Hexadecanuclear Mn^II₂Mn^III₁₄ Molecular Torus Built from in Situ Tandem Ligand Transformations

Abstract

14 (trz) 14 (thetach) 4 (μ 3 -O) 8 (H 2 O) 10 ](ClO 4 ) 6 (Mn16), containing two Mn II and 14 Mn III ions, is constructed from mixed in situ generated ligands, 1,2,3-triazole (Htrz) and 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane (H 3 thetach). Remarkably, both ligands were not initially added into the reaction system, and their formations involve the in situ ligand decomposition and subsequent condensation reactions. The core of Mn16 is an elongated torus comprised of eight Mn atoms and four [Mn 2 O 2 ] subunits bridged by oxo or alkoxide. The high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) of Mn16 dissolved in CH 3 CN indicates its structure remains intact as +3 and +4 species. Temperature and field dependent magnetization revealed predominantly antiferromagnetic exchange interactions within the cluster. The work provides one-pot synthesis of high-nuclearity manganese clusters using the ligands generated by in situ reactions in a tandem fashion.

A new twist on an old ligand: a [Mn16] double square wheel and a [Mn10] contorted wheel

“…The first, 16 in 1999, was the monomer [Cr(CO)3(LH3)] and the second, in 2019, an aesthetically pleasing [Mn16] complex in which the ligand was generated serendipitously in-situ. 17…”

A Frustrated [Mn18] Wheel-of-Wheels

“…A search of the Cambridge Structural Database (CSD) reveals just four hits in 3d transition metal chemistry. The first was the monomer [Cr(CO)3(LH3)], 15 the second an aesthetically pleasing [Mn16] complex in which the ligand was generated serendipitously in-situ, 16 and the third and fourth structurally related [Mn16] and [Mn10] square wheels. 17…”

Synthesis, Structures and Magnetic Properties of CuII and CoII Compounds Based on Asymmetric 5‐(1H‐Imidazole‐1‐yl)‐3‐pyridine Carboxylic Acid

“…[17][18][19] On the other hand, another important consideration in designing such materials is the nature of ligands, functional groups, donor atoms, and so on. [20][21][22][23][24] Despite the fact that various organic ligands have been studied as potential linker, the effective and facile method for the design of interesting magnetic compounds is still the appropriate choice of well-designed organic ligands as bridges or building block. In the present report, we select an asymmetric 5-(1H-imidazole-1-yl)-3-pyridine carboxylic acid (Himpc) as a potential linker due to the following structural features.…”

“…On the other hand, another important consideration in designing such materials is the nature of ligands, functional groups, donor atoms, and so on . Despite the fact that various organic ligands have been studied as potential linker, the effective and facile method for the design of interesting magnetic compounds is still the appropriate choice of well‐designed organic ligands as bridges or building block.…”