SYNTHESIS AND PROPERTIES OF SCANDIUM CARBOXYLATE METAL-ORGANIC FRAMEWORKS Berenice González Santiago A Thesis Submitted for the Degree of PhD at the University of St Andrews 2015 Full metadata for this item is available in St Andrews Research Repository at: http://research-repository.st-andrews.ac.uk/ Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/6904 This item is protected by original copyright Synthesis and properties of scandium carboxylate metal-organic frameworks This thesis is submitted in partial fulfilment for the degree of Doctor of Philosophy in the Faculty of Science of the University of St Andrews by Berenice González Santiago, MSc September 2014 Supervisor: Prof. Paul A. Wright University of St Andrews Declarations 1. I, Berenice González Santiago, hereby certify that this thesis, which is approximately 40000 words in length, has been written by me, that it is the record of work carried out by me and that it has not been submitted in any previous application for a higher degree. I was admitted as a research student in September, 2010 and as a candidate for the degree of Doctor of Philosophy in October, 2011 the higher study for which this is a record was carried out in the University of St Andrews between 2010 and 2014. Date ……………………. Signature of Candidate …………………….. 2. I hereby certify that the candidate has fulfilled the conditions of the Resolution and Regulations appropriate for the degree of PhD in the University of St Andrews and that the candidate is qualified to submit this thesis in application for that degree. Date ……………………. Signature of Supervisor ……………………. 3. In submitting this thesis to the University of St Andrews I understand that I am giving permission for it to be made available for use in accordance with the regulations of the University Library for the time being in force, subject to any copyright vested in the work not being affected thereby. I also understand that the title and the abstract will be published, and that a copy of the work may be made and supplied to any bona fide library or research worker, that my thesis will be electronically accessible for personal or research use unless exempt by award of an embargo as requested below, and that the library has the right to migrate my thesis into new electronic forms as required to ensure continued access to the thesis. I have obtained any third-party copyright permissions that may be required in order to allow such access and migration, or have requested the appropriate embargo below. Embargo on all of printed copy and electronic copy for the same fixed period of one year on the following ground: Publication would preclude future publication. Date ………………………. Signature of Candidate ……………………… Signature of Supervisor ……………………… ii Acknowledgements I am so grateful to CONACyT-Mexico for the scholarship awarded which made it possible to carry out my PhD. Also, many thanks to the School of chemistry at St. Andrews for co- funding. Thanks to SEP-complemento for the grant awarded for the term dates 2013-2014. Firstly, I would like to express my sincerest gratitude to my supervisor Prof. Paul A. Wright, for the opportunity to be part of his group. Thanks for the feedback, suggestions, for your patience and taking time to answer my questions, and for the endless support you have given me in so many ways. I thank Professor Alex Slawin and Dr. David Cordes at St. Andrews, Dr. Stephen Moggach and Jorge Sotelo at Edinburgh, for their help and support with the crystallography data. Thanks to Dr. Sharon Ashbrook, Dr. Valerie Seymour and Scott Sneddon for the collection and analysis of solid-state NMR data. I owe huge thanks to Mrs Silvia Williamson for the training on how to use the instruments, and for the collection of adsorption and thermal analysis data. Thanks to everyone in the Wright group including past members Dr. John Mowat, and Dr. Jurgen Kahr for all their background input on MOFs. I am lucky to have the ongoing support of great office mates; Dr. Magdalena Lozinska and David Prince. I would also like to give special thanks to Alessandro Turrina and Dr. Alex Greenway for helpful discussions about my research over the last year. Thanks to all my friends here in St Andrews, with special thanks to Pernille Lau and J. Carlos H. Reta, for their company and kindness; to all my friends from Mexico, who have always brought a smile to my face. Also, I would like to thank Professors; Ana Maria Soto E., Miguel Angel Garcia S. and Hugo Sanchez S., for their enthusiasm and encouraging me to come here. I am hugely indebted to my mother and relatives for their endless support. iii Dedicated to The memory of my father My family And Salvador, who makes life fun. Rise up like the sun Labor till the work is done. iv Abstract This work investigated the synthesis, characterisation and properties of known and novel scandium carboxylate Metal-organic Frameworks (MOFs). The first part reports the performance of these Sc-MOFs as Lewis acid catalysts. The porous MOF scandium trimesate MIL-100(Sc) and the scandium terephthalates such as MIL-101(Sc), MIL-88B(Sc) and MIL- 68(Sc) (prepared as the Sc-analogue for the first time), and scandium biphenyldicarboxylate MIL-88D(Sc) were prepared and tested as Lewis acid catalysts. Chromium MIL-101 and MIL-100 and scandium-exchanged zeolites were prepared for comparison. Moreover, successful encapsulation of the phosphotungstate polyoxometalates (POMs) in the cavities of MIL-101(Sc) enhanced the stability of this material. These scandium and chromium MOFs, POM-MOF composites and scandium-exchanged zeolite were tested as heterogeneous catalysts in the carbonyl ene reaction between α-methyl styrene and ethyl trifluoropyruvate. This showed that MIL-100(Sc) was the best catalyst for this reaction, achieving a conversion of 99% to the desired product. The stabilized MIL-101(Sc) was also very active, but less selective for this reaction. Acetalisation of acetaldehyde was also studied, and in this reaction the isoreticular MOFs MIL-88(B) and MIL-88D(Sc) were the most active and selective catalysts. For this reaction, the activity of MIL-100(Sc) was low, which was attributed to reduce pore size and blockage. Functionalisation of the range of scandium terephthalates such as MIL-101(Sc), MIL- 88B(Sc), MIL-68(Sc), Sc2BDC3,and MIL-53(Sc) particularly with –NH2 groups, made up the second main part of this research. Solvothermal synthesis were performed at lower temperatures and using mixed solvents to synthesize these amino-terephthalate MOFs, often for the first time, and their adsorption properties were studied, particularly for the adsorption of CO2. v The synthesis of pure Sc2(NH2-BDC)3 and Sc2(Br-BDC)3 was achieved for first time by a solvothermal route, lower temperatures, and mixed solvents. This approach yielded large crystals suitable for single crystal diffraction and microcrystal IR spectroscopy. Post- synthetic modification (PSM) of Sc2(NH2-BDC)3 was explored by incorporation of NO2- groups into the framework by solvent-assisted ligand exchange. The adsorption properties of functionalised and post-modified materials were compared with those of Sc2BDC3 and Sc2(NO2-BDC)3 for methanol and hydrocarbons This study demonstrated that Sc2BDC3 and Sc2(NH2-BDC)3 give the higher uptakes while the –Br and –NO2 forms display shape selectivity for n-alkanes over iso-alkanes. Amino-functionalised MIL-53(Sc) was prepared for the first time using a mixed ligand approach, so that 10-20% of a second functionalised terephthalate ligand (NO2, Br, -(OH)2) was required for successful single phase synthesis in addition to amino-terephthalic acid. The materials were characterised using PXRD, TGA and gas adsorption, which confirms the samples show a range of behaviour for CO2 adsorption. Notably, the `breathing´ behaviour is strongly dependent on the type of functionalisation. Finally, the exploratory synthesis of novel scandium MOFs, using isophthalic acid (IA) and its amino and nitro- derivatives, 2,5-furandicarboxylate (FDA) and the porphyrin tetra(carboxyphenyl)porphyrin (TCPP) as linkers was carried out and six novel materials were synthesized, three of which gave crystals large enough for their structure to be determined by single crystal diffraction. Further characterisation was carried out by PXRD, TGA and solid-state NMR. Some of these materials have been shown to be porous to CO2 and N2. vi Publications arising from this work 1. L. Mitchell, B. Gonzalez-Santiago, J. P. S. Mowat, M. E. Gunn, P. Williamson, N. Acerbi, M. L. Clarke and P. A. Wright. Remarkable Lewis acid catalytic performance of the scandium trimesate metal organic framework MIL-100(Sc) for C–C and C=N bond-forming reactions. Cat. Sci. Tech., 2013, 3, 606-617. DOI: 10.1039/c2cy20577g 2. Alex Greenaway, Berenice Gonzalez-Santiago, Paul M. Donaldson, Mark D. Frogley, Gianfelice Cinque, Jorge Sotelo, Stephen Moggach, Eleni Shiko, Stefano Brandani, Russell F. Howe and Paul A. Wright In situ synchrotron IR microspectroscopy of CO2 adsorption on single crystals of the functionalised MOF, Sc2(BDC-NH2)3 Angew. Chem. Int. Ed., 2014, 53, 13483–13487. DOI: 10.1002/anie.201408369 vii Abbreviation Explanation (OH)2-BDC 2, 5 -Dihydroxyterephthalic acid 3D Three-dimensional a Unit cell parameter b Unit cell parameter BDC Terephthalic acid (Benzene dicarboxylic acid) BET Brunauer-Emmet-Teller BPDC Biphenyl-4,4-dicarboxylic acid Br-BDC 2-Bromoterephthalic acid BTC Trimesic acid (Benzene tricarboxylic acid) c Unit cell parameter CHN carbon, hydrogen and nitrogen