Transition metal complexes are widely applied in the physical and biological sciences. They play pivotal roles in aspects of catalysis, synthesis, materials science, photophysics and bioinorganic chemistry. Our understanding of transition metal complexes originates from Alfred Werner's realisation that their three-dimensional shape influences their properties and reactivity. 1 The intrinsic link between shape and electronic structure is now firmly underpinned by molecular orbital theory. 2-5 Despite over a century of advances in this field, transition metal complexes remain limited to a handful of well understood geometries. Archetypal geometries for six-coordinate transition metals are octahedral and trigonal prismatic. Although deviations from ideal bond angles and lengths are common, 6 alternative parent geometries are staggeringly rare. 7 Hexagonal planar transition metals are restricted to those found in condensed metallic phases, 8 the hexagonal pores of coordination polymers, 9 or clusters containing more than one transition metal in close proximity. 10,11 Although [Ni(P t Bu)6] could be assigned as a hexagonal planar complex, 12,13 a molecular orbital analysis ultimately led to the conclusion that it is best described as a 16electron complex with a trigonal planar geometry. 14 Here we report the isolation and structural characterisation of the first simple coordination complex in which six ligands form bonds with a central transition metal in a hexagonal planar arrangement. The discovery has the potential to open up new design principles and new ways of thinking about transition metal complexes which could impact multiple fields of science.
The reactions of a series of β-diketiminate stabilised aluminium dihydrides with ruthenium bis(phosphine), palladium bis(phosphine) and palladium cyclopentadienyl complexes is reported.
New heterometallic hydride complexes that involve the addition of {Mg−H} and {Zn−H} bonds to group 10 transition metals (Pd, Pt) are reported. The side‐on coordination of a single {Mg−H} to Pd forms a well‐defined σ‐complex. In contrast, addition of three {Mg−H} or {Zn−H} bonds to Pd or Pt results in the formation of planar complexes with subtly different geometries. We compare their structures through experiment (X‐ray diffraction, neutron diffraction, multinuclear NMR), computational methods (DFT, QTAIM, NCIPlot), and theoretical analysis (MO diagram, Walsh diagram). These species can be described as snapshots along a continuum of bonding between ideal trigonal planar and hexagonal planar geometries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.