Molecular and intracomplex dioxomolybdenum(VI) compounds with o-hydroxyazomethines, derivatives of salicylaldehydes and 2-furfurylamine: Crystal structures of 3-methoxysalicylidene-2-furfurylamine (HL2) and the binuclear complex [{MoO2(L2)(MeOH)}2(μ-O)]