Transition metal-catalyzed efficient and green transformations of P(O)-H compounds to functional organophosphorus compounds.

Organophosphorus compounds are of high importance in organic synthesis, catalysis, biochemistry, pharmaceuticals, and material science. In this mini review, we summarize our recent studies on transition metal-catalyzed green and atom efficient transformations of P(O)-H bonds to various versatile organophosphorus compounds, including the highly regio- and stereoselective P(O)-H additions to carbon-carbon unsaturated compounds, asymmetric hydrophosphorylation reactions, and dehydrogenative coupling reactions of P(O)-H compounds with carbon-H and heteroatom-H compounds. These new reactions provide efficient, general and practical ways for the preparation of a variety of well-defined functional organophosphorus compounds. Mechanistic aspects related to the catalytic processes are also discussed.

[The VUV luminescence properties and the Ce3+-->Tb3+ energy transfer in the (Sr, Ba)Al12O19].

The (Sr, Ba)Al12O19 : RE3+ (RE = Ce, Tb) compounds have been synthesized by the solid state reaction technology. The single-phase magnetoplumbite-type crystal structure has been identified by the X-ray diffraction analysis. The 302 nm peak and approximately 340 nm not-clear shoulder are correspondence to the 5d-->2 F5/2 and 5d-->2 F7/2 transitions in the emission spectrum, respectively. The 158 nm peak and 260 nm peak are separately contributed to the host absorption and 4f-5d transition of Ce3+ in the excitation spectrum. The characteristic emission of 5 D3-->7 Fj (j = 2, 3, 4, 5) and 5 D4-->7 Fj (j = 4, 5, 6) transitions in the range of 400-600 nm are assigned in the emission spectrum of (Sr, Ba)Al12O19 : Tb0.05(3+). The approximately 160 nm peaks arises from the overlap of the Tb3+ -O2- charge transfer band and the host absorption The 193 nm and 233 nm peaks are attributed by the spin-allowed 4f-5d transition and the spin-forbidden transition, respectively. The overlap between the emission of Ce3+ and the f-f transition absorption of Tb3+ exists in the (Sr, Ba)Al12O19 : Tb3+, Ce3+ compounds. The luminescence intensity of Tb3+ increases with the increase of the Ce3+ ion concentration When the Ce3+ ion concentration reaches about 0.03 mole, the luminescence intensity of Tb3+ ion is nearly two times comparing with the non-codoping Ce3+ ion compounds. When the emission wavelength is 543 nm, the excitation spectra exhibit the 4f-5d absorption of Ce3+ besides the host absorption and 4f-5d transitions of Tb3+ in the (Sr, Ba)Al12O19 : Tb3+, Ce3+ compounds. According to the excitation spectrum, the part of the emission of Tb3+ comes from the absorption of Ce3+ ion Therefore, it is illustrated that the Ce3+-->Tb3+ energy transfer has been existed in the (Sr, Ba)Al12O19 : RE3+ (RE = Ce, Tb) compounds.

2,6-Bis(1-isopropyl-5-phenyl-1H-pyrazol-3-yl)pyridine.

In the title compound, C(29)H(29)N(5), the central pyridine ring and the two pyrazole rings are approximately coplanar, the dihedral angles between the pyridine and pyrazole rings being 3.94 (12) and 14.84 (12)°. The pyrazole and phenyl rings on each side of the mol-ecule are twisted with dihedral angles of 46.72 (8) and 73.39 (8)°. One phenyl ring inter-acts with a pyrazole ring of a neighbouring mol-ecule via a weak inter-molecular C-H⋯π inter-action, which stabilizes the mol-ecular packing.