Dative Au→Al Interactions: Crystallographic Characterization and Computational Analysis

Abstract

Hitherto unknown Au→Al interactions have been evidenced upon coordination of the geminal phosphorus-aluminum Lewis pair Mes2 PC(=CHPh)AltBu2 (Mes=2,4,6-trimethylphenyl). Four different gold(I) complexes featuring alkyl (Me), aryl (Ph, C6F5), and alkynyl (C≡CPh) co-ligands have been prepared. X-ray diffraction analyses show that P→Au→Al bridging coordination induces noticeable bending of the ligand (the PCAl bond angle shrinks by 13°). This new type of transition metal→Lewis acid interaction has been analyzed by DFT calculations.

Evidence for genuine hydrogen bonding in gold(I) complexes

“…As reported herein, this strategy proved fruitful and enabled us to form and authenticate hydrogen-bonded gold(I) complexes. It is worthwhile to note the structural analogy existing between the target compounds and the Au complexes deriving from (P,B) and (P,Al) ambiphilic ligands we reported previously, in which the Lewis acid moiety coordinates as a σ-acceptor Z-type ligand, with Au acting as a Lewis base (34)(35)(36).…”

Cooperation between Transition Metals and Lewis Acids: A Way To Activate H2 and HE bonds

“…As apparent from spectroscopic and crystallographic data, the ensuing complex 3 features a significant Pt!B interaction, despite the strain associated with the small NPtB bite angle (668). [11] The presence of a single donor buttress in the ligand increases the flexibility towards incoming substrates and 3 was found to irreversibly activate H 2 (1 atm, RT). The C À H bond of phenylacetylene is also readily cleaved to give an original hydride complex in which the PhCC moiety is transferred to B and side-on coordinated to platinum.…”

Strongly Polarized Iridiumδ−–Aluminumδ+ Pairs: Unconventional Reactivity Patterns Including CO2 Cooperative Reductive Cleavage

“…In the case of late transition metals, which feature higher electronegativities in comparison to Al (1.61 on the Pauling scale), the binding of hard Al-based ligands, acting as σ-acceptors, can reverse the classical ligand→TM bonding situation and confer unique electronic properties to the resulting complexes, which opens up attractive opportunities for cooperative reactivity. Although a range of Z-type metal–alane L n M–AlX 3 Lewis adducts are known, − complexes featuring X-type metal–aluminum L n M–AlX 2 (L′ m ) ( m = 0, 1) covalent bonds are much more rare (Scheme ) and their reactivity remains almost unexplored. − …”