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Title: The Dialuminene Ar iPr8 AlAlAr iPr8 (Ar iPr8 =C 6 H‐2,6‐(C 6 H 2 ‐2,4,6‐ i Pr 3 ) 2 ‐3,5‐ i Pr 2 )
Abstract Careful analysis of the crystals formed in the reduction of AriPr8AlI2(AriPr8=C6H‐2,6‐(C6H2‐2,4,6‐iPr3)2‐3,5‐iPr2) with sodium on sodium chloride showed them to contain the long sought‐after dialuminene AriPr8AlAlAriPr8(1) that forms alongside the previously characterized alanediyl :AlAriPr8. The single crystal X‐ray structure of1revealed a nearly planar,trans‐bent C(ipso)AlAlC(ipso) core with an Al−Al distance of 2.648(2) Å. The molecular and electronic structure of1are consistent with an Al−Al double dative interaction augmented with diradical character and stabilized by dispersion interactions. Density functional theory calculations showed that the reactivity of :AlAriPr8with dihydrogen involves1, not :AlAriPr8, as the reactive species. In contrast, the reaction of :AlAriPr8with ethylene gave two products, the 1,4‐dialuminacyclohexane AriPr8Al(C2H4)2AlAriPr8(2) and the aluminacyclopentane AriPr8Al(C4H8) (3), that can both form from the aluminacyclopropane intermediate AriPr8Al(C2H4). Although the [2+2+2] cycloaddition of1with two equivalents of ethylene was also calculated to be exergonic, it is likely to be kinetically blocked by the numerous isopropyl substituents surrounding the Al−Al bond. Attempts to fine‐tune the steric bulk of the terphenyl ligand to allow stronger Al−Al bonding were unsuccessful, leading to the isolation of the sodium salt of a cyclotrialuminene, Na2[AlAriPr6]3(4), instead of AriPr6AlAlAriPr6.  more » « less
Award ID(s):
2152760
PAR ID:
10688646
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
VCH-Wiley
Date Published:
Journal Name:
Angewandte Chemie
Volume:
136
Issue:
52
ISSN:
0044-8249
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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