Intercalation of alkylamines into dehydrated and hydrated zinc phenyiphosphonates

Abstract

Primary amines, C_nH_2n+1NH₂(n= 3–8), were intercalated into layered anhydrous zinc phenylphosphonate Zn(O₃PC₆H₅) and its monohydrate Zn(O₃PC₆H₅)·H₂O when the host compounds were brought into contact with liquid amines. In both cases, 1 mol of amine was intercalated forming layered compounds of composition Zn(O₃PC₆H₅)·(RNH₂) as characterized by powder X-ray diffraction, thermogravimetry and infrared spectroscopy. The amines coordinate to the zinc atoms at the site vacated by the water molecule. A plot of the interlayer distances of the intercalates vs. the number of carbon atoms in the alkyl chain of the amine gives a straight line with a slope of 1.24 Å, which indicates that the alkyl chains are most likely packed as an interdigitated monolayer with a tilt angle of 78° with respect to the mean plane of the layer. A comparison of the intercalation reactions of Zn, Co and Cu methyl- and phenyl-phosphonates is included in the discussion section.