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A CuII complex (1) of a bis-pyridine-dioxime ligand and its one-electron oxidized analog (1-ox) were thoroughly characterized by various spectroscopic techniques, including X-ray absorption spectroscopy. 1-ox was found to be a CuII complex of a ligand iminoxyl radical and represents the first example of such a type. Reorganization energy (λ) of 2.12 eV was determined for the 1-ox/1 couple, which is considerably higher than the type 1 protein and synthetic CuIII/II(OH) complexes. [ABSTRACT FROM AUTHOR]

The development of high‐performance photocatalytic systems for CO2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb‐free halide perovskite Cs2AgBiBr6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 μmol g−1 h−1 for visible‐light‐driven CO2‐to‐CO conversion coupled with water oxidation to O2, over 8 times of the unmodified Cs2AgBiBr6 (36±8 μmol g−1 h−1), also far surpassing the documented systems (<150 μmol g−1 h−1). Besides the improved intrinsic activity, electrochemical, computational, ex‐/in situ X‐ray photoelectron and X‐ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs2AgBiBr6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis. [ABSTRACT FROM AUTHOR]

The development of high-performance photocatalytic systems for CO 2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb-free halide perovskite Cs 2 AgBiBr 6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 μmol g -1  h -1 for visible-light-driven CO 2 -to-CO conversion coupled with water oxidation to O 2 , over 8 times of the unmodified Cs 2 AgBiBr 6 (36±8 μmol g -1  h -1 ), also far surpassing the documented systems (<150 μmol g -1  h -1 ). Besides the improved intrinsic activity, electrochemical, computational, ex-/in situ X-ray photoelectron and X-ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs 2 AgBiBr 6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis., (© 2024 Wiley-VCH GmbH.)

Herein, we show that the reaction of a mononuclear Fe III (OH) complex ( 1 ) with N -tosyliminobenzyliodinane (PhINTs) resulted in the formation of a Fe IV (OH) species ( 3 ). The obtained complex 3 was characterized by an array of spectroscopic techniques and represented a rare example of a synthetic Fe IV (OH) complex. The reaction of 1 with the one-electron oxidizing agent was reported to form a ligand-oxidized Fe III (OH) complex ( 2 ). 3 revealed a one-electron reduction potential of -0.22 V vs Fc + /Fc at -15 °C, which was 150 mV anodically shifted than 2 ( E red = -0.37 V vs Fc + /Fc at -15 °C), inferring 3 to be more oxidizing than 2 . 3 reacted spontaneously with (4-OMe-C 6 H 4 ) 3 C • to form (4-OMe-C 6 H 4 ) 3 C(OH) through rebound of the OH group and displayed significantly faster reactivity than 2 . Further, activation of the hydrocarbon C-H and the phenolic O-H bond by 2 and 3 was compared and showed that 3 is a stronger oxidant than 2 . A detailed kinetic study established the occurrence of a concerted proton-electron transfer/hydrogen atom transfer reaction of 3 . Studying one-electron reduction of 2 and 3 using decamethylferrocene (Fc*) revealed a higher k et of 3 than 2 . The study established that the primary coordination sphere around Fe and the redox state of the metal center is very crucial in controlling the reactivity of high-valent Fe-OH complexes. Further, a Fe III (OMe) complex ( 4 ) was synthesized and thoroughly characterized, including X-ray structure determination. The reaction of 4 with PhINTs resulted in the formation of a Fe IV (OMe) species ( 5 ), revealing the presence of two Fe IV species with isomer shifts of -0.11 mm/s and = 0.17 mm/s in the Mössbauer spectrum and showed Fe IV /Fe III potential at -0.36 V vs Fc + /Fc couple in acetonitrile at -15 °C. The reactivity studies of 5 were investigated and compared with the Fe IV (OH) complex ( 3 )., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)