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Lozada IB, Ortiz RJ, Braun JD, Williams JAG, Herbert DE. Donor-Acceptor Boron-Ketoiminate Complexes with Pendent N-Heterocyclic Arms: Switched-on Luminescence through N-Heterocycle Methylation. J Org Chem 2021; 87:184-196. [PMID: 34936362 DOI: 10.1021/acs.joc.1c02138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of intramolecular, donor-stabilized BF2 complexes supported by phenanthridinyl-decorated, β-ketoiminate chelating ligand scaffolds is described, along with their characterization by spectroscopy and X-ray diffraction. In solution, the relative orientation of the pendent phenanthridinyl arm is fixed despite not coordinating to the boron center, and a well-resolved through-space interaction between a phenanthridinyl C-H and a single fluorine atom can be observed by 19F-1H NOE NMR spectroscopy. The neutral compounds are nonetheless only weakly luminescent in fluid solution, ascribed to nonradiative decay pathways enabled by rotation of the N-heterocyclic unit. Methylation of the phenanthridinyl nitrogen restricts this rotation, "switching on" comparably strong emission in solution. Modeling by density functional theory (DFT) and time-dependent DFT (TDDFT) indicates that the character of the lowest energy excitation changes upon methylation, with shallow calculated potential energy surfaces of the neutral complexes consistent with their lack of significant radiative decay.
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Affiliation(s)
- Issiah B Lozada
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Robert J Ortiz
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Jason D Braun
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | | | - David E Herbert
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
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2
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Maar RR, Katzman BD, Boyle PD, Staroverov VN, Gilroy JB. Cationic Boron Formazanate Dyes**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ryan R. Maar
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Benjamin D. Katzman
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Paul D. Boyle
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Viktor N. Staroverov
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Joe B. Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
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3
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Maar RR, Katzman BD, Boyle PD, Staroverov VN, Gilroy JB. Cationic Boron Formazanate Dyes*. Angew Chem Int Ed Engl 2021; 60:5152-5156. [PMID: 33217138 DOI: 10.1002/anie.202015036] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Indexed: 12/12/2022]
Abstract
Incorporation of cationic boron atoms into molecular frameworks is an established strategy for creating chemical species with unusual bonding and reactivity but is rarely thought of as a way of enhancing molecular optoelectronic properties. Using boron formazanate dyes as examples, we demonstrate that the wavelengths, intensities, and type of the first electronic transitions in BN heterocycles can be modulated by varying the charge, coordination number, and supporting ligands at the cationic boron atom. UV-vis absorption spectroscopy measurements and density-functional (DFT) calculations show that these modulations are caused by changes in the geometry and extent of π-conjugation of the boron formazanate ring. These findings suggest a new strategy for designing optoelectronic materials based on π-conjugated heterocycles containing boron and other main-group elements.
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Affiliation(s)
- Ryan R Maar
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Benjamin D Katzman
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Paul D Boyle
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Viktor N Staroverov
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Joe B Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
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4
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Buguis FL, Maar RR, Staroverov VN, Gilroy JB. Near‐Infrared Boron Difluoride Formazanate Dyes. Chemistry 2021; 27:2854-2860. [DOI: 10.1002/chem.202004793] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Indexed: 01/26/2023]
Affiliation(s)
- Francis L. Buguis
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Ryan R. Maar
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Viktor N. Staroverov
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Joe B. Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
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5
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Mu G, Jiang C, Teets TS. Dinuclear Complexes of Flexidentate Pyridine-Substituted Formazanate Ligands. Chemistry 2020; 26:11877-11886. [PMID: 32608094 DOI: 10.1002/chem.202002351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The utility of flexidentate pyridyl-substituted formazanate ligands for assembling dinuclear coordination complexes with iridium(III) and/or platinum(II) building blocks is demonstrated herein. The dinuclear complexes are prepared either via a stepwise strategy, adding one metal unit at a time, or via one-pot self-assembly. Eight of the new complexes, including both mononuclear precursors and dinuclear products, are structurally characterized by single-crystal X-ray diffraction and NMR spectroscopy, revealing several distinct binding modes of the formazanates. All complexes are characterized by UV/Vis absorption spectroscopy and cyclic voltammetry. The frontier orbitals are primarily localized on the formazanate ligand, and a characteristic, intense formazanate-centered π→π* absorption band is observed in the absorption spectra.
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Affiliation(s)
- Ge Mu
- Department of Chemistry, University of Houston, Lamar Fleming Jr. Building, 3585 Cullen Blvd., Houston, 77204-5003, USA
| | - Chenggang Jiang
- Department of Chemistry, University of Houston, Lamar Fleming Jr. Building, 3585 Cullen Blvd., Houston, 77204-5003, USA
| | - Thomas S Teets
- Department of Chemistry, University of Houston, Lamar Fleming Jr. Building, 3585 Cullen Blvd., Houston, 77204-5003, USA
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6
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Gilroy JB, Otten E. Formazanate coordination compounds: synthesis, reactivity, and applications. Chem Soc Rev 2020; 49:85-113. [DOI: 10.1039/c9cs00676a] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inorganic complexes of an emerging class of chelating N-donor ligands, formazanates, offer a unique combination of structurally tunable coordination modes, redox activity, and optoelectronic properties.
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Affiliation(s)
- Joe B. Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario
- London
- Canada
| | - Edwin Otten
- Stratingh Institute for Chemistry
- University of Groningen
- 9747 AG Groningen
- The Netherlands
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7
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Dhindsa JS, Melenbacher A, Barbon SM, Stillman MJ, Gilroy JB. Altering the optoelectronic properties of boron difluoride formazanate dyes via conjugation with platinum(ii)-acetylides. Dalton Trans 2020; 49:16133-16142. [DOI: 10.1039/c9dt03417j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The absorption, emission, and electrochemical properties of conjugates of boron difluoride formazanate dyes and Pt(ii)-acetylides are systematically studied.
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Affiliation(s)
- Jasveer S. Dhindsa
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
- The Centre for Advanced Materials and Biomaterials Research (CAMBR)
| | - Adyn Melenbacher
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Stephanie M. Barbon
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
- The Centre for Advanced Materials and Biomaterials Research (CAMBR)
| | | | - Joe B. Gilroy
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
- The Centre for Advanced Materials and Biomaterials Research (CAMBR)
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Sharma N, Barbon SM, Lalonde T, Maar RR, Milne M, Gilroy JB, Luyt LG. The development of peptide–boron difluoride formazanate conjugates as fluorescence imaging agents. RSC Adv 2020; 10:18970-18977. [PMID: 35518290 PMCID: PMC9053952 DOI: 10.1039/d0ra02104k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/01/2020] [Indexed: 12/15/2022] Open
Abstract
Two new fluorescence imaging probes have been synthesized by incorporating a versatile alkyne-substituted boron difluoride formazanate precursor with peptides through copper-catalyzed alkyne–azide cycloaddition. The formazanate dye was appended to a C-terminal amino acid of ghrelin for imaging the growth hormone secretagogue receptor (GHSR-1a). To demonstrate versatile bioconjugation chemistry, the formazanate dye was added to the N-terminus of bombesin for targeting the gastrin releasing peptide receptor (GRPR). These are the first examples of using this emerging class of dyes, boron difluoride formazanates, for the labelling of biomolecules. Conjugation of a boron difluoride formazanate dye to receptor targeting peptides provides cancer imaging agents for fluorescence microscopy.![]()
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Affiliation(s)
- Neha Sharma
- Department of Chemistry
- University of Western Ontario
- London
- Canada
| | | | - Tyler Lalonde
- Department of Chemistry
- University of Western Ontario
- London
- Canada
| | - Ryan R. Maar
- Department of Chemistry
- University of Western Ontario
- London
- Canada
| | - Mark Milne
- London Regional Cancer Program
- Lawson Health Research Institute
- London
- Canada
| | - Joe B. Gilroy
- Department of Chemistry
- University of Western Ontario
- London
- Canada
| | - Leonard G. Luyt
- Department of Chemistry
- University of Western Ontario
- London
- Canada
- London Regional Cancer Program
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