Synthesis, Structures and Magnetism of Mn(II)-Gd(III) Mixed-metal Complexes of 2,6-Dipicolinoylbis (N,N-diethylthiourea)

A novel Mn(II)-Gd(III) mixed-metal complex has been synthesized by one-pot reaction in methanolic solution of GdCl3, Mn(CH3OO)2∙4H2O and the organic ligand 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2L) with 1:2:3 molar ratio. The structure of the complex was elucidated by IR spectroscopy, and single crystal X-ray diffraction, while the magnetic properties were studied by SQUID measurements in the temperature range of 10 ÷ 330 K. The complex is comprised of one Gd3+ ion, two Mn2+ cations, and three dianionic ligands {L}2- with the chemical composition of [GdMn2(L)3](PF6). The magnetic interaction between Mn(II) and Gd(III) is weakly ferromagnetic with J = + 0,027 cm-1.

A twofold interpenetrating three-dimensional heterometallic metal–organic framework with pcu topology based on 2-methylbiphenyl-4,4′-dicarboxylic acid

The 2-methylbiphenyl-4,4′-dicarboxylate (mbpdc2−) ligand has versatile coordination modes and can be used to construct multinuclear structures. Despite this, reports of the synthesis of coordination complexes involving this ligand are scarce. The title compound, poly[[triaquadi-μ3-hydroxido-hexakis(μ4-2-methylbiphenyl-4,4′-dicarboxylato)calcium(II)hexazinc(II)] monohydrate], {[CaZn6(C15H10O4)6(OH)2(H2O)3]·H2O} n , has been prepared by the hydrothermal assembly of Zn(NO3)2·6H2O, CaCl2 and 2-methylbiphenyl-4,4′-dicarboxylic acid. Two ZnII atoms adopt a four-coordinated distorted tetrahedral geometry by bonding to three O atoms from three different 2-methylbiphenyl-4,4′-dicarboxylate (mbpdc2−) dianionic ligands and one bridging hydroxide O atom. For the remaining ZnII atom, a five-coordinate environment is completed half the time by one carboxylate O atom, and then the same carboxylate O atom and an aqua O atom are present the other half of the time, giving a six-coordinate environment. The CaII atom is coordinated by six O atoms to give an octahedral coordination geometry. The supramolecular secondary building unit (SBU) is a hamburger-like heptanuclear unit (Zn6CaO30) and these units are interconnected through mbpdc2− carboxylate groups to generate a three-dimensional framework with the pcu topology. The single net leaves voids that are filled by mutual interpenetration of an independent equivalent framework in a twofold interpenetrating architecture. The title compound shows thermal stability up to 673 K. The excitation and luminescence data showed the emission of a bright-blue fluorescence.

A new one-dimensional cadmium(II) coordination polymer incorporating 4-[4-(1H-imidazol-1-yl)phenyl]pyridine and 5-hydroxybenzene-1,3-dicarboxylate ligands

The design and synthesis of new organic lgands is important to the rapid development of coordination polymers (CPs). However, CPs based on asymmetric ligands are still rare, mainly because such ligands are usually expensive and more difficult to synthesize. The new asymmetric ligand 4-[4-(1H-imidazol-1-yl)phenyl]pyridine (IPP) has been used to construct the title one-dimensional coordination polymer,catena-poly[[[aqua{4-[4-(1H-imidazol-1-yl-κN3)phenyl]pyridine}cadmium(II)]-μ-5-hydroxybenzene-1,3-dicarboxylato-κ3O1,O1′:O3] monohydrate], {[Cd(C8H4O5)(C14H11N3)2(H2O)]·H2O}n, under hydrothermal reaction of IPP with CdIIin the presence of 5-hydroxyisophthalic acid (5-OH-H2bdc). The CdIIcation is coordinated by two N atoms from two distinct IPP ligands, three carboxylate O atoms from two different 5-OH-bdc2−dianionic ligands and one water O atom in a distorted octahedral geometry. The cationic [Cd(IPP)2]2+nodes are linked by 5-OH-bdc2−ligands to generate a one-dimensional chain. These chains are extended into a two-dimensional layer structureviaO—H...O and O—H...N hydrogen bonds and π–π interactions.

Ru alkylidene compounds bearing tridentate, dianionic ligands: Lewis acid activation and olefin metathesis

The series of tridentate complexes were prepared and shown to react with BCl3 to give the complexes affording neutral and cationic complexes sequentially. The generated five coordinate cations were evaluated in standard preliminary tests for olefin metathesis catalysis.

Synthesis and structures of mononuclear and dinuclear gallium complexes with α-diimine ligands: reduction of the metal or ligand?

A series of gallium complexes with different oxidation states of ligand and metal were obtained, both monoanionic and dianionic ligands can be further reduced, where reduction of the radical monoanionic α-diimine ligand into dianion or of Ga (+3) into the lower oxidation state Ga (+2) or Ga (+1.5) takes place.