Tasuku Ito

Plant GSK3 proteins regulate xylem cell differentiation downstream of TDIF–TDR signalling

During plant radial growth typically seen in trees, procambial and cambial cells act as meristematic cells in the vascular system to self-proliferate and differentiate into xylem cells. These two processes are regulated by a signalling pathway composed of a peptide ligand and its receptor; tracheary element differentiation inhibitory factor (TDIF) and TDIF RECEPTOR (TDR). Here we show that glycogen synthase kinase 3 proteins (GSK3s) are crucial downstream components of the TDIF signalling pathway suppressing xylem differentiation from procambial cells. TDR interacts with GSK3s at the plasma membrane and activates GSK3s in a TDIF-dependent fashion. Consistently, a specific inhibitor of plant GSK3s strongly induces xylem cell differentiation through BRI1-EMS SUPPRESSOR 1 (BES1), a well-known target transcription factor of GSK3s. Our findings provide insight into the regulation of cell fate determination in meristem maintenance.

A two-dimensional bimetallic assembly, [Ni(pn)2]2[Fe(CN)6]ClO4-2H2O, with a square structure

A bimetallic assembly, [Ni(pn)2]2[Fe(CN)6]ClO4·2H2O, has a two-dimensional square network structure, formed from Fe–CN–Ni(pn)2–NC–Fe linkages, and shows ferromagnetic ordering.

Syntheses, structures, and magnetic properties of multinuclear complexes constructed with complexed ligands, [M(bpca)2]+ (M=Cr(III), Fe(III), Co(III); Hbpca=bis(2-pyridylcarbonyl)amine)

Abstract Two trinuclear complexes [Fe(II)(ClO4)2{M(III)(bpca)2}2](ClO4)2 (M=Co for 1 and Fe for 2) and three chain complexes catena-[Fe(II)(ClO4)2{M(III)(bpca)2}]ClO4 (M=Co for 3, Cr for 4, and Fe for 5) were synthesized and structures for all complexes and magnetic properties for 3–5 were investigated (Hbpca=bis(2-pyridylcarbonyl)amine). All of these complexes consist of {trans-Fe(II)(ClO4)2} unit(s) and cationic complexed ligands, {M(III)(bpca)2}+, in an alternate arrangement. In 3–5, perchlorate anions in the {trans-Fe(II)(ClO4)2} unit are bound to a high-spin Fe(II) ion with relatively short distances in the range from 2.131(3) to 2.157(3) A. The cationic complex ligands in 1 and 2 act as a bidentate terminal ligand whereas in 3–5 they act as a bis-bidentate bridging ligand. In 3, very weak ferromagnetic interaction occurs between Fe(II) ions via the diamagnetic complexed ligand [Co(III)(bpca)2]+. In both 4 and 5 antiferromagnetic interactions occur between high-spin Fe(II) and Cr(III) ions in 4 and high-spin Fe(II) and low-spin Fe(III) ions in 5, respectively. Compound 5 shows ferrimagnetic behavior at low temperature. A plot of 1/χM versus T above 50 K for 4 and 5 obey the Curie–Weiss law with negative Weiss constants of θ=−12.5(4) K for 4 and −15.3(6) K for 5, respectively. The temperature dependence of χMT for 5 was further analyzed by the Seiden model from which the J value was estimated as −13.8(3) cm−1 (H=−J[SFe(II)i+SFe(II)i+1]·SFe(III)i).

Assembly of imino nitroxides with Ag(I) and Cu(I) ions

Abstract Magnetic interactions between coordinated imino nitroxides through the diamagnetic Cu(I) and Ag(I) ions, and radical assemblies by means of coordination to Ag(I) and Cu(I) ions are discussed.

Syntheses, structures and magnetic properties of multinuculear manganese complexes with Schiff base ligands

Abstract Multinulear manganese complexes with Schiff base ligands, [{MnIII4(μ3-O)(sae)4(μ-N3)(CH3OH)}2(μ-N3)]N3 ([1]N3), [MnIII6(μ3-O)2(sae)6(NCS)2] (2) and [MnII4MnIII2(sae)6(CH3OH)2Cl2] (3) (H2sae=2-salicylideneaminoethanol), were prepared and the crystal structures and magnetic properties were studied.

Structures and magnetic properties of metal cubes

Abstract Structures and magnetic properties of copper(II), nickel(II) and manganese(II) cubes are presented. In the cubes, four metal ions are assembled into the cubes by tridentate Schiff base ligands. Magnetic succeptibility measurements revealed the copper and nickel cubes have high-spin ground state, while the manganese cube has a S =0 spin ground state.

Reactions of metal complexes with carbohydrates: isolation and characterization of novel nickel(II) complexes containing N-glycoside ligands derived from amino sugars

Determination de la structure cristalline du complexe [Ni(D-N-gl-en) 2 ]Bx 2 •4H 2 O, avec D-N-gl-en=[amino-2 ethylamino]-1 amino-2 didesoxy-1,2-D-glucose

A binuclear copper(II) complex with both metal ions bound within a 22-membered homologue of Curtis-type tetraaza macrocyclic ligands

Synthese du macrocycle hexamethyl-2,2,4,13,13,15 tetraaza-1,5,12,16cyclodocosane et preparation et structure aux RX du complexe dinucleaire du Cu(II) a pont di-μ-alcoxo

UTILIZATION OF CHEMICAL AND STRUCTURAL CHARACTERISTICS OF TETRAAZA CYCLOALKANE COMPLEXES

Abstract The research investigations aiming at taking advantage of the chemical and structural consequences of ligand macrocyclization are reviewed with regard to the three features as follows: (1) Tetraazacycloalkane complexes which take up carbon dioxide as ROCO2 − or R2NCO2 −; (2) Correlation between axial and inplane coordination bond lengths in tetragonal six-coordinate complexes of trans-MX2N4-type (MyCo3+, Ni2+, and Zn2+)-X-ray structural and ab initio MO studies and (3) Stabilization of high oxidation states of metal ions and its application to chemistry of one-dimensional halogen-bridged M2+-M4+ mixed valence complexes.

Controlling the construction of trinuclear, 1-D, and 2-D Ni(II)Fe(II)/Fe(II)Fe(II) complexes: selective syntheses, structures, and magnetic properties

The reaction of [Ni(bpca)2] (1) and [Fe(H2O)6](ClO4)2 gave a trinuclear complex 3, five 1-D chain complexes 4a–e, and a 2-D honeycomb complex 5. The selective syntheses of these complexes were achieved by controlling the reaction conditions such as reaction stoichiometry, solvents, and the presence/absence of supporting ligands. 3 consists of a central {Fe(trans-H2O)2}2+ moiety and two units of 1 acting as terminal bidentate ligands. 4a–e consist of an alternating arrangement of Fe(II) ions and 1 which acts as a bis-bidentate bridging ligand. 5 has a honeycomb structure with hexagons involving twelve metal ions, six Ni(II) ions in 1 and six Fe(II) ions, and holds the large cavity which includes counter ions, chloroform, and water molecules. The reaction of [Fe(bpca)2] (2) and [Fe(H2O)6](ClO4)2 also gave a 2-D honeycomb complex 6 which is isostructural to 5. Magnetic data for 3 and 4a indicate a ferromagnetic interaction between adjoining Ni(II) ions and the Fe(II) ions, due to the strict orthogonality of the magnetic orbitals.