • (S)-XylBINAP/(S)-DAIPEN-Ru
    • (S)-XylBINAP/(S,S)-DPEN-Ru
    • RuCl2[(S)-tolBINAP](pica)
    • RuCl[(S,S)-TsDPEN](η6-p-cymene)
    • Ru(OTf)(TsDPEN)(p-cymene)
    • BINAP-Ru(II) dicarboxylate complexes

ENANTIOSELECTIVE EPOXIDATION / HKR / DKR

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Statements:
  • Transition metal complexes are used for chiral and non-chiral epoxidation of internal and prochiral olefins
  • The epoxides are important intermediates for host of industrially important products
  • In cases where epoxides are required in high optical purity, racemic epoxides can be subjected to Hydrolytic kinetic resolution (HKR), Aminolytic kinetic resolution (AKR), Dynamic kinetic resolutions (DKR)
  • Suggested catalysts:
    • Mn, Co, Cr, Al complexes of chiral SALEN ligands
ASYMMETRIC ISOMERIZATION

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Double bond migration reactions
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Statements:
  • Rh-catalyzed asymmetric isomerization of allylic amines into the corresponding enamines is one of the most revered industrial organic transformation in asymmetric catalysis
  • It has accommodated a wide range of substrates and is a key step in the industrial production of menthol
  • Other industrially important isomerization is migration of terminal double bond to produce selectively trans-internal olefins
  • Commercially important products like isoeugenol and trans-anetheole are produced by these transformations
  • Suggested catalysts:
    • Ru(acac)3
    • RuHCl(CO)(PPh3)3
    • Rh/Pd complexes
Tree of popular asymmetric organic transformations

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At Chiral India event in Mumbai where our technical director Dr. Abdi Is a speaker. With Basu Agarwal
Basu Agarwal

Basu Agarwal

CEO at Synthesis with Catalysts Pvt Ltd
Phone 9999972051 (Mobile)
Email
IM basu.ag@gmail.com (Google Talk)
Chiral India 2017, Nov7-8 Ramada plaza palm grove, Juhu, Mumbai, India
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