4 research outputs found
Through-Space Intervalence Charge Transfer as a Mechanism for Charge Delocalization in Metal–Organic Frameworks
Understanding
the nature of charge transfer mechanisms in 3-dimensional
metal–organic frameworks (MOFs) is an important goal owing
to the possibility of harnessing this knowledge to design electroactive
and conductive frameworks. These materials have been proposed as the
basis for the next generation of technological devices for applications
in energy storage and conversion, including electrochromic devices,
electrocatalysts, and battery materials. After nearly two decades
of intense research into MOFs, the mechanisms of charge transfer remain
relatively poorly understood, and new strategies to achieve charge
mobility remain elusive and challenging to experimentally explore,
validate, and model. We now demonstrate that aromatic stacking interactions
in ZnÂ(II) frameworks containing cofacial thiazoloÂ[5,4-<i>d</i>]Âthiazole (TzTz) units lead to a mixed-valence state upon electrochemical
or chemical reduction. This through-space intervalence charge transfer
(IVCT) phenomenon represents a new mechanism for charge transfer in
MOFs. Computational modeling of the optical data combined with application
of Marcus–Hush theory to the IVCT bands for the mixed-valence
framework has enabled quantification of the degree of charge transfer
using both <i>in situ</i> and <i>ex situ</i> electro-
and spectro-electrochemical methods. A distance dependence for the
through-space electron transfer has also been identified on the basis
of experimental studies and computational calculations. This work
provides a new window into electron transfer phenomena in 3-dimensional
coordination space, of relevance to electroactive MOFs where new mechanisms
for charge transfer are highly sought after, and to understanding
biological light-harvesting systems where through-space mixed-valence
interactions are operative
Through-Space Intervalence Charge Transfer as a Mechanism for Charge Delocalization in Metal–Organic Frameworks
Understanding
the nature of charge transfer mechanisms in 3-dimensional
metal–organic frameworks (MOFs) is an important goal owing
to the possibility of harnessing this knowledge to design electroactive
and conductive frameworks. These materials have been proposed as the
basis for the next generation of technological devices for applications
in energy storage and conversion, including electrochromic devices,
electrocatalysts, and battery materials. After nearly two decades
of intense research into MOFs, the mechanisms of charge transfer remain
relatively poorly understood, and new strategies to achieve charge
mobility remain elusive and challenging to experimentally explore,
validate, and model. We now demonstrate that aromatic stacking interactions
in ZnÂ(II) frameworks containing cofacial thiazoloÂ[5,4-<i>d</i>]Âthiazole (TzTz) units lead to a mixed-valence state upon electrochemical
or chemical reduction. This through-space intervalence charge transfer
(IVCT) phenomenon represents a new mechanism for charge transfer in
MOFs. Computational modeling of the optical data combined with application
of Marcus–Hush theory to the IVCT bands for the mixed-valence
framework has enabled quantification of the degree of charge transfer
using both <i>in situ</i> and <i>ex situ</i> electro-
and spectro-electrochemical methods. A distance dependence for the
through-space electron transfer has also been identified on the basis
of experimental studies and computational calculations. This work
provides a new window into electron transfer phenomena in 3-dimensional
coordination space, of relevance to electroactive MOFs where new mechanisms
for charge transfer are highly sought after, and to understanding
biological light-harvesting systems where through-space mixed-valence
interactions are operative
Through-Space Intervalence Charge Transfer as a Mechanism for Charge Delocalization in Metal–Organic Frameworks
Understanding
the nature of charge transfer mechanisms in 3-dimensional
metal–organic frameworks (MOFs) is an important goal owing
to the possibility of harnessing this knowledge to design electroactive
and conductive frameworks. These materials have been proposed as the
basis for the next generation of technological devices for applications
in energy storage and conversion, including electrochromic devices,
electrocatalysts, and battery materials. After nearly two decades
of intense research into MOFs, the mechanisms of charge transfer remain
relatively poorly understood, and new strategies to achieve charge
mobility remain elusive and challenging to experimentally explore,
validate, and model. We now demonstrate that aromatic stacking interactions
in ZnÂ(II) frameworks containing cofacial thiazoloÂ[5,4-<i>d</i>]Âthiazole (TzTz) units lead to a mixed-valence state upon electrochemical
or chemical reduction. This through-space intervalence charge transfer
(IVCT) phenomenon represents a new mechanism for charge transfer in
MOFs. Computational modeling of the optical data combined with application
of Marcus–Hush theory to the IVCT bands for the mixed-valence
framework has enabled quantification of the degree of charge transfer
using both <i>in situ</i> and <i>ex situ</i> electro-
and spectro-electrochemical methods. A distance dependence for the
through-space electron transfer has also been identified on the basis
of experimental studies and computational calculations. This work
provides a new window into electron transfer phenomena in 3-dimensional
coordination space, of relevance to electroactive MOFs where new mechanisms
for charge transfer are highly sought after, and to understanding
biological light-harvesting systems where through-space mixed-valence
interactions are operative
Through-Space Intervalence Charge Transfer as a Mechanism for Charge Delocalization in Metal–Organic Frameworks
Understanding
the nature of charge transfer mechanisms in 3-dimensional
metal–organic frameworks (MOFs) is an important goal owing
to the possibility of harnessing this knowledge to design electroactive
and conductive frameworks. These materials have been proposed as the
basis for the next generation of technological devices for applications
in energy storage and conversion, including electrochromic devices,
electrocatalysts, and battery materials. After nearly two decades
of intense research into MOFs, the mechanisms of charge transfer remain
relatively poorly understood, and new strategies to achieve charge
mobility remain elusive and challenging to experimentally explore,
validate, and model. We now demonstrate that aromatic stacking interactions
in ZnÂ(II) frameworks containing cofacial thiazoloÂ[5,4-<i>d</i>]Âthiazole (TzTz) units lead to a mixed-valence state upon electrochemical
or chemical reduction. This through-space intervalence charge transfer
(IVCT) phenomenon represents a new mechanism for charge transfer in
MOFs. Computational modeling of the optical data combined with application
of Marcus–Hush theory to the IVCT bands for the mixed-valence
framework has enabled quantification of the degree of charge transfer
using both <i>in situ</i> and <i>ex situ</i> electro-
and spectro-electrochemical methods. A distance dependence for the
through-space electron transfer has also been identified on the basis
of experimental studies and computational calculations. This work
provides a new window into electron transfer phenomena in 3-dimensional
coordination space, of relevance to electroactive MOFs where new mechanisms
for charge transfer are highly sought after, and to understanding
biological light-harvesting systems where through-space mixed-valence
interactions are operative