Can't fight the SEEPR: Simultaneous electrochemical electron paramagnetic resonance reveals that a molecule containing nitronyl nitroxide (NN) radical (structure and red layer) is redox-active, with switchability between oxidized reduced states. An organic NN device utilizes dual p- n-type properties in memory device.

Chemically directed assembly of nanoscale materials is often an attractive alternative to techniques such as chemical vapor deposition or lithography. In this paper the synthesis one-dimensional (1D) assemblies solid poly(pyrrole)—the Figure shows a transmission electron microscope image—and use metal nanoparticles templates for hollow polymeric nanocapsules (see cover) are described.

Scanning tunneling microscopy and local conductance mapping show spin-state coexistence in bilayer films of Fe[(H2Bpz2)2bpy] on Au(111) that is independent temperature between 131 300 K. This modification bulk behavior attributed part to the unique packing constraints film promote deviations from behavior. The density states measured for different spin shows high-spin molecules have a smaller transport gap than low-spin are agreement with functional theory calculations.

The growth of films [H2B(pz)2]Fe(II)(bpy) on Au(111) is characterized from the bilayer film to multilayer regime. Scanning tunneling microscopy shows a transition well-ordered, uniform poorly-ordered at larger thicknesses. Previous local spectroscopy and conductance mapping in permit identification coexisting molecular spin-states all temperatures. New ultraviolet photoelectron consistent with this picture agreement density states calculated by functional theory. In thicker polycrystalline...

Photoinduced electron spin polarization (ESP) is reported in the electronic ground states of three Pt(II) complexes comprised two S = 1/2 nitronyl nitroxide (NN) radicals attached through different length para-phenylethynyl bridges to 3,6 positions a catecholate (CAT, donor) and 4,4′-di-tert-butyl-2,2′-bipyridine (bpy, acceptor). Complexes 1–3 have from 17 41 bonds separating NN display cw-EPR spectra consistent with |JNN-NN| ≫ |aN|, ≥ < respectively, where JNN-NN magnetic exchange coupling...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of phenyl ring torsional rigidity on the photophysical behavior tetraphenylethylenesDavid A. Shultz and Marye Anne FoxCite this: J. Am. Chem. Soc. 1989, 111, 16, 6311–6320Publication Date (Print):August 1, 1989Publication History Published online1 May 2002Published inissue 1 August 1989https://pubs.acs.org/doi/10.1021/ja00198a049https://doi.org/10.1021/ja00198a049research-articleACS PublicationsRequest reuse permissionsArticle...

The thermal-induced and photoinduced valence tautomerism of a series Co(dioxolene)(2)(4-X-py)(2) complexes (dioxolene = 3,5-di-tert-butylcatecholate or 3,5-di-tert-butylsemiquinonate; 4-X-py 4-(X)pyridine, X H (1), OMe (2), Me (3), CN (4), Br (5), NO(2) (6)) is described. thermal (ls-Co(III)(SQ)(Cat)(4-X-py)(2) <--> hs-Co(II)(SQ)(SQ)(4-X-py)(2)) only observed for 4, 5, 6 where each accompanied by hysteresis loop ca. 5 K. When crystalline sample 4-6 held at 10 K in SQUID magnetometer...

The preparation and characterization of three new donor–bridge–acceptor biradical complexes are described. Using variable-temperature magnetic susceptibility, EPR hyperfine coupling constants, the results X-ray crystal structures, we evaluate both exchange electronic couplings as a function bridge length for two quintessential molecular bridges: oligo(para-phenylene), β = 0.39 Å–1 oligo(2,5-thiophene), 0.22 Å–1. This report represents first direct comparison exchange/electronic distance...

A combination of variable-temperature EPR spectroscopy, electronic absorption and magnetic susceptibility measurements have been performed on Tp(Cum,Me)Zn(SQ-m-Ph-NN) (1-meta) a donor-bridge-acceptor (D-B-A) biradical that possesses cross-conjugated meta-phenylene (m-Ph) bridge spin singlet ground state. The experimental results interpreted in the context detailed bonding excited-state computations order to understand structure 1-meta. reveal important contributions ground-state...

A change in the sign of ground-state electron spin polarization (ESP) is reported complexes where an organic radical (nitronylnitroxide, NN) covalently attached to a donor-acceptor chromophore via two different meta-phenylene bridges (bpy)Pt(CAT-m-Ph-NN) (mPh-Pt) and (bpy)Pt(CAT-6-Me-m-Ph-NN) (6-Me-mPh-Pt) (bpy = 5,5'-di-tert-butyl-2,2'-bipyridine, CAT 3-tert-butylcatecholate, m-Ph meta-phenylene). These molecules represent new class chromophores that can be photoexcited with visible light...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTpH-Gated Single-Electron Tunneling in Chemically Modified Gold NanoclustersLouis C. Brousseau, Qi Zhao, David A. Shultz, and Daniel L. FeldheimView Author Information Department of Chemistry, North Carolina State University Raleigh, 27695 Cite this: J. Am. Chem. Soc. 1998, 120, 30, 7645–7646Publication Date (Web):July 21, 1998Publication History Received15 April 1998Published online21 July inissue 1 August...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEvaluation of potential ferromagnetic coupling units: the bis(TMM) [bis(trimethylenemethane)] approach to high-spin organic moleculesS. Joshua Jacobs, David A. Shultz, Rakesh Jain, Julie Novak, and Dennis DoughertyCite this: J. Am. Chem. Soc. 1993, 115, 5, 1744–1753Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March...

Using first principles calculations, we predict a complex multifunctional behavior in cobalt bis(dioxolene) valence tautomeric compounds. Molecular spin-state switching is shown to dramatically alter electronic properties and corresponding transport properties. This spin state dependence has been demonstrated for technologically relevant coordination polymers of tautomers as well novel conjugated with functionalization. As result, these materials are proposed promising candidates spintronic...

Transient absorption and emission spectroscopic studies on a series of diimineplatinum(II) dichalcogenolenes, LPtL′, reveal charge-separated dichalcogenolene → diimine charge-transfer (LL′CT) excited-state lifetimes that display remarkable nonperiodic dependence the heteroatoms ligand. Namely, there is no linear relationship between observed principle quantum number E donors. The results are explained in terms heteroatom-dependent singlet–triplet (S–T) energy gaps anisotropic covalency...

Excited state processes involving multiple electron spin centers are crucial elements for both spintronics and quantum information processing. Herein, we describe an addressable excited mechanism precise control of polarization. This derives from magnetic exchange couplings that occur between the spins a photogenerated electron–hole pair organic radical. The process is initiated by absorption photon followed ultrafast relaxation within manifold. leads to dramatic changes in polarization...

Both the sign and intensity of photoinduced electron spin polarization (ESP) in electronic ground state doublet (2S0/D0) chromophore-radical complexes can be controlled by changing nature metal ion. The consist an organic radical (nitronyl nitroxide, NN) covalently attached to a donor–acceptor chromophore via m-phenylene bridge, (bpy)M(CAT-m-Ph-NN) (1) (bpy = 4,4′-di-tert-butyl-2,2′-bipyridine, M PdII (1-Pd) or PtII (1-Pt), CAT 3-tert-butylcatecholate, m-Ph meta-phenylene). In both...

Ground-state electron spin polarization (ESP) is generated in radical elaborated (bpy)Pt(CAT-NN) and (bpy)Pt(CAT-p-Me2PhMe2-NN) (bpy = 5,5'-di-tert-butyl-2,2'-bipyridine, CAT 3-tert-butylcatecholate, p-Ph para-phenylene, NN nitronylnitroxide). Photoexcitation produces an exchange-coupled, three-spin, charge-separated doublet 2S1 (S chromophore excited singlet configuration) state that rapidly decays to a 2T1 (T triplet state. The SQ-bridge-NN bond torsions affect the magnitude of exchange...

We report molecular structures and temperature-dependent magnetic susceptibility data for several new metal complexes of heterospin triplet ground-state biradical ligands. The ligands are comprised both nitronyl-nitroxide (NN) semiquinone (SQ) spin carriers. Five compounds five-coordinate MII (M = Mn, Co, Ni, Cu, Zn), one is a six-coordinate NiII complex. were structurally characterized. During copper complex formation reaction with methanol occurs to form unique methoxy-substituted SQ ring....

A magnetostructural correlation (conformational electron spin exchange modulation) within an isostructural series of biradical complexes is presented. X-ray crystal structures, variable-temperature paramagnetic resonance spectroscopy, zero-field splitting parameters, and magnetic susceptibility measurements were used to evaluate molecular conformation coupling in this molecules. Our combined results indicate that the ferromagnetic portion couplings occurs via cross-conjugated pi-systems,...

The thermal- and photoinduced valence tautomerism of a cobalt bis(dioxolene) complex is described. thermal conversion precipitous, complete within 10 K, accompanied by 5 K hysteresis loop (107 < T(1/2) 112 K). Rapid quenching (300 --> in ca. s) result trapping the metastable Co(II)-state at low temperatures through intermolecular hydrogen bonding. This lattice stabilization results unmatched kinetic stability for tautomer from 10-50 with residual hs-Co(II) persisting until about 90 K.

The synthesis and characterization of an Fe(III) catecholate-nitronylnitroxide (CAT-NN) complex (1-NN) that undergoes spin-crossover is described. Our aim to determine whether the intraligand exchange coupling semiquinone-nitronylnitroxide Fe(II)(SQ-NN) excited state resulting from irradiation CAT → LMCT band would affect either intrinsic photophysics or iron event when compared lacking nitronylnitroxide radical (1). X-ray crystallographic analysis provides bond lengths consistent with a...

Photoinduced electron spin polarization (ESP) is reported in the ground state of a series complexes consisting an organic radical (nitronylnitroxide, NN) covalently attached to donor-acceptor chromophore either directly or via para-phenylene bridges substituted with 0-4 methyl groups. These molecules represent class chromophores that undergo visible light excitation produce initial exchange-coupled, three-spin [bpy•-, CAT•+ (= semiquinone, SQ) and NN•], charge-separated doublet 2S1 (S =...

Solid-state variable-temperature, variable-field magneto-photoluminescence experiments have been performed on the emissive excited triplet state (T1) of ligand-to-ligand charge transfer (LL′CT) complex (qdt)Pt(dbbpy) (qdt = quinoxaline-2,3-dithiolate; dbbpy 4,4′-di-tert-butyl-2-2′-bipyridine). We observe a strong temperature and magnetic field dependence PL spectra, spin–lattice relaxation among ms levels within T1 appears to be accelerated due both ZFS in presence applied field, allowing...