The formation of adducts of tris(pentafluorophenyl)borane with strongly coordinating anions such as CN(-) and [M(CN)(4)](2)(-) (M = Ni, Pd) is a synthetically facile route to the bulky, very weakly coordinating anions [CN[B(C(6)F(5))(3)](2)](-) and [M[CNB(C(6)F(5))(3)](4)](2-) which are isolated as stable NHMe(2)Ph(+) and CPh(3)(+) salts. The crystal structures of [CPh(3)][CN[B(C(6)F(5))(3)](2)] (1), [CPh(3)][ClB(C(6)F(5))(3)] (2), [NHMe(2)Ph](2)[Ni[CNB(C(6)F(5))(3)](4)].2Me(2)CO (4b.2Me(2)CO), [CPh(3)](2)[Ni[CNB(C(6)F(5))(3)](4)].2CH(2)Cl(2) (4c.2CH(2)Cl(2)), and [CPh(3)](2)[Pd[CNB(C(6)F(5))(3)](4)].2CH(2)Cl(2) (5c.2CH(2)Cl(2)) are reported. The CN stretching frequencies in 4 and 5 are shifted by approximately 110 cm(-1) to higher wavenumbers compared to the parent tetracyano complexes in aqueous solution, although the M-C and C-N distances show no significant change on B(C(6)F(5))(3) coordination. Zirconocene dimethyl complexes L(2)ZrMe(2) [L(2) = Cp(2), SBI = rac-Me(2)Si(Ind)(2)] react with 1, 4c or 5c in benzene solution at 20 degrees C to give the salts of binuclear methyl-bridged cations, [(L(2)ZrMe)(2)(mu-Me)][CN[B(C(6)F(5))(3)](2)] and [(L(2)ZrMe)(2)(mu-Me)](2)[M[CNB(C(6)F(5))(3)](4)]. The reactivity of these species in solution was studied in comparison with the known [[(SBI)ZrMe](2)(mu-Me)][B(C(6)F(5))(4)]. While the latter reacts with excess [CPh(3)][B(C(6)F(5))(4)] in benzene to give the mononuclear ion pair [(SBI)ZrMe(+).B(C(6)F(5))(4)(-)] in a pseudo-first-order reaction, k = 3 x 10(-4) s(-1), [(L(2)ZrMe)(2)(mu-Me)][CN[B(C(6)F(5))(3)](2)] reacts to give a mixture of L(2)ZrMe(mu-Me)B(C(6)F(5))(3) and L(2)ZrMe(mu-NC)B(C(6)F(5))(3). Recrystallization of [Cp' '(2)Zr(mu-Me)(2)AlMe(2)][CN[B(C(6)F(5))(3)](2)] affords Cp' '(2)ZrMe(mu-NC)B(C(6)F(5))(3) 6, the X-ray structure of which is reported. The stability of [(L(2)ZrMe)(2)(mu-Me)](+)X(-) decreases in the order X = [B(C(6)F(5))(4)] > [M[CNB(C(6)F(5))(3)](4)] > [CN[B(C(6)F(5))(3)](2)] and increases strongly with the steric bulk of L(2) = Cp(2) << SBI. Activation of (SBI)ZrMe(2) by 1 in the presence of AlBu(i)(3) gives extremely active ethene polymerization catalysts. Polymerization studies at 1-7 bar monomer pressure suggest that these, and by implication most other highly active ethene polymerization catalysts, are strongly mass-transport limited. By contrast, monitoring propene polymerization activities with the systems (SBI)ZrMe(2)/1/AlBu(i)(3) and CGCTiMe(2)/1/AlBu(i)(3) at 20 degrees C as a function of catalyst concentration demonstrates that in these cases mass-transport limitation is absent up to [metal] approximately 2 x 10(-5) mol L(-1). Propene polymerization activities decrease in the order [CN[B(C(6)F(5))(3)](2)](-) > [B(C(6)F(5))(4)](-) > [M[CNB(C(6)F(5))(3)](4)](2-) >> [MeB(C(6)F(5))(3)](-), with differences in activation barriers relative to [CN[B(C(6)F(5))(3)](2)](-) of DeltaDeltaG = 1.1 (B(C(6)F(5))(4)(-)), 4.1 (Ni[CNB(C(6)F(5))(3)](4)(2-)) and 10.7-12.8 kJ mol(-)(1) (MeB(C(6)F(5))(3)(-)). The data suggest that even in the case of very bu...

The new bis(imino)pyrrole ligand 2,5-C4H2NH(CH==NC6H3Pri2)2 (HL1) reacts with Zr(NMe2)4 to give the 1:1 complex (L1)Zr(NMe2)3 (1), whereas the mono(imino)pyrrole 2-C4H3NH(CH==NC6H3Pri2) (HL2) substitutes two amido ligands to give (L2)2Zr(NMe2)2 (2). The lithium salt LiL1 reacts with ZrCl4 to give (L1)ZrCl2(µ-Cl)2Li(OEt2)2 (3), while the reaction of LiL2 with ZrCl4 or treating 2 with Me3SiCl gives (L2)2ZrCl2. Iron(II) chloride reacts with LiL1 to afford the bis(ligand) complex Fe(L1)2 (5), while only one pyrrolato ligand is incorporated on reacting LiL1 with CoCl2(thf) to give [Li(thf)4][CoCl2L1] (6a). On warming, 6a readily loses thf to give [Li(thf)2][CoCl2L1] (6b). By contrast, LiL2 reacts with CoCl2 and NiCl2 to give the halide-free complexes Co(L2)2 and Ni(L2)2, respectively. The crystal structures of HL1 and complexes 1, 2 and 5 are reported. In all cases the potentially tridentate ligand L1 is two-coordinate. Mixtures of the halide-free bis(ligand) complexes with methylaluminoxane do not show any activity for ethene polymerisation; however, 3 and 4 catalyse the polymerisation of ethene, while 6 has moderate activity for the oligomerisation of ethene and propene to linear and branched products

Reaction between ZnR2 and [H(OEt 2 ) 2 ][B(C 6 F 5 ) 4 ] in ether leads to the salts [RZn(OEt 2 ) 3 ]-[B(C 6 F 5 ) 4 ], while mixtures of ZnR 2 (R ) Me, Et) and B(C 6 F 5 ) 3 in toluene-d 8 undergo facile alkyl/C 6 F 5 group exchange to give Zn(C 6 F 5 ) 2 ‚(toluene). Mixtures of ZnR 2 and B(C 6 F 5 ) 3 in hydrocarbon/diethyl ether solvent mixtures react with alkyl transfer to afford the ion pairs [RZn(OEt 2 ) 3 ][RB(C 6 F 5 ) 3 ], whereas the reaction of ZnEt 2 with [Ph 3 C][B(C 6 F 5 ) 4 ] in toluene-d 8 proceeds with β-H abstraction to give ethene and Ph 3 CH, with the subsequent rapid formation of Zn(C 6 F 5 ) 2 .