Macrocyclic metal complexes: Part XXII-Dinuclear macro cyclic fluoroborobridged complexes of cobalt(II) and nickel(II)

944-947Dinuclear fluoroboro-bridged macrocyclic complexes have been synthesised by treating boron trifluoride on bis-(diacetylazinedihydrazone)dinickel(II)/dicobalt(II) complexes. The complexes possess the stoichiometry [M2(DAADHBF2)2X4] (BF4)2 {M= Co(II), X = Cl- , Br-, I-, SCN-; M = Ni(II), X = SCN-}. They are ionic in nature and the IR spectral data show the existence of fluoroboro groups as > BF and BF species. Pairs of former group occur as bridgeheads, each encompassing two adjacent NH2groups in the inner-sphere of the macrocyclic ligand frame and the latter occupies the outer coordination sphere of the complex. Polarographic redox studies show three single-electron redox steps and the thermodynamic parameters, viz. E 1/21.2, values point to the macrocyclic structure of the complexes