Synthesen und Strukturen von Aluminium‐Fluor‐Sauerstoff‐Clustern

Abstract

Je nach Größe der Substituenten R und R′ erhält man beim Umkristallisieren von (2,6‐R2C6H3)[Si(R′)‐Me2]NAlF2 · THF nur die Ausgangsverbindungen zurück ‐ oder aber größere Cluster. Deren Ecken sind mit Aluminiumatomen, die Kanten mit Fluoratomen besetzt (Teil einer Clusterstruktur im Kristall siehe rechts). Im Zentrum des Tetrakishexaeders befindet sich, umgeben von sechs Aluminiumatomen, ein Sauerstoffatom; dieser Strukturtyp war bei Molekülverbindungen bisher nur von d‐ und f‐Elementen bekannt.magnified image

An Alternative Approach to Al2O2 Ring Systems by Unexpected Cleavage of Stable Al−F− and Si−O− Bonds

“…Reaction of TMA, DMAF, and DIBAH with (Me 3 Si) 2 O. In 1997 we reported on the cleavage of THF with aluminum difluorides RAlF 2 ; consequently, we investigated the cleavage of the silyl ether (Me 3 Si) 2 O with TMA and DMAF, respectively, but we were not successful in the cleavage of the strong Si−O bond. Both reactions were done with mixtures of Me 2 Al x ( x = Me, F) without any solvent under reflux (in the case of DMAF/(Me 3 Si) 2 O, for 36 h; in the case of TMA/(Me 3 Si) 2 O, for 14 days), but no reaction was observed in either the 29 Si NMR or the 1 H NMR spectra.…”

Synthesis and structural characterization of an unusual heptameric aluminum imide and the surface fluorination products of the Al7N7 and Al4C4N4 cores

“…The four shorter Al-Al edges are each bridged by a N atom, and every N atom is connected to another Al atom by a CH 2 group. Moreover every N atom À178.1 (2,6-Me 2 C 6 H 3 )N{Si(t-Bu)Me 2 }AlF 2 ÁTHF [14] À175.0 (n-Bu 4 N) 2 (PhPO 3 AlF 2 ) 2 [17] À180.0 (n-Bu 4 N) 2 (t-BuPO 3 AlF 2 ) 2 [17] À179.5 (n-Bu 4 N)(RMeAlF 2 ) (R ¼ Me) [18] À154.8 (n-Bu 4 N)(RMeAlF 2 ) (R ¼ (Me 3 Si) 3 C) [18] À145.9 (Me 4 N)(i-Bu 2 AlF 2 ) [19] À149.4 (Ph 4 P)(i-Bu 2 AlF 2 ) [19] À151.7 (1-AdCH 2 NAl) 7 [15], (n-Bu 4 N) 2 (PhPO 3 -AlF 2 ) 2 (1.659 Å ), (n-Bu 4 N) 2 (t-BuPO 3 AlF 2 ) 2 (1.666 Å ) [17]). A comparison of the 19 F NMR shifts of compounds having only terminal Al-F bonds is given in Table 4.…”

Playing the Keyboard of Fluorine Chemistry,

“…Treatment of [(Me 3 Si) 3 CAlF 2 ] 3 with 2,4,6-trimethylpyridine hydrogen fluoride results in the ring opening and the formation of [Me 3 C 5 H 2 NH] + [(Me 3 Si) 3 CAlF 3 ] - (Figure ), while the reaction of n -Bu 4 NHF 2 and AlMe 3 gives the stable difluoride [ n -Bu 4 N][AlMe 2 F 2 ] with elimination of methane. Presently we are investigating in general the reaction of an organometallic compound and a hydrogen difluoride salt to yield the corresponding organometallic difluoride anion 21 Plot of the cation [AlF 2 (THF) 4 ] + and the anion of [((Me 3 Si) 3 C) 2 Al 2 F 5 ] - .

22 Perspective view of the core of the aluminum−fluorine−oxygen cluster.

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“…In this sense we were interested in the preparation of fluorine complexes with weak and strong interactions . We thought to achieve this goal by assembling an organometallic fluoride cluster where the added metal ion is outside the core with no fluoride interactions.…”