Ti and Zr complexes of ferrocenyl amidinates

Abstract

Preparation of a N-ferrocenyl-amidinate complex was achieved by employing (TMEDA)Li[(CpFeC(5)H(4))NC(Ph)NSiMe(3)] (1) to prepare Cp*Zr[(CpFeC(5)H(4))NC(Ph)NSiMe(3)]Cl(2) (2). Complex 2 exhibited poor polymerization activity and thus a series of C-ferrocenyl bis(amidinate) complexes of the type M(L)(2)Cl(2) (M = Zr, 4; M = Ti, 5; L = (CyNC(CpFeC(5)H(4))NCy) were synthesized via reaction of ferrocenyl-amidine, H(L) and M(NMe(2))(2)Cl(2) (M = Ti, Zr·2THF). Half sandwich mono(amidinate) complexes, Cp'ZrLCl(2) (Cp' = Cp, 7; Cp' = Cp*, 8), were prepared by the reaction of Cp'ZrCl(3) with Li(L) and subsequently alkylated to give M(L)(2)Me(2) (M = Zr, 9; M = Ti, 11), CpZr(L)(CH(2)Ph)(2) (12) and Cp*Zr(L)Me(2) (10) with the appropriate alkylating agent. Abstraction of a methyl group from 7 with B(C(6)F(5))(3) and [Ph(3)C][B(C(6)F(5))(4)] proceeded cleanly to give [{CyNC(CpFeC(5)H(4))NCy}(2)ZrMe][MeB(C(6)F(5))(3)] 13 and [{CyNC(CpFeC(5)H(4))NCy}(2)ZrMe][B(C(6)F(5))(4)] 14, respectively. Similarly, the analogous CpZr and Cp*Zr derivatives LZr{CyNC(CpFeC(5)H(4))NCy}CH(2)Ph] [PhCH(2)B(C(6)F(5))(3)] L = Cp 15, Cp* 17 and [LZr{CyNC(CpFeC(5)H(4))NCy}CH(2)Ph][B(C(6)F(5))(4)] L = Cp 16, Cp* 18 were prepared. Cyclic voltammetry studies on the metal complexes containing ferrocenyl-amidinates reveal quasi reversible oxidation and reduction waves for the ferrocene/ferrocenium couple. The dichloride complexes (4-8) activated with MAO and dialkyl complexes (9,10) activated with B(C(6)F(5))(3) and [Ph(3)C][B(C(6)F(5))(4)] showed low ethylene polymerization activities.

A Novel Diiminopyridine Ligand Containing Redox Active Co(III) Mixed Sandwich Complexes

“…The reaction mixture was then centrifuged, washed with THF (3 × 10 mL) and CH 2 Cl 2 (3 × 10 mL), and dried in vacuo to give a fine light orange-red powder (0. (7) 73.78 (15) 68.81 (14) 68.71 (7) 67.72(7) N(2)−M(1)−N (3) 73.99 (16) 73.28 (7) 73.63 (15) 68.82 (14) 68.79 (7) 69.17(7) N(1)−M(1)−N (3) 147.08 (16) 145.99 (7) 146.35 (14) 136.44 (14) 136.87 (7) 133.97(7) …”

“…The ligand (15) was treated separately with either GeCl 2 ·dioxane or SnCl 2 in a 1:2 stoichiometric ratio in THF at room temperature. After 5 min the initially red solutions turned dark green-blue.…”

Amidine- and amidinate-functionalised N-heterocyclic carbene complexes of silver and chromium

“…15,16 The versatility of the amidine ligands has further been expanded thanks to their tuning scope by relatively straightforward and adaptable synthetic methods and the additional functionalisation of the amidine core by the attachment of pendant arms bearing classical donor groups at the amine terminus (A in Scheme 1) such as ω-dialkylamino-alkyl-, β-hydroxyalkyl-, β-(2-pyridyl)ethyl-, 2-lutidinyl-, ferrocenyl-. [17][18][19][20][21][22] Less frequently and relatively recently pendant groups have been attached to the amidine and amidinato functionality at the C atom of the amidine using a flexible linker (this excludes guanidines and phosphaguanidines) as shown in B, Scheme 1. Known examples of L 2 donors include 2-pyridyl-, 23 2-furyl-, 24 carboranyl-, 25 and phenoxy- 26 groups, giving rise to tridentate or 'heteroscorpionate' ligand architectures, 27 with potential dynamic behaviour, hemilability and denticity changes.…”

Investigating a Redox Active Samarium Complex in Catalytic Reactions

“…Despite the broad scope of substituents, there are only few known examples of amidinates functionalized by a ferrocenyl entity in the backbone (Scheme 1, A–C ) [15–18] . The corresponding complexes are mainly transitional metal derivatives, [15–16,19] though there is one report including rare earth elements [20] . In most of these complexes cyclohexyl substituents are bound to the nitrogen atoms of the amidinate function (Scheme 1, A ).…”