Kaisa Helttunen's Old Home Page

# Publications

  1. Małgorzata Pamuła, Evgeny Bulatov, Kaisa Helttunen
    Binding of ion pairs and neutral guests by aryl-extended meso‑p-hydroxyphenyl calix[4]pyrrole: The interplay between three binding sites (opens new window)
    J. Mol. Struct, 2023, 1273, 134268. doi:10.1016/j.molstruc.2022.134268 Graphical Abstract The binding properties of the calix[4]pyrrole host possessing three binding sites were studied by a combination of DFT, NMR, and XRD methods. Binding of acetate, benzoate and chloride anions takes place exo-cavity, while acetonitrile or adiponitrile occupies the deep aromatic endo-cavity leading to crystallization of two-dimensional sheets or dimeric capsules.
  2. Kaisa Helttunen
    Anion responsive molecular switch based on a doubly strapped calix[4]pyrrole (opens new window)
    Eur. J. Org. Chem., 2022, e202200647. doi:10.1002/ejoc.202200647 Graphical Abstract Chloride, acetate and benzoate anions binding with relatively low affinities are kinetically trapped between the straps within the cavity of a doubly strapped calix[4]pyrrole receptor. The complexation is accompanied by a conformational change of the host reminiscent of an insect being captured in a Venus flytrap.
  3. Emilia J. Virtanen, Siiri Perämäki, Kaisa Helttunen, Ari Väisänen, Jani O. Moilanen
    Alkyl-substituted aminobis(phosphonates) - efficient precipitating agents for rare earth elements, thorium, and uranium in aqueous solutions (opens new window)
    ACS Omega, 2021, 6, 23977-23987. doi:10.1021/acsomega.1c02982 Graphical Abstract This study reports six simple water-soluble aminobis(phosphonate) ligands, which separate selectively thorium, uranium, and scandium from rare earth elements with improved separation factors in comparison to traditional oxalate precipitation agents. The aminobis(phosphonate) ligands were found to form Y, La and Lu metal complexes with fewer ligands than traditional separation agents like DEHPA, thus requiring less precipitation agent.
  4. Małgorzata Pamuła, Maija Nissinen, Kaisa Helttunen
    Correlating solution- and solid-state structures of conformationally flexible resorcinarenes: significance of a sulfonyl group in intramolecular self‐inclusion (opens new window)
    Chem. Eur. J., 2020, 26, 7374-7383. doi:10.1002/chem.201905211 Graphical Abstract In this paper we show that a conformationally flexible resorcinarene macrocycle forms a self-inclusion complex in the solid state and adopts a similar folded conformation also in solution. The study was made using VT-NMR, XRD and computational methods.
  5. Kaisa Helttunen, Riia Annala, Aku Suhonen, Juho Iloniemi, Elina Kalenius, Gemma Aragay, Pablo Ballester, Heikki M. Tuononen, Maija Nissinen
    Oligoamide foldamers as helical chloride receptors – the influence of electron withdrawing substituents on anion binding interactions (opens new window)
    Chem. Asian J., 2019, 14, 647-654. doi:10.1002/asia.201801869 Graphical Abstract The incorporation of electron‐withdrawing substituents in aryl amide foldamers stabilizes the formation of 1:2 host–guest complexes with chloride anions.
  6. Kaisa Helttunen, Riia Annala, Aku Suhonen, Elisa Nauha, Juha Linnanto, Maija Nissinen
    Supramolecular chirality and symmetry breaking of fluoride complexes of achiral foldamers (opens new window)
    CrystEngComm, 2017, 19, 5184-5187. doi:10.1039/C7CE01109A Graphical Abstract Fluoride binding of achiral oligoamide foldamers produces polar and chiral crystal structures and induces exceptional symmetry breaking of the bulk sample.
  7. Kaisa Helttunen, Maija Nissinen
    Inverted molecular cups: 1-D and 2-D Ag(I) coordination polymers from resorcinarene bis-thiacrowns (opens new window)
    CrystEngComm, 2016, 18, 4944-4951. doi:10.1039/c6ce00243a Graphical Abstract Exo-cavity binding into resorcinarene based inverted molecular cups creates 1-D and 2-D silver coordination polymers with argentophilic interactions.
  8. Kaisa Helttunen, Albano Galán, Pablo Ballester, Johan Bergenholtz, Maija Nissinen
    Solid lipid nanoparticles from amphiphilic calixpyrroles (opens new window)
    J. Colloid Interface Sci., 2016, 464, 59-65. doi:10.1016/j.jcis.2015.11.012
  9. Aku Suhonen, Ian S. Morgan, Elisa Nauha, Kaisa Helttunen, Heikki M. Tuononen, Maija Nissinen
    The effect of a rigid sulfonamide bond on molecular folding: a case study (opens new window)
    Cryst. Growth Des., 2015, 15, 2602–2608. doi:10.1021/acs.cgd.5b00424
  10. Kaisa Helttunen, Tiia-Riikka Tero, Maija Nissinen
    Influence of lower rim C-methyl group on crystal forms and metal complexation of resorcinarene bis-crown-5 (opens new window)
    CrystEngComm, 2015, 17, 3667–3676. doi:10.1039/C5CE00311C
  11. Ludovico G. Tulli, Negar Moridi, Wenjie Wang, Kaisa Helttunen, Markus Neuburger, David Vaknin, Wolfgang Meier, Patrick Shahgaldian
    Polymorphism control of an active pharmaceutical ingredient beneath calixarene-based Langmuir monolayers (opens new window)
    Chem. Commun., 2014, 50, 3938-3940. doi:10.1039/C4CC00928B
  12. Kaisa Helttunen, Lauri Lehtovaara, Hannu Häkkinen, Maija Nissinen
    Crystal structures and density functional theory calculations of o- and p-nitroaniline derivatives: combined effect of hydrogen bonding and aromatic interactions on dimerization energy (opens new window)
    Cryst. Growth Des., 2013, 13, 3603-3612. doi:10.1021/CG4005714
  13. Aku Suhonen, Elisa Nauha, Kirsi Salorinne, Kaisa Helttunen, Maija Nissinen
    Structural analysis of two foldamer-type oligoamides - the effect of hydrogen bonding on solvate formation, crystal structures and molecular conformation (opens new window)
    CrystEngComm, 2012, 14, 7398-7407. doi:10.1039/C2CE25981H
  14. Kaisa Helttunen, Negar Moridi, Patrick Shahgaldian, Maija Nissinen
    Resorcinarene bis-crown silver complexes and their application as antibacterial Langmuir-Blodgett films (opens new window) Ph.D. Thesis
    Org. Biomol. Chem., 2012, 10, 2019-2025. doi:10.1039/C2OB06920B
  15. Kaisa Helttunen, Kirsi Salorinne, Tahnie Barboza, Hélène Campos Barbosa, Aku Suhonen, Maija Nissinen
    Cation binding resorcinarene bis-crowns: the effect of lower rim alkyl chain length on crystal packing and solid lipid nanoparticles (opens new window) Ph.D. Thesis
    New J. Chem, 2012, 36, 789-795. doi:10.1039/C2NJ20981K
  16. Kaisa Helttunen, Elisa Nauha, Anni Kurronen, Patrick Shahgaldian, Maija Nissinen
    Conformational polymorphism and amphiphilic properties of resorcinarene octapodands (opens new window) Ph.D. Thesis
    Org. Biomol. Chem., 2011, 9, 906-914. doi:10.1039/C0OB00602E
  17. Kaisa Helttunen, Patrick Shahgaldian
    Self-assembly of amphiphilic calixarenes and resorcinarenes in water (opens new window) Ph.D. Thesis
    New J. Chem., 2010, 34, 2704-2714 (perspective article). doi:10.1039/C0NJ00123F
  18. Kaisa Helttunen, Piotr Prus, Minna Luostarinen, Maija Nissinen
    Interaction of aminomethylated resorcinarenes with rhodamine B (opens new window) Ph.D. Thesis
    New J. Chem., 2009, 33, 1148-1154. doi:10.1039/B820409H
  19. Vesa P. Hytönen, Juha A.E. Määttä, Einari A. Niskanen, Juhani Huuskonen, Kaisa J. Helttunen, Katrin K. Halling, Henri R. Nordlund, Kari Rissanen, Mark S. Johnson, Tiina A. Salminen, Markku S. Kulomaa, Olli H. Laitinen, Tomi T. Airenne
    Structure and characterization of a novel chicken biotin-binding protein A (BBP-A) (opens new window)
    BMC Structural Biology, 2007, 7. doi:10.1186/1472-6807-7-8
  20. Vesa P. Hytönen, Jarno Hörhä, Tomi T. Airenne, Einari A. Niskanen, Kaisa J. Helttunen, Mark. S. Johnson, Tiina A. Salminen, Markku S. Kulomaa, Henri R. Nordlund
    Controlling quaternary structure assembly: subunit interface engineering and crystal structure of dual chain avidin (opens new window)
    J. Mol. Biol., 2006, 359, 1352-1363. doi:10.1016/j.jmb.2006.04.044