Resorcinarene-Based Cavitands: from Structural Design and Synthesis to Separations Applications
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Brigham Young University BYU ScholarsArchive Theses and Dissertations 2013-03-18 Resorcinarene-Based Cavitands: From Structural Design and Synthesis to Separations Applications Na Li Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Biochemistry Commons, and the Chemistry Commons BYU ScholarsArchive Citation Li, Na, "Resorcinarene-Based Cavitands: From Structural Design and Synthesis to Separations Applications" (2013). Theses and Dissertations. 3520. https://scholarsarchive.byu.edu/etd/3520 This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Resorcinarene-Based Cavitands: From Structural Design and Synthesis to Separations Applications Na Li A dissertation submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Doctor of Philosophy John D. Lamb, Chair Roger G. Harrison Matthew R. Linford David V. Dearden Richard K. Watt Department of Chemistry and Biochemistry Brigham Young University March 2013 Copyright © 2013 Na Li All Rights Reserved ABSTRACT Resorcinarene-Based Cavitands: From Structural Design and Synthesis to Separations Applications Na Li Department of Chemistry and Biochemistry, BYU Doctor of Philosophy Resorcinarenes are cyclic tetramers that are synthesized by the condensation of resorcinol and various aldehydes. The upper and lower rims can be modified with substituents that provide specific selectivity and other chemical features. In this work, resorcinarene-based macrocyclic ligands with specific selectivities have been designed, synthesized and applied to chiral amine discrimination and transition metal ion separations. These resorcinarenes fall into two categories. In the first type, the upper rims of resorcinarenes were modified with amino acid groups, including chiral alanine groups. The lower rims were modified with –CH3, or –C11H23 groups. The structures were studied by nuclear magnetic resonance (NMR), mass spectrometry (MS), dynamic light scattering (DLS), and sustained off-resonance irradiation collision induced dissociation (SORI-CID) techniques in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The binding strength between the resorcinarenes with amines was studied by 1H NMR titration. Among these new resorcinarenes, the chiral alanine undecyl resorcinarenes acid (AUA) showed chiral discrimination among chiral secondary amines. The AUA ligands were adsorbed onto 55% cross-linked styrene-divinylbenzene resin and used as cation-exchangers in ion chromatography (IC) for transition metal ion separations. The AUA IC column showed selectivity for Cu2+ when no chelating eluent was used in the eluent, a selectivity which was not observed with a commercial column containing standard cation-exchangers. Six metal ions (Cu2+, Mn2+, Co2+, Ni2+, Cd2+, and Zn2+) were separated on the AUA column within a reasonable time with a simple oxalic acid gradient eluent. The second type of resorcinarene-based ligand, cyclenbowl, contains four cyclen units on the upper rim and four –C11H23 chains on the lower rim. The column packed with cyclenbowl adsorbed onto polystyrene showed selectivity for Cu2+ over five other transition metal ions including Mn2+, Co2+, Ni2+, Cd2+, and Zn2+ ions. The preconcentration of Cu2+ at the parts per billion level from a high concentration matrix of Mn2+, Co2+, Ni2+, Cd2+, and Zn2+ ions 2+ was achieved using HNO3 eluent. Recovery of Cu was greater than 98%. Furthermore, the other five transition metal ions were well separated on the cyclenbowl column with an oxalic acid eluent gradient. Keywords: resorcinarene, chiral recognition, ion chromatography, selectivity, transition metal ions, preconcentration, macrocyclic ligands, separations ACKNOWLEDGEMENTS I have been supported and inspired by my family, friends, supervisor Dr. John D. Lamb, and my committee members during my Ph. D. study. When looking back the way that I have passed, I have enormous appreciation for those individuals and Brigham Young University. The great educational opportunity that BYU offered me not only taught me knowledge, but also taught me love and faith. The study and research experience in a different culture not only increased my professional knowledge, but also opened my eyes, inspired my thoughts and made me reflect on the values that I believed before. This unique experience at BYU will benefit my whole life. While working with Dr. Lamb, I have appreciated his mentorship and the research opportunity that he provided me. His keen insights always enlightened me. Every experimental result and every paper that I have published were finished under his zealous help and instruction. I would like to thank Dr. Roger Harrison for the valuable discussions in my synthesis and NMR work. He was always patient to me and willing to give me suggestions both in work and life. I also would like to express my gratitude to my Ph.D. committee members, Dr. David V. Dearden, Dr. Richard K. Watt, and Dr. Matthew R. Linford for their good advice and guidance through my research. Their advice in my yearly progress report always gave me inspiration in my research. Finally, I would like to give my special thanks to my dear sister Qing who accompanied me through all the ups and downs in my life. I dedicate this book to my mother Aiqin Gao and father Senlin Li for their support, sacrifice, understanding, and love throughout my life. TABLE OF CONTENTS ABSTRACT .................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iii TABLE OF CONTENTS ............................................................................................................... iv Chapter 1 Ion Chromatography and Membrane Separations Using Macrocyclic Ligands ............ 1 1. Introduction ............................................................................................................................. 2 2. Selective binding by macrocyclic ligands ............................................................................... 3 2.1 Structures of macrocycles used in ion chromatography and membrane separations ......... 4 2.2 Macrocyclic ligand characteristics which influence selectivity ......................................... 6 2.2.1 Size-fit and conformational changes ........................................................................... 6 2.2.2 Donor type, number, and position ............................................................................. 11 2.2.3 Substitution effects on complexation selectivity ....................................................... 14 2.3 Ion effect on macrocycle selectivity ................................................................................ 15 2.4 Solvent ............................................................................................................................. 16 3. Ion chromatography (IC) ....................................................................................................... 19 3.1 Principles of suppressed IC .............................................................................................. 19 3.2 New perspectives of IC .................................................................................................... 23 4. Application of macrocycles to ion chromatography ............................................................. 25 iv 4.1 Macrocyclic ligands in the stationary phase .................................................................... 26 4.1.1 Crown ethers .............................................................................................................. 26 4.1.2 Crown ethers in the mobile phase ............................................................................. 32 4.1.3 Crown ethers in detection systems ............................................................................ 36 4.2 Cryptands in ion chromatography .................................................................................... 36 4.3 Calixarenes in ion chromatography ................................................................................. 43 4.4 Cyclodextrins ................................................................................................................... 45 5. Liquid membranes ................................................................................................................. 49 5.1 Facilitated transport mechanism and membrane types .................................................... 49 5.2 Macrocyclic carriers in liquid membranes ....................................................................... 52 6. Conclusions ........................................................................................................................... 64 Chapter 2 Application of Resorcinarene Derivatives in Chemical Separations ........................... 77 1. Introduction ........................................................................................................................... 77 2. High Performance Liquid Chromatography (HPLC) ............................................................ 82 3. Gas Chromatography