Controlling the Singlet−Triplet Splitting in Bisverdazyl Diradicals:  Steps toward Magnetic Polymers

Green, Michael T.; McCormick, Thomas A.

doi:10.1021/ic981424l

Cited by 27 publications

(21 citation statements)

References 16 publications

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“…Computational studies by Green and co-workers have subsequently supported this idea. 15 This contrasts with recently published work where the interaction between two verdazyls mediated by copper() was very small (≈2 cm Ϫ1 ). 16 In order to further probe the copper()-verdazyl interaction and in particular, the role of ancillary ligands, we have been studying the coordination chemistry of the chelating monoverdazyl 1,5-dimethyl-3-(2-pyridyl)-6-oxoverdazyl (pyvd).…”

Section: Introductionmentioning

confidence: 60%

Spin distribution in copper(i) phosphine complexes of verdazyl radicals

Brook

Abeyta

2002

J. Chem. Soc., Dalton Trans.

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Section: Introductionmentioning

confidence: 60%

Spin distribution in copper(i) phosphine complexes of verdazyl radicals

Brook

Abeyta

2002

J. Chem. Soc., Dalton Trans.

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“…7 Most of the diradicals constructed solely from verdazyl radicals and a suitable spacer are either antiferromagnetically coupled or very weakly ferromagnetically coupled. 3d,e, 10,11 The coupling constants of the diradicals constructed solely from nitronyl nitroxide radicals along with polyenic spacers also follow the same trend. 2 Recently, Polo et al investigated mixed diradicals constructed from tetrathiafulvalene (TTF) and verdazyl and obtained moderately high positive coupling constants (J, of the order of 167 cm -1 ) for most of them.…”

Section: Introductionmentioning

confidence: 67%

Very Strongly Ferromagnetically Coupled Diradicals from Mixed Radical Centers: Nitronyl Nitroxide Coupled to Oxoverdazyl via Polyene Spacers

2009

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We predict extremely large and positive intramolecular magnetic exchange coupling constants (J) for coupled diradicals constructed from nitronyl nitroxide (NN) and oxoverdazyl (o-VER). These radicals have the general formula o-VER(N)-nC-NN where nC represents an olefinic spacer with n = 0, 2, 4, 6, and 8. Species like o-VER(C)-nC-NN have negative coupling constants. The atoms in the parentheses show the point of attachment of the coupler to the verdazyl moiety. Both the N-linked series and C-linked series have comparable stability. The triplet molecular geometries were optimized by the density functional (UB3LYP) method using the 6-311 g(d,p) basis set. This was followed by single-point UB3LYP calculations using 6-311++g(3df,3pd) basis. To calculate J, single-point broken-symmetry computations were performed on the optimized triplet geometries and using the same basis set. The N-linked diradicals coupled through conjugated polyenes are topologically different. These are found to have coupling constants of the order of 1000 cm(-1), whereas the C-linked diradicals show coupling constants of the order of -100 cm(-1). In general, for both cases, the absolute magnitude of the coupling constant decreases with the increase in the length of the spacer.

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“…It should be noted that Cu I complexes with two radical ligand units like [Cu(L1) 2 ] + are extremely rare and almost exclusively restricted to a few complexes with two verdazyl radical ligands. [ 48 , 49 , 50 , 51 , 52 , 53 ] Interestingly, the singlet‐triplet energy difference in these systems could be tuned and strongly depends on the coordination mode.…”

Section: Resultsmentioning

confidence: 99%

A Copper(I) Complex with Two Unpaired Electrons, Synthesised by Oxidation of a Copper(II) Complex with Two Redox‐Active Ligands

et al. 2021

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Two homoleptic copper(II) complexes [Cu(L1)2] and [Cu(L2)2] with anionic redox‐active ligands were synthesised, one with urea azine (L1) and the other with thio‐urea azine (L2) ligands. One‐electron oxidation of the complexes initiates an unprecedented redox‐induced electron transfer process, leading to monocationic copper(I) complexes [Cu(L1)2]+ and [Cu(L2)2]+ with two oxidised ligands. While [Cu(L1)2]+ is best described as a CuI complex with two neutral radical ligands that couple antiferromagnetically, [Cu(L2)2]+ is a CuI complex with two clearly different ligand units in the solid state and with a magnetic susceptibility close to a diamagnetic compound. Further one‐electron oxidation of the complex with L1 ligands results in a dication [Cu(L1)2]2+, best described as a CuI complex with a twofold oxidised, monocationic ligand and a neutral radical ligand. The stability in at least three redox states, the accumulation of spin density at the ligands and the facile ligand‐metal electron transfer make these complexes highly attractive for a variety of applications; here the catalytic aerobic oxidation of alcohols to aldehydes is tested.

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Controlling the Singlet−Triplet Splitting in Bisverdazyl Diradicals: Steps toward Magnetic Polymers

Cited by 27 publications

References 16 publications

Spin distribution in copper(i) phosphine complexes of verdazyl radicals

Spin distribution in copper(i) phosphine complexes of verdazyl radicals

Very Strongly Ferromagnetically Coupled Diradicals from Mixed Radical Centers: Nitronyl Nitroxide Coupled to Oxoverdazyl via Polyene Spacers

A Copper(I) Complex with Two Unpaired Electrons, Synthesised by Oxidation of a Copper(II) Complex with Two Redox‐Active Ligands

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