Alkali-Metal-Templated Assembly of Two High-Nuclearity Cobalt Clusters Based on Thiacalix[4]arene

Abstract

Two novel thiacalix[4]arene-based high-nuclea r i t y c o b a l t c l u s t e r s , [Na 2 Co 24 (BTC4A) 6 (PO 4 ) 6 (HCOO) 6 butylthiacalix[4]arene, DMC = N,N′-dimethylcarbamic acid anion, dma = dimethylamine), have been solvothermally prepared and structurally characterized. Compounds 1 and 2 are each capped by six Co 4 -BTC4A molecular building blocks (MBBs) and six phosphate linkers and other different auxiliary anions, possessing an eicositetranuclear Co 24 core templated by alkali-metal cations. In essence, compound 1 is templated by two Na + cations with an attractive interaction in the center of the core, while 2 is templated by one K + with a larger radius. Such differences "convert" an oval-shaped Co 24 disklike core in 1 to a circular core in 2. Interestingly, 2 contains both anionic and cationic KCo 24 cores, representing the largest cobalt aggregate salt reported, to the best of our knowledge. In addition, magnetic measurements of 1 and 2 were investigated, revealing the existence of antiferromagnetic interactions between the magnetic Co II centers.

Thiacalixarene-Supported Irregular Co26 and Ni28 High-Nuclearity Clusters with Pyridyl-Diphosphonates: Strategies to Create Active Metal Sites and Fabricate Multicomponent Materials

“…To achieve such a goal, auxiliary ligands with different coordination sites and asymmetry nature may facilitate assembly of PCCs with labile bonds. The 1-hydroxy-2-(3-pyridinyl)­ethylidene-1,1-diphosphonic acid (risedronic acid, H 5 L, Scheme b) has been proven to be an efficient multidentate ligand with diversified coordination modes and excellent coordination ability to metal ions due to its eight potential coordination sites. − It may be a good choice and convenient for the construction of calixarene-based PCCs with rich labile coordination bonds based on the following considerations: (i) N coordination site of pyridine ligands usually bond to metal ions in monodentate mode with an average coordination hindrance; − (ii) the phosphate/phosphonate ligands (two pairs for H 5 L) with three coordinatively active oxygen can capture more metal ions with various modes; ,− (iii) the hydroxyl site located in the middle of H 5 L is readily for binding additional metal sites; (iv) the high asymmetry nature of H 5 L. − …”

Constructing calixarene-supported high nuclearity Co27, Co28 and Ni18Na6 clusters with triazoles as co-bridges

“…16 Calixarenes, a kind of macrocyclic ligand with methylene/ heteroatom-bridging phenolic groups, have been documented to be effective multidentate ligands to build polynuclear clusters and cages. [17][18][19][20][21][22][23] Recently, a large number of polymetallic clusters based on calixarenes, especially thiacalix [4]arene, with interesting geometries and novel properties have been reported. 24,25 Such compounds can be constructed by simple calixarene assembly or combination of metal-calixarene units and small molecules.…”

Rare double spin canting antiferromagnetic behaviours in a [Co24] cluster

“…21,22 Therefore highnuclearity Co 2+ clusters are favorable for preparing magnetic materials, since these clusters have a high spin ground state and significant anisotropy which are two necessary conditions for clusters behaving as a single-molecule magnet (SMM). Until now, a large number of Co 2+ clusters have been reported, [21][22][23][24][25] but the nuclearity of complexes more than 20 is just a few, such as metallomacrocycle Co 24 , 26…”