Topic
Norbornene
About: Norbornene is a research topic. Over the lifetime, 5628 publications have been published within this topic receiving 104495 citations. The topic is also known as: norbornylene & norcamphene.
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TL;DR: These two rare three-coordinate nickel(I) complexes exhibit paramagnetic properties as measured by their EPR and 1H NMR spectra and could polymerize norbornene to afford addition-type polynorbornene (PNB) with high molecular weight.
Abstract: Reaction of lithium salts of anilido-imine ligands bearing bulky substituentes on the nitrogen donor atoms with trans-chloro(phenyl)bis(triphenylphosphane)nickel(II) results in the formation of two rare three-coordinate nickel(I) complexes [(Ar1NCHC6H4NAr2)Ni(I)PPh3] (1: Ar1 = Ar2 = 2,6-i-Pr2C6H3; 2: Ar1 = 2,6-Me2C6H3, Ar2 = 2,6-i-Pr2C6H3). The molecular structures of complexes 1 and 2 have been confirmed by single crystal X-ray analyses. These two complexes exhibit paramagnetic properties as measured by their EPR and 1H NMR spectra. After being activated with methylaluminoxane (MAO) these complexes could polymerize norbornene to afford addition-type polynorbornene (PNB) with high molecular weight Mw (106 g mol−1), catalytic activities being high, up to 2.82 × 107 gPNB mol−1Ni h−1.
72 citations
TL;DR: In this article, a complex of the type W(CHtBu)(NAr)Cl2(dme) (Ar = 2,6-diisopropylphenyl) with PCl5 in dimethoxyethane is presented.
72 citations
TL;DR: A novel 1,3,4-substituted 1,2,3-triazolium salt was found to function as an effective precursor for the synthesis of the first structurally characterized cationic silver(I) and ruthenium(II)carbene complexes of overall 1:2 ligand-to-metal stoichiometry.
72 citations
TL;DR: In this article, the neutral nickel complexes PhC(NSiMe3)2Ni(acac) and NiMe2Py2 have been synthesized and characterized by low-temperature X-ray diffraction analysis.
72 citations
TL;DR: DFT calculations on styrene hydrogenation using CaN''2 show that styrene oligomerization competes with styrene Hydrogenation, and protonation of the benzylcalcium intermediate with N''H is a low-energy escape route, thus avoiding oligomersization.
Abstract: Alkaline earth metal amides (AeN''2 : Ae=Ca, Sr, Ba, N''=N(SiMe3 )2 ) catalyze alkene hydrogenation (80-120 °C, 1-6 bar H2 , 1-10 mol % cat), with the activity increasing with metal size Various activated C=C bonds (styrene, p-MeO-styrene, α-Me-styrene, Ph2 C=CH2 , trans-stilbene, cyclohexadiene, 1-Ph-cyclohexene), semi-activated C=C bonds (Me3 SiCH=CH2 , norbornadiene), or non-activated (isolated) C=C bonds (norbornene, 4-vinylcyclohexene, 1-hexene) could be reduced The results show that neutral Ca or Ba catalysts are active in the challenging hydrogenation of isolated double bonds For activated alkenes (eg styrene), polymerization is fully suppressed due to fast protonation of the highly reactive benzyl intermediate by N''H (formed in the catalyst initiation) Using cyclohexadiene as the H source, the first Ae metal catalyzed H-transfer hydrogenation is reported DFT calculations on styrene hydrogenation using CaN''2 show that styrene oligomerization competes with styrene hydrogenation Calculations also show that protonation of the benzylcalcium intermediate with N''H is a low-energy escape route, thus avoiding oligomerization
72 citations