Bis(imino)quaterpyridine-bearing multimetallic late transition metal complexes as ethylene oligomerisation catalysts.

The bis(imino)quaterpyridine, 6,6'''-{(2,4,6-i-Pr(3)C(6)H(2))N=CMe}(2)-2,2':6',2'':6'',2'''-C(20)H(12)N(4) (L(tripp)), can be prepared in good yield by the condensation reaction of 6,6'''-bis(acetyl)quaterpyridine with 2,4,6-triisopropylaniline; the 2,6-diisopropylphenyl derivative 6,6'''-{(2,6-i-Pr(2)C(6)H(3))N=CMe}(2)-2,2':6',2'':6'',2'''-C(20)H(12)N(4) (L(dipp)) is also reported. Reactions of L(tripp) with 2.5 equivalents of MX(2) (MX(2) = CoCl(2), CoBr(2), (DME)(2)NiCl(2) and FeCl(2)) in n-butanol at 100 degrees C overnight results in self-assembly to form the paramagnetic salts [(L(tripp))M(2)X(3)](2)[MX(4)] [M = Co, X = Cl (1a); M = Co, X = Br (1b); M = Ni, X = Cl (2); M = Fe X = Cl (3)] in moderate yield.

Sterically variable dizinc complexes bearing bis(iminopyridyl)phenolate ligands: synthesis, structures and reactivity studies.

A series of chiral dizinc complexes of the type [(2,6-{ArN=C(Me)C5H3N}2C6H3O)Zn2(micro-Cl)Cl2] [Ar=2,6-i-Pr2C6H3 (), 2,6-Me2C6H3 (), 2,4,6-Me3-C6H2 (), 2,4-Me2C6H3 ()] can be conveniently prepared in good yield by the template reaction of 2,6-{O=C(Me)C5H3N}2C6H3OH with an excess of the corresponding aniline and two equivalents of zinc dichloride in n-BuOH at elevated temperature. Alternatively, the pro-ligands, 2,6-{(ArN=C(Me)C5H3N}2C6H3OH [Ar=2,6-i-Pr2C6H3 (L1-H), 2,6-Me2C6H3 (L2-H), 2,4,6-Me3C6H2 (L3-H), 2,4-Me2C6H3 (L4-H)], can be isolated and then treated with two equivalents of zinc dichloride to afford . Interaction of with two equivalents of NaOAc in the presence of TlBF4 gives the diacetate-bridged salt [(L1)Zn2(micro-OAc)2](BF4) () while with Nadbm (dbm=dibenzoylmethanato) the bis(dbm)-chelated salt [(L1)Zn2(dbm)2](BF4) () is obtained.

Spacially confined M2 centers (M = Fe, Co, Ni, Zn) on a sterically bulky binucleating support: synthesis, structures and ethylene oligomerization studies.

Two new bulky aryl-bridged pyridyl-imine compartmental (pro)ligands, 2,6-{(2,6-i-Pr(2)C6H3)N=C(Me)C5H3N}2C6H3Y (Y = H L1, OH L2-H), have been prepared in moderate to good overall yields via a Stille-type cross-coupling approach. The molecular structure of L2-H reveals a transoid configuration within the pyridyl-imine units with a hydrogen-bonding interaction maintaining the phenol coplanar with one of the adjacent pyridine rings. The interaction of 2 equiv of MX2 with L1 in n-BuOH at 110 degrees C gives the binuclear complexes, [(L1)M2X4] (M = Fe, X = Cl (1a); M = Co, X = Cl (1b); M = Ni, X = Br (1c); M = Zn, X = Cl (1d)), in which the metal centers adopt distorted tetrahedral geometries and occupy the two pyridyl-imine cavities in L1.

Mono- vs. bi-metallic assembly on a bulky bis(imino)terpyridine framework: a combined experimental and theoretical study.

The bis(imino)terpyridine ligands, 6,6''-{(2,6-i-Pr2C6H3)N=CR}2-2,2':6',2''-C15H9N3 (R = H L1, Me L2), have been prepared in high yield from the condensation reaction of the corresponding carbonyl compound with two equivalents of 2,6-diisopropylaniline. The molecular structure of L2 reveals a transoid relationship between the imino and pyridyl nitrogen groups throughout the ligand framework. Treatment of aldimine-containing L1 with one equivalent or an excess of MX2 in n-BuOH at 110 degrees C gives the mononuclear five-coordinate complexes, [(L1)MX2] (M = Fe, X = Cl 1a; M = Ni, X = Br 1b; M = Zn, X = Cl 1c), in which the metal centre occupies the terpyridine cavity and the imino groups pendant.