Snapshot of cyclooctyne ring-opening to a tethered alkylidene cyclic polymer catalyst.

Cyclooctyne reacts with the trianionic pincer ligand supported alkylidyne [ BuOCO]WCC(CH)(THF) (1) to yield tungstacyclopropene (3) and tungstacyclopentadiene (4) complexes. The ratio of 3 and 4 in the reaction mixture depends on the stoichiometry of the reaction. The maximum concentration of 3 occurs with one equiv.

Mononuclear Four-Coordinate Bis-Fluoride Bis-NHC Complexes of Chromium(II), Iron(II), and Cobalt(II).

The reaction between silylamido complexes of Cr(II), Fe(II), and Co(II) and IMes·2HF salt in the presence of IMes (IMes = 1,3-dimesitylimidazol-2-ylidene) led to isolation of Cr(IMes)F (), Fe(IMes)F (), and Co(IMes)F (). X-ray structural studies revealed that adopts square planar geometry, while and have distorted tetrahedral geometry. Magnetic susceptibility studies of , , and were consistent with high-spin complexes, = 2 for / and = 3/2 for .

A family of mono-, di-, and tetranuclear Dy complexes bearing the ligand 2,6-diacetylpyridine bis(picolinoylhydrazone) and exhibiting slow relaxation of magnetization.

The systematic investigation of the general reaction scheme Dy/X/LH, where X = Cl, CFSO, ClO, MeCO, and LH is the pocket-type ligand 2,6-diacetylpyridine bis(picolinoylhydrazone), resulting from the condensation of 2,6-diacetylpyridine with picolinic acid hydrazide, has led to a new family of mono-, di-, and tetranuclear metal complexes of the formulae [DyCl(LH)(MeOH)]Cl (1), [Dy(OSCF)(LH)(MeOH)(HO)](OSCF) (2), [Dy(LH)(MeOH)(HO)](ClO) (3), and [Dy(OH)(OCMe)(L)] (4), respectively. The organic chelate undergoes metal-assisted amide-iminol tautomerism and adopts the neutral zwitterionic, and single- and double-deprotonated forms, respectively, upon coordination with the metal center(s). Interestingly, the different forms of the ligand LH/LH/L act independently as penta-, hexa-, and heptadentate, either as single-chelating or chelating and bridging, thus yielding new Dy compounds of various nuclearities and different magnetic properties.