Study on Novel Structure of 4,4'-Bipyridine bis(salicylato)borate Hydrate

Borate compounds have been the intensive subjects of crystallographic study for the last century.There is a great interest preparing the anhydrous main group or transition metal borate compounds 1-3 .Alkali-metals bis(salicylato)borates have also received the most attention, since the lithium organoborates had been considered as the lithium battery electrolytes 4 .Studies of organic base bis(salicylato)-borates have been less extensive.Piperidinium bis(salicylato)borate is reported in the literature 5 .In this paper, the 4,4'-bipyridine bis(salicylato)borate dihydrate is reported.All commercially obtained reagent-grade chemicals were used without further purification.A mixture of SnCl2 (0.1 mmol, 0.019 g), dilute HCl (0.2 mL), 4,4'-bipyridine (0.1 mmol, 0.016 g), salicylic acid (0.1 mmol, 0.014 g) and boric acid (0.1 mmol, 0.006 g) were added into 20 mL water with 10 % ethanol and heated for 6 h at 394 K.The solution was obtained by filtration after cooling the reaction to room temperature.Colourless block single crystals suitable for X-ray measurements were obtained after a few weeks.The crystal structure of 4,4'-bipyridine bis(salicylato)borate hydrate (Fig. 1) is built up of 4,4'-bipyridine cation, bis(salicylato)borate anion and water molecules.The crystal data and structure refinement is shown in Table -1.Boron atom is coordinated by four O atoms from two salicylic acid.The distance d (B-O) are in the range of 1.441-1.486Å.The angles of O-B-O are in the range of 106.0-112.8º.The torsion angles of C1-O1-B1-O6, C3-O3-B1-O4 and C10-O6-B1-O1 are 99.0,143.8and 90.9º, respectively.Selected bond lengths and bond angles are shown inTable-2.