Stern-Gerlach experiments of one-dimensional metal-benzene sandwich clusters: Mn(C6H6)m (M = Al, Sc, Ti, and V)

A molecular beam of multilayer metal-benzene organometallic clusters Mn(C6H6)m (M = Al, Sc, Ti, and V) was produced by a laser vaporization synthesis method, and their magnetic deflections were measured. Multidecker sandwich clusters of transition-metal atoms and benzene Scn(C6H6)n+1 (n = 1, 2) and Vn(C6H6)n+1 (n = 1-4) possess magnetic moments that increase monotonously with n. The magnetic moments of Al(C6H6), Scn(C6H6)n+1, and Vn(C6H6)n+1 are smaller than that of their spin-only values as a result of intracluster spin relaxation, an effect that depends on the orbital angular momenta and bonding characters of the orbitals containing electron spin. While Ti(C6H6)2 was found to be nonmagnetic, Tin(C6H6)n+1 (n = 2, 3) possess nonzero magnetic moments. The mechanism of ferromagnetic spin ordering in M2(C6H6)3 (M = Sc, Ti, V) is discussed qualitatively in terms of molecular orbital analysis. These sandwich species represent a new class of one-dimensional molecular magnets in which the transition-metal atoms are formally zerovalent.     

Two-photon excitation of confined biexcitons in CuCl quantum dots

We have studied direct creation processes of confined biexcitons in CuCl quantum dots by polarization-dependent resonant two-photon excitation spectroscopy. The two-photon absorption band for the lowest state of the biexciton (total angular momentum J=0) which appears on the lower energy side of confined exciton band was identified from the analysis of the polarization dependence of the photoluminescence excitation spectrum of the biexciton. Furthermore, the two-photon excitation process for the excited state of the biexciton (J=2) was also found with polarization dependence different from the J=0 biexciton state.     

Effect of TRX-liposomes size on their prolonged circulation in rats

Newly formulated cationic liposomes (TRX-liposomes) with four different mean diameters were injected into twelve male rats via the lateral tail vein in order to evaluate the effect of liposomal size on pharmacokinetic parameters. TRX-liposomes disappeared from the blood according to the one-compartment model and demonstrated maximum and minimum half-lives of ca. 14 h (mean diameter of 114.3 nm) and ca. 5 h (mean diameter of 285.9 nm), respectively. This prolonged half-life tended to decrease at the boundary of 114.3 nm mean diameter. The optimal size (114.3 nm) for prolonged circulation of TRX-liposomes was consistent with that of pegylated liposomes such as Doxil((R)), however, the half-life was different among these liposomes. The electric charge of the TRX-liposomal surface is assumed to be responsible for this difference. The results of the present study will be very useful in the design of long-circulating cationic liposomes.     

Rate constants of the O(D) reactions with N2, O2, N2O, and H2O at 295 K

Using a technique of laser flash photolysis coupled with vacuum ultraviolet laser-induced fluorescence spectroscopy, the rate coefficients of O(¹D) reactions with N₂, O₂, N₂O, and H₂O at 295 ± 2 K have been determined to be , k_O2=(4.06±0.24)×10^-11, k_N2O=(1.35±0.08)×10^-10 and . The quoted uncertainties include estimated errors and are the 95% confidence level. The k_N2 and k_N2O values obtained are larger than the current NASA/JPL recommendations by 26% and 16%, respectively, although they are still within the error limits associated with the recommendations.