Tailored cationic palladium(II) compounds as catalysts for highly selective dimerization and polymerization of vinylic monomers: Synthetic and mechanistic aspects

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00028a066· OSTI ID:6152598

Jiang, Z; Sen, A ^[1]

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1. Pennsylvania State Univ., University Park (United States)

The electrophilic palladium(II)compounds Pd(2,6-di-tert-butylpyridine)[sub 2](CH[sub 3]NO[sub 2])[sub 2](BF[sub 4])[sub 2] (1), Pd(PPh[sub 3])[sub 2](BF[sub 4])[sub 2] (2), and Pd(Ph[sub 2]PCH[sub 2]CH[sub 2]PPh[sub 2])(BF[sub 4])[sub 2] (3) were found to be highly selective catalysts for the acyclic dimerization of vinyl monomers (styrene, ethylene, and propylene) and the linear polymerization of p-divinylbenzene, the reactions proceeding through a carbocationic mechanism. One manifestation of the high selectivity was the ability to catalyze the dimerization of ethylene in the presence of propylene and styrene in the presence of [alpha]-methylstyrene even though the second member of each pair was normally significantly more reactive in reactions involving carbocationic intermediates. The linear polymerization of p-divinylbenzene involved in step-growth mechanism. The synthesis of a telechelic polymer through cross-coupling between the terminal vinyl groups of linear poly(p-divinylbenzene) and the vinyl group of a functionalized styrene derivative was also achieved. The reaction rates for the linear dimerization of styrene and the linear polymerization of p-divinylbenzene were found to be first order in the monomer concentration and fractional order in the catalyst concentration. Mathematical modeling indicated that the fractional order in the catalyst concentration was due to preequilibria involving anion dissociation from the metal center, and actually, the catalytic species in the case of 2 was found to be the dication, Pd(PPh[sub 3])[sub 2][sup 2+]. 17 refs., 6 figs., 4 tabs.

• DOE Contract Number: FG02-84ER13295
• OSTI ID: 6152598
• Journal Information: Organometallics; (United States), Journal Name: Organometallics; (United States) Vol. 12:4; ISSN ORGND7; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
ALKENES
ALKYLATED AROMATICS
AROMATICS
CATALYSIS
CATALYSTS
CHEMICAL REACTIONS
DIMERIZATION
DIVINYLBENZENE
ETHYLENE
HYDROCARBONS
KINETICS
MAGNETIC RESONANCE
MATHEMATICAL MODELS
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
PALLADIUM COMPOUNDS
POLYMERIZATION
PROPYLENE
REACTION KINETICS
RESONANCE
STYRENE
TRANSITION ELEMENT COMPOUNDS