“…Previous reports reveal that croconate is a polydent ligand (Chen et al, 2005, Maji et al, 2003, Wang et al, 2002, Sletten et al, 1998. According to the concept of 'molecular self-organization′ and 'molecular engineering′, transition metal croconates associated with another ligand such as terpyridine (Castro et al 2002), bis((bis(2-pyridylcarbonyl) amido (Maji et al, 2003), 2,2′-bipyridine (Castro et al, 1992) or the tetrakis(2-pyridyl)pyrazine (Carranza et al 2004) show interesting properties in magnetism, biochemistry, catalyst et al…”