Provided is a 2,3-bisphosphinopyrazine derivative represented by the following general formula (1), wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent an optionally substituted straight-chain or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted cycloalkyl group, an optionally substituted adamantyl group, or an optionally substituted phenyl group, R.sup.5 represents an optionally substituted alkyl group having 1 to 10 carbon atoms or an optionally substituted phenyl group, each R.sup.5 may be the same group or a different group, R.sup.6 represents a monovalent substituent, n denotes an integer of 0 to

##STR00001##

A catalyst system including the product of the combination of an unbridged Group 4 metallocene compound and a 2,6-bis(imino)pyridyl iron complex is provided. A process for the polymerization of monomers (such as olefin monomers) and a polymer produced therefrom are also provided.

The invention describes single-site metal catalysts such as Pt single-site centers on powdered oxide supports with a 1,10-phenanthroline-5,6-dione (PDO) or bis-pyrimidyltetrazine (BMTZ) ligand on powdered MgO, Al.sub.2O.sub.3, or CeO.sub.2.

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

Metal-organic frameworks (MOFs) may have Zn(II), Pb(II), and/or Cd(II) as a central metal ion, a 4,4-bipyridylethylene (bpe) ligand as a first ligand; and fumaric acid (fum) and/or oxalic acid (ox) as a second ligand, wherein the 4,4-bipyridylethylene ligands are stacked in the MOF, and wherein a distance between two consecutive 4,4-bipyridylethylene ligands is less than 5 . Cycloadditions, particularly photoinduced [2+2] cycloadditions may be catalyzed by such MOFs, and/or the conversion of photoinduced [2+2] cycloadditions in inventive MOFs may be increased by mechanical force, such as by grinding.

This application pertains to amine-functionalized polymers by ring-opening metathesis (ROMP) of amine functionalized cycloalkenes.

A catalyst system including the product of the combination of an unbridged Group 4 metallocene compound and a 2,6-bis(imino)pyridyl iron complex is provided. A process for the polymerization of monomers (such as olefin monomers) and a polymer produced therefrom are also provided.

The present invention discloses a method for preparing surface-active onion-like carbon nanospheres based on vapor deposition, comprising: directly preparing high-surface-activity onion-like carbon nanospheres formed by coating ferroferric oxide nano-particles on an onion-like graphitized shell by taking liquid small organic molecule alkane n-dodecane as a carbon source to perform chemical vapor deposition at high temperature of 650700 C. in an inert carrier gas environment with existence of a ferrocene catalyst. An onion-like carbon nanosphere product prepared according to the present invention has good surface activity and thermal stability, is wide in practicability, and can be widely applied to the fields of adsorbing materials, energy storage materials, catalytic materials, medical materials and the like.

The present invention relates to a catalyst system comprising a transition metal compound on a solid carrier which is a surface-reacted calcium carbonate. The invention further relates to a method for manufacturing said catalyst system and to its use in heterogeneous catalysis.

A method for preparing a porous nano-fiber heterostructure photocatalytic filter screen includes: preparing a noble metal nanostructure with tunable spectra and a heterostructure composite photocatalyst of a photocatalytic material; and preparing a large area and multilayer porous nano-fiber filter screen structure, while utilizing a scattering enhancement effect of metal nanoparticles in an porous optical fiber to realize repeated conduction of sunlight in the optical fiber and finally interact with the composite photocatalyst on a surface to improve photocatalytic efficiency. Preparation of the heterostructure composite photocatalyst with a wide spectral response of and tunable visible to infrared band spectra is realized, at the same time, with reference to high adsorbability, high light transmission of nanometer fiber and unique optical characteristics of metal nanoparticles, an air purification filter screen with a high sunlight utilization rate and a high catalytic degradation capability is creatively provided.