A transition metal borylene
complex stabilized by a non-
carbonyl ligand set: formation
by spontaneous halide loss to
give an extremely short metal-
-boron bond (video).
(work by David Addy)
New sterically demanding ligand systems
In recent work we have been examining the synthesis and application of novel, highly sterically demanding amido ligands in both main group and transition metal chemistry. Related aryl ligands have been utilized to great effect in recent years in the stabilization of metal complexes containing low coordinate, unsaturated metal centres. Such compounds are of great interest, not only from a fundamental bonding perspective (e.g. quintuple bonds involving Cr), but also because of the potential for useful reactivity displayed, for example, by low coordinate transition metal cations.
We have been seeking to extend this approach to related N-donor systems, initially focusing on the 1,8-disubstituted carbazolyl ligand class, as easily synthesized alternatives to the very widely-used terphenyl ligands. Initial studies using the dichlorogallium complexes as probes of ligand bulk, imply that these systems offer an even more sterically protected pocket than their more celebrated terphenyl counterparts. More recently the bis- and tetra-tert-butylcarbazolyl frameworks have been used to give access to M(I) species (M = Ga, In, Tl), the structural and reaction chemistry of which are currently under investigation.
Sterically demanding ligands
(right) The polymeric structure of
solid tetra-tert-butylcarbazolyl indium(I).
New chemistry (video)
A mixed valence In(I)/In(II) system
Stabilized by amido ligands. Click
(work of Hassanatu Mansaray)