Structure and magnetism of two new linear trinuclear copper(II) clusters obtained from the tetradentate N2O2 ligand bis(2-hydroxybenzyl)-1,3-diaminopropane

Synthesis, Structure, and Magnetic Properties of Linear Trinuclear CuII and NiII Complexes of Porphyrin Analogues Embedded with Binaphthol Units

A porphyrin analogue embedded with (S)-1,1′-bi-2-naphthol units was synthesized without reducing optical purity of the original binaphthol unit. This new macrocyclic ligand provides the hexaanionic N4O4 coordination environment that enables a linear array of three metal ions. That is, it provides the square planar O4 donor set for the central metal site and the distorted square planar N2O2 donor set for the terminal metal sites. In fact, a CuII3 complex with a Cu(1)–Cu(2) distance of 2.910 Å, a Cu(1)–Cu(2)–Cu(1′) angle of 174.7°, and a very planar Cu2O2 diamond core was obtained. The variable-temperature 1H-NMR study of the CuII3 complex showed increasing paramagnetic shifts for the naphthyl protons as temperature increased, which suggests strong antiferromagnetic coupling of CuII ions. The temperature dependence of the magnetic susceptibility indicated antiferromagnetic coupling both for the CuII3 complex (J = −434 cm−1) and for the NiII3 complex (J = −49 cm−1). The linear (L)M(µ-OR)2M(µ-OR)2M(L) core in a rigid macrocycle cavity made of aromatic components provides robust metal complexes that undergo reversible ligation at the apical sites of the central metal.

Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn)

Six homo/heterotrinuclear Cu^IIM^IICu^II (M = Mn–Zn) compounds derived from salicylaldehyde-trans-1,2-diaminocyclohexane, which is a rarely utilized ligand, are reported.

Crystal structure of a new homo trinuclear Ni(II) complex with μ-cyanoacetato bridge

Ni(II)-Ni(II)-Ni(II) homo-trinuclear linear complex was prepared using bis-N,N′(2-hydroxybenzyl)-1,3-propanediamine in DMF (dimethyl formamide) medium. μ-bridges between metal nuclei are formed using formate, acetate, chloroacetate and benzoate ions. The structure of the homo-trinuclear complex was determined with X-ray diffraction method. It was found that the terminal Ni(II) ions have a N2O4 coordination sphere and central Ni(II) ion has a O6 octahedral coordination sphere. The chelate ring, formed by the coordination of terminal Ni atoms and aminic nitrogen atoms, was found to have a chair conformation. The complexes were elucidated by the use of thermogravimetry and differential thermal analysis method. In acetate, chloroacetate, cyanoacetate and benzoate containing complexes thermal dissociation of DMF took place first while in formate containing complex it was observed that formate bridges and the complex degraded together with the dissociation of DMF moiety. It was observed that the thermal stability of carboxylate μ-bridge affects the thermal stability of the homo-nuclear complex. The average bond energies of coordinated DMF molecules were determined and these coordinative bond energies were found to be in the dimension of that of hydrogen bonds.

Dichlorido-1κCl,3κCl-bis-{μ-2,2'-[pro-pane-1,3-diylbis(imino-methyl-ene)]di-phenol-ato}-1:2κO,N,N',O':O,O';2:3κO,O':O,N,N',O'-tricopper(II)

The title linear trinuclear copper(II) complex, [Cu₃(C₁₇H₂₀N₂O₂)₂Cl₂], was obtained from N,N′-bis­(2-hydroxy­benz­yl)-1,3-propane­diamine and CuCl₂. The overall charge of the three Cu²⁺ ions is balanced by four deprotonated phenol groups and two Cl⁻ ligands. The complex is centrosymmetric with the central Cu²⁺ occupying a special position (). This Cu²⁺ ion is coordinated by the four phenolate O atoms in a square-planar fashion. The second Cu²⁺ occupies a general position in a square-pyramidal fashion. Two phenolate O atoms and two amine N form the basal plane, with Cl⁻ ligands occupying the fifth coordination site.