A structural study of dimethylaluminum carboxylato and hydrazonato complexes

Crystal structure of bis(μ2-tri-phenyl-acetato-κO:κO')bis(diisobutylaluminium)

Single crystals of the title compound, [Al(iBu)2(O2CCPh3)]2 or [Al2(C4H9)4(C20H15O2)2], have been formed in the reaction between tris-(tetra-hydro-furan)-tris-(tri-phenyl-acetato)-neodymium, [Nd(Ph3CCOO)3(THF)3], and triiso-butyl-aluminium, Al(iBu)3, in hexane followed by low-temperature crystallization (243 K) from the reaction mixture. The structure has triclinic (P ) symmetry at 120 K. The dimeric complex [Al(iBu)2(O2CCPh3-μ-κO:κO')]2 is located about an inversion centre. The tri-phenyl-acetate ligand displays a μ-κO:κO'-bridging coordination mode, leading to the formation of an octa-gonal Al2O4C2 core. The complex displays HPh⋯CPh inter-molecular inter-actions.

Structure investigations of group 13 organometallic carboxylates

The octet-compliant group 13 organometallics with highly polarized bonds in the metal coordination sphere exhibit a significant tendency to maximize their coordination number through the formation of adducts with a wide range of neutral donor ligands or by self-association to give aggregates containing tetrahedral and higher coordinated aluminium centres, and even in some cases molecular complexes equilibrate with ionic species of different coordination numbers of the metal centre. This work provides a comprehensive overview of the structural chemistry landscape of the group 13 carboxylates. Aside from a more systematic approach to the general structural chemistry of the title compounds, the structure investigations of [R₂M(μ-O₂CPh)]₂-type benzoate complexes (where M = B, Al and Ga) and their Lewis acid-base adducts [(R₂M)(μ-O₂CPh)(py-Me)] are reported. DFT calculations were also performed to obtain a more in-depth understanding of both the changes in the bonding of group 13 organometallic carboxylate adducts with a pyridine ligand.

Synthesis of the bulkym-terphenyl phenol Ar*OH (Ar* = C6H3-2,6-Mes2, Mes = 2,4,6-trimethylphenyl) and the preparation and structural characterization of several of its metal complexes

The bulky m-terphenyl phenol Ar*OH 1 (Ar* = C6H3-2,6-Mes2, Mes = 2,4,6-trimethylphenyl) was synthesized via the treatment of Ar*Li with nitrobenzene. The phenol 1 is prepared in modest to good yield using this method. Attempts were also made to prepare 1 through oxidation of the bulky boronic acid Ar*B(OH)2with Oxone®, but this reaction was not suitable for preparative-scale reactions. Side products of the reaction between Ar*Li and nitrobenzene were identified as Ar*[N(O)Ph] and [C6H5N(O)]2and were characterized by X-ray crystallography and EPR spectroscopy. A variety of main-group and transition-metal complexes of Ar*OH were prepared, namely Sn(OAr*)2, Ge(OAr*)2, [N(SiMe3)2]Ge(OAr*), [Me2Al(OAr*)]2, and Ti(NMe2)(OAr*)2. All compounds were characterized spectroscopically and most were studied by single-crystal X-ray diffraction as well.Key words: m-terphenyl, main-group compounds, X-ray crystallography, multinuclear NMR spectroscopy, EPR spectroscopy.

Flexible coordination of the carboxylate ligand in tin(ii) amides and a 1,3-diaza-2,4-distannacyclobutanediyl

A series of tin(II) amido complexes possessing m-terphenyl carboxylate ligands have been prepared. These complexes, namely [(Me(3)Si)(2)NSn(mu-O(2)CC(6)H(2)Ph(3))](2), [(Me(3)Si)(2)NSn(mu-O(2)CC(6)H(3)Mes(2))](2), and [(Me(3)Si)(2)NSn(mu-O(2)CC(6)H(2)Mes(2)Me)](2) [Mes = 2,4,6-trimethylphenyl], are the first structurally characterized examples of tin(II) carboxylate complexes exhibiting discrete Sn(2)O(4)C(2) heterocyclic cores. Initial reactivity studies led to the isolation of a 1,3-diaza-2,4-distannacyclobutanediyl, [(Mes(2)C(6)H(3)CO(2))Sn(mu-NSiMe(3))](2). This molecule possesses a Sn(2)N(2) heterocyclic core and it was crystallised as both the CH(2)Cl(2) and Et(2)O solvates. Although the tin atoms in this molecule have a formal oxidation state of 3+, preliminary computational studies on this molecule suggest that it is best described as a ground state singlet. Finally, the X-ray crystal structure of (CH(2)Cl)(Cl)Sn[N(SiMe(3))(2)](2), the product of oxidative addition of CH(2)Cl(2) to Sn[N(SiMe(3))(2)](2), is also presented herein.

From the reactivity of N-heterocyclic carbenes to new chemistry in ionic liquids

N-Heterocyclic carbenes have numerous applications in synthetic chemistry. We detail the reactivity and chemistry of these molecules including investigations into their reactions with small reagents, their use for the preparation of polarised azines and their potential application as NLO materials. The chemistry of imidazolium salts, which are related to NHCs by the addition of a proton, is also discussed. New chemistry for ionic liquids is also revealed.