Synthesis, Magnetic Properties, and X‐ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [MII4(HL2)4(OAc)4]

Scheurer, Andreas; Korzekwa, Jana; Nakajima, Takayuki; Hampel, Frank; Buling, Anna; Derks, Christine; Neumann, M.; Joly, L.; Petukhov, K.; Gieb, Klaus; Müller, Paul; Kuepper, K.; Meyer, Karsten

doi:10.1002/ejic.201402988

Cited by 11 publications

(5 citation statements)

References 140 publications

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“…The worldwide quest for clean hydrogen fuel production through photocatalytic water splitting is widely inspired by nature’s {CaMn 4 O 5 } oxygen evolving complex (OEC) as a major paradigm for the construction of low-cost and robust water oxidation catalysts (WOCs). − Knowledge transfer between molecular WOC mechanisms − and heterogeneous catalyst optimization is a forefront task of current artificial photosynthesis research. − While major progress was made in the demanding synthesis and analysis of Mn-cubane OEC replicas, − {Co III 4 O 4 } cubane WOCs emerged as alternative and active model systems for both fundamental studies − and the construction of molecular photoanodes. − In our previous work, we equipped {Co II 4 O 4 } WOC types as versatile targets ,− with bioinspired features for remarkably flexible ligand shells, protonation states, and electronic as well as nuclear structures. − …”

Section: Introductionmentioning

confidence: 99%

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

et al. 2017

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The future of artificial photosynthesis depends on economic and robust water oxidation catalysts (WOCs). Cobalt-based WOCs are especially promising for knowledge transfer between homogeneous and heterogeneous catalyst design. We introduce the active and stable {CoO} cubane [Co(dpy{OH}O)(OAc)(HO)](ClO) (CoO-dpk) as the first molecular WOC with the characteristic {HO-Co(OR)-OH} edge-site motif representing the sine qua non moiety of the most efficient heterogeneous Co-oxide WOCs. DFT-MD modelings as well as in situ EXAFS measurements indicate the stability of the cubane cage in solution. The stability of CoO-dpk under photocatalytic conditions ([Ru(bpy)]/SO) was underscored with a wide range of further analytical methods and recycling tests. FT-IR monitoring and HR-ESI-MS spectra point to a stable coordination of the acetate ligands, and DFT-MD simulations along with H/H exchange experiments highlight a favorable intramolecular base functionality of the dpy{OH}O ligands. All three ligand types enhance proton mobility at the edge site through a unique bioinspired environment with multiple hydrogen-bonding interactions. In situ XANES experiments under photocatalytic conditions show that the {CoO} core undergoes oxidation to Co(III) or higher valent states, which recover rather slowly to Co(II). Complementary ex situ chemical oxidation experiments with [Ru(bpy)] furthermore indicate that the oxidation of all Co(II) centers of CoO-dpk to Co(III) is not a mandatory prerequisite for oxygen evolution. Moreover, we present the [CoNi(dpy{OH}O)(OAc)(HO)](ClO) (CoNiO-dpk) series as the first mixed Co/Ni-cubane WOCs. They newly bridge homogeneous and heterogeneous catalyst design through fine-tuned edge-site environments of the Co centers.

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Section: Introductionmentioning

confidence: 99%

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

et al. 2017

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“…The Co-O bond lengths fall in the range 1.9434 (17)-2.1786 (17) Å , and the Co-N bond lengths are in the range 2.018 (2)-2.185 (2) Å . There is a large family of tetranuclear Co II complexes, and most of these clusters have Co 4 O 4 cubane or defective dicubane cores (Habib et al, 2012;Gao et al, 2015;Scheurer et al, 2015;Ahmed et al, 2007;Zhang et al, 2011Zhang et al, , 2014. Only a few complexes possesses a linear tetranuclear Co II core (Barrios et al, 2009;Aguilà et al, 2011;Irving et al, 1975;Vreshch et al, 2010).…”

Section: Figurementioning

confidence: 99%

Crystal structure and magnetic properties of a linear tetranuclear Co^IIcluster

et al. 2016

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Polynuclear complexes are an important class of inorganic functional materials and are of interest particularly for their applications in molecular magnets. Multidentate chelating ligands play an important role in the design and syntheses of polynuclear metal clusters. A novel linear tetranuclear Co(II) cluster, namely bis{μ3-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis{μ2-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis(1,10-phenanthroline)tetracobalt(II), [Co4(C14H11NO2)4(C12H8N2)2], was prepared under solvothermal conditions through a mixed-ligand synthetic strategy. The structure was determined by X-ray single-crystal diffraction and bulk purity was confirmed by powder X-ray diffraction. The complex molecule has a centrosymmetric tetranuclear chain-like structure and the four Co(II) ions are located in two different coordination environments. The Co(II) ions at the ends of the chain are in a slightly distorted octahedral geometry, while the two inner Co(II) ions are in five-coordinate distorted trigonal bipyramidal environments. A magnetic study reveals ferromagnetic Co(II)...Co(II) exchange interactions for the complex.

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“… 22 − 25 As a result, the draft and assembly of the polynuclear metal cluster-based coordination cages are already charming and yet remain a synthetic challenge. 26 − 28 While most advances concerned the challenging preparation and characterization of the Mn-cluster oxygen evaluation conversion {OEC} mimic, 29 − 35 {Co 4 O 6 } cubane water oxidation catalysts {WOCs} appear to be preferred and ideal typical plan model systems for the essential oxidation reaction 36 − 40 and the creation of excellent photoanodes. 41 − 48 …”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Clusterization Process to Prepare [(NNCO)₆Co₄Cl₂] as a Novel Double-Open-Co₄O₆ Cubane Cluster: SXRD Interactions, DFT, Physicochemical, Thermal Behaviors, and Biomimicking of Catecholase Activity

et al. 2022

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A novel double-open-cubane (NNCO) 6 Co 4 Cl 2 cluster with a Co 4 O 6 core was made available under aqua-ultrasonic open atmosphere conditions for the first time. The ultrasonic clusterization of the (3,5-dimethyl-1 H -pyrazol-1-yl)methanol (NNCOH) ligand with CoCl 2 ·6H 2 O salts in ethanol yielded a high-purity and high-yield cluster product. Energy-dispersive X-ray (EDX), Fourier transform infrared (FT-IR), and ultraviolet (UV)–visible techniques were used to elucidate the clusterization process. The double-open-Co 4 O 6 cubane structure of the (NNCO) 6 Co 4 Cl 2 cluster was solved by synchrotron single-crystal X-ray diffraction (SXRD) and supported by density functional theory (DFT) optimization and thermogravimetric/differential TG (TG/DTG) measurements; moreover, the DFT structural parameters correlated with the ones determined by SXRD. Molecular electrostatic potential (MEP), Mulliken atomic charge/natural population analysis (MAC/NPA), highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO), density of states (DOS), and GRD quantum analyses were computed at the DFT/B3LYP/6-311G(d,p) theory level. The thermal behavior of the cluster was characterized to support the formation of the Co 4 O 6 core as a stable final product. The catalytic property of the (NNCO) 6 Co 4 Cl 2 cluster was predestined for the oxidation process of 3,5-DTBC diol (3,5-di- tert -butylbenzene-1,2-diol) to 3,5-DTBQ dione (3,5-di- tert -butylcyclohexa-3,5-diene-1,2-dione).

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Synthesis, Magnetic Properties, and X‐ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [M^II₄(HL²)₄(OAc)₄]

Cited by 11 publications

References 140 publications

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

Crystal structure and magnetic properties of a linear tetranuclear Co^IIcluster

Ultrasonic Clusterization Process to Prepare [(NNCO)₆Co₄Cl₂] as a Novel Double-Open-Co₄O₆ Cubane Cluster: SXRD Interactions, DFT, Physicochemical, Thermal Behaviors, and Biomimicking of Catecholase Activity

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Synthesis, Magnetic Properties, and X‐ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [MII4(HL2)4(OAc)4]

Cited by 11 publications

References 140 publications

{Co4O4} and {CoxNi4–xO4} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

{Co4O4} and {CoxNi4–xO4} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

Crystal structure and magnetic properties of a linear tetranuclear CoIIcluster

Ultrasonic Clusterization Process to Prepare [(NNCO)6Co4Cl2] as a Novel Double-Open-Co4O6 Cubane Cluster: SXRD Interactions, DFT, Physicochemical, Thermal Behaviors, and Biomimicking of Catecholase Activity

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Synthesis, Magnetic Properties, and X‐ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [M^II₄(HL²)₄(OAc)₄]

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

{Co₄O₄} and {Co_xNi_4–xO₄} Cubane Water Oxidation Catalysts as Surface Cut-Outs of Cobalt Oxides

Crystal structure and magnetic properties of a linear tetranuclear Co^IIcluster

Ultrasonic Clusterization Process to Prepare [(NNCO)₆Co₄Cl₂] as a Novel Double-Open-Co₄O₆ Cubane Cluster: SXRD Interactions, DFT, Physicochemical, Thermal Behaviors, and Biomimicking of Catecholase Activity