Ni₃ versus Ni₃₀: A Truncated Octahedron Metal–Organic Cage Constructed with [Ni₅(CN)₄]⁶⁺ Squares and Tripodal Tris‐tacn Ligands That are Large and Flexible

Abstract

Reactions of trinickel complex of tripodal tris-tacn ligand N(CH -m-C H -CH tacn) (L, tacn=1,4,7-triazacyclononane) in acetonitrile-methanol solution with and without phosphate led to two complexes of distinct nuclearities, [(Ni Cl) (CH OH) (HPO )L](PF ) (Ni , 1) and [(Ni (CN) (H O) Cl) L ]Cl (Ni , 2). Ligand L takes upward and downward conformation in the structure of 1 and 2, respectively. It is proposed that phosphate directs the upward conformation of Ni L to form 1. In the absence of phosphate, Ni L assembles with cyanide ions, which are formed by Ni-catalyzed C-CN bond cleavage of acetonitrile, to give a nano-sized Ni cage. Complex 2 represents a discrete truncated octahedron cage assembled with [Ni (CN) ] squares and large and flexible triangular ligands, which is scarcely observed for self-assembled metal-organic cages. The magnetic properties of 1 and 2 were examined, showing intriguing magnetic properties.

Merohedral icosahedral M48 (M = CoII, NiII) cage clusters supported by thiacalix[4]arene

“…For example, the Mn 84 torus can be formally built by alternating linear [Mn 3 O 4 ] and cubic [Mn 4 O 2 (OMe) 2 ] units;11 the record-setting Fe 64 cage consists of Fe 8 units linked by H 3 tea (triethanolamine) ligands,12 while the spheroidal Cu 36 cluster can be formally constructed from metal–organic units 13,14. The structural modularity of such PCCs suggests the possibility of assembling even larger polynuclear species by using preformed cluster building units in combination with various bridging ligands, in a stepwise fashion or formally from a one-pot reaction 15–17. Efforts along this line have indeed produced much success.…”

Carboxylate Bridge Controlled Formation of Tetra‐ and Pentanuclear Nickel(II) Complexes: Synthesis, Crystal Structure, Spectroscopy and Magnetic Properties

“…Recently, the synthesis and characterization of multinuclear complexes of 3d metal ions have emerged as an active area of research, not only because of their relevance to bioinorganic chemistry and new magnetic materials, but also due to their aesthetically pleasing structures . In this regard, there is considerable interest in the design of multinuclear nickel complexes containing defined number of nickel(II) ions in a determined spatial arrangement .…”