A Two-Step Valence Tautomeric Transition in a Dinuclear Cobalt Complex

Alley, Kerwyn G.; Poneti, Giordano; Aitken, Jade B.; Hocking, Rosalie K.; Moubaraki, Boujemaa; Murray, Keith S.; Abrahams, Brendan F.; Harris, Hugh H.; Sorace, Lorenzo; Boskovic, Colette

doi:10.1021/ic3002527

Cited by 54 publications

(38 citation statements)

References 21 publications

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“…and 3D VT CPs. This is particularly interesting since only a single VT CP of dimensionality higher than one has been reported to date, 64 and higher dimensional VT CPs are particularly promising for achieving enhanced cooperativity of the VT transition, as well as for transferring the VT properties to more technologically convenient platforms such as gels, films and nanoparticles for future applications in devices.…”

Section: Methodsmentioning

confidence: 99%

Valence Tautomerism in One-Dimensional Coordination Polymers

et al. 2016

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The combination of the divergent bis-pyridyl linking ligands 1,2-bis(4-pyridyl)ethane (1,2-bpe), 4,4'-trans-azopyridine (azpy), and 1,3-bis(4-pyridyl)propane (1,3-bpp) with cobalt and 3,5-di-tert-butyldioxolene (3,5-dbdiox) ligands has afforded the complexes [Co(3,5-dbdiox)2(1,2-bpe)]∞ (1), [Co(3,5-dbdiox)2(azpy)]∞ (2), [trans-Co(3,5-dbdiox)2(1,3-bpp)]∞ (3a), and [cis-Co(3,5-dbdiox)2(1,3-bpp)]∞ (3b). All species are 1D coordination polymers that crystallize as solvated forms; the geometric isomers 3a,b cocrystallize. Complexes 1, 2, and 3a exhibit around the Co centers a trans disposition of the N-donor atoms from the pyridyl linkers, while an unusual cis disposition is evident in 3b. Single-crystal X-ray structural analysis at 100 or 130 K of solvated forms of these complexes indicates that all complexes possess the {Co(III)(3,5-dbcat)(3,5-dbsq)} (3,5-dbcat = 3,5-di-tert-butylcatecholate; 3,5-dbsq = 3,5-di-tert-butylsemiquinonate) charge distribution at the temperature of data collection. Variable-temperature magnetic susceptibility studies reveal that 1, 1·1.5MeCN·2H2O, 2·2EtOH, and 3·MeCN·H2O (3 = 3a·3b) all exhibit thermally induced valence tautomeric (VT) transitions above 200 K. Multiple heating and cooling cycles indicate that in some cases the behavior is strongly dependent on desolvation processes. Most notably, further desolvation of 1·1.5MeCN·2H2O above 340 K affords χmT values that suggest unusual ferromagnetic coupling in the {hs-Co(II)(3,5-dbsq)2} valence tautomer. Compound 3·MeCN·H2O exhibits a two-step VT transition that may be ascribed to the presence of the cis and trans geometric isomers. Compounds 1, 1·1.5MeCN·2H2O, 2·2EtOH, and 3·MeCN·H2O all also exhibit a single photoinduced VT transition, comparable to those generally observed for nonpolymeric cobalt-dioxolene complexes.

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Section: Methodsmentioning

confidence: 99%

Valence Tautomerism in One-Dimensional Coordination Polymers

et al. 2016

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“…The two trans axial positions are occupied by the pyridine N atoms from the bridging ligand, forming a one-dimensional infinite linear chain by the bridging 4,4 0 -bipy ligands. The bond distances in 2,3-LH 2 ligand can reflect whether it is in the catecholate or semiquinonate oxidation state [15,[20][21][22] (6) Å, which also provide adequate support for SQ-Co(III)-Cat formulation.…”

Section: Crystal Structurementioning

confidence: 99%

Synthesis, crystal structure and valence tautomerism of a 4,4′-bipyridine-bridged one-dimensional chiral cobalt complex

Cheng

Zhang

et al. 2015

Journal of Molecular Structure

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“…[25][26][27][28][29][30][31][32][33][34][35][36] Among the non-copper complexes produced as mimics for catechol oxidase the number of cobalt complexes studied as models for catechol oxidase is relatively low ( Table 1). [37][38][39][40][41][42] Co II/III complexes are also known to show valence tautomerism [43][44][45][46][47][48][49] in the presence of dioxolene type substrates. A number of Co III complexes reported to exhibit valence tautomerism bear a higher number of oxygen donors per metal ion [50][51][52] compared to nitrogen donors, which is the main difference in the design while attempting to mimic catechol oxidase activity using Co II/III complexes.…”

Section: Introductionmentioning

confidence: 99%