Self-assembling of Mn12 molecular nanomagnets on FIB-patterned Au dot matrix

We have developed a novel strategy to build arrays of magnetic nanodots on the 100 nm scale, which exploits the potentialities of both bottom-up and top-down approaches, by self-assembling sulfur-functionalized Mn12 single molecule magnets (SMMs) on patterned Au dot matrices nanofabricated by FIB (focus ion beam). In this way, we demonstrate the capability to assemble SMMs in ordered arrays, where the magnetic information can be easily addressed, being the single bit represented by a 2D distribution of few hundred Mn12 clusters, grafted on top of each 100 × 100 nm² Au dot. Moreover, the chosen Mn12 functionalization is expected to favour a preferential orientation of the grafted molecule with the easy magnetization axis normal to the surface.     

Regiochemical control of the ring-opening of aziridines by means of chelating processes. Part 4: Regioselectivity of the opening reactions with MeOH of 1-(benzyloxy)-2,3- and -3,4-N-(methoxycarbonyl)aziridoalkanes under condensed and gas-phase operating conditions

The regioselectivity of the addition reaction of MeOH both in the condensed phase (MeOH/H₂SO₄) and in the gas-phase (MeOH/D₃⁺) was examined in a series of activated aziridines. The results indicate that gas-phase operating conditions are particularly favorable for the occurrence of D⁺-mediated chelated bidentate species, which influence the regioselectivity of the opening process. In the condensed phase, the chelating MeOH/LiClO₄ protocol turned out to be decidedly less effective for regioselectivity and also in determining the composition of the reaction mixture.     

A new effective method for the resolution of prochiral olefins : Stereoselective coordination in [PtCl3 (olefin)]− induced by crystallization

Crystallization of [PtCl₃(olefin)]^? [($\text{S}$-C₆H₅CH(CH₃)N(CH₃)₃]⁺ compounds (olefin = prochiral olefins) affords a single diastereoisomer through a second-order asymmetric transformation.     

Influence of charge carriers on magnetic order in lightly doped manganites, detected by μSR: Evidence for a superparamagnetic transition to the antiferromagnetic state

We detected two spontaneous precession frequencies in antiferromagnetic pure LaMnO₃, the end member of different families of charge-doped manganites. The muon site and local field orientation are identified for one frequency, which provides a measure of the staggered magnetization. We present additional zero and longitudinal field muon relaxation data on an LaMnO_3.045 sample in which a new regime appears above an intermediate temperatureT*, where regions of magnetic order coexist with domains of fluctuating moments. These results are discussed in terms of nucleation of the ordered phase in a superparamagnetic matrix.     

Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes. Part 15: Regioselectivity of the opening reactions with MeOH of remote O-substituted regio- and diastereoisomeric pyranosidic epoxides under condensed- and gas-phase operating conditions

The regiochemical behavior of pairs of regio- and diastereoisomeric epoxides derived from the 3,4,5,6-tetrahydro-2H-pyrane system, bearing an acetal group as the remote functionality, was determined in the acid methanolysis in the condensed phase (cd-phase) and in the reaction with MeOH in the gas-phase using a gaseous acid (D₃⁺), as the promoting agent. With only one exception, the results obtained in the opening process of these epoxides indicate the incursion in the gas-phase of D⁺-mediated chelated bidentate species able to modify the regiochemical result found in the methanolysis in the cd-phase.     

关于具有σ-结构的г-环

<正> 本文将[1]中结合环的σ-结构扩充到Г-环。关于Г-环的σ-结构,在[2]中已作过一些讨论。     

μSR measurement of the superconducting condensate reduction induced by Zn in underdoped, optimally doped and overdoped YBCO

We present an extensive study on the parallel reduction of T_c and the condensate density in ceramic YBCO samples, upon substitution of Cu by Zn. Strong evidence is collected in support of non magnetic pair breaking in a d‐wave pairing state. This revised version was published online in August 2006 with corrections to the Cover Date.