Hydrolysis of glycosides with microgel catalysts.

A dormant macromolecular catalyst was prepared by polymerization of an aqueous styrene-butyl acrylate miniemulsion in the presence of a new polymerizable pentadentate ligand. The catalyst was activated by binding Cu(II) ions to the ligand site and then explored for its ability to hydrolyze glycosidic bonds in alkaline solution. The performance was correlated to the catalytic activity shown by low molecular weight analogs.

Macromolecular salen catalyst with largely enhanced catalytic activity.

A dinuclear copper(II) Schiff-base complex was immobilized in a poly(acrylate) matrix by emulsion polymerization. The spheric microbeads were used for aerobic catalytic oxidation of 3,5-di-tert-butylcatechol into 3,5-di-tert-butylquinone in methanol at ambient temperature to study the contribution of the macromolecular matrix to the overall rate acceleration of the reaction. The polymeric catalyst catalyzes the oxidation about 1 order of magnitude faster (kcat/knon = 470,000) than its low molecular weight analogue (kcat/knon = 60,000).

A sugar's choice: coordination to a mononuclear or a dinuclear copper(II) complex?

We proposed a decisive role of the number of metal ions at the sugar binding site for carbohydrate-coordinating copper(II) complexes. To verify this hypothesis, we studied the binding of the representatively chosen carbohydrates D-ribose (7), D-mannose (8), D-glucose (9), and D-maltose (10) to structurally related mono- and dinuclear copper(II) complexes in alkaline solution. All carbohydrates coordinate to the metal complexes in a 1:1 molar ratio.

A sugar discriminating binuclear copper(II) complex.

We investigated the complex formation between various underivatized carbohydrates and the binuclear copper(II) complex 1, Cu(2)(bpdpo). A combined approach of UV/vis and CD spectroscopic investigations shows a large discrimination ability of 1 for structurally closely related monosaccharides in alkaline solution. The dominating form of the binuclear copper(II) complex consists of a [Cu(2)L(-)(H)(OH)(2)](+) species between pH 11 and 13, as determined from pH-dependent spectrophotometric titration experiments.

[Incidence and management of acute left main coronary artery dissection as a complication of acute transluminal coronary angioplasty].

Out of 1730 consecutive patients undergoing percutaneous transluminal coronary angioplasty (PTCA) of left descending coronary artery (LAD) or circumflex artery (CX) five patients (0.3%) suffered an acute dissection of left main coronary artery. In three patients dissection developed because of manipulation of the guiding catheter.