Cyanide-Bridged Molecular Squares with Ferromagnetically Coupled dπ, dσ, and pπ Spin System

Cyanide-bridged molecular squares of [FeII2CuII2(μ-CN)4(dmbpy)4(impy)2](ClO4)4·4CH3OH·C6H6 (1) and of [FeIII2CuII2(μ-CN)4(dmbpy)4(impy)2](ClO4)6·4CH3OH·4H2O (2) (dmbpy = 4,4‘-dimethyl-2,2‘-bipyridine; impy = 2-(2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy) were prepared. In the squares of 1 and 2, the Fe(II/III) (low spin) and Cu(II) ions are alternately bridged by the cyanide groups, in which the cyanide carbon atoms coordinated to the Fe(II) ions and Cu(II) ions are coordinated by imino nitroxide. Magnetic susceptibility measurements for 1 and 2 revealed that the Cu(II) ion and imino nitroxide are ferromagnetically coupled with a fairly strong coupling constant (JCu-radical > 300 K) and act as triplet species. In 1 the Cu(II)−radical moieties are magnetically separated by the Fe(II) ions. In the square of 2, dπ (Fe(III)), dσ (Cu(II)), and pπ (imino nitroxide) spins are alternately assembled, and this situation allowed the square to have an S = 3 spin ground state. The exchange coupling constant of Fe(III) and the Cu(II)−radical moiety in 2 was estimated to be J = 4.9 cm-1 (H = −2J∑SFe·SCu-radical)

Peculiarity in the Electronic Structure of Cu(II) Complex Ferromagnetically Coupled with Bisimino Nitroxides

By means of the electron spin resonance (ESR) technique, we have investigated the electronic structures of the tridentate imino nitroxyl diradical complex with copper(II) (Cu−bisimpy), which has a square planar structure and a ground quartet state with an extremely strong ferromagnetic exchange interaction, and its related compounds (bisimpy = 2,6-bis(1′-oxyl-4′,4′,5′,5′-tetramethyl-4′,5′-dihydro-1′H-imidazol-2′-yl)pyridine). It was clarified that Cu−bisimpy had unique magnetic orbitals, compared with the biradical ligand (bisimpy), a zinc(II) biradical complex (Zn−bisimpy) and a copper(II) terpyridine complex (Cu−tpy) (tpy = 2,2′;6′,2′′-terpyridine). Multifrequency ESR spectroscopy provided a reliable set of magnetic parameters of Cu−bisimpy, which has a small g anisotropy (gx = 2.02, gy = 2.01, gz = 2.08) and small hyperfine coupling with Cu (|Ax| = 42.0 MHz, |Ay| ≤ 14 MHz, |Az| = 153 MHz) but huge zero-field splitting (D = +17.4 GHz, E = −1.0 GHz). The maximum principal axis of zero-field interaction (zZF) is perpendicular to the z axis for the g and A tensors, which is normal to the molecular plane. These characteristics of the magnetic properties prove that the substantial spin transfer from the dx2−y2 orbital of copper to the n-orbitals of the ligand is caused by a σ-type covalent bonding effect between the central metal and the ligand nitrogens. The covalent bonding effect produces carbene configurations on the nitrogen atoms of the imino nitroxyl radicals. The carbene configuration was concluded to be the main reason for the strong ferromagnetic coupling in Cu−bisimpy. Multifrequency electron spin resonance spectroscopy clarified the unique electronic structure of a square planar copper(II) complex with an imino nitroxyl diradical, which undergoes a strong ferromagnetic interaction caused by a covalent bonding effect

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particles

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particle

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particles

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particle

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particles

Patterning Reactive Microdomains inside Polydimethylsiloxane Microchannels by Trapping and Melting Functional Polymer Particle

<i>Citrus</i> species and accessions used in this study.

z<p>Classification number and Latin names using Tanaka’s system <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062574#pone.0062574-Tanaka1" target="_blank">[53]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062574#pone.0062574-Tanaka2" target="_blank">[54]</a>.</p>y<p>Latin name using Single’s system <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062574#pone.0062574-Swingle1" target="_blank">[1]</a>.</p>x<p>A: Faculty of Agriculture, Saga University, B: Saga Prefectural Fruit Tree Research Station, C: Faculty of Agriculture, Kagoshima University, and D: National Institute of Fruit Tree Science, Japan.</p

Photographs of <i>Feronia limonia</i> and <i>Feroniella oblata</i> leaves.

<p>Photographs of <i>Feronia limonia</i> and <i>Feroniella oblata</i> leaves.</p

Experimental and Theoretical Studies on Ferromagnetically Coupled Metal Complexes with Imino Nitroxides

Copper(II), zinc(II), and nickel(II) complexes with tridentate imino nitroxyl diradicals, [CuCl(bisimpy)(MeOH)](PF6) (1), [ZnCl2(bisimpy)] (2), and [NiCl(bisimpy)(H2O)2]Cl·2H2O (3) (bisimpy = 2,6-bis(1‘-oxyl-4‘,4‘,5‘,5‘-tetramethyl-4‘,5‘-dihydro-1‘H-imidazol-2‘-yl)pyridine), were prepared, and their magnetic properties were studied. In 1, the Cu(II) ion has a square pyramidal coordination geometry, of which the equatorial coordination sites are occupied by three nitrogen atoms from the bisimpy and a chloride ion. The coordination geometry of the Zn(II) ion in 2 can be described as a trigonal bipyramid, with two chloride ions and a bisimpy. In 3, the Ni(II) ion has a distorted octahedral coordination geometry, of which four coordination sites are coordinated by the bisimpy and chloride ion, and two water molecules occupy the remaining cis positions. Magnetic susceptibility and EPR measurements revealed that in 1 and 3 the Cu(II) and Ni(II) ions with imino nitroxyl diraicals were ferromagnetically coupled, with the coupling constants J (H = −2Jij∑SiSj) of +165(1) and 109(2) cm-1, respectively, and the intraligand ferromagnetic interactions in 1−3 were very weak. DFT molecular orbital calculations were performed on the diradical ligand, 1, and 2 to study the spin density distribution before and after coordination to the metal ions

Neighbor-joining tree of the <i>matK</i> genes from accessions belonged to Aurantioideae.

<p>Numbers at the nodes indicate bootstrap values (% over 1,000 replicates).</p

Neighbor-joining tree of the <i>matK</i> genes from accessions belonged to “true citrus fruit trees.”

<p>Numbers at the nodes indicate bootstrap values (% over 1,000 replicates). Numbers in parenthesis indicates the number of accessions. <i>Citrus depressa</i>^z contains 6 accessions (Kaachi, Mikanguwa, Shiikunin, Shiikuribu, Ishikunibu, and Okitsu strains). <i>Citrus depressa</i>^y contains 2 accessions (Fusubuta and Kabishi).</p