Two pairs of chiral lanthanide–oxo clusters Ln14 induced by amino acid derivatives?

CrystEngComm Pub Date: 2021-08-24 DOI: 10.1039/D1CE00948F

Abstract

Two pairs of pure enantiomers of high-nuclearity chiral lanthanide–oxo clusters with the formulas [Y14(L)16(μ3-OH)16(H2O)20]·(ClO4)10·xH2O (x ≈ 55; L = L-L? for L-Y14; L = D-L? for D-Y14) and [Dy14(L)16(μ3-OH)16(H2O)20]·(ClO4)10·xH2O (x ≈ 67; L = L-L? for L-Dy14; L = D-L? for D-Dy14) were prepared in the presence of chiral ligands N-acetyl-L-alanine (L-HL) and N-acetyl-D-alanine (D-HL). Structural analysis showed that four cubane-like units as building blocks sharing vertices formed the lanthanide–oxo cluster unit {(ClO4)2@[Y12(μ3-OH)16]}18+ with two ClO4? as anion templates. The remaining Y3+ ions were connected to the opposite position of {(ClO4)2@[Y12(μ3-OH)16]}18+ through four L-L?, respectively. High-resolution electrospray ionization mass spectrometry (HRESI-MS) captured the signals of the cluster fragment {Y12(OH)16?x(O)x} (x = 4, 5, 6, 7, 8) and the unbroken dimer of {Y12(L-L)12(OH)16?x(O)x}2 (x = 4, 5, 12) from L-Y14 in a mixed solution of methanol and dichloromethane, suggesting that {Ln12(OH)16?x(O)x} is a stable cluster unit that could be further assembled into higher-nuclearity lanthanide–oxo clusters in solution. The solid-state circular dichroism (CD) spectra of compounds L-Y14/D-Y14 and L-Dy14/D-Dy14 displayed mirror symmetry effects in the range of 220–250 nm. The study of magnetic properties showed that L-Dy14 had a weak antiferromagnetic interaction and displayed SMM-like behavior in the absence of a dc field.

Graphical abstract: Two pairs of chiral lanthanide–oxo clusters Ln14 induced by amino acid derivatives
Recommended Literature