428 ISSN 1087-6596, Glass Physics and Chemistry, 2018, Vol. 44, No. 5, pp. 428–432. © Pleiades Publishing, Ltd., 2018. Original Russian Text © O.I. Silyukov, S.A. Kurnosenko, I.A. Zvereva, 2018, published in Fizika i Khimiya Stekla. Intercalation of Methylamine into the Protonated Forms of Layered Perovskite-Like Oxides HLnTiO 4 (Ln = La and Nd) O. I. Silyukov a, *, S. A. Kurnosenko a , and I. A. Zvereva a a St. Petersburg State University, St. Petersburg, 199034 Russia *e-mail: oleg.silyukov@spbu.ru Received January 16, 2018 Abstract—New hybrid organic-inorganic derivatives HLnTiO 4 · CH 3 NH 2 (Ln = La and Nd) are obtained via the intercalation of methylamine into the interlayer space of protonated layered perovskite-like titanates HLnTiO 4 . The existence of three stable methylamine derivatives, namely, α-, β-, and γ-forms, is found for each of the titanates. The thermal stability of the obtained intercalation products is studied and their struc- tural parameters are determined. Keywords: layered titanate, methylamine, intercalation, organic-inorganic compounds, hydrothermal microwave synthesis DOI: 10.1134/S1087659618050176 The complete ordering of A and Ln cations between two interlayer spaces which separate blocks with the structure of perovskite is fulfilled in the struc- ture of layered perovskite-like oxides ALnTiO 4 (A = an alkali metal and Ln = lanthanide), which belong to the Ruddlesden–Popper phases. Protonated layered per- ovskite-like oxides HLnTiO 4 (Fig. 1) can be obtained from the alkaline forms of ALnTiO 4 via ion exchange in solutions of acids [1]. They can be used as the initial com- pounds for the synthesis of new perovskite-like deriva- tives via ion exchange [2] and pyrolysis [3], as well as for the preparation of nanostructured composites [4]. The products of the intercalation (insertion) of organic compounds into the interlayer space of layered oxides are of interest as precursors for splitting the lat- ter to monolayers—nanoscale objects which possess a large specific surface area and, as a result, are promis- ing catalysts, photocatalysts, and materials for elec- tronics [5]. There is also a possibility of using the intercalates in the synthesis of hybrid materials and their monolayers with a surface modified by organic functional groups covalently bound to it. The corre- sponding process of the addition of organic molecules with the formation of covalent bonds between them and the layered oxide is called grafting and makes it possible to obtain organic-inorganic derivatives which potentially have a variety of practical applications [6]. Among organic substances which are potentially capable of intercalating into the interlayer space of lay- ered perovskite-like titanates, the highest activity in reactions of this type should be expected from organic bases (in particular, amines), which are partially trans- formed into the cationic (protonated) form in aqueous media possessing enhanced affinity to the layers of the oxide bearing a partially negative charge. However, currently, the intercalation of amines and other organic bases into layered perovskite-like titanates is understudied; particularly, there is information about the preparation of amino derivatives only for three- layered oxides H 2 Ln 2 Ti 3 O 10 [6, 7]. In addition, the set of bases being used is often limited to n-butylamine and expensive tetrabutylammonium hydroxide [8, 9], while there is no published information about the inter- calation of the simplest amines for many layered oxides. In particular, the possibility for the preparation of organic-inorganic derivatives of the protonated forms of single-layered perovskite-like titanates HLnTiO 4 has not been reported to date. The aim of this work was to synthesize hybrid methylamine derivatives HLnTiO 4 · CH 3 NH 2 (Ln = La and Nd) based on the protonated forms of layered titanates HLnTiO 4 and to characterize the obtained products. The phase composition of the obtained samples was controlled via X-ray diffraction analysis (Rigaku Minif lex II, CuK α radiation, range of angles 2θ = 3°– 60°, scanning speed of 10°/min, and step size of 0.01°). The structural parameters were determined using the Topas software. Thermal stability was studied via the simultaneous thermal analysis on a Netzsch STA 449 F1 Jupiter instrument with a Netzsch QMS 403C Aëolos quad- rupole mass spectrometer in the range of temperatures of 35–800°C (the rate of heating was 10°C/min and the purging gas was argon). The infrared absorption spectra were recorded on a Shimadzu IRAffinity-1 Fourier-transform IR spec- trometer in a spectral range of 400–4000 cm −1 (a step of 1 cm −1 and tableting in KBr).