Examination of the conformational restraints to a chiral diimine bridged 2,2′-bipyridine

Same head, different scaffold: a plethora of structural motifs assembled from silver(i) and ditopic 2,2′-bipyridine ligands

“…The yellow solid that formed was collected by filtration, washed with water and dried in air. {[Ag (7)][BF 4 ]} n was isolated as a yellow solid (34.0 mg, 60.9%). 1…”

“…Treatment of hydrazine hydrate with two equivalents of 2,2 0bipyridine-6-carbaldehyde and one equivalent of AgBF 4 resulted in the formation of a yellow solid. In the electrospray mass spectrum, the highest peak envelope (m/z 1031.3) corresponded to [Ag 2 (7) 2 BF 4 ] + , while the base peak (m/z 471.1) was assigned to 29 The most striking structural feature of the [Ag 4 (7) 4 ] 4+ cation is the arrangement of the ligands (Fig. 9).…”

“…In principle, there are two additional isomers with sequence descriptors AABABBAB and BABABBAA (Scheme 3). The [Ag 4 (7) 4 ] 4+ cation adopts one of these unusual hybrid structures (Scheme 3, hybrid structure I) in which each of the red ligands in Fig. 9 span one side of the Ag 4 unit, while the ligands coloured blue generate a helical motif threading from one side to the other.…”

“…Although this hybrid structure-type has been observed before in a tetracobalt complex, 37 attention does not previously appear to have been drawn to the distinction between the hybrid assemblies and the two more typical motifs depicted in Scheme 3. Since the quality of the structure of [Ag 4 (7) 4 ][BF 4 ] 4 $3H 2 O was not ideal, we collected full datasets on seven different crystals, and screened many more. However, we were unable to obtain better quality data.…”

“…2,3 Although aldehyde-diamine condensation is well established for the preparation of a vast range of Schiff base and macrocyclic ligands, 4 species combining a diimine backbone with multiple oligopyridine metal-binding domains have received little attention. [1][2][3][5][6][7] In contrast, pyridine-containing analogues have been widely investigated, and these include Schiff base ligands prepared by condensation of pyridine-2-carbaldehyde and simple aliphatic diamines or hydrazine. [8][9][10][11][12][13][14] Blackman has recently described the condensation of 2,2 0bipyridine-6-carbaldehyde with ethane-1,2-diamine, propane-1,2-diamine and hexane-1,6-diamine followed by borohydride reduction to give a family of hexadentate ligands with saturated spacers between the two bpy domains (bpy ¼ 2,2 0 -bipyridine).…”