Covalent Titanium Aryldioxy One-, Two-, and Three-Dimensional Networks and Their Examination as Ziegler−Natta Catalysts

Treatment of (iPrO)4Ti with 2,7-dihydroxynaphthalene at 100 °C afforded the one-dimensional ladder [cis-Ti(μ2,7-OC10H6O)2py2]n (1: C30H22N2O4Ti, orthorhombic, P212121, a = 9.866(2) Å, b = 15.962(3) Å, c = 16.223(3) Å, Z = 4), in pyridine, and the stacked ladder, two-dimensional [Ti(μ2,7-OC10H6O)2(4-picoline)2·(4-picoline)0.5]n (2: C70H59N5O8Ti2, triclinic, P1̄, a = 10.814(2) Å, b = 16.785(3) Å, c = 18.020(4) Å, α = 93.88(3)°, β = 107.31(3)°, γ = 108.77(3)°, Z = 2), in 4-picoline. A disruption of intramolecular edge-to-face and intermolecular face-to-face π-stacking interactions in 1 by the Me group of the 4-picoline causes the structural change to 2. These derivatives and related two- and three-dimensional covalent metal organic networks (CMON) were assayed for ethylene and propylene polymerization activity via the addition of methylaluminoxane. CMON are mediocre Ziegler−Natta catalysts that generate polydisperse, linear polyethylene and atactic polypropylene. The data are best accommodated by viewing the degradation of CMON into numerous active sites of differing activity.