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Chiesa A, Guidi T, Carretta S, Ansbro S, Timco GA, Vitorica-Yrezabal I, Garlatti E, Amoretti G, Winpenny REP, Santini P. Magnetic Exchange Interactions in the Molecular Nanomagnet Mn_{12}. Phys Rev Lett 2017; 119:217202. [PMID: 29219408 DOI: 10.1103/physrevlett.119.217202] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 06/07/2023]
Abstract
The discovery of magnetic bistability in Mn_{12} more than 20 years ago marked the birth of molecular magnetism, an extremely fertile interdisciplinary field and a powerful route to create tailored magnetic nanostructures. However, the difficulty to determine interactions in complex polycentric molecules often prevents their understanding. Mn_{12} is an outstanding example of this difficulty: although it is the forefather and most studied of all molecular nanomagnets, an unambiguous determination of even the leading magnetic exchange interactions is still lacking. Here we exploit four-dimensional inelastic neutron scattering to portray how individual spins fluctuate around the magnetic ground state, thus fixing the exchange couplings of Mn_{12} for the first time. Our results demonstrate the power of four-dimensional inelastic neutron scattering as an unrivaled tool to characterize magnetic clusters.
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Affiliation(s)
- A Chiesa
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - T Guidi
- ISIS Facility, Rutherford Appleton Laboratory, OX11 0QX Didcot, United Kingdom
| | - S Carretta
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
| | - S Ansbro
- School of Chemistry and Photon Science Institute, University of Manchester, M13 9PL Manchester, United Kingdom
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, Grenoble Cedex 9 F-38042, France
| | - G A Timco
- School of Chemistry and Photon Science Institute, University of Manchester, M13 9PL Manchester, United Kingdom
| | - I Vitorica-Yrezabal
- School of Chemistry and Photon Science Institute, University of Manchester, M13 9PL Manchester, United Kingdom
| | - E Garlatti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
| | - G Amoretti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
| | - R E P Winpenny
- School of Chemistry and Photon Science Institute, University of Manchester, M13 9PL Manchester, United Kingdom
| | - P Santini
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
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Crossley DL, Kahan RJ, Endres S, Warner AJ, Smith RA, Cid J, Dunsford JJ, Jones JE, Vitorica-Yrezabal I, Ingleson MJ. A modular route to boron doped PAHs by combining borylative cyclisation and electrophilic C-H borylation. Chem Sci 2017; 8:7969-7977. [PMID: 29568443 PMCID: PMC5853289 DOI: 10.1039/c7sc02793a] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022] Open
Abstract
Starting from simple alkynes, sequential borylative cyclisation/electrophilic C–H borylation represents a simple modular route to novel B-doped PAHs.
Heteroatom doping into polyaromatic hydrocarbons (PAHs) is a powerful approach for modifying key physical properties, however, there are extremely few modular routes that enable facile formation of B-, B2- and B,N-(specifically not containing direct B–N bonds) doped PAHs despite the growing importance of these materials. Sequential, one pot borylative cyclisation/intramolecular electrophilic C–H borylation of naphthyl-alkynes provides a simple new route to access novel B-, B,N- and B2-doped (PAHs). The initial products, dihydronaphthalene/dihydroquinoline B-mesityl PAHs, were reacted with [Ph3C][BF4]/pyridyl base to form the oxidised B-, and B,N-doped PAHs. However, for B-triisopropylphenyl (Trip) PAH congeners oxidation has to be performed prior to Trip installation due to preferential oxidation of an isopropylaryl moiety to the styrene. This alternative sequence enables access to Trip-B-PAHs and to structurally constrained B and B2-PAHs. Analysis of the solid state structures and optoelectronic properties of these PAHs confirm that frontier orbital energies, extended packing structures, Stokes shift and quantum yields all can be rationally modified using this methodology. The simplicity of this synthetic approach makes it a powerful tool for rapidly generating novel bench stable boron doped PAHs, which is important for facilitating further structure–property relationship studies and the wider utilisation of these materials in optoelectronic applications.
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Affiliation(s)
- D L Crossley
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - R J Kahan
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - S Endres
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - A J Warner
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - R A Smith
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - J Cid
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - J J Dunsford
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - J E Jones
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - I Vitorica-Yrezabal
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
| | - M J Ingleson
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK .
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Escande A, Crossley DL, Cid J, Cade IA, Vitorica-Yrezabal I, Ingleson MJ. Inter- and intra-molecular C–H borylation for the formation of PAHs containing triarylborane and indole units. Dalton Trans 2016; 45:17160-17167. [DOI: 10.1039/c6dt03526d] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Inter-/intra-molecular electrophilic C–H borylation of C4-substituted indoles enables the formation of fused polycyclic aromatic structures containing triarylborane and N-heterocyclic units.
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Affiliation(s)
- A. Escande
- School of Chemistry
- University of Manchester
- Manchester
- UK
| | | | - J. Cid
- School of Chemistry
- University of Manchester
- Manchester
- UK
| | - I. A. Cade
- School of Chemistry
- University of Manchester
- Manchester
- UK
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Crossley DL, Cade IA, Clark ER, Escande A, Humphries MJ, King SM, Vitorica-Yrezabal I, Ingleson MJ, Turner ML. Enhancing electron affinity and tuning band gap in donor-acceptor organic semiconductors by benzothiadiazole directed C-H borylation. Chem Sci 2015; 6:5144-5151. [PMID: 29142733 PMCID: PMC5666683 DOI: 10.1039/c5sc01800e] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/06/2015] [Indexed: 12/22/2022] Open
Abstract
Electrophilic borylation using BCl3 and benzothiadiazole to direct the C-H functionalisation of an adjacent aromatic unit produces fused boracyclic materials with minimally changed HOMO energy levels but significantly reduced LUMO energy levels. In situ alkylation and arylation at boron using Al(alkyl)3 or Zn(aryl)2 is facile and affords boracycles that possess excellent stability towards protic solvents, including water, and display large bathochromic shifts leading to far red/NIR emission in the solid state with quantum yields of up to 34%. Solution fabricated OLEDs with far red/NIR electroluminescence are reported with EQEs > 0.4%.
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Affiliation(s)
- D L Crossley
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - I A Cade
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - E R Clark
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - A Escande
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - M J Humphries
- Cambridge Display Technology Limited , Unit 3, Cardinal Park, Cardinal Way , Godmanchester , PE29 2XG , UK
| | - S M King
- Cambridge Display Technology Limited , Unit 3, Cardinal Park, Cardinal Way , Godmanchester , PE29 2XG , UK
| | - I Vitorica-Yrezabal
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - M J Ingleson
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
| | - M L Turner
- School of Chemistry , University of Manchester , Manchester , M13 9PL , UK . ;
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Abstract
The unexpected 1,1/1,2 isomerisation of the diolate in B2cat2 is observed on addition of Lewis bases.
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Affiliation(s)
- I. A. Cade
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - W. Y. Chau
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | | | - M. J. Ingleson
- School of Chemistry
- The University of Manchester
- Manchester
- UK
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