Synthesis and Characterization of a Series of Novel Heptanuclear Trigonal-Prismatic Polyhedra with Different Edge-Ligands

Abstract

Herein we present an improved synthesis of 5,5′‐diamino‐2,2′‐bipyridine (1) starting from the pyrrole‐protected aminopyridine 4. By standard reactions 1 can easily be transformed into the imine‐ or amide‐bridged dicatechol–bipyridine ligands L1‐H4 and L2‐H4. Whereas ligand L1 readily forms homodinuclear helicates [(L1)3Ti2]4−, the attempted formation of mono‐, tri‐, or even oligonuclear coordination compounds from this ligand did not work. However, the amide‐connected ligand L2 affords mononuclear ([(L2‐H4)PdCl2], [(L2‐H4)3Zn]2+), dinuclear ([(L2)3Ti2]4−), and heterotrinuclear coordination compounds ([(L2)3Ti2Zn]2−).

A Molecular Pair of [GdNi3] Tetrahedra Bridged by Water Molecules

“…Other combinations of Cu II , Ln III , and amino acids in water have led to another family of clusters with a [LnCu 6 ] core showing with a very regular trigonal prism of Cu II ions centered by the Ln III metal 15. This arrangement is also accessible with Ni II or Co II in aqueous media,16, 17 although these metals have also unveiled a related topology of centered [LnM 6 ] regular octahedra 17. Interestingly, the use of nonaqueous media, such as acetonitrile, also leads to octahedral clusters, but does not produce the prisms 18.…”

Magnetic lanthanide–transition-metal organic–inorganic hybrid materials: From discrete clusters to extended frameworks

“…For example, Einaga and coworkers reported a cyano-bridged dinuclear Ln-TM compound showing photoinduced magnetization [31], and high nuclearity Ln-TM SMMs constructed from carboxylic acids ligands have also been obtained, but most of Ln-TM clusters are based on the following three kinds of ligands: Schiff-base [43][44][45][46], pyridonates [28,[47][48][49] and amino acids [49][50][51][52].…”

Pentanuclear {Cr2Ln3} (Ln = Dy, Tb) Heterometallic Clusters Based on an Amino Acid Ligand: Slow Relaxation of Magnetization and Substitution Reactions

“…In addition, the reactions were also influenced by pH. The best yield was obtained at pH 5.4, with no reaction occurring at pH < 3.0, consistent with the preparation of other 3d–4f high‐nuclearity clusters bearing AA ligands 16a,16b,17b. The {Ln 3 Cr 2 } clusters bear nine terminal water molecules and are also soluble in water, which prompted us to investigate the possibility of connecting the clusters into infinite coordination polymers through ditopic linkers by the substitution of terminal water molecules.…”