The first stable lithium complex of a pentadentate macrocycle incorporating sp2-nitrogen donor atoms only; the X-ray crystal structure of [Li(L2)(MeOH)][PF6]{L2= 6,13-(bis-2-hydroxyethyl)-6H,13H-tripyrido[cd,fg,lm][1,2,4,7,9,10,13]heptazapentadecine}