Planar Tetracoordinate Carbon Atoms in M 4 C Square Sheets (M = Ni, Pd, and Pt) Sandwiched between the Large π‐Coordinating Ligands [C 8 H 8 ] 2– and [C 9 H 9 ] –

Abstract

Using the strategy of transition metal coordination together with that of large π-coordinating ligand complexation for planar tetracoordinate carbon (ptC) atoms, we present in this work a systematical DFT investigation on the possibility of ptC centers in M 4 C square sheets sandwiched in [C n H n ]M 4 C[C n' H n' ] complexes (M = Ni, Pd, Pt; n, n' = 8, 9) with the planar π-coordinating ligands [C 8 H 8 ] 2― and [C 9 H 9 ] ― . Introduction of a ptC center into an M 4 square sheet to form four effective ptC-M bonds helped to stabilize the [C n H n ]M 4 C[C n' H n' ] complexes thermodynamically, and the π-coordinating [C 8 H 8 ] 2― and [C 9 H 9 ] ― ligands were found to match the M 4 C middle decks both geometrically and electronically. Planar tetracoordinate boron (ptB) and nitrogen (ptN) behave similarly to ptC in these sandwich structures. These model sandwich complexes invite experimental syntheses and characterizations in order to open up a new area in coordination chemistry for planar tetracoordinate carbon and other non-metal atoms.