Octahedral Alkylbis(phenoxy‐imine)tin(IV) Complexes: Effect of Substituents on the Geometry of the Complexes and Their Reactivity Toward Ionizing Species and Ethylene

Abstract

The synthesis and characterization of the organo-tin compounds L 2 SnR 2 [L = N-(3,5-dichlorosalicylidene)aniline; R = CH 3 (1), R = CH 2 Ph (2)] and LЈ 2 SnR 2 [3: LЈ = N-(3-tert-butylsalicylidene)aniline, R = CH 2 Ph] are described herein. NMR studies showed a highly symmetric structure for complex 1, with the alkyl groups in a trans configuration, and the presence of at least two isomers in fluxional equilibrium for compounds 2 and 3. Single-crystal X-ray characterization for compound 2 showed an octahedral geometry with the alkyl groups in trans relationship. The reactivity of the synthesized compounds toward ionizing agents was studied by NMR spectroscopy. For compounds 1 and 2 formation of cationic

FI Catalysts for Olefin Polymerization—A Comprehensive Treatment

“…Pappalardo and co-workers synthesized (L FI ) 2 SnX 2 (X = alkyl) complexes 279 − 285 and investigated them as ethylene oligomerization catalysts. , Complexes with a perfluorophenyl group on the R 1 ( 279 , 281 ) only afforded mixtures of decomposition products in the presence of ionizing reagents, such as [(C 6 H 5 )NH(CH 3 ) 2 ] + [B(C 6 F 5 ) 4 ] − , B(C 6 F 5 ) 3 , and [C(C 6 H 5 ) 3 ] + [B(C 6 F 5 ) 4 ] − . On the other hand, non-fluorinated complexes 280 and 282 formed cationic species through alkyl abstraction by borate compounds.…”

“…337 Pappalardo and co-workers synthesized (L FI ) 2 SnR 2 (R = alkyl) complexes (as a mimic of the group 4 metal complexes) via a salt metathesis reaction of (L FI )Na and the corresponding Cl 2 SnR 2 in dry THF. 343,344 These Sn complexes were configurationally fluxional in solution in their neutral states and could be activated by [Ph 3 C][B(C 6 F 5 ) 4 ] into cationic species, thus exhibiting ethylene oligomerization activities.…”

In search for a pentacoordinated monoorgano stannyl cation

“…Metathesis of halogenides with alkali metal or silver salts of WCAs is a convenient way of stabilization of electrophilic and coordinatively unsaturated cations [14]. The most common and easily accessible WCAs are fluoroalkoxy aluminates [Al(OR F ) 4 [38,39], and fluoroaryl borates [BAr F 4 ] À (Ar F = C 6 F 5 [40,41], 3,5-(CF 3 ) 2 C 6 H 3 [42][43][44][45]). Upon addition of Ag[Al(OCH(CF 3 ) 2 ) 4 ] to a solution of PhSn(OCH 2 CH 2 NMe 2 ) 2 Cl (5) in dichloromethane immediate precipitation of AgCl takes place.…”

“…There are only single examples of the types: tetracoordinated triorgano cation B [25], pentacoordinate diorgano cation D [26], and even fully inorganic pentacoordinate cation F [24]. Pentacoordinated monoorgano stannyl cations E are still elusive, although several attempts were made at their isolation [3,4,24] [27].…”

“…Since these species are heavy analogs of carbocations R 3 C + , there is fundamental interest associated with their stability, bonding patterns and reactivity. In addition, they have received increasing interest in applied research as catalysts for the polymerization of alkenes [3,4], acylation of alcohols [5,6], and the Diels-Alder cycloaddition [7,8]. Several stannylium ions A were isolated in the solid state [9][10][11][12][13].…”