AlCp* as a Directing Ligand: CH and SiH Bond Activation at the Reactive Intermediate [Ni(AlCp*)₃]

The reaction of the group-13 alkyls ER3 (E=Al, Ga, In; R=CH2t-Bu, CH2 SiMe3) with the platinum-complex [(dcpe)Pt(H)(CH2t-Bu)]

“…This kind of transition metal aluminium chemistry holds promise for even more unusual observations, as the structures of [M(AlCp * ) 5 ] (M = Fe, Ru) [13] again turned out to exhibit more complexity as initially thought: Two C-H bonds of the methyl groups of the Cp * -ligands are activated and the coordination sphere around the metal centres contain only three unchanged Al I Cp * ligands besides two Al III centers being linked to M by hydride M-H-Al bridges in addition to M-Al donor acceptor bonds. This situation appears to be quite similar to the complex [(Cp * Al) 3 Ni(l-H)Al(g 1 Cp * )(Ph)] mentioned above [12]. In addition, we recently found a related and intriguing example of C-C bond activation most likely taking place at the low valent main group center E (Al, Ga) rather than involving directly the transition metal center in the case of the rearrangement of [Cp * Rh(CH 3 ) 2 (ECp * )] into the zwitterionic rhodenocenium/gallanate complexes [Cp * Rh{g 5 -C 5 Me 4 (GaMe 3 )}] [14].…”

“…This situation is also nicely illustrated by the existence of the homoleptic complexes [Pt(ER) 4 [11]. Interestingly, it was found, that low coordinated congeners [Ni(AlCp * ) 3 ], which are thought to exist as intermediates in the course of the synthesis of the saturated [Ni(AlCp * ) 4 ], show interesting reactivity and activate aromatic C-H bonds and Si-H bonds, for example [12]. This kind of transition metal aluminium chemistry holds promise for even more unusual observations, as the structures of [M(AlCp * ) 5 ] (M = Fe, Ru) [13] again turned out to exhibit more complexity as initially thought: Two C-H bonds of the methyl groups of the Cp * -ligands are activated and the coordination sphere around the metal centres contain only three unchanged Al I Cp * ligands besides two Al III centers being linked to M by hydride M-H-Al bridges in addition to M-Al donor acceptor bonds.…”

Transition Metal Chemistry of Low Valent Group 13 Organyls

“…Indeed, the electronically and sterically saturated monomeric complexes [M(ECp*) 4 ] turn out to be completely kinetically inert. [39] In sharp contrast, however, the related unsaturated cluster…”

“…3 (AlCp*Ph)] (11) in almost quantitative yields (Scheme 9). [39] Scheme 9. Synthesis of 7c, 11 and 12 As shown by NMR spectroscopy, the C 6 H 6 in 11 is not exchanged by C 6 Similarly, in the presence of HSiEt 3 (Scheme 9), the formation of the hydrosilyl complex [Ni(AlCp*) 3 [42] The solid-state structure of 13 indeed exhibits a central iron atom in a distorted trigonal bipyramidal coordination environment.…”

Der Mackay‐Cluster [Cu43Al12](Cp*)12: Ein offenschaliges 67‐Elektronen‐Superatom mit metallähnlicher elektronischer Struktur

“…[20] Während die niedrigere Oberflächenenergie von Al im Vergleich zu Cu fürl etzteres verantwortlich gemacht wurde,w ird im Fall von 1 die symmetrische Anordnung der Aluminiumatome sicherlich stark durch den sterischen Anspruch des Al-gebundenen Cp*-Liganden beeinflusst. -Abstand von 1.923 liegt im erwarteten Bereich [24][25][26] und ist nur wenig länger als im kleineren Cluster [Cu 6 (AlCp*) 6 (N= CHPh)H 3 ]. Diese Werte sind den typischen d Cu-Al -Abständen in den intermetallischen Festkçrper-Referenzverbindungen CuAl 2 (2.587(4) ) [21] und Cu 9 Al 4 (2.468(2)-2.737(3)) ähnlich.…”