An Original Supramolecular Helicate from a Bipyridine–Bipyrazine Ligand Strand and Ni^II by Self‐Assembly

Abstract

A new discrete supramolecular pseudo-helicate has been obtained from a saturated heterotopic methylbipyrazyl-methylbipyridyl ligand strand and NiCl 2 . The X-ray structure of the dinuclear complex shows the 2-oxapropylene bridge oxygen atoms are engaged in coordination to the octahedral metal centre and a selective ligand inter-strand orientation is promoted in the complex. The crystal packing shows a perfect regular linear arrangement of the asymmetric units giving a

Synthesis and characterization of new Pd(ii) and Pt(ii) complexes with 3-substituted 1-(2-pyridyl)imidazo[1,5-a]pyridine ligands

“…The ligands 1-(2-pyridyl)-3-arylimidazo[1,5-a]pyridine L n (n= 1-3) (Figure 3) were readily synthesized, in good yields, by reacting suitable aromatic aldehydes with 2,2'-dipyridylketone and ammonium acetate in hot acetic acid, using minor modifications to the published procedures. 22 On the other hand, the ligand 1-(2-pyridyl)-3-benzylimidazo[1,5-a]pyridine, L 4 , was synthesized following a different procedure due to the instability of the corresponding aliphatic imine which is formed during the synthesis. 23 The structure of the ligands was assessed by 1 H NMR spectroscopy: multi-dimensional NMR experiments were employed to assign all the proton signals (see Table 1).…”

“…The most salient features are: 1) a significant upfield shift of the H8 signal upon complexation ( δ 7.82 ppm vs δ 8.70 ppm in the free ligand); 2) a downfield shift of the signal related to the proton H6' (δ 9.00 ppm vs δ 8.61 ppm in the free ligand). The alterations of the substituents in ligands L 2 , L 3 and L 4 offer different possibilities for the potential formation of cyclometalated species. With L 2 and L 3 ligands we wanted to exploit the possibility of the C-H activation in the methyl group in the ortho position, thereby leading to the formation of a 6-membered metallacycle featuring less ring strain with respect to analogous 5membered cycles expected with L 1 .…”

“…Ir(I), Pd(II), Pt(II), Au(III)) is dominated by the use of bidentate nitrogen donors as supporting ligands, wherein 2,2'-bipyridines and 1,10-phenanthrolines are the most important examples. 1 In particular, the extraordinary coordination properties of 2,2'-bipyridines in metal-catalyzed reactions 2 have led to a myriad of applications in a variety of fields, including macromolecular chemistry, 3 supramolecular chemistry, 4 materials chemistry, 5 photochemistry 6 and electrochemistry. 7 Following our continuous interest in the study of the reactivity of bidentate nitrogen ligands, 8 we decided to investigate the coordinating behaviour of a series of aromatic N-heterocyclic ligands containing the imidazo[1,5-a]pyridine skeleton (Figure 1) 9 i.e.…”

Catalytic Oxidation of 2-Amino-3-Sulfhydryl Propanoic Acid (ASPA) by 2,6- Dicarboxypyridinium Fluorochromate (DCPFC) : A Kinetic and Mechanistic Study

“…2-(Pyridin-2-yl)Pyridine has found its application in various fields of chemistry such as macromolecular, supramolecular, material chemistry, photochemistry, electrochemistry due to their extraordinary coordination properties, as ligands in metal-catalysed reactions [37][38][39][40][41][42][43] . 2-(Pyridin-2-yl)Pyridine framework bears pendent chiral substituents, they have been studied as potential ligands in Metal -Catalysed Asymmetric reactions.…”

Applications of Bolm’s Ligand in Enantioselective Synthesis

“…In general, 2,2 -bipyridines have found application in various fields of chemistry-such as macromolecular chemistry [1], supramolecular chemistry [2], material chemistry [3], photochemistry [4], electrochemistry [5]-and, due to their extraordinary coordination properties, as ligands in metal-catalyzed reactions [6]. Compared to other commonly used ligands, such as phosphines and cyclopentadienes, they are remarkably stable towards both air and moisture, which is advantageous during their preparation, handling, and storage.…”