Mn(II) and Cu(II) Complexes of a Dithiadiazolyl Radical Ligand:  Monomer/Dimer Equilibria in Solution

Britten, James F.; Hearns, Nigel G. R.; Preuss, Kathryn E.; Richardson, John F.; Bin-Salamon, Sofi

doi:10.1021/ic0619456

Cited by 60 publications

(72 citation statements)

References 54 publications

(37 reference statements)

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“…8). Both the Mn II and Cu II complexes exhibit monomer/dimer equilibria in solution [68]. By contrast, crystalline Fe II and Ni II complexes are isostructural with the Co II complex, thus are not dimerized in the solid state [69].…”

Section: Transition Metal Complexesmentioning

confidence: 98%

Metal-radical coordination complexes of thiazyl and selenazyl ligands

Preuss

2015

Coordination Chemistry Reviews

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Section: Transition Metal Complexesmentioning

confidence: 98%

Metal-radical coordination complexes of thiazyl and selenazyl ligands

Preuss

2015

Coordination Chemistry Reviews

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“…10–13 In recent years, π–π interactions have been incorporated in the design of functional molecular materials featuring tunable optical and conductive properties. 14–19 In biology, π–π interactions between tetrapyrrolic macrocycles are key to numerous electron transfer processes, 20 such as those originating at the bacteriochlorophyll dimer ( special pair ) in bacterial photosynthetic reaction centers.…”

Section: Introductionmentioning

confidence: 99%

Interactions of Metal-Based and Ligand-Based Electronic Spins in Neutral Tripyrrindione π Dimers

et al. 2017

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The ability of tetrapyrrolic macrocycles to stabilize unpaired electrons and engage in π–π interactions is essential for many electron-transfer processes in biology and materials engineering. Herein, we demonstrate that the formation of π dimers is recapitulated in complexes of a linear tripyrrolic analog of naturally occurring pigments derived from heme decomposition. Hexaethyltripyrrindione (H3TD1) coordinates divalent transition metals (i.e., Pd, Cu, Ni) as a stable dianionic radical and was recently described as a robust redox-active ligand. The resulting planar complexes, which feature a delocalized ligand-based electronic spin, are stable at room temperature in air and support ligand-based one-electron processes. We detail the dimerization of neutral tripyrrindione complexes in solution through electron paramagnetic resonance (EPR) and visible absorption spectroscopic methods. Variable-temperature measurements using both EPR and absorption techniques allowed determination of the thermodynamic parameters of π dimerization, which resemble those previously reported for porphyrin radical cations. The inferred electronic structure, featuring coupling of ligand-based electronic spins in the π dimers, is supported by density functional theory (DFT) calculations.

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“…[3][4][5][6][7][8][9][10] In the majority of cases these radicals associate in the solid state to form π*-π* dimers, although a number of monomeric DTDA radicals have been reported. 1,2,[11][12][13][14][15][16] This dimerization is typically associated with short intra-dimer S···S contacts around 2.9 -3.1 Å.…”

Section: Introductionmentioning

confidence: 99%

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Constantinides

Carter

Eisler

et al. 2017

Crystal Growth & Design

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ABSTRACT:The syntheses and characterization of the aryl-substituted dithiadiazolyls, 2 -Cl-5 -X-C 6 H 3 CNSSN • [1 (X = F), 2 (X = Cl), 3 (X = Br), 4 (X = I)] are described. In all four cases the radicals adopt distorted stacks of π*-π* dimers with inter-stack S···X contacts. In 1 (monoclinic P2/c) S···Cl contacts are manifested through a non-crystallographic 3-fold axis forming supramolecular trimers whereas the inter-stack S…X contacts in 2 (triclinic P-1), 3 and 4 (which form an isostructural pair, orthorhombic Pna2 1 ) form supramolecular chains. While all the structures adopt π*-π* cis-oid dimer motifs, tuning the halogen modifies the intra-dimer S···S distance. Variable temperature SQUID magnetometry and X-band CW-EPR studies revealed the presence of a thermally accessible triplet state in all cases, with the singlet-triplet separation appearing in the order 1 > 2 > 3 > 4, consistent with a reduction in the overlap integral with increasing intra-dimer S···S separation. Variable temperature structural studies on both 2 and 4 reveal a structural evolution from a distorted π-stack motif towards a regular π-stacked array on warming. This is particularly pronounced in 2 where the intermolecular S…S separations along the stacking direction converge on a regular 3.6 Å spacing at ambient temperature.3

show abstract

Mn(II) and Cu(II) Complexes of a Dithiadiazolyl Radical Ligand: Monomer/Dimer Equilibria in Solution

Cited by 60 publications

References 54 publications

Metal-radical coordination complexes of thiazyl and selenazyl ligands

Metal-radical coordination complexes of thiazyl and selenazyl ligands

Interactions of Metal-Based and Ligand-Based Electronic Spins in Neutral Tripyrrindione π Dimers

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

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