Nickel Chelate Complexes of 2-Alkylphenylphosphanylphenolates: Synthesis, Structural Investigation and Use in Ethylene Polymerization

✍ Scribed by Joachim Heinicke; Manuela Koesling; Robert Brüll; Wilhelm Keim; Hans Pritzkow

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 340 KB
• Volume: 2000
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/(sici)1099-0682(200002)2000:2<299::aid-ejic299>3.0.co;2-j

✦ Synopsis

2-Diphenylphosphanyl-and 2-alkylphenylphosphanyl-4-hindered or retarded. The reactivity of 1d remains high towards nickel salts in polar solvents, but in contrast to 1a-c, methylphenols 1 or their silyl ethers 2 and equimolar amounts of nickelocene react in benzene preferably to give yielding 4, a sparingly soluble green trans-bis(P-O-chelate) nickel complex 6d is formed. Complexes formed in situ from orange-brown diamagnetic cyclopentadienylnickel chelate complexes [η-CpNi(P ʝ O)] (3). Addition of a second 1 or 2 and Ni(COD) 2 in toluene catalyze the polymerization of ethylene. The cyclopentadienyl (P ʝ O) complexes 3, however, equivalent of 1 or 2 affords (RR) and (SS) diastereoisomers of cis-bis(P ʝ O-chelates) 4a-c (R = Ph, Me, iPr) or the are too stable to be active in this process. The crystal and molecular structure of 3c and 4c are described. unsymmetrical cis-bis(P ʝ O-chelate) 5, whereas with bulkier substituted derivatives 1d or 2d (R = tBu) the second step is phenols and Ni(COD) 2 . The influence of substituents on