An octanuclear copper(II) complex containing the gem-diol anionic form of di-2-pyridyl ketone (dpd-2H) and 2-hydroxypyridine: Synthesis, crystal structure, and properties of [Cu-8(dpd-2H)(4)(mu(2)-O2CMe)(4){2-(OH)C5H4N}(4)]-(ClO4)(4)center dot 4H(2)O