Abstract
The recent discovery of metal−metal bonding and valence
delocalization in the dilanthanide complexes (CpiPr5)2Ln2I3 (CpiPr5 = pentaisopro-
pylcyclopentadienyl; Ln = Y, Gd, Tb, Dy) opened up the prospect of harnessing the
4fn5dz21 electron configurations of non-traditional divalent lanthanide ions to access
molecules with novel bonding motifs and magnetism. Here, we report the trinuclear
mixed-valence clusters (CpiPr5)3Ln3H3I2 (1-Ln, Ln = Y, Gd), which were synthesized
via potassium graphite reduction of the trivalent clusters (CpiPr5)3Ln3H3I3.
Structural, computational, and spectroscopic analyses support valence delocalization
in 1-Ln resulting from a three-center, one-electron σ bond formed from the 4dz2 and
5dz2 orbitals on Y and Gd, respectively. Dc magnetic susceptibility data obtained for
1-Gd reveal that valence delocalization engenders strong parallel alignment of the σ-
bonding electron and the 4f electrons of each gadolinium center to afford a high-spin
ground state of S = 11. Notably, this represents the first clear instance of metal−
metal bonding in a molecular trilanthanide complex, and the large spin−spin exchange constant of J = 168(1) cm−1 determined for
1-Gd is only the second largest coupling constant characterized to date for a molecular lanthanide compound.
delocalization in the dilanthanide complexes (CpiPr5)2Ln2I3 (CpiPr5 = pentaisopro-
pylcyclopentadienyl; Ln = Y, Gd, Tb, Dy) opened up the prospect of harnessing the
4fn5dz21 electron configurations of non-traditional divalent lanthanide ions to access
molecules with novel bonding motifs and magnetism. Here, we report the trinuclear
mixed-valence clusters (CpiPr5)3Ln3H3I2 (1-Ln, Ln = Y, Gd), which were synthesized
via potassium graphite reduction of the trivalent clusters (CpiPr5)3Ln3H3I3.
Structural, computational, and spectroscopic analyses support valence delocalization
in 1-Ln resulting from a three-center, one-electron σ bond formed from the 4dz2 and
5dz2 orbitals on Y and Gd, respectively. Dc magnetic susceptibility data obtained for
1-Gd reveal that valence delocalization engenders strong parallel alignment of the σ-
bonding electron and the 4f electrons of each gadolinium center to afford a high-spin
ground state of S = 11. Notably, this represents the first clear instance of metal−
metal bonding in a molecular trilanthanide complex, and the large spin−spin exchange constant of J = 168(1) cm−1 determined for
1-Gd is only the second largest coupling constant characterized to date for a molecular lanthanide compound.
Original language | English |
---|---|
Pages (from-to) | 8996-9002 |
Journal | Journal of the American Chemical Society |
Volume | 145 |
Early online date | 17 Apr 2023 |
DOIs | |
Publication status | Published - 26 Apr 2023 |