Modified Bipyridines: 5,5′-Diamino-2,2′-bipyridine Metal Complexes Assembled into Multidimensional Networks via Hydrogen Bonding and π–π Stacking Interactions

Abstract

A new synthetic route for the synthesis of 5,5′‐diamino‐2,2‐bipyridine (5) based on the coupling of 2‐chloro‐5‐aminopyridine in the presence of NiCl2 × 6 H2O/PPh3/Zn in dimethylformamide is described. The reactions of the potentially ambidentate ligand 5 with salts of the transition metals Mn, Fe, Ni, Cu, Zn, Ag, and Cd gave a variety of 13 metal–ligand complexes depending on the anion, the crystallization conditions and the metal‐to‐ligand ratio. The complexes obtained were characterized by thermal analyses, NMR including 113Cd‐NMR, IR, and for the iron complex 57Fe‐Mößbauer spectroscopy. The structure of eight of the compounds was elucidated by X‐ray crystallography. All of these metal complexes show a bipyridine–metal coordination. The amino functionality was never involved in metal coordination. The intermolecular arrangement is dictated by hydrogen bonding from the amino functionality and by π–π stacking of the bipyridine rings.

Modulating the Photoluminescence of Bridged Silsesquioxanes Incorporating Eu3+-Complexed n,n′-Diureido-2,2′-bipyridine Isomers: Application for Luminescent Solar Concentrators

“…37,38 A mixture of 5,5 0 -bis(2, 5-dimethylpyrrol-1-yl)-2,2 0 -bipyridine 38 (3.50 g, 10.2 mmol), hydroxylamine hydrochloride (21.3 g, 307 mmol), triethylamine (11.5 mL, 82 mmol), ethanol (75 mL), and water (30 mL) was heated under reflux for 20 h. The mixture was cooled to room temperature then basified to pH 12, using a 1 M sodium hydroxide solution. After distilling off the triethylamine and ethanol at atmospheric pressure, the residual mixture was cooled to 4°C for 3 h, yielding off-white crystals of 5,5 0 -diamino-2,2 0 -bipyridine dihydrate.…”

The Coordination Chemistry of 3,3′-Diamino-2,2′-bipyridine and Its Dication: Exploring the Role of the Amino Groups by X-ray Crystallography

“…In contrast, the 1:1 complex of copper(II) chloride with 5,5Ј-diamino-2,2Јbipyridine adopts a tetracoordinate structure with even shorter CuϪN bond lengths of 1.981(1) Å . [25] Interestingly, a derivative of 3-amino-2,2Ј-bipyridine-6-carboxylate is reported to bind copper(II) through both a deprotonated amino group, a pyridine nitrogen and a carboxylate group. [26] …”

Synthesis and Crystal Structure of Manganese(II) Bipyridine Carboxylato Complexes: [(bipy)2MnII(μ-C2H5CO2)2MnII(bipy)2](ClO4)2 and [MnII(ClCH2CO2)(H2O)(bipy)2]ClO4 · H2O (bipy = 2,2′-bipyridine)

“…1. Cis-arrangement and bite angle are as seen e. g. in [Mn(N 3 ) 2 (5,5'-diaminobipy) 2 ] [22] and in [Mn(NCS) 2 (bipy) 2 ] [23]. The two metal atoms are bridged by two propionato groups.…”