Synthese und Struktur des ersten dimeren Iminoalans mit einem Al₂N₂‐Heterocyclus

Abstract

Ein nahezu ideal planarer AI2N2‐Ring als zentrale Einheit und den niedrigsten Oligomerisationsgrad der Verbindungsklasse weist das dimere Iminoalan 1 auf, das aus (Cp*Al)4 und Me3SiN3 entsteht. Daß sich kein Heterocuban bildet, ist auf den sterischen Anspruch der Cp*‐ und SiMe3‐Gruppen zurückzuführen.

Mechanistic Insight into the NN Bond‐Cleavage of Azo‐Compounds that was Induced by an AlAl‐bonded Compound [L2−AlIIAlIIL2−]

“…The average AlÀN bond-lengths for the fourmembered Al 2 N 2 rings was 1.832 , and the exocyclic AlÀN bonds (to the a-diimine ligand L) were much longer (average 1.928 ). These bond-lengths were comparable to the reported values, such as 1.824 in the four-membered ring of [(Mes*AlNPh) 2 ] (Mes* = 2,4,6-(tBu) 3 C 6 H 2 ), [24b] 1.970-2.013 in [Cp*AlA C H T U N G T R E N N U N G (m-NH(C 6 H 2 -4,6-Me 2 -2-CH 2 ))], [26] and 1.804 (average) in [CpAlN(2,6-iPr 2 C 6 H 3 )] 2 . [27] As in typical Al 2 N 2 rings, [24] the endocyclic N-Al-N angles (average 86.368) in compounds 2-5 were smaller than the Al-N-Al angles (average 92.038).…”

Synthesis and Reactivity Tetrahedral Clusters Containing of the Monovalent Elements Aluminium, Gallium, Indium, and Thallium

“…The compound (Cp*Al) 3 SB2 was formed, of which the crystal structure could not be determined up to now [49], It was supposed that the molecular structure consists of a trigonal bipyramide with the Al atoms in the equatorial plane. Mesitylazide gave a four-membered A1 2 N 2 heterocycle and by C-H activation the insertion of aluminium into C-H bonds of the methyl subsituents of the mesityl groups [52]. The alkylgallium(I) and alkylindium(I) compounds gave different products on the reaction with white phosphorus, of which up to now only the structure of the gallium derivative has been determined by X-ray methods (Equation 16) [43], It can be described by the insertion of alkylgallium groups in three P-P bonds of the initial P 4 tetrahedron.…”

“…The alkylgallium(I) and alkylindium(I) compounds gave different products on the reaction with white phosphorus, of which up to now only the structure of the gallium derivative has been determined by X-ray methods (Equation 16) [43], It can be described by the insertion of alkylgallium groups in three P-P bonds of the initial P 4 tetrahedron. 4 Synthesis and Reactivity ofTetrahedral Clusters Containing the Monovalent Elements Aluminium, Each nitrogen atom of the heterocycle is attached to a Anther terminal aluminium atom, which has either two cyclopentadienyl or one cyclopentadienyl and one bis(trimethylsilyl)amido ligand ( Equation 17) [52], Sterically more shielded silyl azides gave the expected cyclic iminoalanes with A1 2 N 2 heterocycles bound to cyclopentadienyl and silyl groups [53], Reaction of (Cp*Al) 4 with diphenylsilicon difluoride yielded the insertion product of two cyclopentadienylaluminium fragments into the Si-F bonds [49]. Ga-C(SiMe 3 ) 3 r \ (AlCp*) 4 was further successfully reacted with azides.…”

Stable, Monomeric Imides of Aluminum and Gallium: Synthesis and Characterization of [{HC(MeCDippN)2}MN-2,6-Trip2C6H3] (M=Al or Ga; Dipp=2,6-iPr2C6H3; Trip=2,4,6-iPr3C6H2)

“…94 kcal mol −1 for isoelectronic acetylene),6 which are consistent with B−N triple bonding. In contrast, the lowest degree of association known for congeneric aluminum or gallium imides occurs in the dimers of the general formula (RMNR′) 2 (M=Al7–9 or Ga10) which have planar M 2 N 2 (M=Al or Ga) core structures. We now show that the reaction [Eq.…”

“…This increases the likelihood of association. On the other hand, the reaction between a univalent metal species and an organoazide7, 11 (e.g., [Eq. (1)]) increases the metal coordination number, and leaves that of nitrogen unchanged, with the result that steric crowding becomes greater.…”