Ever since Nugent first reported a practical, catalytic method for the enantioselective opening of meso-epoxides with trimethylsilyl azide (TMSN3), [1] such desymmetrization reactions of epoxides and aziridines using a variety of nucleophiles have been the subject of extensive research. The less developed ring-opening reactions, those of meso-aziridines by carbon and nitrogen nucleophiles, give...

[reaction: see text]. Yttrium-salen complexes effect transacylation between enolesters and chiral secondary alcohols, resulting in varying degrees of kinetic resolution. Even though the enantioselectivity remains modest (k(fast)/k(slow) up to 4.81), these results represent the first demonstration of a conceptually new metal-catalyzed acyl transfer process that results in kinetic resolution. On ...

Ligand substitution reactions and catalytic hydroamination/cyclization of aminoalkenes have been studied with a new oxazolinylborato yttrium compound, tris(4,4-dimethyl-2-oxazolinyl)phenylborato bis(trimethylsilylmethyl)yttrium ([Y(kappa(3)-To(M))(CH(2)SiMe(3))(2)(THF)], 1). THF exchange in 1 is rapid at room temperature, and activation parameters obtained by simulation of (1)H NMR spectra acqu...

the structure of the nonaaquayttrium (iii) bromate, [y(h2o)9](bro3)3, at low temperature (100 k) has been studied by means of single-crystal x-ray diffraction. crystallography shows a hexagonal unit cell, space group p63/mmc (no. 194) with z = 2, a = b = 11.7104(11) å, c = 6.6259(5) å and v = 786.90(12) å3 at 100 k. the hydrated trivalent yttrium(iii) ion forms a tricapped trigonal prism, in wh...

The possibility of intense radiation short-wave exchange spin waves excited in a thin transition layer at the internal boundary bilayer ferrite-ferrite structure is shown. Modelling processes has been exemplified by tangentially magnetized film ferric-yttrium garnet. It was found that one-way character. were radiated into with decreased magnetization. Their group velocities an order magnitude l...

We show here that the yttrium is immiscible and precipitates with various sizes in body centred cubic V$_{0.6}$Ti$_{0.4}$ alloy superconductor. The number size of are found to depend on amount added. Precipitates up 30~$\mu$m containing 5 at.\% yttrium. large line disorders generated by addition this be effective pinning magnetic flux lines. While superconducting transition temperature increase...

A new approach to fast-neutron dosimeq is described. It involves circulating a liquid with dissolved chemicals between a localized neutron field and a remote area where neutron-induced radioactivities are measured continuously. This approach employs reactions whch generate relatively short-lived radioactive byproducts. Sensitivity to the neutron energy spectrum is achieved by choosing several r...

Patients with malignant tumors originating from the biliary tree have a poor prognosis, since only a minority of tumors can be resected and most palliative regimens have shown only limited success. We present two patients with unresectable tumors, who were treated with trans-arterial (90)yttrium radioembolization: a patient with an infiltrating gallbladder carcinoma and a patient with an extens...

Deprotonation of the yttrium-arsine complex [Cp'3Y{As(H)2Mes}] (1) (Cp'=η(5)-C5H4Me, Mes=mesityl) by nBuLi produces the μ-arsenide complex [{Cp'2Y[μ-As(H)Mes]}3] (2). Deprotonation of the As-H bonds in 2 by nBuLi produces [Li(thf)4]2[{Cp'2Y(μ3-AsMes)}3Li], [Li(thf)4]2[3], in which the dianion 3 contains the first example of an arsinidene ligand in rare-earth metal chemistry. The molecular struc...