Complexation Behavior Between Cu²⁺、Co²⁺、Ni²⁺ And AAPTS,and Intercalation Behavior Of M（AAPTS）_n²⁺ In The Interleaves Of Layered HNbWO₆or HTaWO₆

Intercalation chemistry has attracted much attention for decades. Intercalation oftransition-metal complexes into the interlayer spaces of layered transition-metal oxidethrough the stepwise ion-exchange route should be an effective way for constructingnew-type functional materials. In this study, complexation behavior of some transitionmetallic ions with3-(2-aminoethylamino)propyltrimethoxysiane (abbreviated asAAPTS), and the intercalating reaction between the complex M(AAPTS)n2+andn-propylamine-pre-expanded layered niobium-tungsten acid (denoted simply asC3-HNbWO6) or n-propylamine-pre-expanded layered tantalum-tungsten acid(denoted as C3-HTaWO6) were investigated. The structures of the layeredintermediates and final layered products were thoroughly characterized by means ofpowder XRD, FT-IR, DR UV-Vis and SEM etc.The main research work and findings are summarized as follows:(1) Studies on intercalation reaction between M(AAPTS)n2+(M=Cu, Co) andC3-HNbWO6or C3-HTaWO6, and studies on co-pillaring of HNbWO6andHTaWO6with MOxand SiO2A mixture of Cu(NO3)2·3H2O (or CoCl2·6H2O) and methanol, was mixed withAAPTS, giving rise to a solution containing complex ions M(AAPTS)n2+(M=Cu,Co). After the freshly-prepared solution was subjected to react with C3-HNbWO6orC3-HTaWO6, both M(AAPTS)n2+ions and AAPTS molecules were intercalated intothe interleaves of the layered hosts. When the intercalates were washed withdeionized water, the intercalated AAPTS molecules hydrolyzed and polymerized insitu, generating silicon-containing polymeric cations. Our results indicated that then(M2+)/n(AAPTS) ratio affected significantly the intercalation behavior. By heattreatment at673K in air, M(AAPTS)n2+and silicon-containing polymeric cations inthe interlayer regions converted into oxides, thus the co-pillaring of the layeredtransition-metal oxides (HNbWO6or HTaWO6) with MOxand SiO2were achieved.(2) Intercalation behavior of AAPTS and Ni2+in the interleaves of C3-HNbWO6or C3-HTaWO6, and in-situ complexation between Ni2+and AAPTS in the limited interlayer spaceUnlike Cu2+and Co2+, Ni2+was not easy to form dative bonds with AAPTS inmethanol. When a methanol solution containing Ni2+and AAPTS was mixed withC3-HNbWO6or C3-HTaWO6powder, the n-propylammonium ions in the interleavesof the n-propylamine-pre-expanded layered intermediates were firstly expelled out,then Ni2+ions were in situ combined with AAPTS molecules in the interlayer regions,forming Ni(AAPTS)n2+ions. It should be pointed out that Ni(AAPTS)32+was too bigto be formed in the limited interlayer space. Therefore, the nickel species in theinterlayer regions existed mainly in Ni(AAPTS)22+or Ni(AAPTS)2+form. After theas-synthesized layered products were calcined at673K in air atmosphere, theNiO-SiO2-copillared layered HNbWO6and HTaWO6were obtained.