Tris-{Hydridotris(1-pyrazolyl)borato}lanthanide Complexes: Synthesis, Spectroscopy, Crystal Structure and Bonding Properties

Abstract

Complexes of trivalent lanthanides (Ln) with the hydridotris(1-pyrazolyl)borato (Tp) ligand Ln[η3-HB(N2C3H3)3]3 (LnTp3) were subjected to a joint experimental–theoretical analysis. X-ray diffraction experiments have been performed on CeTp3, NdTp3, SmTp3, GdTp3, and TbTp3 in the nine-fold coordination and on DyTp3, HoTp3, ErTp3, TmTp3, YbTp3, and LuTp3 in the eight-fold coordination form. Density functional theory (DFT) calculations were carried out for all 15 LnTp3 complexes. They extended the X-ray diffraction data available on the LnTp3 compounds and facilitated a straightforward interpretation of trends in the structural parameters. As a result of the joint analysis, significant steric strain in the equatorial coordination sites of the nine-coordinate structures was recognized. Trends in the bonding properties were elucidated by energy decomposition and quantum theory of atoms in molecules (QTAIM) analysis of the electron density distribution. These results revealed the major electrostatic character of the Ln…Tp bonding and fine variation of charge transfer effects across the Ln row.

HERFD-XANES and RIXS Study on the Electronic Structure of Trivalent Lanthanides across a Series of Isostructural Compounds

“…Detailed structural and spectroscopic investigations have been carried out on LnTp 3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Tb, and Yb). 35 − 42 …”

“…The LnTp 3 compounds from La to Tb are nine-coordinated, while the compounds of the heavier ions (Dy to Lu) are eight-coordinated. Detailed structural and spectroscopic investigations have been carried out on LnTp 3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Tb, and Yb). − …”

Competing Metal–Ligand Interactions in Tris(cyclopentadienyl)-cyclohexylisonitrile Complexes of Trivalent Actinides and Lanthanides

“…Based on the anionic character of Cp, the M-Cp interactions were predominantly ionic. Accordingly, this interaction was governed by the M 3+ ionic radii [40] and resulted in a gradual decrease in the metal-ligand bond distances, as observed in numerous studies on series of Ln complexes [41][42][43][44][45][46], specifically those on Ln complexes with Cp-type ligands [47,48].…”

“…Based on the anionic character of Cp, the M-Cp interactions were predominantly ionic. Accordingly, this interaction was governed by the M 3+ ionic radii [40] and resulted in a gradual decrease in the metal-ligand bond distances, as observed in numerous studies on series of Ln complexes [41][42][43][44][45][46], specifically The metal-ligand distances were determined by the competing bonding interactions of the two types of ligands with the M 3+ ions. Based on the anionic character of Cp, the M-Cp interactions were predominantly ionic.…”

Tris(carbene)borates; alternatives to cyclopentadienyls in organolanthanide chemistry

“…1, an N 3donor that has a long history in f-block chemistry. 43,44 The C3 Fig. 1 Multidentate ligands with anionic borate backbones as potential replacements for carbocyclic anions such as cyclopentadienyl, Cp − .…”