Halogen Bonding Facilitates Intersystem Crossing in Iodo-BODIPY Chromophores

Lee, Yumin; Malamakal, Roy M.; Chenoweth, David M.; Anna, Jessica M.

doi:10.1021/acs.jpclett.9b03753

Cited by 36 publications

(35 citation statements)

References 64 publications

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“…Triplet excited state formation is also observed in other heavyatom-free BODIPY photosensitisers (Filatov, 2019). Halogenated BODIPY monomers also have an ESA feature in this region attributed to the formation of a triplet excited state (Sabatini et al, 2011;Lee et al, 2020). Figure 6D displays the decay associated spectra (DAS) for the polymer in CD 3 CN.…”

Section: Transient Absorption Spectroscopymentioning

confidence: 77%

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

et al. 2020

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A novel 4,4-difuoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) copolymer with diethynylbenzene has been synthesised, and its ability to act as a photosensitiser for the photocatalytic generation of hydrogen was investigated by time-resolved spectroscopic techniques spanning the ps-to ns-timescales. Both transient absorption and time-resolved infrared spectroscopy were used to probe the excited state dynamics of this photosensitising unit in a variety of solvents. These studies indicated how environmental factors can influence the photophysics of the BODIPY polymer. A homogeneous photocatalytic hydrogen evolution system has been developed using the BODIPY copolymer and cobaloxime which provides hydrogen evolution rates of 319 µmol h −1 g −1 after 24 h of visible irradiation.

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Section: Transient Absorption Spectroscopymentioning

confidence: 77%

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

et al. 2020

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“…Concomitant with this change is growth of an induced absorption band centered at 440 nm attributed to the Mes-I's lowest excited triplet (T1) state on the basis of prior photoinduced absorption spectra of BODIPY dyes. [49][50][51][52] Global target analysis of this data (See SI for details) is used to extract an ISC rate of 197 ps (kISC = 5.1 × 10 9 s -1 ). TA spectra of Mes-Cl and Mes-Br show similar spectral evolution, albeit with lower ISC rates (Figure 4b Table 1).…”

Section: Resultsmentioning

confidence: 99%

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Stafford¹,

Ahn²,

Raulerson³

et al. 2020

Preprint

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Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

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“…Interestingly, the mono‐halogenated derivatives did not engage in halogen bonded assembly and produced 1D chains via CH⋅⋅⋅F hydrogen bonding, despite the presence of the same XB‐donor (−NO 2 ) and acceptor (Br, I) entities. Anna and co‐workers have studied the role of halogen bonding in promoting intersystem crossing (ISC) in a diiodo‐BODIPY in presence of XB‐accepting pyridine solvent by ultrafast transient absorption spectroscopy [121] . Halogen bonding facilitates the enhancement of the intersystem crossing rate constant ( k ISC ) of diiodo‐BODIPY, critical for the formation of the triplet state.…”

Section: Halogen Bonded Supramolecular Polymers and Materialsmentioning

confidence: 99%

Recent Developments in Polymeric Assemblies and Functional Materials by Halogen Bonding

Biswas

Das

2021

ChemNanoMat

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Polymers have long been known to us for their versatile utility in our daily lives. With many years of successful advancement in controlled polymer synthesis and supramolecular chemistry, currently an amalgamation of these two fields is becoming increasingly important for generating modern‐day emerging polymeric materials. Hydrogen bonding and other noncovalent interactions like π‐stacking, host‐guest interaction, electrostatic interaction, metal‐ligand coordination have been explored much to this context, unlike the recently emerged halogen bonding, which indeed shows advantageous features like superior hydrophobicity, directionality and polar solvent resistance compared to ubiquitous hydrogen bonding. Hence, rendering these properties of halogen bonding into polymeric domain for generating functional materials for application in advance nanotechnologies is highly desirable. In the recent years, substantial progress has been made in fulfilling this challenging goal. This is evident from the escalating number of scientific publications in this research area every year. In this minireview, we have summarized the most recent developments in the field of halogen bonded polymeric assemblies and supramolecular polymers and discussed them in the context of their emerging materials properties and functions. Emphasis is given on highlighting various design criteria adopted in crystal engineering, covalent and supramolecular polymers in the past five years for constructing diverse organic functional materials, viz. liquid crystals, photoresponsive and photochromic materials, biomaterials and gels, self‐healing materials and many others by virtue of this highly directional supramolecular tool. In conclusion, a brief perspective on the advantages, challenges and future prospects in this rapidly growing field of research is discussed.

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Halogen Bonding Facilitates Intersystem Crossing in Iodo-BODIPY Chromophores

Cited by 36 publications

References 64 publications

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Recent Developments in Polymeric Assemblies and Functional Materials by Halogen Bonding

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