{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T15:28:57Z","timestamp":1789658937302,"version":"4.0.1"},"reference-count":34,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T00:00:00Z","timestamp":1789430400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001824","name":"CZECH SCIENCE FOUNDATION","doi-asserted-by":"publisher","award":["23-06562"],"award-info":[{"award-number":["23-06562"]}],"id":[{"id":"10.13039\/501100001824","id-type":"DOI","asserted-by":"publisher"}]},{"award":["23-06562"],"award-info":[{"award-number":["23-06562"]}],"id":[{"id":"https:\/\/ror.org\/01pv73b02","id-type":"ROR","asserted-by":"publisher"}]},{"name":"MINISTRY OF EDUCATION, YOUTH AND SPORTS\u2014CZECH REPUBLIC","award":["LM2023037"],"award-info":[{"award-number":["LM2023037"]}],"id":[{"id":"https:\/\/ror.org\/037n8p820","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Guanidinium-intercalated derivatives of \u03b1- and \u03b3-zirconium hydrogen phosphate, zirconium 2-sulfoethylphosphonate, and zirconium 4-sulfophenylphosphonate were successfully synthesized by treatment of the host materials with aqueous guanidine carbonate solutions at room temperature. In contrast, hydrothermal treatment at 180 \u00b0C proved unsuitable for the preparation, as guanidine underwent decomposition, leading predominantly to the formation of ammonium-intercalated phases and, in some cases, partial degradation of the host structure. The synthesized materials were characterized by powder X-ray diffraction, elemental analysis, thermogravimetric analysis, and infrared spectroscopy. The combined results confirmed the incorporation of guanidinium ions into the interlayer space together with variable amounts of co-intercalated water. Spectroscopic data further indicated the formation of extensive hydrogen-bonding networks involving guanidinium ions, water molecules, and acidic groups of the host frameworks. Proton conductivity measurements revealed a pronounced dependence on relative humidity, with conductivity increasing as the water content of the materials increased. Nevertheless, the conductivities of all guanidinium intercalates remained lower than those of the corresponding parent zirconium phosphates and phosphonates. Temperature-dependent conductivity measurements suggested that proton transport proceeds predominantly via a vehicle mechanism in both hydrated and dehydrated states. The prepared intercalates exhibited reversible dehydration and rehydration behavior and retained their structural integrity during conductivity measurements.<\/jats:p>","DOI":"10.3390\/molecules31183263","type":"journal-article","created":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T08:16:48Z","timestamp":1789460208000},"page":"3263","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Guanidinium Intercalation into Layered Zirconium Phosphates and Phosphonates: Synthesis, Structure, and Ionic Conductivity"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7163-2476","authenticated-orcid":false,"given":"Kl\u00e1ra","family":"Mel\u00e1nov\u00e1","sequence":"first","affiliation":[{"name":"Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentsk\u00e1 95, 532 10 Pardubice, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9972-4177","authenticated-orcid":false,"given":"Tom\u00e1\u0161","family":"Plech\u00e1\u010dek","sequence":"additional","affiliation":[{"name":"Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentsk\u00e1 95, 532 10 Pardubice, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0936-7090","authenticated-orcid":false,"given":"Ludv\u00edk","family":"Bene\u0161","sequence":"additional","affiliation":[{"name":"Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentsk\u00e1 95, 532 10 Pardubice, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Petr","family":"Kut\u00e1lek","sequence":"additional","affiliation":[{"name":"Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Studentsk\u00e1 95, 532 10 Pardubice, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Shearan, S.J.I., Stock, N., Emmerling, F., Demel, J., Wright, P.A., Demadis, K.D., Vassaki, M., Costantino, F., Vivani, R., and Sallard, S. (2019). New Directions in Metal Phosphonate and Phosphinate Chemistry. Crystals, 9.","DOI":"10.3390\/cryst9050270"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Clearfield, A., and Demadis, K. (2012). Metal Phosphonate Chemistry: From Synthesis to Applications, RSC Publishing. [1st ed.].","DOI":"10.1039\/9781849733571"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.matdes.2018.05.041","article-title":"Zirconium phosphate (ZrP)-based functional materials: Synthesis, properties and applications","volume":"155","author":"Xiao","year":"2018","journal-title":"Mater. Des."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"14551","DOI":"10.1039\/D4DT00757C","article-title":"Recent advances and perspectives for intercalation layered compounds. Part 2: Applications in the field of catalysis, environment and health","volume":"53","author":"Bisio","year":"2024","journal-title":"Dalton Trans."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"14525","DOI":"10.1039\/D4DT00755G","article-title":"Recent advances and perspectives on intercalation layered compounds part 1: Design and applications in the field of energy","volume":"53","author":"Bisio","year":"2024","journal-title":"Dalton Trans."},{"key":"ref_6","unstructured":"Demadis, K. (2026). Proton conductivity of zirconium phosphates and phosphonates. Phosphonate Chemistry, Technology and Applications Industrial, Environmental, and Energy Applications, Elsevier. [1st ed.]."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ssi.2019.03.005","article-title":"From layered zirconium phosphates and phosphonates to nanofillers for ionomeric membranes","volume":"336","author":"Casciola","year":"2019","journal-title":"Solid State Ion."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1016\/0167-2738(86)90066-4","article-title":"Protonic Conduction of Intercalation Compounds of alpha-Zirconium Phosphate with Propylamine","volume":"22","author":"Casciola","year":"1986","journal-title":"Solid State Ion."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/0167-2738(89)90013-1","article-title":"Influence of the Guest Molecules on the Protonic Coduction of Anhydrous Intercalation Compounds of alpha-Zirconium Hydrogen Phosphate with Diamines","volume":"35","author":"Casciola","year":"1989","journal-title":"Solid State Ion."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/0167-2738(93)90361-6","article-title":"Intercalation Compounds of Zirconium Phosphates with Substituted Pyrazoles and Imidazoles and Their AC Conductivity","volume":"61","author":"Casciola","year":"1993","journal-title":"Solid State Ion."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/0167-2738(91)90128-X","article-title":"Intercalation Compounds of alpha-Zirconium Hydrogen Phosphate with Heterocyclic Bases and Their ac Conductivity","volume":"46","author":"Casciola","year":"1991","journal-title":"Solid State Ion."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/0167-2738(94)90244-5","article-title":"NMR Investigation on Molecular Mobility of Pyrazole and Pyridazine Intercalated in Layered Alpha-Zirconium Phosphate","volume":"68","author":"Blumenfeld","year":"1994","journal-title":"Solid State Ion."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/0167-2738(91)90129-Y","article-title":"Proton conductivity of zirconium carboxy n-alkyl phosphates with an alpha layered structure","volume":"46","author":"Alberti","year":"1991","journal-title":"Solid State Ion."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/0167-2738(94)00273-U","article-title":"Zirconium 2-amino ethyl phosphonate: Preparation, characterization and preliminary study of its electrical conductivity and intercalation properties","volume":"77","author":"Casciola","year":"1995","journal-title":"Solid State Ion."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/0167-2738(92)90235-H","article-title":"Protonic Conductivity of Layered Zirconium Phosphonates Containing -SO3H Groups Pt. 1. Preparation and Characterization of a Mixed Zirconium Phosphonate of Composition Zr(O3PR)0.73(O3PR\u2019)1.27.nH2O, with R = -C6H4-SO3H and R\u2019 = -CH2-OH","volume":"50","author":"Alberti","year":"1992","journal-title":"Solid State Ion."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2893","DOI":"10.1016\/j.ssi.2005.09.042","article-title":"Preparation and characterization of alpha-layered zirconium phosphate sulfophenylphosphonates with variable concentration of sulfonic groups","volume":"176","author":"Alberti","year":"2005","journal-title":"Solid State Ion."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1016\/j.ssi.2010.03.034","article-title":"Synthesis and Characterization of New Zirconium 4-Sulfophenylphosphonates","volume":"181","author":"Zima","year":"2010","journal-title":"Solid State Ion."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1016\/j.jssc.2019.05.019","article-title":"Microcomposites of zirconium phosphonates with a conducting polymer, polyaniline: Preparation, spectroscopic study and humidity sensing","volume":"276","author":"Melanova","year":"2019","journal-title":"J. Solid State Chem."},{"key":"ref_19","unstructured":"Database PDF-5+ (2026). Joint Committee on Powder Diffraction Standards, International Centre of Diffraction Data."},{"key":"ref_20","unstructured":"Socrates, G. (1997). Infrared Characteristic Group Frequencies, John Wiley & Sons, Inc.. [2nd ed.]."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"116257","DOI":"10.1016\/j.ssi.2023.116257","article-title":"Characterization and properties of layered tetragonal metal phosphonates with sulfoethyl and sulfophenyl groups","volume":"397","author":"Zima","year":"2023","journal-title":"Solid State Ion."},{"key":"ref_22","first-page":"421","article-title":"Mechanism of Proton Transport in Powder Compacts of Acid Salts with alpha-Layered Structure","volume":"109","author":"Alberti","year":"1979","journal-title":"Gazz. Chim. Ital."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/0923-1137(89)90110-3","article-title":"Preparation of gamma-Zirconium phosphate microcrystals with high degree of crystallinity and proton conductivity of their hydrogen and ammonium forms","volume":"11","author":"Alberti","year":"1989","journal-title":"React. Polym."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"12508","DOI":"10.1021\/acs.inorgchem.6b02308","article-title":"Significantly dense two-dimensional hydrogen bond network in a layered zirconium phosphate leading to high proton conductivities in both water assisted low-temperature and anhydrous intermediate temperature regions","volume":"55","author":"Gui","year":"2016","journal-title":"Inorg. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"6093","DOI":"10.1039\/D1CE00852H","article-title":"A water-stable open-framework zirconium (IV) phosphate and its water assisted high proton conductivity","volume":"23","author":"Yu","year":"2012","journal-title":"CrystEngComm"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"8182","DOI":"10.1039\/D2DT01035F","article-title":"Ionothermal synthesisof a highly crystalline zirconium phosphate proton conductor","volume":"51","author":"Gui","year":"2022","journal-title":"Dalton. Trans."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"610","DOI":"10.1021\/cm950192a","article-title":"Proton conductivity: Materials and applications","volume":"8","author":"Kreuer","year":"1996","journal-title":"Chem. Mater."},{"key":"ref_28","first-page":"208","article-title":"Vehicle mechanism, A new model for the interpretation of the conductivity of fast proton conductors","volume":"122","author":"Weppner","year":"1982","journal-title":"Angew. Chem. Int. Ed. Engl."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"6146","DOI":"10.1021\/jacs.8b02598","article-title":"Unigue proton transportation pathway in a robust inorganic coordination polymer leading to intrinsically high and sustainable anhydrous proton conductivity","volume":"140","author":"Gui","year":"2018","journal-title":"J. Am. Chem. Soc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"e202218421","DOI":"10.1002\/anie.202218421","article-title":"Anhydrous superprotonic conductivityx in the zirconium acid triphosphate ZrH5(PO4)3","volume":"62","author":"Fop","year":"2023","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"9409","DOI":"10.1021\/ic101200f","article-title":"High Yield Precipitation of Crystalline alpha-Zirconium Phosphate from Oxalic Acid Solutions","volume":"49","author":"Capitani","year":"2010","journal-title":"Inorg. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1039\/DT9950000111","article-title":"X-Ray powder structure and Rietveld refinement of \u03b3-zirconium phosphate, Zr(PO4)(H2PO4).2H2O","volume":"24","author":"Poojary","year":"1995","journal-title":"J. Chem. Soc. Dalton Trans."},{"key":"ref_33","unstructured":"(2026, August 09). ZSimpWin 3,50, EChem Software, B. Yeum, AMETEK Scientific Instruments, Ann Arbor (Michigan, USA), 1999\u20132013. Available online: http:\/\/www.echemsw.com."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2013","DOI":"10.1021\/ie50477a041","article-title":"Standard Solutions for Humidity Control at 25\u00b0 C","volume":"41","author":"Stokes","year":"1949","journal-title":"Ind. Eng. Chem."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/18\/3263\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T04:15:34Z","timestamp":1789618534000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/18\/3263"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,15]]},"references-count":34,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["molecules31183263"],"URL":"https:\/\/doi.org\/10.3390\/molecules31183263","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,15]]}}}