Hernández-Apaolaza Lourdes, García-Marco Sonia, Nadal Paloma, Lucena Juan J, Sierra Miguel A, Gómez-Gallego Mar, Ramírez-López Pedro, Escudero Rosa
Departamento de Química Agrícola, Facultad de Ciencias, CVII, Universidad Autónoma, 28049 Madrid, Spain.
J Agric Food Chem. 2006 Jun 14;54(12):4355-63. doi: 10.1021/jf0605749.
The synthesis of commercial EDDHA produces o,o-EDDHA as the main reaction product, together with a mixture of regioisomers (o,p-EDDHA and p,p-EDDHA) and other unknown byproducts also able to complex Fe3+. These compounds have been obtained by direct synthesis, and their structures have been determined by ESI-MS analysis as oligomeric EDDHA-like products, formed by polysubstitution in the phenolic rings. Short-term experiments show that the iron complexes of samples enriched in these oligomeric byproducts have adequate stability in solution, but a significant amount of them is lost after interaction with soils and soil materials. Mildly chlorotic cucumber plants are able to reduce iron better from o,p-EDDHA/Fe3+ than from the iron complexes of the oligomeric byproducts. In hydroponics, the chlorotic soybean susceptible plants have a lower potential for Fe absorption from these byproducts than from o,o-EDDHA/Fe3+ and from o,p-EDDHA/Fe3+. In the studied conditions, the iron chelates of EDDHA byproducts do not have the long-lasting effect shown by o,o-EDDHA/Fe3+ and present a less efficient fast-action effect than the o,p-EDDHA/Fe3+.
商业用乙二胺二邻苯基乙酸（EDDHA）的合成产生以邻，邻-EDDHA作为主要反应产物，同时伴有区域异构体（邻，对-EDDHA和对，对-EDDHA）混合物以及其他同样能够与Fe3+络合的未知副产物。这些化合物通过直接合成获得，其结构已通过电喷雾质谱（ESI-MS）分析确定为类EDDHA低聚物产物，由酚环中的多取代形成。短期实验表明，富含这些低聚物副产物的样品的铁络合物在溶液中具有足够的稳定性，但与土壤和土壤物质相互作用后会损失大量此类络合物。轻度褪绿的黄瓜植株从邻，对-EDDHA/Fe3+中还原铁的能力强于从低聚物副产物的铁络合物中还原铁的能力。在水培条件下，褪绿的易感大豆植株从这些副产物中吸收铁的潜力低于从邻，邻-EDDHA/Fe3+和邻，对-EDDHA/Fe3+中吸收铁的潜力。在所研究的条件下，EDDHA副产物的铁螯合物不具有邻，邻-EDDHA/Fe3+所显示的长效作用，且与邻，对-EDDHA/Fe3+相比，其快速作用效果较差。
