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

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

The fascinating story of olefin (or alkene) metathesis (eq
1) began almost five decades ago, when Anderson and
Merckling reported the first carbon-carbon double-bond
rearrangement reaction in the titanium-catalyzed polymerization of norbornene. Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer carbon chains...”. In 1967, Calderon and co-workers named this metal-catalyzed redistribution of carbon-carbon double bonds olefin metathesis, from the Greek word “μeτάθeση”, which means change of position. These contributions have since served as the foundation for an amazing research field, and olefin metathesis currently represents a powerful transformation in chemical synthesis, attracting a vast amount of interest both in industry and academia.

https://core.ac.uk/download/pdf/4884240.pdf

Ruthenium-based heterocyclic carbene-coordinated olefin metathesis catalysts.

The Golden Age of Transfer Hydrogenation

Selected Recent Advances in the Synthesis of Bioactive Compounds Using Olefin Metathesis as a Key Step.

Lanthanide Coordination Polymers from 1,3-Bis(4-Carboxybenzyl) Benzimidazolium Chloride: Synthesis, Crystal Structure and Luminescence Properties

Towards New Generations of Metathesis Metal—Carbene Precatalysts

81 Previous papers in this series (1, 2), pointed out that ruthenium indenylidene and vinylidene complexes, 1 and 2, where R is a phenyl (Ph) or a cyclohexyl (Cy) substituent, constitute a convenient alternative to the first generation Grubbs ruthenium alkylidene metathesis pre-catalysts, 3 and 4 (3, 4), used on a large scale in organic (5–9) and polymer syntheses (10–14). Variations in the ligand sphere of the ruthenium atom have been made. These involve mainly the association of certain ancillary ligands, such as Nheterocyclic carbenes (imidazolin-2-ylidene and its saturated derivative), heterocyclic N-donating ligands (pyridine or different N-heterocycles), Oand O,N-chelated ligands (such as phenyl isopropoxy, Schiff-bases), 5 to 12, (R = Ph or Cy, R′ = Ph or Me) (15–31). However, the synthesis of novel metathesis initiators of improved accessibility and with a better application profile is still a challenge to organometallic and metathesis researchers. DOI:10.1595/147106706X112996

https://www.technology.matthey.com/wp-content/uploads/pdf/81-94-pmr-apr06.pdf

Ruthenium Allenylidene Complexes A PROMISING ALTERNATIVE IN METATHESIS CATALYSIS

Convenient routes for synthesis of ruthenium vinylidene complexes have been described, the majority of which use alkynes along with a ruthenium source as the main starting materials. Their successful application as efficient precatalysts in synthesis of heterocyclic and carbocyclic compounds by ring-closing metathesis of alpha,omega-dienes and in the synthesis of polymers by ring-opening metathesis polymerization of cyclooctene, norbornene, 5-substituted norbornene and dicyclopentadiene are fully illustrated. Relevant aspects concerning the activity and stereoselectivity in metathesis reactions of this type of Ru complexes are highlighted

Valerian Dragutan

Papers

Selected Recent Advances in the Synthesis of Bioactive Compounds Using Olefin Metathesis as a Key Step.

Lanthanide Coordination Polymers from 1,3-Bis(4-Carboxybenzyl) Benzimidazolium Chloride: Synthesis, Crystal Structure and Luminescence Properties

Towards New Generations of Metathesis Metal—Carbene Precatalysts

Ruthenium Allenylidene Complexes A PROMISING ALTERNATIVE IN METATHESIS CATALYSIS

Synthetic Approach to Ruthenium Vinylidene Complexes and Their Applications in Metathesis Catalysis