scholarly journals Solvent-induced on/off switching of intramolecular electron transfer in a cyanide-bridged trigonal bipyramidal complex

2016 ◽  
Vol 45 (43) ◽  
pp. 17104-17107 ◽  
Author(s):  
Rong-Jia Wei ◽  
Ryohei Nakahara ◽  
Jamie M. Cameron ◽  
Graham N. Newton ◽  
Takuya Shiga ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Transition ◽  
Intramolecular Electron Transfer ◽  
Thermally Induced ◽  
Trigonal Bipyramidal ◽  
Transition Behaviour

A cyanide-bridged trigonal bipyramidal [Co3Fe2] cluster shows solvent-driven reversible on/off switching of its thermally induced electron-transfer-coupled spin transition behaviour.

scholarly journals Time-Resolved Spectroscopy of Photo-Induced Electron Transfer in Dinuclear and Tetranuclear Fe/Co Prussian Blue Analogues

2020 ◽  
Author(s):  
Jennifer Zimara ◽  
Hendrik Stevens ◽  
Rainer Oswald ◽  
Serhiy Demeshko ◽  
Sebastian Dechert ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Prussian Blue ◽  
Variable Temperature ◽  
Spin Transition ◽  
Acetonitrile Solution ◽  
Time Resolved ◽  
Thermally Induced ◽  
Prussian Blue Analogues ◽  
Charge Transfer Dynamics

The dynamics of photo-driven charge transfer-induced spin transition (CTIST) in two Fe/Co Prussian Blue Analogues (PBAs) is revealed by femtosecond IR and UV/vis pump-probe spectroscopy. Depending on temperature the known tetranuclear square-type complex [Co<sub>2</sub>Fe<sub>2</sub>(CN)<sub>6</sub>(tp*)<sub>2</sub>(4,4’-dtbbpy)<sub>4</sub>](PF<sub>6</sub>)<sub>2</sub> (<b>1</b>) exists in two electronic states. In acetonitrile solution at <240 K the low temperature (<b>LT</b>) phase is prevalent consisting of low-spin Fe(II) and low-spin Co(III), [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>LS</sub>]<sub>2</sub>. Temperature rise causes thermally induced CTIST towards the high temperature (<b>HT</b>) phase consisting of low-spin Fe(III) and high-spin Co(II), [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>]<sub>2</sub>, being prevalent at >300 K. Photo-excitation into the intervalence charge transfer (IVCT) band of the <b>LT</b> phase at 800 nm induces electron transfer in one Fe-Co edge of PBA <b>1</b> and produces a [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>LS</sub>] intermediate which by spin crossover (SCO) is stabilized within 400 fs to a long-lived (>1 ns) [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>]. In contrast, IVCT excitation of the <b>HT</b> phase at 400 nm generates a [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>HS</sub>] species with a lifetime of 3.6 ps. Subsequent back-electron transfer populates the vibrationally hot ground state, which thermalizes within 8 ps. The newly synthesized dinuclear PBA, [CoFe(CN)<sub>3</sub>(tp*)(pz*<sub>4</sub>Lut)]ClO<sub>4</sub> (<b>2</b>), provides a benchmark of the <b>HT</b> phase of <b>1</b>, i.e. [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>], as verified by variable temperature magnetic susceptibility measurements and <sup>57</sup>Fe Mößbauer spectroscopy. The photo-induced charge transfer dynamics of PBA <b>2</b> indeed is almost identical to that of the <b>HT</b> phase of phase of PBA <b>1</b> with a lifetime of the excited [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>HS</sub>] species of 3.8 ps.

scholarly journals Time-Resolved Spectroscopy of Photo-Induced Electron Transfer in Dinuclear and Tetranuclear Fe/Co Prussian Blue Analogues

2020 ◽  
Author(s):  
Jennifer Zimara ◽  
Hendrik Stevens ◽  
Rainer Oswald ◽  
Serhiy Demeshko ◽  
Sebastian Dechert ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Prussian Blue ◽  
Variable Temperature ◽  
Spin Transition ◽  
Acetonitrile Solution ◽  
Time Resolved ◽  
Thermally Induced ◽  
Prussian Blue Analogues ◽  
Charge Transfer Dynamics

The dynamics of photo-driven charge transfer-induced spin transition (CTIST) in two Fe/Co Prussian Blue Analogues (PBAs) is revealed by femtosecond IR and UV/vis pump-probe spectroscopy. Depending on temperature the known tetranuclear square-type complex [Co<sub>2</sub>Fe<sub>2</sub>(CN)<sub>6</sub>(tp*)<sub>2</sub>(4,4’-dtbbpy)<sub>4</sub>](PF<sub>6</sub>)<sub>2</sub> (<b>1</b>) exists in two electronic states. In acetonitrile solution at <240 K the low temperature (<b>LT</b>) phase is prevalent consisting of low-spin Fe(II) and low-spin Co(III), [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>LS</sub>]<sub>2</sub>. Temperature rise causes thermally induced CTIST towards the high temperature (<b>HT</b>) phase consisting of low-spin Fe(III) and high-spin Co(II), [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>]<sub>2</sub>, being prevalent at >300 K. Photo-excitation into the intervalence charge transfer (IVCT) band of the <b>LT</b> phase at 800 nm induces electron transfer in one Fe-Co edge of PBA <b>1</b> and produces a [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>LS</sub>] intermediate which by spin crossover (SCO) is stabilized within 400 fs to a long-lived (>1 ns) [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>]. In contrast, IVCT excitation of the <b>HT</b> phase at 400 nm generates a [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>HS</sub>] species with a lifetime of 3.6 ps. Subsequent back-electron transfer populates the vibrationally hot ground state, which thermalizes within 8 ps. The newly synthesized dinuclear PBA, [CoFe(CN)<sub>3</sub>(tp*)(pz*<sub>4</sub>Lut)]ClO<sub>4</sub> (<b>2</b>), provides a benchmark of the <b>HT</b> phase of <b>1</b>, i.e. [Fe<sup>III</sup><sub>LS</sub>Co<sup>II</sup><sub>HS</sub>], as verified by variable temperature magnetic susceptibility measurements and <sup>57</sup>Fe Mößbauer spectroscopy. The photo-induced charge transfer dynamics of PBA <b>2</b> indeed is almost identical to that of the <b>HT</b> phase of phase of PBA <b>1</b> with a lifetime of the excited [Fe<sup>II</sup><sub>LS</sub>Co<sup>III</sup><sub>HS</sub>] species of 3.8 ps.

Intramolecular Electron Transfer Mediated by a Tetrathiafulvalene Bridge in a Purely Organic Mixed-Valence System

2003 ◽  
Vol 42 (24) ◽  
pp. 2765-2768 ◽  
Author(s):  
Nicolas Gautier ◽  
Frédéric Dumur ◽  
Vega Lloveras ◽  
José Vidal-Gancedo ◽  
Jaume Veciana ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Mixed Valence ◽  
Intramolecular Electron Transfer
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