A newly developed chiral linear tridentate ligand, R-PN(H)N (R = H or Ph), possesses Ph2P and PyCH2NH groups at C(2) and C(2') positions of the 1,1'-binaphthyl skeleton without or with a C(3)-Ph substituent. The steric effect of C(3)-Ph and the electronic effect of the DMSO coligand realize the facial selective generation of fac-RuCl2(Ph-PN(H)N)(dmso) and fac-[Ru(H-PN(H)N)(dmso)3](BF4)2, respectively. Both an H-Ru-sp 3 N-H reaction site responsible for the donor-acceptor bifunctional catalyst (DACat) and a fence/plane chiral context were constructed by means of the following advantageous points: i) the sp 3 P, sp 3 N, and sp 2 N ligating atoms have different electronic properties; ii) DMSO trans to sp 3 N strongly coordinates to Ru and is fixed by a PyC(6)H-O=S hydrogen bond; and iii) the single NH function simplifies the DACat reaction site. The synergistic effect has led to success in the asymmetric hydrogenation of sterically demanding ketones. Structural characteristics of first-row transition metal complexes of R-PN(H)N have been also investigated.
NiO/CoFeB/Cu/CoFeB spin valves with B content of 0 to 10 at.% were prepared to
investigate the dependence of the giant magnetoresistance(GMR) effect on the thickness of free
magnetic layers. In the spin valves, GMR effects were observed even when the free magnetic layers
were very thin, 1 or even 0.5 nm. For lower B content, the magnetoresistance (MR) ratio rapidly
increased with the increase of free magnetic layer thickness, while for higher B content, the MR ratio
was maximum at the thickness roughly equal to the mean free path of electrons in the magnetic layers.
By using the Camley-Barnas model, the value of the MR ratio and the resistivity can be consistently
explained if the specular reflection of electrons is considered at the interface between magnetic and
nonmagnetic layers.
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