Aluminium alkyl and aryloxide complexes of pyrazine and bipyridines: synthesis and structure

Abstract

The reaction of AlMe(3) and [((t)Bu)(2)Al(micro-OPh)](2) with pyrazine (pyz), 4,4'-bipyridine (4-4'-bipy), 1,2-bis(4-pyridyl)ethane (bpetha) and 1,2-bis(4-pyridyl)ethylene (bpethe) yields (Me(3)Al)(2)(micro-pyz)(1), (Me(3)Al)(2)(micro-4,4'-bipy)(2), (Me(3)Al)(2)(micro-bpetha)(3), (Me(3)Al)(2)(micro-bipethe)(4), Al((t)Bu)(2)(OPh)(pyz)(5), [((t)Bu)(2)Al(OPh)](2)(micro-4,4-bipy)(6a), [((t)Bu)(2)Al(OPh)](2)(micro-bpetha)(7a), [((t)Bu)(2)Al(OPh)](2)(micro-bipethe)(8a). Compounds 1-4, 6a and 7a have been confirmed by X-ray crystallography. In solution compounds 1-4 undergo a rapid ligand-dissociation equilibrium resulting in a time-average spectrum in the (1)H NMR. In contrast, the solution equilibria for compounds 5-8a are sufficiently slow such that the mono-aluminium compounds may be observed by (1)H NMR spectroscopy: Al((t)Bu)(2)(OPh)(4,4-bipy)(6b), Al((t)Bu)(2)(OPh)(bpetha)(7b) and Al((t)Bu)(2)(OPh)(bpethe)(8b). The inability to isolate [((t)Bu)(2)Al(OPh)](2)(micro-pyz) and the relative stability of each complex is discussed with respect to the steric interactions across the bridging ligand (L) and the electronic effect on one Lewis acid-base interaction by the second Lewis acid-base interaction on the same ligand.

Electron‐Rich, Lewis Acidic Diborane Meets N‐Heterocyclic Aromatics: Formation and Electron Transfer in Cyclophane Boranes

“…Moreover, a dibora‐compound with the reduced form of this organic linker was synthesized (Figure b) . In addition, there are some further examples for complexes of heavier Group 13 homologues (Al, Ga, and In) with bipyridine and pyrazine that exhibit a high structural variety potentially useful for constructing for example, MOFs and other functional materials …”

“…[19,20] In addition, there are some furthere xamples for complexeso fh eavier Group 13 homologues( Al, Ga, and In) with bipyridine and pyrazine that exhibit ah ighs tructural varietyp otentially useful for constructing for example, MOFs and other functional materials. [21][22][23] Motivated by the resultsa nd promising properties of cyclophanes, we present herein the first representatives of an ew class of easily accessible viologen cyclophanes with cationic redox-active diborane linkersa nd investigate on af urtherm acrocycle based on pyrazine. This contributions hould extend the repertoire of known boracyclophanes and offer an alternative for possible applications as catalytically redox-active reaction centers.…”

AlMe3, GaMe3 and InMe3 Adducts of N,N‐Bis(2‐{pyrid‐2‐yl}ethyl)hydroxylaminato Rare‐Earth Metal Complexes and Their Molecular Dynamics

“…The N-Al bond can be compared to those in the trimethylaluminium-(4-dimethylaminopyridine) adduct with a value of 2.016(2) Å [27] or to the N,NЈ-bis(trimethylaluminium)-4,4Ј-bipyridine adduct with bond lengths of 2.032(2). [28] In complex 14 GaMe 3 was employed instead as Lewis acid leading to the corresponding coordination motif with bond lengths: O(1)-Ga(1) at 2.038(3) and N(3)-Ga (2) The same structural motif but with Sm and Al as the two underlying metals is realised in compound 16. The structural parameters are mostly analogous to those of compounds 13-15.…”

On-Surface Atom-by-Atom-Assembled Aluminum Binuclear Tetrabenzophenazine Organometallic Magnetic Complex

“…It shifts its central pyrazine slightly away from its original bridge site (see (Methyl)3)2-pyrazine. 13 On the Au(111) surface, the consequence of this intermediate oxidation state is that the Al2-molecule complex is magnetic as probed using the Kondo effect. Indeed, the analysis of the spin distribution on the Al2-complex (see Fig.…”