Metal−Organotetraphosphonate Inorganic−Organic Hybrids: Crystal Structure and Anticorrosion Effects of Zinc Hexamethylenediaminetetrakis(methylenephosphonate) on Carbon Steels

The synthesis and structural characterization of the first polymeric M−HDTMP organic−inorganic hybrids are described [M = Zn2+, Ca2+; HDTMP = hexamethylenediaminetetrakis(methylenephosphonate)]. The 3D crystal structure of the Zn2+ analogue [Zn(HDTMP)·H2O] is described. The Zn center is found in a distorted octahedral environment of phosphonate oxygens. There is a long Zn···O interaction (2.622 Å) originating from a protonated −P−OH group. Synergistic combinations of Zn2+ and the tetraphosphonate are found to form films that protect against the corrosion of carbon steels.本文详述了首例聚合型M-HDTMP有机-无机杂化物的合成与结构表征[其中M代表Zn²+、Ca²+；HDTMP为六亚甲基二胺四亚甲基膦酸（hexamethylenediaminetetrakis(methylenephosphonate)）]。文中对Zn²+对应杂化物[Zn(HDTMP)·H₂O]的三维晶体结构进行了报道：锌中心处于由膦酸氧原子构成的畸变八面体配位环境中，且存在一段源自质子化-P-OH基团的长程Zn···O相互作用，键长为2.622 Å。研究表明，Zn²+与该四膦酸酯的协同复合体系可形成防护膜，实现对碳钢腐蚀的抑制。