{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T15:20:59Z","timestamp":1783092059052,"version":"3.54.6"},"reference-count":58,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T00:00:00Z","timestamp":1765152000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Airlangga Research Fund Universitas Airlangga","award":["337\/UN3.15\/PT\/2023"],"award-info":[{"award-number":["337\/UN3.15\/PT\/2023"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Noncovalent interactions are key to the stability of lignin dimers, the primary components of bio-oil. However, their specific influence on the infrared spectra remains poorly understood. Using dispersion-corrected density-functional theory (APFD\/6-311++G(d,p)), we conducted a comparative analysis of the structures and infrared spectra of four lignin derivatives\u2014benzene, phenol, anisole, and guaiacol\u2014as monomers and dimers. Our study reveals that distinct vibrational shifts and newly emerging peaks observed in the calculated infrared spectra of the dimers can be attributed to the formation of \u03c3\u00b7\u00b7\u00b7\u03c0 and \u03c0\u00b7\u00b7\u00b7\u03c0 stacking, hydrogen bonding, attractive van der Waals, and steric repulsion interactions. We extended the study to 3,3\u2032-dimethoxy-1,1\u2032-biphenyl-2,2\u2032-diol, a guaiacyl moiety with a C\u2013C linkage. The results indicate that the structure in which both guaiacol units adopt an anti\u2013syn conformation is more stable\u2014minimizing steric repulsion between hydroxyl groups\u2014than configurations in which one guaiacol unit adopts either anti\u2013anti or gauche\u2013anti conformation. These differences are clearly reflected in their distinctive infrared spectral signatures.<\/jats:p>","DOI":"10.3390\/molecules30244694","type":"journal-article","created":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T10:35:51Z","timestamp":1765190151000},"page":"4694","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["The Role of Noncovalent Interactions in the Infrared Spectra of Lignin Model Compounds: A DFT Study"],"prefix":"10.3390","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7224-5731","authenticated-orcid":false,"given":"Febdian","family":"Rusydi","sequence":"first","affiliation":[{"name":"Research Center for Quantum Engineering Design, Faculty of Science and Technology, Universitas Airlangga, Jl. Mulyorejo, Surabaya 60115, East Java, Indonesia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6687-1488","authenticated-orcid":false,"given":"Lusia Silfia Pulo","family":"Boli","sequence":"additional","affiliation":[{"name":"Physics Study Program, Universitas Jenderal Soedirman, Jl. Dr. Soeaparno 61, Purwokerto 53123, Central Java, Indonesia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8700-1414","authenticated-orcid":false,"given":"Indri Badria","family":"Adilina","sequence":"additional","affiliation":[{"name":"Research Center for Catalysis, National Research and Innovation Agency, KST BJ Habibie, Tangerang Selatan 15314, Banten, Indonesia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4148-0744","authenticated-orcid":false,"given":"Wahyu Tri","family":"Cahyanto","sequence":"additional","affiliation":[{"name":"Physics Study Program, Universitas Jenderal Soedirman, Jl. Dr. Soeaparno 61, Purwokerto 53123, Central Java, Indonesia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3228-2570","authenticated-orcid":false,"given":"Stewart F.","family":"Parker","sequence":"additional","affiliation":[{"name":"ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, Oxfordshire, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1834-5619","authenticated-orcid":false,"given":"Ferensa","family":"Oemry","sequence":"additional","affiliation":[{"name":"Research Center for Quantum Physics, National Research and Innovation Agency, KST BJ Habibie, Tangerang Selatan 15314, Banten, Indonesia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"117904","DOI":"10.1016\/j.indcrop.2023.117904","article-title":"Agricultural Wastes: A Practical and Potential Source for the Isolation and Preparation of Cellulose and Application in Agriculture and Different Industries","volume":"208","author":"Riseh","year":"2024","journal-title":"Ind. Crops Prod."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1481","DOI":"10.1016\/j.ijhydene.2021.10.122","article-title":"A Comprehensive Review on Lignocellulosic Biomass Biorefinery for Sustainable Biofuel Production","volume":"47","author":"Rodionova","year":"2022","journal-title":"Int. J. Hydrog. Energy"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1016\/j.joei.2019.03.005","article-title":"Utilization of Lignin: A Sustainable and Eco-Friendly Approach","volume":"93","author":"Kumar","year":"2020","journal-title":"J. Energy Inst."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"136815","DOI":"10.1016\/j.jclepro.2023.136815","article-title":"Lignocellulosic Biomass from Agricultural Waste to the Circular Economy: A Review with Focus on Biofuels, Biocomposites and Bioplastics","volume":"402","author":"Mujtaba","year":"2023","journal-title":"J. Clean. Prod."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/j.biortech.2018.09.072","article-title":"From Lignin to Valuable Products\u2013Strategies, Challenges, and Prospects","volume":"271","author":"Wang","year":"2019","journal-title":"Bioresour. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"116824","DOI":"10.1016\/j.indcrop.2023.116824","article-title":"Towards Functionalized Lignin and Its Derivatives for High-Value Material Applications","volume":"200","author":"Yu","year":"2023","journal-title":"Ind. Crops Prod."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4154","DOI":"10.1039\/D3GC00565H","article-title":"Renewable Lignin and Its Macromolecule Derivatives: An Emerging Platform toward Sustainable Electrochemical Energy Storage","volume":"25","author":"Yang","year":"2023","journal-title":"Green Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1039\/C3EE43081B","article-title":"Upgrading of Lignin-Derived Bio-Oils by Catalytic Hydrodeoxygenation","volume":"7","author":"Saidi","year":"2014","journal-title":"Energy Environ. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"21429","DOI":"10.1021\/acs.jpcc.9b01890","article-title":"Hydrodeoxygenation of Guaiacol as a Bio-Oil Model Compound over Pillared Clay-Supported Nickel-Molybdenum Catalysts","volume":"123","author":"Adilina","year":"2019","journal-title":"J. Phys. Chem. C"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1227","DOI":"10.1002\/cssc.201000157","article-title":"Lignin as Renewable Raw Material","volume":"3","author":"Dobado","year":"2010","journal-title":"ChemSusChem"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1629","DOI":"10.1002\/cssc.201100133","article-title":"Understanding the Fast Pyrolysis of Lignin","volume":"4","author":"Patwardhan","year":"2011","journal-title":"ChemSusChem"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"597","DOI":"10.2533\/chimia.2015.597","article-title":"Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism","volume":"69","author":"Ma","year":"2015","journal-title":"Chimia"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1007\/s10086-006-0834-z","article-title":"Pyrolysis Reactions of Various Lignin Model Dimers","volume":"53","author":"Kawamoto","year":"2007","journal-title":"J. Wood Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4238","DOI":"10.1002\/cssc.202000989","article-title":"An Introduction to Model Compounds of Lignin Linking Motifs; Synthesis and Selection Considerations for Reactivity Studies","volume":"13","author":"Lahive","year":"2020","journal-title":"ChemSusChem"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.fuel.2014.03.013","article-title":"Formation of Phenolic Oligomers during Fast Pyrolysis of Lignin","volume":"128","author":"Bai","year":"2014","journal-title":"Fuel"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1186\/s13321-022-00627-2","article-title":"LigninGraphs: Lignin Structure Determination with Multiscale Graph Modeling","volume":"14","author":"Wang","year":"2022","journal-title":"J. Cheminform"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2314","DOI":"10.1021\/acs.biomac.3c00186","article-title":"Lignin Structure and Reactivity in the Organosolv Process Studied by NMR Spectroscopy, Mass Spectrometry, and Density Functional Theory","volume":"24","author":"Karlsson","year":"2023","journal-title":"Biomacromolecules"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1007\/s00894-017-3257-4","article-title":"The Role of Weak Interactions in Lignin Polymerization","volume":"23","author":"Dobado","year":"2017","journal-title":"J. Mol. Model."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1021\/acs.jpclett.2c03299","article-title":"\u03c0-Stacking Isomerism in Polycyclic Aromatic Hydrocarbons: The 2-Naphthalenethiol Dimer","volume":"14","author":"Saragi","year":"2023","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1016\/j.apcatb.2018.07.073","article-title":"Revealing the Pathways of Catalyst Deactivation by Coke during the Hydrodeoxygenation of Raw Bio-Oil","volume":"239","author":"Palos","year":"2018","journal-title":"Appl. Catal. B"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"171101","DOI":"10.1063\/1.2198828","article-title":"An Experimental Value for the B1u C-H Stretch Mode in Benzene","volume":"124","author":"Erlekam","year":"2006","journal-title":"J. Chem. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"13881","DOI":"10.1021\/jp906285b","article-title":"Free Radical Scavenging Properties of Guaiacol Oligomers: A Combined Experimental and Quantum Study of the Guaiacyl-Moiety Role","volume":"113","author":"Anouar","year":"2009","journal-title":"J. Phys. Chem. A"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1798","DOI":"10.1021\/jp961910z","article-title":"Infrared Spectroscopy of (Phenol) n+ (N=2-4) and (Phenol-Benzene)+ Cluster Ions","volume":"101","author":"Fujii","year":"1997","journal-title":"J. Phys. Chem. A"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"164304","DOI":"10.1063\/1.1881232","article-title":"IR\/UV and UV\/UV Double-Resonance Study of Guaiacol and Eugenol Dimers","volume":"122","author":"Longarte","year":"2005","journal-title":"J. Chem. Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"14343","DOI":"10.1021\/jp903236z","article-title":"The Gas Phase Anisole Dimer: A Combined High-Resolution Spectroscopy and Computational Study of a Stacked Molecular System","volume":"113","author":"Pietraperzia","year":"2009","journal-title":"J. Phys. Chem. A"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2191","DOI":"10.1021\/ed500563w","article-title":"Investigating Hydrogen Bonding in Phenol Using Infrared Spectroscopy and Computational Chemistry","volume":"91","author":"Fedor","year":"2014","journal-title":"J. Chem. Educ."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1021\/cr9900331","article-title":"Noncovalent Interactions: A Challenge for Experiment and Theory","volume":"100","author":"Hobza","year":"2000","journal-title":"Chem. Rev."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1007","DOI":"10.1016\/j.cpc.2013.10.026","article-title":"Critic2: A Program for Real-Space Analysis of Quantum Chemical Interactions in Solids","volume":"185","author":"Johnson","year":"2014","journal-title":"Comput. Phys. Commun."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"6498","DOI":"10.1021\/ja100936w","article-title":"Revealing Noncovalent Interactions","volume":"132","author":"Johnson","year":"2010","journal-title":"J. Am. Chem. Soc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"12165","DOI":"10.1039\/c2cp41395g","article-title":"Revealing Non-Covalent Interactions in Solids: NCI Plots Revisited","volume":"14","author":"Johnson","year":"2012","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"580","DOI":"10.1002\/jcc.22885","article-title":"Multiwfn: A Multifunctional Wavefunction Analyzer","volume":"33","author":"Lu","year":"2012","journal-title":"J. Comput. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2191","DOI":"10.1039\/c2sc20045g","article-title":"Rethinking the Term \u201cPi-Stacking.\u201d","volume":"3","author":"Martinez","year":"2012","journal-title":"Chem. Sci."},{"key":"ref_33","unstructured":"Johnson, D.W., and Hof, F. (2017). Modern Computational Approaches to Understanding of Aromatics. Aromatic Interactions: Frontiers in Knowledge and Application, The Royal Society of Chemistry."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"523","DOI":"10.1021\/acs.cgd.8b01630","article-title":"The Nature and Applications of \u03c0-\u03c0 Interactions: A Perspective","volume":"19","author":"Thakuria","year":"2019","journal-title":"Cryst. Growth Des."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"e02409","DOI":"10.1016\/j.heliyon.2019.e02409","article-title":"The Transition State Conformational Effect on the Activation Energy of Ethyl Acetate Neutral Hydrolysis","volume":"5","author":"Rusydi","year":"2019","journal-title":"Heliyon"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"10854","DOI":"10.1021\/ja802849j","article-title":"Substituent Effects in the Benzene Dimer Are Due to Direct Interactions of the Substituents with the Unsubstituted Benzene","volume":"130","author":"Wheeler","year":"2008","journal-title":"J. Am. Chem. Soc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5525","DOI":"10.1021\/ja00170a016","article-title":"The Nature of \u03c0-\u03c0 Interactions","volume":"112","author":"Hunter","year":"1990","journal-title":"J. Am. Chem. Soc."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1835","DOI":"10.1021\/ct8002282","article-title":"Benzene Dimer: Dynamic Structure and Thermodynamics Derived from on-the-Fly Ab Initio DFT-D Molecular Dynamic Simulations","volume":"4","author":"Hobza","year":"2008","journal-title":"J. Chem. Theory Comput."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"11263","DOI":"10.1021\/jp204628g","article-title":"Direct Infrared Absorption Spectroscopy of Benzene Dimer","volume":"115","author":"Chandrasekaran","year":"2011","journal-title":"J. Phys. Chem. A"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"154104","DOI":"10.1063\/1.3382344","article-title":"A Consistent and Accurate Ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) for the 94 Elements H-Pu","volume":"132","author":"Grimme","year":"2010","journal-title":"J. Chem. Phys."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1002\/jcc.20078","article-title":"Accurate Description of van Der Waals Complexes by Density Functional Theory Including Empirical Corrections","volume":"25","author":"Grimme","year":"2004","journal-title":"J. Comput. Chem."},{"key":"ref_42","unstructured":"Linstrom, P.J., and Mallard, W.G. (2025, October 29). Infrared Spectra, NIST Chemistry WebBook, NIST Standard Reference Database Number 69, Available online: https:\/\/webbook.nist.gov\/chemistry\/."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/S0166-1280(01)00390-6","article-title":"Solvent Effects on Vibrational Modes: Ab-Initio Calculations, Scaling and Solvent Functions with Applications to the Carbonyl Stretch of Dialkyl Ketones","volume":"544","author":"Cappelli","year":"2001","journal-title":"J. Mol. Struct."},{"key":"ref_44","first-page":"1521","article-title":"Solvent Effects in Infrared Spectroscopy a Computational Approach","volume":"89","author":"Louis","year":"1996","journal-title":"Mol. Phys."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"14065","DOI":"10.1021\/acs.jpcb.5b07706","article-title":"Transition Dipoles from 1D and 2D Infrared Spectroscopy Help Reveal the Secondary Structures of Proteins: Application to Amyloids","volume":"119","author":"Dunkelberger","year":"2015","journal-title":"J. Phys. Chem. B"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1295","DOI":"10.1039\/D2RA07177K","article-title":"Inconsistent Hydrogen Bond-Mediated Vibrational Coupling of Amide I","volume":"13","author":"Chakrabarty","year":"2023","journal-title":"RSC Adv."},{"key":"ref_47","unstructured":"Shapiro, F., and Williams, M. (1999). Infrared Spectral Interpretation: A Systematic Approach, CRC Press. [1st ed.]."},{"key":"ref_48","unstructured":"Roberts, E., Kinney, C., and Coleman, D. (2002). Quantitative Spectroscopy: Theory and Practice, Academic Press. [1st ed.]."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1103\/RevModPhys.73.515","article-title":"Phonons and Related Crystal Properties from Density-Functional Perturbation Theory","volume":"73","author":"Baroni","year":"2001","journal-title":"Rev. Mod. Phys."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1356","DOI":"10.2136\/sssaj1988.03615995005200050028x","article-title":"Oxidative Coupling and Polymerization of Guaiacol, a Lignin Derivative","volume":"52","author":"Simmons","year":"1988","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_51","unstructured":"Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V., Petersson, G.A., and Nakatsuji, H. (2019). Gaussian 16, Revision C.01, Gaussian, Inc."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"4989","DOI":"10.1021\/ct300778e","article-title":"A Density Functional with Spherical Atom Dispersion Terms","volume":"8","author":"Austin","year":"2012","journal-title":"J. Chem. Theory Comput."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"34022","DOI":"10.1021\/acsomega.3c04907","article-title":"First-Principles Study of the Dispersion Effects in the Structures and Keto-Enol Tautomerization of Curcumin","volume":"8","author":"Madinah","year":"2023","journal-title":"ACS Omega"},{"key":"ref_54","unstructured":"Glendening, E.D., Reed, A.E., Carpenter, J.E., and Weinhold, F. (2003). NBO Version 3.1, Gaussian Inc."},{"key":"ref_55","unstructured":"Socrates, G. (2001). Infrared and Raman Characteristic Group Frequencies: Tables and Charts, Wiley. [3rd ed.]."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Shimanouchi, T. (1972). Tables of Molecular Vibrational Frequencies, National Bureau of Standards. Consolidated Volume I.","DOI":"10.6028\/NBS.NSRDS.39"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1155","DOI":"10.1016\/0584-8539(83)80019-1","article-title":"The vibrational spectrum of anisole","volume":"39","author":"Balfour","year":"1983","journal-title":"Spectrochim. Acta A"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"24576","DOI":"10.1021\/acs.jpcc.8b06555","article-title":"Guaiacol Adsorption and Decomposition on Platinum: Insights from IR Spectroscopy and DFT Calculations","volume":"122","author":"Scoullos","year":"2018","journal-title":"J. Phys. Chem. C"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/24\/4694\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T10:38:22Z","timestamp":1765190302000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/24\/4694"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,8]]},"references-count":58,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["molecules30244694"],"URL":"https:\/\/doi.org\/10.3390\/molecules30244694","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,8]]}}}