Category: News

ESR analyses of picket fence MnII and 6th ligand coordinated FeIII porphyrins (S = 5/2) and a CoII(hfac) complex (S = 3/2) with sizable ZFS parameters revisited: a full spin Hamiltonian approach and quantum chemical calculations

Dalton Trans., Published online (2018). (DOI:10.1039/C8DT02988A) The fictitious spin-1/2 (effective spin-1/2) Hamiltonian approach has been the putative method to analyze the conventional fine-structure/hyperfine ESR spectra of high spin metallocomplexes with sizable zero-field splitting (ZFS) tensors since the early 1950s, and the approach gives salient principal geff-values far from g = 2 without explicitly affording their […]

Reversible solution pi-dimerization and long multicenter bonding in a stable phenoxyl radical

Chemistry – A European Journal Chem. Eur. Journal, 24, pp.14906-14910 (2018). (DOI:10.1002/chem.201802204) Reversible solution p-dimerization is observed in the stable neutral phenoxyl radical 2,6-bis-(8-quinolylamino)-4-(tertbutyl) phenoxyl baqp and is spectroscopically characterized. This behavior, not previously observed for p-extended phenoxyl radicals, is relevant to the formation of long multicenter bonding in the p-dimer at low temperature akin […]

Fe-Transferrins or their homologues in ex-vivo mushrooms as identified by ESR spectroscopy and quantum chemical calculations: a full spin-Hamiltonian approach for the ferric sextet state with intermediate zero-field splitting parameters

Food Chemistry Volume 266, 15 November 2018, Pages 24-30 Fe-transferrins/their homologues in ex-vivo mushrooms were identified by ESR spectroscopy at liquid helium temperature, 4 K. The ESR fine-structure signals from Grifola frondosa were analyzed by spectral simulation with a full spin-Hamiltonian approach, determining the spin Hamiltonian parameters of the ferric iron species bound in the […]

Using optimal control methods with constraints to generate singlet states in NMR

J. Magn. Reson., 291, pp.14-22 (2018). DOI:10.1016/j.jmr.2018.03.005 A method is proposed for optimizing the performance of the APSOC (Adiabatic-Passage Spin Order Conversion) technique, which can be exploited in NMR experiments with singlet spin states. In this technique magnetization-to-singlet conversion (and singlet-to-magnetization conversion) is performed by using adiabatically ramped RF-fields. Optimization utilizes the GRAPE (Gradient Ascent […]

Behaviour of DFT-based approaches to the spin– orbit term of zero-field splitting tensors: a case study of metallocomplexes, MIII(acac)3 (M = V, Cr, Mn, Fe and Mo)

Phys. Chem. Chem. Phys., 19, pp.30128-30138 (2017). DOI: 10.1039/C7CP05533a Spin–orbit contributions to the zero-field splitting (ZFS) tensor (DSO tensor) of MIII(acac)3 complexes (M = V, Cr, Mn, Fe and Mo; acac = acetylacetonate anion) are evaluated by means of ab initio (a hybrid CASSCF/MRMP2) and DFT (Pederson–Khanna (PK) and natural orbital-based Pederson–Khanna (NOB-PK)) methods, focusing on the behaviour […]

Analyses of sizable ZFS and magnetic tensors of high spin metallocomplexes

Phys. Chem. Chem. Phys., 19, pp.24769-24791 (2017). DOI: 10.1039/C7CP03850J The fictitious spin-1/2 Hamiltonian approach is the putative method to analyze the fine-structure/hyperfine ESR spectra of high spin metallocomplexes having sizable zerofield splitting (ZFS), thus giving salient principal g-values far from around g = 2 without explicitly providing their ZFS parameters in most cases. Indeed, the significant departure of the g-values […]

Synthesis and Magnetic Properties of Trioxytriphenylamine Dimers in Di(radical cationic) States

Chem, Eur. J., accepted (2017). DOI: 10.1002/chem.201703220   Three structural isomers of trioxytriphenylamine (TOT) dimers, 4,4”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (4), 3,3”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (5), and 3,4”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (6) were prepared and their electronic and magnetic properties in the di(radical cationic) states were investigated. The X-ray crystal structure analysis demonstrated that the TOT moieties of all the di(radical cation)s have planar structures […]

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