Bidentate forms of β-triketimines: syntheses, characterization and outstanding performance of enamine-diimine cobalt complexes in isoprene polymerization.

New cationic enamine-β-diimine cobalt complex [LCoBr·THF][BArF] () and its neutral analogue [LCoBr2] () where L = [(2,4,6-Me3-C6H2)NHCMe[double bond, length as m-dash]C{CMe[double bond, length as m-dash](N-2,4,6-Me3(C6H2))}2] and BArF(-) = [{3,5-(CF3)2C6H3}4B](-), were synthesised and then characterized by single-crystal X-ray diffraction, MALDI-MS, IR and elemental analysis. These complexes, the first examples reported where putatively tridentate β-triketimines prefer a bidentate coordination mode, were examined as catalysts for the polymerization of isoprene, activated by diethylaluminium chloride (DEAC) or ethylaluminium sesquichloride (EASC). The weakly coordinating BArF anion in strongly improved activity in comparison to .

Thallophilic Tl(i)-Tl(i) contacts mediated by Tl-aryl interactions. A computational study.

A computational study is presented of a complex of thallium with a neutral β-triketimine ligand which was found to form dimers with close Tl-Tl interactions. Single point energies, using the crystallographic structures, suggest that the system is bound only when BArF counter ions are included in the calculations. Energy decomposition analysis of the system was carried out in order to investigate the nature of the bonding.

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene.

Three β-triketimine ligands, (L(1): [CH{CMeN(2,4,6-Me3-C6H2)}2C(CMe3N(2-MeO-C6H4)], L(2): [CH{CMeN(2,4-Me2-C6H3)}2C(CMe3N(2-MeO-C6H4)] and L(3): [CH{CMeN(2-Me-C6H4)}2C(CMe3N(2-MeO-C6H4)]), were synthesized and then characterized by (1)H and (13)C{(1)H} NMR spectroscopy, elemental analysis and electrospray (ES) MS. β-triketimine cobalt(ii) complexes were then prepared by the interaction of cobalt(ii) bromide with L(1-3) in the presence of NaBArF (BArF = [{3,5-(CF3)2-C6H3}4B](-) ). Five-coordinate dimeric bromide-bridged species [(LCoμ-Br)2][BArF]2 were obtained.

Thallophilic interactions and Tl-aryl π-interactions are competitive with cation-cation repulsion: [LTl2L]2+ dications as salts of weakly co-ordinating anions.

The synthesis and characterization by single-crystal X-ray diffraction of two thallium salts of the non-co-ordinating anion [B{3,5-(CF3)2C6H3}4] are reported. They possess Tl-Tl contacts supported by Tl-aryl interaction. This cation association overcomes both electrostatic repulsion and cation-anion size and charge matching considerations in the [LTl2L](2+) dications so formed.

Light group 13 chloride diazadiene complexes: consequences of varying substituent bulk.

BCl3 cyclizes diazadiene (2,6-Pr(i)2C6H3NCH)2 1 through a dichloroborated intermediate [(2,6-Pr(i)2C6H3NCHCl)2BCl] to give, in polar aprotic solvents, a spontaneously dehyrochlorinated C-chloro diazaborole 4. In contrast, reaction of AlCl3 with 1 forms only acyclic mono- or di-adducts 5a/b and 6. Alkali metal reductions of gave mixtures of 4 and diazaborole [(2,6-Pr(i)2C6H3NCH)2BCl] 7.

A magnesium-bis(diaryldiketiminate) complex.

The 1:1 of reaction of dibutylmagnesium with the ligand 2-[(2-isopropylphenyl)amino]-4-[(2-isopropylphenyl)imino]pent-2-ene gives only the 1:2 metal-ligand compound bis[N,N'-bis(2-isopropylphenyl)pentane-2,4-diiminato]magnesium(II), [Mg(C(23)H(29)N(2))(2)], as an isolated solid. The coordination geometry about the Mg atom is distorted tetrahedral [N-Mg-N angles range from 90.73 (5) to 136.

Reversible C-C bond formation: solid state structure of the aldol-like addition product of adamantanone to a 1,5-diazapentadienyllithium, and its solution state retro-aldol dissociation.

Analysis of crystals of the lithium complex of the tripodal ligand formed upon addition of adamantanone to a 1,5 diazapentadienyllithium complex reveals a long C-C bond which ruptures upon dissolution in non-co-ordinating solvents.

Alkaline Earth Diazapentadienyl Compounds: Structure of [Ba {(C H )NC(Me)CHC(Me)N(C H )} {(SiMe ) N}].

Three different bonding modes in one molecule! The diazapentadienyl ligands in the title compound 1 adopt η ,η -N,N-chelating plus η -terminal, η η -N,N chelating plus η -bridging, and novel η -N plus η -1-aza-allyl bonding modes. R=cyclohexyl.