Titanium and zirconium complexes of dianionic and trianionic amine-phenolate-type ligands in catalysis of lactide polymerization.

The synthesis of alkoxotitanium(IV) and -zirconium(IV) complexes of seven chelating tetradentate di- or trianionic amine-phenolate ligands belonging to three families and their application in L-lactide polymerization are described. The isopropoxotitanium complexes were synthesized by a direct reaction between the ligand precursors and titanium tetraisopropoxide, whereas the zirconium complexes were synthesized by various routes. For titanium, complexes of all seven ligands could be synthesized.

Vanadium(III) and vanadium(V) amine tris(phenolate) complexes.

The coordination chemistry of amine tris(phenolate) ligands around V(III) and V(V) is described for the first time. Three amine tris(phenolate) ligands were employed featuring different steric and electronic influence exerted by the phenolate substituents in the ortho and para positions being either t-Bu, Me, or Cl. V(III) complexes of all ligands (1-3) were readily obtained by reaction between the ligand precursors and VCl3(THF)3 in the presence of triethylamine.

Living polymerization and block copolymerization of alpha-olefins by an amine bis(phenolate) titanium catalyst.

An amine bis(phenolate) dibenzyl titanium complex having a methoxy donor on a side arm leads, upon activation with tris(pentafluorophenyl)borane, to unique living properties in alpha-olefin polymerization: exceptionally high molecular weight poly(1-hexene) is obtained in a living fashion at room temperature, living polymerization of 1-hexene is obtained above room temperature, and block copolymerization of 1-hexene and 1-octene at room temperature is described as well.

Synthesis and field bioassay of some analogs of sex pheromone of citrus mealybug,Planococcus citri (Risso).

A series of structural analogs of (s+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutanemethanol acetate, sex pheromone of the citrus mealybug,Planococcus citri (Risso), was synthesized. The analogs were tested in a field bioassay in order to determine the structure-activity relationships of the pheromone. All changes in structure reduced the activity of the test compounds, to various degrees.

Spontaneous tendon ruptures in patients treated by chronic hemodialysis.

Patients with renal failure treated by chronic hemodialysis tend to spontaneous tendon ruptures. In five out of 35 patients, 8 ruptured tendons have been found--four quadriceps and four finger tendon ruptures. Finger tendon ruptures are usually ignored by the patients because of the low disabling factor in the presence of more vital problems.

Coma due to hypercalcemia in a patient with Paget's disease and multiple parathyroid adenomata.

A patient with histologically proven coexistent Paget's disease of the bone and parathyroid adenomatosis is described. She developed coma associated with hypercalcemia and underwent successfully surgical removal of two parathyroid adenomata. The differential diagnosis of hypercalcemia in patients with this rare association is discussed and the importance of early surgical treatment is stressed.