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

Abstract

The synthesis and structural chemistry of a series of new divalent transition metal complexes of the bis-bidentate ligand 3,3Ј-diamino-2,2Ј-bipyridine (L1) and its dication L1H 2 are described. Ligand L1 reacts with salts of divalent transition metals to afford the (1:1) metal-ligand complexes (2a−2d) as well as the tris complexes (3a−3f). All complexes were fully characterised by spectroscopic methods and the following compounds [Cu(L1)Cl 2 ] 2 (2a), [Cu(L1)(OAc) 2 ] (2b), [Zn(L1) 3 ][OTf] 2 (3a), and [Zn(L1) 3 ][ZnCl 4 ] (3e and 3f) were structurally characterised. Results from single crystal X-ray diffraction measurements indicate that formation of an intramolecular hydrogen bond between the two amino groups allows the ligand to coordinate divalent metal ions through their diimine binding sites. Furthermore, the structure of compound 2a reveals that it crystallises as a dimer in which each copper ion is bound to two pyridine nitrogen atoms and [a]

4,4′-Bis(2,2,2-trifluoroethoxymethyl)-2,2′-bipyridine

“…Compound (I) exhibits a crystallographic inversion centre at the mid-point of the pyridine C ipso -C ipso bond and crystallizes in the space group P2 1 /n. Many free bpy ligands described in the literature [Cambridge Structural Database (CSD; Allen, 2002) refcodes EDOXAW and EDOXEA (Maury et al, 2001), FOBRUK and FOBSAR (Iyer et al, 2005), KIDNAP (Vogtle et al, 1990), MILZUC (Heirtzler et al, 2002), NAMKAN02 (Zhang et al, 2003), NOFZUD (Sengü l et al, 1998), UHIBAO (Viau et al, 2003), VEXQAQ (Spek et al, 2000), VEXQAQ01 (Rice et al, 2002) and VOLLAJ (Butler & Soucy-Breau, 1991)] also possess a crystallographic centre of inversion, two distinctive consequences of which are the planarity of the connected pyridyl units and their anti arrangement (Alboré s et al, 2004;Iyer et al, 2005). The planar bpy C 10 N 2 group in (I) has a weak N1Á Á ÁH3 i -C3 i interaction [symmetry code: (i) Àx + 1, Ày + 1, Àz + 1], suggested by the NÁ Á ÁH distance of 2.49 Å , although the angle organic compounds Acta Cryst.…”

Stability of Immobilization of Bipyridine‐proline on Zn‐Modified Bimodal Mesoporous Silicas and Recyclable Catalytic Performance in Asymmetric Aldol Reaction

“…The bimodal mesoporous SiO 2 (BMMs) possess a high surface area (>700 m 2 /g), large pore volume (up to 3.5 cm 3 /g), modifiable surface and controllable bimodal mesopores with small ordered mesopores of around 3 nm and the large mesopores (15‐50 nm) of uniform intra‐nanoparticle . (2 S,2’S)‐N,N’‐([2,2’‐bipyridine]‐3,3’‐diyl) bis(pyrrolidine‐2‐carboxamide) (abbreviated as Z) was synthesized by our collaborator, which presents a good catalytic activity for asymmetric aldol reaction under homogeneous system ,. In our previous studies, a novel heterogeneous chiral catalyst (Z‐BMMs) was prepared via immobilization of Z onto the mesoporous channels of BMMs (Z‐BMMs) by hydrogen bond method, and showed a higher catalytic activity for asymmetric aldol reaction between cyclohexanone and 4‐nitrobenzaldehyde, as compared to that of homogenous catalysts .…”

Probing the reactivity of a 2,2′-bipyridyl-3,3′-bis-imine ligand by X-ray crystallography

“…The first hydrogen bond is to a bipyridine N atom, with a NIJ3)⋯HIJ2) bond length of 1.81(3) Å and a NIJ3)⋯HIJ2)-NIJ2) angle of 140IJ2)°, similar to the intramolecular hydrogen bonding interactions present in the structure of 3,3′-diamino-2,2′-bipyridine 1. 10 The second hydrogen bond is to the disordered terminal pyridine ring IJNIJ1A)⋯HIJ2): 2.20(3) Å, NIJ1A)⋯HIJ2)-NIJ2): 102.84IJ2)°and NIJ1B)⋯HIJ2): 2.40(3) Å, NIJ1B)⋯HIJ2)-NIJ2): 99.70IJ2)°) but with much less favourable geometry at H. The torsion angle about the NH-C-O-CH 3 system is 60.3°, similar to that found in seven related systems, 27 and is indicative of a stereoelectronic effect between an oxygen lone pair and the N-CIJO) bond. The bond length from the amino group to the pyridine ring is 1.382(3) Å, indicating that this lone pair is conjugated with the aromatic ring.…”

“…3,3′-Diamino-2,2′-bipyridine 1 and the Schiff-base bis-imine ligand 3 were synthesized following the methods described previously. 10,18 All chemicals were commercially available and used as received, unless otherwise stated.…”