Neutral and cationic palladium(II) bis(pyrazolyl)methane complexes
The synthesis, structures, and reactivity of neutral and cationic Pd(II) complexes incorporating bis(pyrazolyl)methane ligands are described. The reaction of (CH{sub 3}CN){sub 2}PdCl{sub 2} with the appropriate bis(pyrazoyl)methane in CH{sub 2}Cl{sub 2}yields {l{underscore}brace}Ph{sub 2}C(3-{sup t}Bu-pz){sub 2}{r{underscore}brace}PdCl{sub 2}(1) and {l{underscore}brace}Ph{sub 2}C(pz){sub 2}{r{underscore}brace}PdCl{sub 2} (2). Steric crowding associated with the {sup t}Bu groups of 1 increases the puckering of the chelate ring (boat conformation) and retards the chelate ring inversion relative to 2. The reaction of {l{underscore}brace}Me{sub 2}C(px){sub 2}{r{underscore}brace}PdMe{sub 2} (3) with p[HNMe{sub 2}Ph][B(C{sub 6}F{sub 5}){sub 4}] yields {l{underscore}brace}Me{sub 2}C(pz){sub 2}{r{underscore}brace}PdMe(NMe{sub 2}Ph){sup +} (4a, B(C{sub 6}F{sub 5}){sub 4}{sup {minus}} salt), while treatment of 3 with [H(OEt{sub 2}){sub 2}][B{l{underscore}brace}3,5(CF{sub 3}){sub 2}C{sub 6}H{sub 3}{r{underscore}brace}{sub 4}] yields {l{underscore}brace}Me{sub 2}C(pz){sub 2}{r{underscore}brace}PdMe(OEt{sub 2}){sup +} (4b, B{l{underscore}brace}3,5-(CF{sub 3}){sub 2}C{sub 6}H{sub 3}{l{underscore}brace}{sub 4}{sup {minus}} salt). Complex 4a reacts with ethylene at {minus}60 C (CD{sub 2}Cl{sub 2}) to yield {l{underscore}brace}Me{sub 2}C(pz){sub 2}{r{underscore}brace}PdMe(CH{sub 2}{double{underscore}bond}CH{sub 2}){sup +} (5, B(C{sub 6}F{sub 5}){sub 4}{sup {minus}}salt) and free NMe{sub 2}Ph. Cation 5 undergoes ethylene insertion at {minus}10 C and oligomerizes ethylene (1 atm) to predominantly linear internal C{sub 8} to C{sub 24} olefins (ca. 0.1 branches per 2 carbons) at 23 C.
- Research Organization:
- Univ. of Iowa, Iowa City (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-88ER13935
- OSTI ID:
- 20003994
- Journal Information:
- Organometallics, Vol. 18, Issue 23; Other Information: PBD: 8 Nov 1999; ISSN 0276-7333
- Country of Publication:
- United States
- Language:
- English
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