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

Cheng, Wei Qin; Li, Guo Ling; Zhang, Ran; Ni, Zhong Hai; Wang, Wen Feng; Sato, Osamu

doi:10.1016/j.molstruc.2015.01.049

Cited by 21 publications

(14 citation statements)

References 29 publications

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“…The effect of the solvent molecules is to lower the cooperativity for VT conversion and result in a broad transition [ÁT ' 100 K in (1S) and 2S]. This observation is supported by previous studies Mulyana et al, 2010;Cheng et al, 2015;Bodnar et al, 2001;Dapporto et al, 2008) where the lattice solvent diminishes the interplay between molecules in the crystalline state during the hs-ls VT transition. In general, larger ÁT values are observed for the mononuclear cobalt bis(dioxolene) VT complexes in the presence of lattice solvent in the crystal structure (Table 2).…”

Section: Lattice Solvent Effects On Valence Tautomerismsupporting

confidence: 75%

Variable-temperature structural studies on valence tautomerism in cobalt bis(dioxolene) molecular complexes

Hathwar

Stingaciu

Richter

et al. 2017

Acta Crystallogr Sect B

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A variable-temperature single-crystal structural study of five valence tautomeric cobalt molecular complexes, Co(3,5-DBSQ)(DBPy) (1), Co(3,5-DBSQ)(DBPy)·1.33CH (1S), Co(3,5-DBSQ)(DCPy)·CH (2S), Co(3,5-DBSQ)(TBPy) (3) and Co(3,5-DBSQ)(TCPy) (4) (S = toluene, 3,5-DBSQ = 3,5-di-tert-butylsemiquinonate, DBPy = 3,5-dibromopyridine, DCPy = 3,5-dichloropyridine, TBPy = 3,4,5-tribromopyridine and TCPy = 3,4,5-trichloropyridine) is reported. The re-crystallization of (1S) in toluene at 277 K resulted in a concomitant formation of a solvent-free polymorph, Co(3,5-DBSQ)(DBPy) (1). Thermally induced valence tautomerism (VT) is observed only in (1S), (1) and (2S) [hs-Co(3,5-DBSQ)L ↔ ls-Co(3,5-DBSQ)(3,5-DBCat)L (hs = high spin, ls = low spin, 3,5-DBCat = 3,5-di-tert-butylcatecholate)], whereas (3) and (4) remain locked in the hs-Co(3,5-DBSQ) state during cooling of the sample. Multi-temperature single-crystal studies demonstrate the change in cobalt coordination environment during the VT conversion. The non-solvated compound (1) shows a sharp VT transition (T ∼ 245 K with ΔT ∼ 10 K) from hs-Co(3,5-DBSQ)(DBPy) to ls-Co(3,5-DBSQ)(3,5-DBCat)(DBPy) oxidation state, whereas the other polymorph with lattice solvent (1S) results in a broad transition (T ∼ 150 K with ΔT ∼ 100 K). This increase in the VT transition temperature for (1) relative to (1S) illustrates the effect of lattice solvent on the VT transition mechanism. Additionally, the influence of halogen substitutions on the pyridine ring is discussed with respect to observed VT behaviour in the studied compounds.

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Section: Lattice Solvent Effects On Valence Tautomerismsupporting

confidence: 75%

Variable-temperature structural studies on valence tautomerism in cobalt bis(dioxolene) molecular complexes

Hathwar

Stingaciu

Richter

et al. 2017

Acta Crystallogr Sect B

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“…The same group reported three 1D VT complexes containing Co-dioxolene units connected by exo-bidentate pyridine ligands, 1,2-bis(4-pyridyl)ethylene, trans -4,4′-azopyridine, and 1,4-bis(4-pyridyl)benzene, one of which displays heat- and light-induced VT transitions . These compounds also exhibit a strong dependence of the nature of the VT transition on the solvation of the compound, as has been observed previously for nonpolymeric VT complexes. − , Finally, Sato and co-workers have very recently reported a thermally induced VT transition for a 1D cobalt-dioxolene CP with 4,4′-bipyridyl ligands linking cobalt bis-dioxolene units with chiral dioxolene ligands …”

Section: Introductionsupporting

confidence: 65%

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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“…[14a,b] 2,3,6,7-tetrahydroxy-9,10-dimethyl-9,10-dihydro-9,10-ethanoanthracene (H 4 thea) is a relatively scarcely studied bis(dioxolene), whose octauranate complexes, [19] as well as manganese(III) [20] and platinum(II) [21] compounds are known. The predicted earlier VT properties of dinuclear cobalt diketonate adducts with thea ligand, [22] as well as evidence of VT in a linear-chain cobalt coordination polymer based on thea, [23] allow us to expect finding new redox-isomeric compounds of this bis(dioxolene). Mono-and dinuclear cobalt dioxolenecomplexes with N,N '-dialkyl-2,11-diaza[3.3]-(2,6)pyridinophanes ( R pyr 2 N 2 , R = Me, i-Pr, t-Bu) and tris(2-pyridylmethyl)amines (TPA and Me 2 TPA) were shown to possess VT and/or SCO behaviour, [3a,5c,8a,b,g,9b,11a,13] which explains the choice of these tetradentate N-donor bases.…”

Section: Introductionmentioning

confidence: 84%

Spin‐State‐Switching Rearrangements of Bis(dioxolene)‐Bridged CrCo Complexes: A DFT Study

et al. 2021

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Density functional theory calculations (UTPSSh/6-311 + + G-(d,p)) of electronic structure, energy characteristics and magnetic properties of a series of heterometallic CrCo complexes comprising redox-active bis(dioxolene) bridging ligands (3,3,3',3'-tetramethyl-5,6,5',6'-tetrahydroxy-1,1'-spiro-bis(indan) and 2,3,6,7-tetrahydroxy-9,10-dimethyl-9,10-dihydro-9,10-ethanoanthracene) and ancillary tetradentate nitrogen-containing bases (tris(2-pyridylmethyl)amine and N,N'-dialkyl-2,11-diaza [3.3]-(2,6)pyridinophane derivatives) were performed. The compounds prone to manifest spin-state switching rearrangements involving cobalt centre have been revealed. Analysis of the results obtained and their comparison with those found previously open wide prospects for the purposeful search for a broad variety of new magnetically bistable heterometallic dinuclear paramagnetic species with a prospect of useful application in the design of smart dynamic materials.

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

Cited by 21 publications

References 29 publications

Variable-temperature structural studies on valence tautomerism in cobalt bis(dioxolene) molecular complexes

Variable-temperature structural studies on valence tautomerism in cobalt bis(dioxolene) molecular complexes

Valence Tautomerism in One-Dimensional Coordination Polymers

Spin‐State‐Switching Rearrangements of Bis(dioxolene)‐Bridged CrCo Complexes: A DFT Study

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