A competetive way to low-viscosity PAO base stocks via heterocene-catalyzed oligomerization of dec-1-ene

Transition Metal–(μ-Cl)–Aluminum Bonding in α-Olefin and Diene Chemistry

“…The activation of L 2 ZrCl 2 by R 3 Al and perfluoroaryl borates was also found to be efficient in α-olefin oligomerization. This type of activation was used in the recent study by Nifant’ev et al, who reported that –CH 2 CH 2 – bridged indeno[1,2- b ]indole ansa -complexes ( Scheme 25 b) demonstrate high efficiency in the synthesis of lightweight oligomers of dec-1-ene ( DP n = 3–5) with uniquely homogeneous molecular structures [ 43 ].…”

“…On the basis of the latest investigations [ 33 , 43 , 161 , 162 ], it can be concluded that the difference in the mechanisms of the L 2 ZrCl 2 + AlR 3 reactions in the absence and presence of MAO (or perfluoroaryl borates) consists of various degrees of ‘chlorination’ for the first-stage products. In the absence of MAO or borate, alkyl transfer from Al to Zr occurs with the formation of LZrR 2 ⋯ClAlR 2 complexes with weak Zr⋯Cl bonds (if R = i Bu, the transformation to Zr–Al hydrides results in heterometallic complexes with stronger Zr–(μ-H)–Al bonds).…”

“… ( a ) Coordination oligomerization of α-olefins; the idealized uniform molecular structure of the oligomers was achieved when using ‘heterocene’ catalysts ( b ) [ 43 ]. …”

“… 1 H NMR spectra (400 MHz, THF-d 8 , 20 °C) of Zr27 . Reprinted with permission from [ 43 ]. Copyright (2022) Elsevier B.V. …”

“…For group 4 metal polymerization catalysts, the conventional Cossee–Arlman mechanism has been expanded by including interactions between the metal center and bulky counterions (XMAO − , B(C 6 F 5 ) 4 − , anionic supports, etc.) [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], and binuclear Zr 2 complexes [ 34 , 36 ]; however, the direct participation of R 2 AlCl in the formation of catalytic species remains hypothetic, even with the results of numerous experimental and theoretical studies [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. It is also an open question whether M–(μ-Cl)–Al species participate in the coordination polymerization of 1,3-dienes.…”