Ethylene polymerization catalysts from supported organotransition metal complexes: I. Pentadienyl derivatives of Ti, V, and Cr

Analysis of the weak interactions within the crystal structures of 33 complexes of various 4′-aromatic derivatives of 2,2′:6′,2″-terpyridine (tpy) shows that interactions that exceed dispersion are dominated, as expected, by cation⋯anion contacts but are associated with both ligand–ligand and ligand–solvent contacts, sometimes multicentred, in generally complicated arrays, probably largely determined by dispersion interactions between stacked aromatic units. With V(V) as the coordinating cation, there is evidence that the polarisation of the ligand results in an interaction exceeding dispersion at a carbon bound to nitrogen with oxygen or fluorine, an interaction unseen in the structures of M(II) (M = Fe, Co, Ni, Cu, Zn, Ru and Cd) complexes, except when 1,2,3-trimethoxyphenyl substituents are present in the 4′-tpy.

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Doubly fused N,N,N-Iron Ethylene Polymerization Catalysts appended with Fluoride Substituents; probing catalytic performance via a combined experimental and MLR study

Catalysis Science & Technology ◽

10.1039/d1cy00821h ◽

2021 ◽

Author(s):

Qiuyue Zhang ◽

Wenhong Yang ◽

Zheng Wang ◽

Gregory A. Solan ◽

Tongling Liang ◽

...

Keyword(s):

Ethylene Polymerization ◽

Catalytic Performance ◽

Chloride Complex ◽

Polymerization Catalysts

Access to six examples of α,α’-bis(imino)-2,3:5,6-bis(pentamethylene)pyridine-iron(II) chloride complex, [2,3:5,6-{C4H8C(N(2-R1-4-R3-6-R2C6H2)}2C5HN] (R1 = Me, R2 = R3 = CH(p-FPh)2 Fe1; R1 = Et, R2 = R3 = CH(p-FPh)2 Fe2; R1 = iPr,...

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The Exchange of Cyclometalated Ligands

Molecules ◽

10.3390/molecules26010210 ◽

2021 ◽

Vol 26 (1) ◽

pp. 210

Author(s):

Alexander D. Ryabov

Keyword(s):

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Bond Activation ◽

Bond Cleavage ◽

Cyclopalladated Complexes ◽

Derivatives Of ◽

Cyclometalated Ligand ◽

Incoming Ligand

Reactions of cyclometalated compounds are numerous. This account is focused on one of such reactions, the exchange of cyclometalated ligands, a reaction between a cyclometalated compound and an incoming ligand that replaces a previously cyclometalated ligand to form a new metalacycle: + H-C*~Z ⇄ + H-C~Y. Originally discovered for PdII complexes with Y/Z = N, P, S, the exchange appeared to be a mechanistically challenging, simple, and convenient routine for the synthesis of cyclopalladated complexes. Over four decades it was expanded to cyclometalated derivatives of platinum, ruthenium, manganese, rhodium, and iridium. The exchange, which is also questionably referred to as transcyclometalation, offers attractive synthetic possibilities and assists in disclosing key mechanistic pathways associated with the C–H bond activation by transition metal complexes and C–M bond cleavage. Both synthetic and mechanistic aspects of the exchange are reviewed and discussed.

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