POLYMERIZATION OF ALPHA-OLEFINS AND BUTADIENE AND CATALYTIC CYCLOTRIMERIZATION OF 1-ALKYNES BY A NEW CLASS OF GROUP-IV CATALYSTS - CONTROL OF MOLECULAR-WEIGHT AND POLYMER MICROSTRUCTURE VIA LIGAND TUNING IN STERICALLY HINDERED CHELATING PHENOXIDE TITANIUM AND ZIRCONIUM SPECIES

A new class of homogeneous catalysts for olefin oligo-polymerization i s reported. These titanium or zirconium sterically hindered chelating alkoxide complexes were prepared by reaction of M(CH(2)Ph)(4) (M = Ti, Zr) or Zr(CH(2)Ph)(2)Cl-2(OEt(2))(2) With the appropriate biphenol or binaphthol, or by reaction of TiCl4 with the diol. Using these method ologies, a range of binaphthoxide and biphenoxide catalysts with varyi ng steric hindrance have been prepared: {1,1'-(2,2',3,3'-OC(10)H(5)SiR (3))}2ZrCl2 {R(3) = Me(3) (1); R(3) = MePh(2) (2); R(3) = Ph(3) (3)}, ,1'-(2,2',3,3'-OC(10)H(5)SiMe(3))}Ti-2(CH(2)Ph)(2) (4), '-(2,2',3,3'-O C(10)H(5)SiMePh(2))}Zr-2(CH(2)Ph)(2) (5), ,1'-(2,2',3,3'-OC(10)H(5)SiP h(3))}Ti-2(CH(2)Ph)(2) {M = Ti (7), M = Zr (8)}, 2,2'-S(4-Me,6-(i)BuC( 6)H(2)O)(2)MX(2) {MX(2) = TiCl2 (10); MX(2) = ZrCl2 (11); MX(2) = Ti(C H(2)Ph)(2) (12)}, {2,2'-S(4-Me,6-(t)BuC(6)H(2)O)(2)}Ti-2 (13), 2,2'-(4 ,6-(t)Bu(2)C(6)H(2)O)(2)MX(2) {MX(2) = Ti(CH(2)Ph)(2) (14); MX(2) = Zr Cl2(THF)(2) (15)}, {2,2'-(4-OMe,6-(t)BuC(6)H(2)O)(2)}Ti-2 (16), 2,2'-( 4-OMe,6-(t)BuC(6)H(2)O)(2)Ti(CH(2)Ph)(2) (17)}, 2,2'-CH2(4-Et,6-(t)BuC (6)H(2)O)(2)TiX(2) {X = CH(2)Ph (18), X = Cl (19), and {2,2'-CH2(4-Et, 6-(t)BuC(6)H(2)O)(2)}Ti-2 (20). This class of L(2)MCl(2) systems can b e regarded as being analogous to the well-documented range of Group IV metallocenes. Alkylation of (O-O)ZrCl2 ((O-O = chelating phenoxide) a llowed access to other alkyl species. Therefore, reaction of 3 with Me Li or Me(3)SiCH(2)Li afforded {1,1'-{2,2',3,3'-OC(10)H(5)SiPh(3)}(2)Zr X(2) {X = Me (6); X = CH(2)SiMe(3) (9)}, respectively. The X-ray cryst al structure of 17 is reported. At 213 K, 17 . 1/2OEt(2) has space gro up P $($) over bar$$ 1 and unit cell dimensions a = 8.757(9) Angstrom, b = 11.840(10) Angstrom, c = 17.135(17) Angstrom, alpha = 98.28(7)deg rees, beta = 90.53(8)degrees, gamma = 101.38(7)degrees, mu(Mo K alpha) = 2.88 cm(-1). Attempts to prepare analogous sterically hindered bina phthiolates were thwarted by the absence of known sterically hindered chelating binaphthiols. Synthetic routes to such ligands were attempte d albeit without success. The chelating phenoxide and binaphthoxide ti tanium and zirconium species, in the presence of an aluminum cocatalys t are active for the oligo-polymerization of alpha-olefins. For the po lymerization of ethylene, rates of up to 4740 kg of PE/mol of catalyst . h (100 kg/g of Ti . h) were obtained. They are active for the polym erization of butadiene and the catalytic cyclotrimerization of termina l acetylenes to 1,2,4- and 1,3,5-trisubstituted benzenes. This ratio o f benzenes is dependent on the steric bulk of the ancillary binaphthol ligands. Steric modifications also have a clear influence on the degr ee of 1-hexene polymerization as well as the tacticity of poly(1-hexen e). In particular, the chelating alkoxide ligand framework can induce stereoregularity. For 1 and 2, with methylaluminoxane as cocatalyst, r egioregular and stereospecific polymerization of 1-hexene is observed to give high molecular weight isotactic polyhexene. Related ligand-dep endent differences in polymer microstructure are observed in the polym erization of butadiene. Cationic complexes have been synthesized. [(C( 10)H(5)SiPh(3)O)(2)Zr(CH(2)Ph)]BPh(4) (21), and zwitterionic )SiPh(3)O )(2)Zr(CH(2)Ph)(eta(6)-PhCH(2))B(C6F5)(3) (22) were made by treatment of 8 with [PhNMe(2)H]BPh(4) and B(C6F5)3, respectively. They are activ e for the polymerization of ethylene.