Crystallographic, Photophysical, NMR Spectroscopic and Reactivity Manifestations of the "8-Heteroaryl Effect" in 4,4-Difluoro-8-(C 4H3 X)-4-bora-3 a,4 a-diaza-s-indacene (X = O, S, Se) (BODIPY) Systems

Kibong Kim, Changbum Jo, Shanmugam Easwaramoorthi, Jooyoung Sung, Dong Ho Kim, David G. Churchill

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

We have synthesized and fully characterized three novel, yet closely related, heterocyclically meso-substituted (BODIPY) fluorophores 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, 2-/3-furyl (7/10); Se, 2-selenenyl (9)) through the use of 2-D NMR (COSY, HSQC, and HMBC), single crystal X-ray diffraction, mass spectrometry, elemental analysis, UV-vis spectroscopy, and fluorescent decay lifetimes, for comparison to the previously reported thienyl species (X = S, 2-/3-thienyl (8/11)). Specifically, 7-11 differ formally by chalcogen (O, S, or Se) or chalcogen placement. Solid state comparisons reveal major effects stemming from subtle structural differences which allows for insights into fluorescent crystal engineering. For the 2-heteroatom substitution, an increase in molecular weight (7 < 8 < 9) correlates with an increasing unit cell-volume, a greater orthogonality for the C4H3X group, and a lower value for φF. Solution and density functional theory (DFT) results reveal interesting platforms for potential in fluorescent studies for neurology. 2-Heterocyclic species show larger λabs,max/em,max values relative to 3-heterocyclic ones, based on electron withdrawing effects. 10 has the greatest φF value herein (0.25, toluene). Fluorescence lifetimes were found to be 2.60 (7), 0.74 (8), 0.27 (9), 4.26 (10), and 1.86 ns (11); λem,max decay was studied for 8. Heterocyclic differences give rise to somewhat different pyrrolic NMR spectroscopic shifts as well. These compounds resist decomposition as seen from titrations with H 2O2, and uniformly undergo λabs,max red-shifting and lowered φF values as they become brominated with Br2.

Original languageEnglish
Pages (from-to)4881-4894
Number of pages14
JournalInorganic Chemistry
Volume49
Issue number11
DOIs
Publication statusPublished - 2010 Jun 7

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Chalcogens
reactivity
Crystal engineering
Nuclear magnetic resonance
neurology
life (durability)
nuclear magnetic resonance
Fluorophores
orthogonality
Toluene
Neurology
decay
Ultraviolet spectroscopy
Titration
titration
Density functional theory
Mass spectrometry
toluene
molecular weight
Substitution reactions

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

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title = "Crystallographic, Photophysical, NMR Spectroscopic and Reactivity Manifestations of the {"}8-Heteroaryl Effect{"} in 4,4-Difluoro-8-(C 4H3 X)-4-bora-3 a,4 a-diaza-s-indacene (X = O, S, Se) (BODIPY) Systems",
abstract = "We have synthesized and fully characterized three novel, yet closely related, heterocyclically meso-substituted (BODIPY) fluorophores 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, 2-/3-furyl (7/10); Se, 2-selenenyl (9)) through the use of 2-D NMR (COSY, HSQC, and HMBC), single crystal X-ray diffraction, mass spectrometry, elemental analysis, UV-vis spectroscopy, and fluorescent decay lifetimes, for comparison to the previously reported thienyl species (X = S, 2-/3-thienyl (8/11)). Specifically, 7-11 differ formally by chalcogen (O, S, or Se) or chalcogen placement. Solid state comparisons reveal major effects stemming from subtle structural differences which allows for insights into fluorescent crystal engineering. For the 2-heteroatom substitution, an increase in molecular weight (7 < 8 < 9) correlates with an increasing unit cell-volume, a greater orthogonality for the C4H3X group, and a lower value for φF. Solution and density functional theory (DFT) results reveal interesting platforms for potential in fluorescent studies for neurology. 2-Heterocyclic species show larger λabs,max/em,max values relative to 3-heterocyclic ones, based on electron withdrawing effects. 10 has the greatest φF value herein (0.25, toluene). Fluorescence lifetimes were found to be 2.60 (7), 0.74 (8), 0.27 (9), 4.26 (10), and 1.86 ns (11); λem,max decay was studied for 8. Heterocyclic differences give rise to somewhat different pyrrolic NMR spectroscopic shifts as well. These compounds resist decomposition as seen from titrations with H 2O2, and uniformly undergo λabs,max red-shifting and lowered φF values as they become brominated with Br2.",
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Crystallographic, Photophysical, NMR Spectroscopic and Reactivity Manifestations of the "8-Heteroaryl Effect" in 4,4-Difluoro-8-(C 4H3 X)-4-bora-3 a,4 a-diaza-s-indacene (X = O, S, Se) (BODIPY) Systems. / Kim, Kibong; Jo, Changbum; Easwaramoorthi, Shanmugam; Sung, Jooyoung; Kim, Dong Ho; Churchill, David G.

In: Inorganic Chemistry, Vol. 49, No. 11, 07.06.2010, p. 4881-4894.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Crystallographic, Photophysical, NMR Spectroscopic and Reactivity Manifestations of the "8-Heteroaryl Effect" in 4,4-Difluoro-8-(C 4H3 X)-4-bora-3 a,4 a-diaza-s-indacene (X = O, S, Se) (BODIPY) Systems

AU - Kim, Kibong

AU - Jo, Changbum

AU - Easwaramoorthi, Shanmugam

AU - Sung, Jooyoung

AU - Kim, Dong Ho

AU - Churchill, David G.

PY - 2010/6/7

Y1 - 2010/6/7

N2 - We have synthesized and fully characterized three novel, yet closely related, heterocyclically meso-substituted (BODIPY) fluorophores 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, 2-/3-furyl (7/10); Se, 2-selenenyl (9)) through the use of 2-D NMR (COSY, HSQC, and HMBC), single crystal X-ray diffraction, mass spectrometry, elemental analysis, UV-vis spectroscopy, and fluorescent decay lifetimes, for comparison to the previously reported thienyl species (X = S, 2-/3-thienyl (8/11)). Specifically, 7-11 differ formally by chalcogen (O, S, or Se) or chalcogen placement. Solid state comparisons reveal major effects stemming from subtle structural differences which allows for insights into fluorescent crystal engineering. For the 2-heteroatom substitution, an increase in molecular weight (7 < 8 < 9) correlates with an increasing unit cell-volume, a greater orthogonality for the C4H3X group, and a lower value for φF. Solution and density functional theory (DFT) results reveal interesting platforms for potential in fluorescent studies for neurology. 2-Heterocyclic species show larger λabs,max/em,max values relative to 3-heterocyclic ones, based on electron withdrawing effects. 10 has the greatest φF value herein (0.25, toluene). Fluorescence lifetimes were found to be 2.60 (7), 0.74 (8), 0.27 (9), 4.26 (10), and 1.86 ns (11); λem,max decay was studied for 8. Heterocyclic differences give rise to somewhat different pyrrolic NMR spectroscopic shifts as well. These compounds resist decomposition as seen from titrations with H 2O2, and uniformly undergo λabs,max red-shifting and lowered φF values as they become brominated with Br2.

AB - We have synthesized and fully characterized three novel, yet closely related, heterocyclically meso-substituted (BODIPY) fluorophores 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, 2-/3-furyl (7/10); Se, 2-selenenyl (9)) through the use of 2-D NMR (COSY, HSQC, and HMBC), single crystal X-ray diffraction, mass spectrometry, elemental analysis, UV-vis spectroscopy, and fluorescent decay lifetimes, for comparison to the previously reported thienyl species (X = S, 2-/3-thienyl (8/11)). Specifically, 7-11 differ formally by chalcogen (O, S, or Se) or chalcogen placement. Solid state comparisons reveal major effects stemming from subtle structural differences which allows for insights into fluorescent crystal engineering. For the 2-heteroatom substitution, an increase in molecular weight (7 < 8 < 9) correlates with an increasing unit cell-volume, a greater orthogonality for the C4H3X group, and a lower value for φF. Solution and density functional theory (DFT) results reveal interesting platforms for potential in fluorescent studies for neurology. 2-Heterocyclic species show larger λabs,max/em,max values relative to 3-heterocyclic ones, based on electron withdrawing effects. 10 has the greatest φF value herein (0.25, toluene). Fluorescence lifetimes were found to be 2.60 (7), 0.74 (8), 0.27 (9), 4.26 (10), and 1.86 ns (11); λem,max decay was studied for 8. Heterocyclic differences give rise to somewhat different pyrrolic NMR spectroscopic shifts as well. These compounds resist decomposition as seen from titrations with H 2O2, and uniformly undergo λabs,max red-shifting and lowered φF values as they become brominated with Br2.

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