Degradations of novel tetranuclear vanadyl glycollates to dinuclear species.

Novel tetranuclear vanadyl glycollates [Ni(phen) 3 ] 2 [V IV 4 O 4 (glyc) 6 ]·23H 2 O ( 1 ) and [Ni(phen) 3 ] 2 [V IV 4 O 4 (glyc) 6 ]·16H 2 O ( 2 ) have been obtained through the capture of bulky nickel phenanthroline cation (H 2 glyc = glycollic acid, phen = 1,10-phenanthroline), and the mixed-ligand complex [V IV 4 O 6 (glyc) 2 (bpy) 4 ]·6H 2 O ( 3 ) (bpy = 2,2′-bipyridine) was isolated with the addition of bpy under hydrothermal condition. Tetrameric 1 and 2 are easily oxidized to dimeric complex [Ni(phen) 3 ][V V 2 O 4 (glyc) 2 ]·5H 2 O ( 4 ), while 3 with bipyridine is stable. The degradation process was traced by IR and XRD experiment. 1 – 4 feature bidentate glycollate that chelates to vanadium atom through α-alkoxy and α-carboxy groups, which were full characterized by elemental analysis, TG, IR, UV–Vis, EPR, XRD and X-ray structural analyses. Bond valence calculation is also performed. [ABSTRACT FROM AUTHOR]