Rare earth cinnamates

In an attempt to improve the anticorrosion properties of unsubstituted rare earth cinnamates, a series of / ara-substituted cinnamates, Ln(4-Rcinn)3.wH20 (R=OH, OMe, NO, Cl) was prepared and found in several cases to provide more effective... 

F. Blin, P. Koutsoukos, P. Klepetsianis and M. Forsyth, The corrosion inhibition mechanism of new rare earth cinnamate compounds — Electrochemical studies Electrochimi. Acta, 52, 6212 (2007). 

Blin F, Leary SG, Wilson K, Deacon GB, Junk PC, Forsyth M (2004) Corrosion mitigation of mild steel by new rare earth cinnamate compounds . Journal of Applied Electrochemistry 34, 591-599. 

Standard corrosion testing such as weight loss. Unear polarization resistance (LPR) and cyclic potentiodynamic polarization (CPP) were used to assess each compound s inhibition efficiency for steel in 0.01 M NaCl solution. Cerium and lanthanum combined with cinnamate and substituted cinnamates produced the most effective corrosion inhibition for steel. As an example, lanthanum 4-nitrocirmamate achieved 92% inhibition for mild steel itmnersed for 7 days in sodium chloride solution. Cerium 4-methoxycinnamate was also effective as a corrosion inhibitor. Electrochemical measurements showed the rare earth cinnamate compounds to be mixed inhibitors, with an initial suppression of anodic processes, followed by a decrease in cathodic processes after longer exposure times. 

Deacon, G.B., Forsyth, C.M., Juiik, P.C., HUder, M., Leary, S.G., etal.. Synthesis and structural properties of anhydrous rare earth cinnamates, [RE(cinnX3)]. Zeitschrift Fur Anorganische Und Allgemeine Chemie, 634(1) 91-97. 

These compounds have included the salicylate, anthianilate, glycolate and cinnamate ligand systems and the synthetic and stmctuial aspects of some of these rare earth complexes follow. 

The heavier rare earths (Ln=Dy, Ho-Lu, Y) also form one-dimensional polymeric chains with all Ln atoms being 7-coordinate. In this stractural type the cinnamate ligands are either bridging tridentate or bridging bidentate... 

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