4‐Substituted and 4,5‐Disubstituted 3,6‐Di(2‐pyridyl)pyridazines: Ligands for Supramolecular Assemblies

Abstract

The syntheses by inverse electron demand Diels-Alder reactions and characterization of 28 members of a family of 3,6-di(2-pyridyl)pyridazines, functionalized in the 4-or 4,5-positions are reported. Single crystal structural data are presented for four representative derivatives.

Crystal structure of 3,6-di-2-pyridinyl-4-pyridazine carbonitrile, C15H9N5

“…It crystallizes with one molecule in the asymmetric unit. The N4-N3 bond length is 1.337(2) Å, C5-N1 = 1.341(2) Å and C11-N5 = 1.336(2) Å and these are comparable to the bond lengths of similar reported molecules [10,17]. The dihedral angles between the planes de ned by N1, C1-C5 and N5, C11-C15 are of 5.47 (0.11)°and 6.96 (0.11)°showing that the planes are coplanar.…”

Substituent Effects in the Solid‐State Assembly of Silver(I) Complexes of 4‐Substituted 3,6‐Di(2‐pyridyl)pyridazines

“…The principle building block in the {[Ag 3 (7) . However, whereas the angles between the least-squares planes of the pyridine and pyridazine rings in the latter are similar, those between the rings containing atoms N1 and N2/N4, and N3 and N2/N4 in each [Ag 2 (7) 2 ] 2+ unit are significantly different [19.5(2) and 69.5(2)°]. The twisting of one pyridine ring switches the coordination environment of the silver(I) atom from four-to three-coordinate and at the same time, allows the pendant pyridine nitrogen donor to bind to another metal ion.…”

“…[7,[10][11][12][13][14][15] Free 3,6-di(2-pyridyl)-pyridazine ligands adopt a trans,trans arrangement. [7,[10][11][12][13][14][15] In [Ag (4) for the two independent cations, those in [Ag (10) 4 ] assemble so that each silver atom is sandwiched between two pyridine rings as shown in Figure 4, although the rings are slipped with respect to one another giving two η 2 -modes of interaction. The closest contacts are Ag1···C10 b 3.310(3) Å and Ag1···C11 b 3.254(3) Å (symmetry code b = x, -1 + y, z), and the Ag···py centroid distance of 3.34 Å is at the longer end of the range quoted for η 6 interactions.…”

“…Structures of ligands 1 to 10 with ring labelling used for NMR spectroscopic assignments; the aryl substituent is ring D. tuted 3,6-di(2-pyridyl)pyridazines as a prelude to an investigation of their complex formation. [7] We now report a study of the reactions of silver(I) tetrafluoroborate with seven 4-substituted 3,6-di(2-pyridyl)pyridazines (4-10, Scheme 2) and the solid-state structures of the isolated complexes.…”

Switching‐on: The Copper Age

“…Tetrazines are precursors via inverse electron demand Diels-Alder reactions to pyridazines and this allows a synthetic procedure for the inclusion of new chromophores [140][141][142]. With this in mind, we have synthesized the ligands: 3,6-di(2-pyridyl)-4,5-diphenylpyridazine L A , 3,6-di(2-pyridyl)-4,5-di(4-pyridyl)-pyridazine L B , and 3,6-di(2-pyridyl)-8,9-diazafluoranthene L C (Scheme 13.1), two of which have been reported elsewhere (L A [143], L C [144]). …”