Portrait of Dr Aniello Palma

Dr Aniello Palma

Lecturer in Organic Chemistry

About

Dr Aniello Palma obtained a Master's degree in Chemistry at the Università di Napoli Federico II, Italy, in 2005. He was subsequently awarded an STMicroelectronics fellowship by the Università di Napoli Federico II, which focused on the preparation of non-volatile memories. In 2006, he joined Professor Donal O’Shea’s group in the Centre for Synthesis and Chemical Biology at University College, Dublin in the Republic of Ireland to begin his PhD entitled 'Synthesis and application of new infra-red fluorophores'. 

After completing his PhD, Aniello moved to London (2011) and began working as a postdoctoral researcher in Professor Anthony Barrett’s (FRS, FMEDSCI) group at Imperial College London. During this time, he worked on a medicinal chemistry project involving the synthesis of cyclin-dependent kinase inhibitors and also developed new methodologies to access poly-b-keto esters. 

In 2015, Aniello joined Professor Oren Scherman’s research group in the Melville Laboratory for Polymer Synthesis at the University of Cambridge. His research projects focused on the synthesis of supramolecular polymers and on the development of supramolecular catalysts. In 2017 he joined the School of Physical Sciences at the University of Kent as a Lecturer in Organic Chemistry.

Research interests

Research in Dr Palma's group sits at the interface between chemistry, biology and material science, focusing on the design of smart and responsive materials prepared via supramolecular approaches and inspired by biological polymers.

Teaching

Aniello teaches modules on chemical reactivity and reaction and on transformations and chirality in organic chemistry.

Supervision

If you are interested in joining the group as a PDRA, please visit the postdoctoral fellowship opportunities webpage and indicate which funding schemes you have in mind when contacting Dr Palma.

We welcome enquiries by email from potential PhD students in the UK and around the world who have (or are about to obtain) a good undergraduate degree in Chemistry or a closely related subject. 

An MSc Research Scholarship provides an exciting opportunity to join a dynamic research department. Please contact Dr Palma (a.palma@kent.ac.uk) to discuss potential research projects.

Publications

Article

  • Barrow, S., Assaf, K., Palma, A., Nau, W. and Scherman, O. (2019). Preferential binding of unsaturated hydrocarbons in aryl-bisimidazolium·cucurbit[8]uril complexes furbishes evidence for small-molecule \(\Pi-\Pi\) interactions. Chemical Science [Online] 10:10240-10246. Available at: https://doi.org/10.1039/C9SC03282G.
    Whilst cucurbit[n]urils (CBn) have been utilized in gas encapsulation, only the smaller CBn (n = 5 and 6) have utility given their small cavity size. In this work, we demonstrate that the large cavity of CB8 can be tailored for gaseous and volatile hydrocarbon encapsulation by restricting its internal cavity size with auxiliary aryl-bisimidazolium (Bis, aryl = phenyl, naphthyl, and biphenyl) guests. The binding constants for light hydrocarbons \(C \le 4\) are similar to those measured with CB6, while larger values are obtained with Bis·CB8 for larger guests. A clear propensity for higher affinities of alkenes relative to alkanes is observed, most pronounced with the largest delocalized naphthalene residue in the auxiliary Bis guest, which provides unique evidence for sizable small-molecule \(\Pi-\Pi\) interactions.
  • Palma, A., Artelsmair, M., Wu, G., Lu, X., Barrow, S., Uddin, N., Rosta, E., Masson, E. and Scherman, O. (2017). Cucurbit[7]uril as a Supramolecular Artificial Enzyme for Diels-Alder Reactions. Angewandte Chemie International Edition [Online] 56:15688-15692. Available at: https://doi.org/10.1002/anie.201706487.
    The ability to mimic the activity of natural enzymes using supramolecular constructs (artificial enzymes) is a vibrant scientific research field. Herein, we demonstrate that cucurbit[7]uril (CB[7]) can catalyse Diels–Alder reactions for a number of substituted and unreactive N-allyl-2-furfurylamines under biomimetic conditions, without the need for protecting groups, yielding powerful synthons in previously unreported mild conditions. CB[7] rearranges the substrate in a highly reactive conformation and shields it from the aqueous environment, thereby mimicking the mode of action of a natural Diels–Alderase. These findings can be directly applied to the phenomenon of product inhibition observed in natural Diels–Alderase enzymes, and pave the way toward the development of novel, supramolecular-based green catalysts.
  • de Nijs, B., Benz, F., Barrow, S., Sigle, D., Chikkaraddy, R., Palma, A., Carnegie, C., Kamp, M., Sundararaman, R., Narang, P., Scherman, O. and Baumberg, J. (2017). Plasmonic tunnel junctions for single-molecule redox chemistry. Nature Communications [Online] 8. Available at: https://doi.org/10.1038/s41467-017-00819-7.
    Nanoparticles attached just above a flat metallic surface can trap optical fields in the nanoscale gap. This enables local spectroscopy of a few molecules within each coupled plasmonic hotspot, with near thousand-fold enhancement of the incident fields. As a result of non-radiative relaxation pathways, the plasmons in such sub-nanometre cavities generate hot charge carriers, which can catalyse chemical reactions or induce redox processes in molecules located within the plasmonic hotspots. Here, surface-enhanced Raman spectroscopy allows us to track these hot-electron-induced chemical reduction processes in a series of different aromatic molecules. We demonstrate that by increasing the tunnelling barrier height and the dephasing strength, a transition from coherent to hopping electron transport occurs, enabling observation of redox processes in real time at the single-molecule level.
  • Groombridge, A., Palma, A., Parker, R., Abell, C. and Scherman, O. (2016). Aqueous interfacial gels assembled from small molecule supramolecular polymers. Chemical Science [Online] 8:1350-1355. Available at: https://doi.org/10.1039/C6SC04103E.
    The self-assembly of a stimuli-responsive aqueous supramolecular hyperbranched polymer from small molecules is reported. This system is composed of ditopic and tritopic guest-functionalised molecules that are able to form heteroternary supramolecular complexes with the macrocyclic host cucurbit[8]uril (CB[8]). We demonstrate that the supramolecular hyperbranched polymer formed is responsive to both photo- and chemical stimuli, exhibiting reversibility. Furthermore, this system is shown to assemble at liquid–liquid interfaces, which upon gelation, is observable on the micrometre scale. This self-healing supramolecular network can act as a soft matter barrier for aqueous microdroplets, inhibiting their coalescence.
  • Sigle, D., Kasera, S., Herrmann, L., Palma, A., de Nijs, B., Benz, F., Mahajan, S., Baumberg, J. and Scherman, O. (2016). Observing Single Molecules Complexing with Cucurbit[7]uril through Nanogap Surface-Enhanced Raman Spectroscopy. The Journal of Physical Chemistry Letters [Online] 7:704-710. Available at: https://doi.org/10.1021/acs.jpclett.5b02535.
    In recent years, single-molecule sensitivity achievable by surface-enhanced Raman spectroscopy (SERS) has been widely reported. We use this to investigate supramolecular host–guest chemistry with the macrocyclic host cucurbit[7]uril, on a few-to-single-molecule level. A nanogap geometry, comprising individual gold nanoparticles on a planar gold surface spaced by a single layer of molecules, gives intense SERS signals. Plasmonic coupling between the particle and the surface leads to strongly enhanced optical fields in the gap between them, with single-molecule sensitivity established using a modification of the well-known bianalyte method. Changes in the Raman modes of the host molecule are observed when single guests included inside its cavity internally stretch it. Anisotropic intermolecular interactions with the guest are found which show additional distinct features in the Raman modes of the host molecule.
  • Palma, A., Serginson, J. and Barrett, A. (2014). Synthesis of poly ? ketoesters via double acylketene trapping. Tetrahedron Letters [Online] 56:674-676. Available at: https://doi.org/10.1016/j.tetlet.2014.12.036.
    The synthesis and characterization of polymeric ? ketoesters is herein reported. These polymers were prepared by allowing highly electrophilic acylketenes, generated in situ via thermolysis of stable 6-substituted-2,2-dimethyl-4H-1,3-dioxin-4-ones, to react with diol co-monomers. A relationship between polymer molecular weights and reaction conditions was established.
  • Grossi, M., Palma, A., McDonnell, S., Hall, M., Rai, D., Muldoon, J. and O’Shea, D. (2012). Mechanistic Insight into the Formation of Tetraarylazadipyrromethenes. The Journal of Organic Chemistry [Online] 77:9304-9312. Available at: https://doi.org/10.1021/jo301972w.
    The tetraarylazadipyrromethene chromophore class has gained increasing attention in the past decade for a diverse set of scientific interests and applications. The most direct synthetic route available for their generation is heating of 4-nitro-1,3-diarylbutan-1-ones with an ammonium source in an alcohol solvent. Despite the practical simplicity, the reaction pathway(s) for these conversions are lengthy and unclear. To gain insight into the steps involved, 15N labeling experiments with MS and NMR analysis were utilized for conversion of 4-nitro-1,3-diphenylbutan-1-one 1 into tetraphenylazadipyrromethene 2 with 15NH4OAc. To permit examination of later stages of the reaction sequence to 2, the 15N-labeled potential intermediate 3,5-diphenyl-1H-pyrrol-2-amine 10 was synthesized. A study of the dimerization pathway utilizing 15N-labeled 10 revealed an unprecedented nitrogen rearrangement in the final stages of the pathway involving a ring-opening/closing of a pyrrole ring. Utilizing 15N labeling experiments we have shown that 2,4-diphenylpyrrole 8 can also react under the reaction conditions with 3,5-diphenyl-2H-pyrrol-2-imine 7 (from oxidation of 10) to produce 2. Overall in the conversion of 1 into 2, two related pathways are ongoing concurrently; the first involves a dimerization of 3,5-diphenyl-2H-pyrrol-2-imine 7, and the other a reaction of 7 with 2,4-diphenylpyrrole 8.
  • Palma, A., Alvarez, L., Scholz, D., Frimannsson, D., Grossi, M., Quinn, S. and O’Shea, D. (2011). Cellular Uptake Mediated Off/On Responsive Near-Infrared Fluorescent Nanoparticles. Journal of the American Chemical Society [Online] 133:19618-19621. Available at: https://doi.org/10.1021/ja208086e.
    Fluorescence imaging, utilizing molecular fluorophores, often acts as a central tool for the investigation of fundamental biological processes and offers huge future potential for human imaging coupled to therapeutic procedures. An often encountered limitation with fluorescence imaging is the difficulty in discriminating nonspecific background fluorophore emission from a fluorophore localized at a specific region of interest. This limits imaging to individual time points at which background fluorescence has been minimized. It would be of significant advantage if the fluorescence output could be modulated from off to on in response to specific biological events as this would permit imaging of such events in real time without background interference. Here we report our approach to achieve this for the most fundamental of cellular processes, i.e. endocytosis. We describe a new near-infrared off to on fluorescence switchable nanoparticle construct that is capable of switching its fluorescence on following cellular uptake but remains switched off in extracellular environments. This permits continuous real-time imaging of the uptake process as extracellular particles are nonfluorescent. The principles behind the fluorescence off/on switch can be understood by encapsulation of particles in cellular organelles which effect a microenvironmental change establishing a fluorescence signal.
  • Batat, P., Cantuel, M., Jonusauskas, G., Scarpantonio, L., Palma, A., O’Shea, D. and McClenaghan, N. (2011). BF2-Azadipyrromethenes: Probing the Excited-State Dynamics of a NIR Fluorophore and Photodynamic Therapy Agent. The Journal of Physical Chemistry A [Online] 115:14034-14039. Available at: https://doi.org/10.1021/jp2077775.
    BF2-Azadipyrromethene dyes are a promising class of NIR emitter (nonhalogenated) and photosensitizer (halogenated). Spectroscopic studies on a benchmark example of each type, including absorption (one and two photon), time-resolved transient absorption (ps–ms) and fluorescence, are reported. Fast photodynamics reveal that intense nanosecond NIR fluorescence is quenched in a brominated analog, giving rise to a persistent (21 ?s) transient absorption signature. Kinetics for these changes are determined and ascribed to the efficient population of a triplet state (72%), which can efficiently sensitize singlet oxygen formation (ca. 74%), directly observed by 1?g luminescence. Photostability measurements reveal extremely high stability, notably for the nonhalogenated variant, which is at least 103-times more stable (?photodeg. = < 10–8) than some representative BODIPY and fluorescein dyes.
  • Palma, A., Tasior, M., Frimannsson, D., Vu, T., Me?allet-Renault, R. and O’Shea, D. (2009). New On-Bead Near-Infrared Fluorophores and Fluorescent Sensor Constructs. Organic Letters [Online] 11:3638-3641. Available at: https://doi.org/10.1021/ol901413u.
    The facile synthesis and photophysical characterization of new on-bead fluorophores and fluorescent sensors are described. The unique covalent immobilization strategy results in highly fluorescent beads with sharp emission profiles between 650 and 800 nm. Illustrative examples include imaging in an aqueous cellular environment and adaptation to include off/on sensing functionality, proven by a prototypical detection of gaseous HCl.
  • Palma, A., Gallagher, J., Müller-Bunz, H., Wolowska, J., McInnes, E. and O’Shea, D. (2009). Co(ii), Ni(ii), Cu(ii) and Zn(ii) complexes of tetraphenylazadipyrromethene. Dalton Transactions [Online]:273-279. Available at: https://doi.org/10.1039/B811764K.
    The synthesis, crystallographic and spectroscopic properties of four divalent isomorphous metal complexes of tetraphenylazadipyrromethene are described.
  • Loudet, A., Bandichhor, R., Burgess, K., Palma, A., McDonnell, S., Hall, M. and O’Shea, D. (2008). B,O-Chelated Azadipyrromethenes as Near-IR Probes. Organic Letters [Online] 10:4771-4774. Available at: https://doi.org/10.1021/ol8018506.
  • Pezzella, A., Palma, A., Iadonisi, A., Napolitano, A. and d’Ischia, M. (2007). The first entry to 5,6-dihydroxy-3-mercaptoindole, 5-hydroxy-3-mercaptoindole and their 2-carbomethoxy derivatives by a mild thiocyanation/reduction methodology. Tetrahedron Letters [Online] 48:3883-3886. Available at: https://doi.org/10.1016/j.tetlet.2007.03.141.
    The hitherto unknown 5,6-dihydroxy-3-mercaptoindole (4a) and its 2-carbomethoxy derivative (4b), as well as the analogous 5-hydroxy 3-mercaptoindoles, have been conveniently obtained as O,S-acetyl derivatives 3a–d by thiocyanation of the corresponding acetoxyindoles 1a–d with the NH4SCN/oxone system followed by SmI2 reduction and acetylation.

Patent

  • Volpe, M., Cimmino, A., Pezzella, A. and Palma, A. (2008). Process for synthesizing halogenated derivatives of fluorescein for use in the production of non-volatile memory devices. [Online]. Available at: https://www.google.ch/patents/US20080061289.
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