Novel Schiff base (E)-2-((4-chloro-3-nitrophenylimino)(phenyl)methyl)-5-methoxyphenol and Mixed Ligand Complexes of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II): synthesis, structure elucidation and potency study as antibacterial, antimalarial, antioxidant, antidibetic and anticancer agents