Expanded Mercaptocalixarenes: A New Kind of Macrocyclic Ligands for Stabilization of Polynuclear Thiolate Clusters.

The syntheses and properties of expanded 4-tert-butyl-mercaptocalix[4]arenes, in which the methylene linkers are replaced by -CH NRCH - or -CH NRCH - and -CH NRCH CH CH NRCH - units, are described. The new macrocycles were obtained in a step-wise manner, utilizing fully protected, i. e.

Probing the magnetic superexchange couplings between terminal Cu ions in heterotrinuclear bis(oxamidato) type complexes.

The reaction of one equivalent of [-BuN][Ni(opboR)] with two equivalents of [Cu(pmdta)(X)] afforded the heterotrinuclear CuNiCu containing bis(oxamidato) type complexes [CuNi(opboR)(pmdta)]X (R = Me, X = NO (); R = Et, X = ClO (); R = Pr, X = NO (); opboR = -phenylenebis(NR-substituted oxamidato); pmdta = ,,',","-pentamethyldiethylenetriamine). The identities of the heterotrinuclear complexes - were established by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction studies, which revealed the cationic complex fragments [CuNi(opboR)(pmdta)] as not involved in any further intermolecular interactions. As a consequence thereof, the complexes - possess terminal paramagnetic [Cu(pmdta)] fragments separated by [Ni(opboR)] bridging units representing diamagnetic = 0 states.

Cavitands incorporating a Lewis acid dinickel chelate function as receptors for halide anions.

The halide binding properties of the cavitand [Ni2(L(Me2H4))](2+) (4) are reported. Cavitand 4 exhibits a chelating N3Ni(μ-S)2NiN3 moiety with two square-pyramidal Ni(II)N3S2 units situated in an anion binding pocket of ∼4 Å diameter formed by the organic backbone of the (L(Me2H4))(2-) macrocycle. The receptor reacts with fluoride, chloride (in MeCN/MeOH), and bromide (in MeCN) ions to afford an isostructural series of halogenido-bridged complexes [Ni2(L(Me2H4))(μ-Hal)](+) (Hal = F(-) (5), Cl(-) (6), and Br(-) (7)) featuring a N3Ni(μ-S)2(μ-Hal)NiN3 core structure.

Structure, magnetic behavior, and anisotropy of homoleptic trinuclear lanthanoid 8-quinolinolate complexes.

Three complexes of the form [Ln(III)3(OQ)9] (Ln = Gd, Tb, Dy; OQ = 8-quinolinolate) have been synthesized and their magnetic properties studied. The trinuclear complexes adopt V-shaped geometries with three bridging 8-quinolinolate oxygen atoms between the central and peripheral eight-coordinate metal atoms. The magnetic properties of these three complexes differ greatly.