There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).

Recent advances in catalytic hydrogenation of carbon dioxide

B. Anionic Ligands 302 IX. Group 9 Catalysts 302 X. Group 10 Catalysts 303 A. Neutral Ligands 303 1. R-Diimine and Related Ligands 303 2. Other Neutral Nitrogen-Based Ligands 304 3. Chelating Phosphorus-Based Ligands 304 B. Monoanionic Ligands 305 1. [PO] Chelates 305 2. [NO] Chelates 306 3. Other Monoanionic Ligands 306 4. Carbon-Based Ligands 306 XI. Group 11 Catalysts 307 XII. Group 12 Catalysts 307 XIII. Group 13 Catalysts 307 XIV. Summary and Outlook 308 XV. Glossary 308 XVI. References 308

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Advances in non-metallocene olefin polymerization catalysis.

One of the most exciting developments in the areas of catalysis, organometallic chemistry, and polymer science in recent years has been the intense exploration and commercialization of new polymerization technologies based on single-site and metallocene coordination olefin polymerization catalysts.1 The vast number of specifically designed/synthesized transition metal complexes (catalyst precursors) and main-group organometallic compounds (cocatalysts) allows unprecedented control over polymer microstructure, the generation of new polymer architectures, and the development of new polymerization reactions. Commercialization of new generations of single-site and metallocene catalyst-based technologies has provided the multibillion pound per year polyolefins industry with the ability to deliver a wide range of new and innovative olefin-based polymers having improved properties.2-4 The intense industrial activity in the field and the challenges to our basic understanding that have come to light have in turn 1391 Chem. Rev. 2000, 100, 1391−1434

/pdf/cocatalysts-for-metal-catalyzed-olefin-polymerization-37a9jvjiei.pdf

Cocatalysts for Metal-Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure−Activity Relationships

Use of Olefin Metathesis to Link Phosphinimide−Cyclopentadienyl Ligand Complexes: Synthesis, Structure, and Ethylene Polymerization Activity

This invention is a solution process for the preparation of high molecular weight ethylene copolymers comprising contacting olefin monomers, with a catalyst system at a polymerization temperature at or above about 80°C with a catalyst system comprising an unbridged Group 4 metal compound having a monocyclopentadienyl ligand, a phosphinimine ligand and at least one uninegative, activation reactive ligand. The process can be practiced at a reaction temperature of at least 80°C to obtain high number average molecular weight polymer.

High temperature solution polymerization process

Mono- and Bimetallic (NacNac)Ni Cyclopentadienyl Complexes†

Hydroboration of tBuC≡CSR with (C6F5)2BH generate the B/S FLPs, (C6F5)2B(RS)C═CH(tBu) (R = ptol, Me). For R = ptol the product Z-1 exhibits Z stereochemistry, is monomeric in solution and is capable of both classical Lewis acid–base and FLP reactivity. Photoisomerization of Z-1 affords E-1, which features an intramolecular S–B interaction promoted by the remote steric influence of the tert-butyl group. E-1 is not active as an FLP under ambient conditions but reacts with phenylacetylene when activated with either heat or light. The stereochemical outcome of the product is dependent on the stimulus employed.

Remote Stereochemistry of a Frustrated Lewis Pair Provides Thermal and Photochemical Control of Reactivity

Analogs of the [4Fe-4S]+ sites of reduced ferredoxins: structural and spectroscopic properties of [(C2H5)4N]3[Fe4S4(S-p-C6H4Br)4] in crystalline and solution phases

Douglas W. Stephan

Papers

Use of Olefin Metathesis to Link Phosphinimide−Cyclopentadienyl Ligand Complexes: Synthesis, Structure, and Ethylene Polymerization Activity

High temperature solution polymerization process

Mono- and Bimetallic (NacNac)Ni Cyclopentadienyl Complexes†

Remote Stereochemistry of a Frustrated Lewis Pair Provides Thermal and Photochemical Control of Reactivity

Analogs of the [4Fe-4S]+ sites of reduced ferredoxins: structural and spectroscopic properties of [(C2H5)4N]3[Fe4S4(S-p-C6H4Br)4] in crystalline and solution phases