{Ni4} Cubanes from enantiomerically pure 2-(1-hydroxyethyl)pyridine ligands: supramolecular chirality

Homometallic {NiII4} cubane-like clusters with a rare chiral core have been prepared via the employment of enantiomerically pure 2-(1-hydroxyethyl)pyridine (Hmpm). Comparison with the achiral cubanes derived from the related 2-pyridinemethanol (Hpym) ligand reveals drastic structural changes as a consequence of the transfer of chirality from the ligands to the whole structure. Their magnetic properties have been related to the structural features of their cubane-type cores.

pH-Dependent structural diversity of a 2-pyridinemethanol Cu complex and its relatively strong magnetic exchange coupling via hydrogen bonding

The diversity of the self-assembled structures of a Cu complex via hydrogen bonding, including a square planar unit, is reported. The Cu complex forms two self-assembled structures by hydrogen bonding, depending on the acidity of the recrystallization conditions. A linear chain structure can be produced under acidic conditions, and a three-dimensional network structure is observed under basic conditions. The linear chain structure is constructed from intermolecular sharing of a hydrogen atom between two 2-pyridinemethanolate units, with an OO distance of 2.412(1) Å and an O-H-O bond angle of 170(3)°. The linear chain structure exhibits relatively strong magnetic coupling (J = -9.91(2) cm^-1) via hydrogen bonding between Cu atoms; this coupling was also confirmed by electron spin resonance experiments. Thermochromic behavior was also observed for the complex.

Green click synthesis of β-hydroxy-1,2,3-triazoles in water in the presence of a Cu(ii)–azide catalyst: a new function for Cu(ii)–azide complexes

A new method for preparing 1,2,3-triazols via a [3+2]-cycloaddition reaction is introduced. The effect of reaction temperature on the epoxide ring opening reactions is also investigated.