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  • Journal article
    Li B, Gao D, Sheppard SA, Tremlett WDJ, Liu Q, Li Z, White AJP, Brown RK, Sun X, Gong J, Li S, Zhang S, Wu X, Zhao D, Zhang C, Wang Y, Zeng XC, Zhu Z, Long NJet al., 2024,

    Highly efficient and scalable p-i-n perovskite solar cells enabled by poly-metallocene interfaces

    , Journal of the American Chemical Society, Vol: 146, Pages: 13391-13398, ISSN: 0002-7863

    Inverted p-i-n perovskite solar cells (PSCs) are easy to process but need improved interface characteristics with reduced energy loss to prevent efficiency drops when increasing the active photovoltaic area. Here, we report a series of poly ferrocenyl molecules that can modulate the perovskite surface enabling the construction of small- and large-area PSCs. We found that the perovskite-ferrocenyl interaction forms a hybrid complex with enhanced surface coordination strength and activated electronic states, leading to lower interfacial nonradiative recombination and charge transport resistance losses. The resulting PSCs achieve an enhanced efficiency of up to 26.08% for small-area devices and 24.51% for large-area devices (1.0208 cm2). Moreover, the large-area PSCs maintain >92% of the initial efficiency after 2000 h of continuous operation at the maximum power point under 1-sun illumination and 65 °C.

  • Journal article
    Walter ERH, Lee LC-C, Leung PK-K, Lo KK-W, Long NJet al., 2024,

    Mitochondria-targeting biocompatible fluorescent BODIPY probes

    , Chemical Science, Vol: 15, Pages: 4846-4852, ISSN: 2041-6520

    An increase in the mitochondrial membrane potential (MMP) is a characteristic feature of cancer and cardiovascular disease. Therefore, it remains of crucial importance to develop new and improved fluorescent probes that are sensitive to the MMP, to report on mitochondrial health and function. Reported here are the design, synthesis, photophysical properties and biological characterisation of a series of BODIPY dyes, BODIPY-Mito-n, for mitochondria-targeted fluorescence imaging applications. Six BODIPY-Mito-n analogues were synthesised under mild conditions, and displayed excellent fluorescence quantum yields of between 0.59 and 0.72 in aqueous environments at physiological pH (pH = 7.4). The incorporation of poly(ethylene glycol) (PEG) chains to the triarylphosphonium cation moiety significantly improved the biocompatibility of the probes (BODIPY-Mito-6, IC50 > 50 μM). All BODIPY-Mito-n compounds demonstrated a high MMP-sensitive localisation in the mitochondria, with Pearson's correlation coefficients (PCC) of between 0.76 and 0.96. Compounds BODIPY-Mito-2 and BODIPY-Mito-6 revealed the highest sensitivity to the MMP, with a decrease in the emission intensity of 62% and 75%, respectively following MMP depolarisation. It is anticipated that the highest MMP sensitivity and enhanced biocompatibility of BODIPY-Mito-6 could lead to the development of new probes for mitochondrial imaging in the future.

  • Journal article
    Bennett TLR, Long NJ, 2023,

    A convenient synthesis of ferrocene-(ethynylphenyl)thioacetates

    , DALTON TRANSACTIONS, Vol: 52, Pages: 16465-16471, ISSN: 1477-9226
  • Journal article
    Yue TTC, Ge Y, Aprile FA, Ma MT, Pham TT, Long NJet al., 2023,

    Site-Specific <SUP>68</SUP>Ga Radiolabeling of Trastuzumab Fab via Methionine for ImmunoPET Imaging

    , BIOCONJUGATE CHEMISTRY, ISSN: 1043-1802
  • Journal article
    Aboagye E, Teh JH, Amgheib A, Fu R, Barnes C, Abrahams J, Ashek A, Wang N, Yang Z, Mansoorudeen M, Long NJ, Aboagye Eet al., 2023,

    Evaluation of [18F]AlF-EMP-105 for molecular imaging of 2 C-Met

    , Pharmaceutics, Vol: 15, Pages: 1-13, ISSN: 1999-4923

    C-Met is a receptor tyrosine kinase that is overexpressed in a range of different cancer types, and has been identified as a potential biomarker for cancer imaging and therapy. Previously, a 68Ga-labelled peptide, [68Ga]Ga-EMP-100, has shown promise for imaging c-Met in renal cell carcinoma in humans. Herein, we report the synthesis and preliminary biological evaluation of an [18F]AlF-labelled analogue, [18F]AlF-EMP-105, for c-Met imaging by positron emission tomography. EMP-105 was radiolabelled using the aluminium-[18F]fluoride method with 46 ± 2% RCY and >95% RCP in 35–40 min. In vitro evaluation showed that [18F]AlF-EMP-105 has a high specificity for c-Met-expressing cells. Radioactive metabolite analysis at 5 and 30 min post-injection revealed that [18F]AlF-EMP-105 has good blood stability, but undergoes transformation—transchelation, defluorination or demetallation—in the liver and kidneys. PET imaging in non-tumour-bearing mice showed high radioactive accumulation in the kidneys, bladder and urine, demonstrating that the tracer is cleared predominantly as [18F]fluoride by the renal system. With its high specificity for c-Met expressing cells, [18F]AlF-EMP-105 shows promise as a potential diagnostic tool for imaging cancer.

  • Journal article
    Lim Kee Chang W, Chan T, Raguseo F, Mishra A, Chattenton D, de Rosales RTM, Long N, Morse Set al., 2023,

    Rapid short-pulses of focused ultrasound and microbubbles deliver a range of agent sizes to the brain

    , Scientific Reports, Vol: 13, ISSN: 2045-2322

    Focused ultrasound and microbubbles can non-invasively and locally deliver therapeutics and imaging agents across the blood–brain barrier. Uniform treatment and minimal adverse bioeffects are critical to achieve reliable doses and enable safe routine use of this technique. Towards these aims, we have previously designed a rapid short-pulse ultrasound sequence and used it to deliver a 3 kDa model agent to mouse brains. We observed a homogeneous distribution in delivery and blood–brain barrier closing within 10 min. However, many therapeutics and imaging agents are larger than 3 kDa, such as antibody fragments and antisense oligonucleotides. Here, we evaluate the feasibility of using rapid short-pulses to deliver higher-molecular-weight model agents. 3, 10 and 70 kDa dextrans were successfully delivered to mouse brains, with decreasing doses and more heterogeneous distributions with increasing agent size. Minimal extravasation of endogenous albumin (66.5 kDa) was observed, while immunoglobulin (~ 150 kDa) and PEGylated liposomes (97.9 nm) were not detected. This study indicates that rapid short-pulses are versatile and, at an acoustic pressure of 0.35 MPa, can deliver therapeutics and imaging agents of sizes up to a hydrodynamic diameter between 8 nm (70 kDa dextran) and 11 nm (immunoglobulin). Increasing the acoustic pressure can extend the use of rapid short-pulses to deliver agents beyond this threshold, with little compromise on safety. This study demonstrates the potential for deliveries of higher-molecular-weight therapeutics and imaging agents using rapid short-pulses.

  • Journal article
    Hamill JM, Ismael A, Al-Jobory A, Bennett TLR, Alshahrani M, Wang X, Akers-Douglas M, Wilkinson LA, Robinson BJ, Long NJ, Lambert C, Albrecht Tet al., 2023,

    Quantum interference and contact effects in the thermoelectric performance of anthracene-based molecules

    , The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter, Vol: 127, Pages: 7484-7491, ISSN: 1932-7447

    We report on the single-molecule electronic and thermoelectric properties of strategically chosen anthracene-based molecules with anchor groups capable of binding to noble metal substrates, such as gold and platinum. Specifically, we study the effect of different anchor groups, as well as quantum interference, on the electric conductance and the thermopower of gold/single-molecule/gold junctions and generally find good agreement between theory and experiments. All molecular junctions display transport characteristics consistent with coherent transport and a Fermi alignment approximately in the middle of the highest occupied molecular orbital/lowest unoccupied molecular orbital gap. Single-molecule results are in agreement with previously reported thin-film data, further supporting the notion that molecular design considerations may be translated from the single- to many-molecule devices. For combinations of anchor groups where one binds significantly more strongly to the electrodes than the other, the stronger anchor group appears to dominate the thermoelectric behavior of the molecular junction. For other combinations, the choice of electrode material can determine the sign and magnitude of the thermopower. This finding has important implications for the design of thermoelectric generator devices, where both n- and p-type conductors are required for thermoelectric current generation.

  • Journal article
    Long NJ, Bhargava S, 2022,

    Professor Edward Abel, FRSC, CBE (1931-2021)

    , DALTON TRANSACTIONS, Vol: 51, Pages: 16781-16783, ISSN: 1477-9226
  • Journal article
    Bourke S, Urbano L, Midson MM, Olona A, Qazi-Choudhry B, Panamarova M, Valderrama F, Long NJ, Dailey L-A, Green Met al., 2022,

    Nearly monodispersed, emission-tuneable conjugated polymer nanoparticles

    , SENSORS & DIAGNOSTICS, Vol: 1, Pages: 1185-1188
  • Journal article
    Cooper SM, Siakalli C, White AJP, Frei A, Miller PW, Long NJet al., 2022,

    Synthesis and anti-microbial activity of a new series of bis(diphosphine) rhenium(v) dioxo complexes

    , DALTON TRANSACTIONS, Vol: 51, Pages: 12791-12795, ISSN: 1477-9226
  • Journal article
    Wilkinson LA, Bennett TLR, Grace IM, Hamill J, Wang X, Au-Yong S, Ismael A, Jarvis SP, Hou S, Albrecht T, Cohen LF, Lambert C, Robinson BJ, Long NJet al., 2022,

    Assembly, structure and thermoelectric properties of 1,1 '-dialkynylferrocene 'hinges'

    , Chemical Science, Vol: 13, Pages: 8380-8387, ISSN: 2041-6520

    Dialkynylferrocenes exhibit attractive electronic and rotational features that make them ideal candidates for use in molecular electronic applications. However previous works have primarily focussed on single-molecule studies, with limited opportunities to translate these features into devices. In this report, we utilise a variety of techniques to examine both the geometric and electronic structure of a range of 1,1′-dialkynylferrocene molecules, as either single-molecules, or as self-assembled monolayers. Previous single molecule studies have shown that similar molecules can adopt an ‘open’ conformation. However, in this work, DFT calculations, STM-BJ experiments and AFM imaging reveal that these molecules prefer to occupy a ‘hairpin’ conformation, where both alkynes point towards the metal surface. Interestingly we find that only one of the terminal anchor groups binds to the surface, though both the presence and nature of the second alkyne affect the thermoelectric properties of these systems. First, the secondary alkyne acts to affect the position of the frontier molecular orbitals, leading to increases in the Seebeck coefficient. Secondly, theoretical calculations suggested that rotating the secondary alkyne away from the surface acts to modulate thermoelectric properties. This work represents the first of its kind to examine the assembly of dialkynylferrocenes, providing valuable information about both their structure and electronic properties, as well as unveiling new ways in which both of these properties can be controlled.

  • Journal article
    Frei A, Rigby A, Yue TTC, Firth G, Ma MT, Long NJet al., 2022,

    To chelate thallium(i) - synthesis and evaluation of Kryptofix-based chelators for Tl-201

    , DALTON TRANSACTIONS, Vol: 51, Pages: 9039-9048, ISSN: 1477-9226
  • Journal article
    Cooper SM, White AJP, Eykyn TR, Ma MT, Miller PW, Long NJet al., 2022,

    N-centered tripodal phosphine Re(V) and Tc(V) oxo complexes: revisiting a [3+2] mixed-ligand approach

    , Inorganic Chemistry: including bioinorganic chemistry, Vol: 61, Pages: 8000-8014, ISSN: 0020-1669

    N-Triphos derivatives (NP3R, R = alkyl, aryl) and asymmetric variants (NP2RXR′, R′ = alkyl, aryl, X = OH, NR2, NRR′) are an underexplored class of tuneable, tripodal ligands in relation to the coordination chemistry of Re and Tc for biomedical applications. Mixed-ligand approaches are a flexible synthetic route to obtain Tc complexes of differing core structures and physicochemical properties. Reaction of the NP3Ph ligand with the Re(V) oxo precursor [ReOCl3(PPh3)2] generated the bidentate complex [ReOCl3(κ2-NP2PhOHAr)], which possesses an unusual AA’BB’XX’ spin system with a characteristic second-order NMR lineshape that is sensitive to the bi- or tridentate nature of the coordinating diphosphine unit. The use of the asymmetric NP2PhOHAr ligand resulted in the formation of both bidentate and tridentate products depending on the presence of base. The tridentate Re(V) complex [ReOCl2(κ3-NP2PhOAr)] has provided the basis of a new reactive “metal-fragment” for further functionalization in [3 + 2] mixed-ligand complexes. The synthesis of [3 + 2] complexes with catechol-based π-donors could also be achieved under one-pot, single-step conditions from Re(V) oxo precursors. Analogous complexes can also be synthesized from suitable 99Tc(V) precursors, and these complexes have been shown to exhibit highly similar structural properties through spectroscopic and chromatographic analysis. However, a tendency for the {MVO}3+ core to undergo hydrolysis to the {MVO2}+ core has been observed both in the case of M = Re and markedly for M = 99Tc complexes. It is likely that controlling this pathway will be critical to the generation of further stable Tc(V) derivatives.

  • Journal article
    Bennett TLR, Alshammari M, Au-Yong S, Almutlg A, Wang X, Wilkinson LA, Albrecht T, Jarvis SP, Cohen LF, Ismael A, Lambert CJ, Robinson BJ, Long NJet al., 2022,

    Multi-component self-assembled molecular-electronic films: towards new high-performance thermoelectric systems

    , Chemical Science, Vol: 13, Pages: 5176-5185, ISSN: 2041-6520

    The thermoelectric properties of parallel arrays of organic molecules on a surface offer the potential for large-area, flexible, solution processed, energy harvesting thin-films, whose room-temperature transport properties are controlled by quantum interference (QI). Recently, it has been demonstrated that constructive QI (CQI) can be translated from single molecules to self-assembled monolayers (SAMs), boosting both electrical conductivities and Seebeck coefficients. However, these CQI-enhanced systems are limited by rigid coupling of the component molecules to metallic electrodes, preventing the introduction of additional layers which would be advantageous for their further development. These rigid couplings also limit our ability to suppress the transport of phonons through these systems, which could act to boost their thermoelectric output, without comprising on their impressive electronic features. Here, through a combined experimental and theoretical study, we show that cross-plane thermoelectricity in SAMs can be enhanced by incorporating extra molecular layers. We utilize a bottom-up approach to assemble multi-component thin-films that combine a rigid, highly conductive ‘sticky’-linker, formed from alkynyl-functionalised anthracenes, and a ‘slippery’-linker consisting of a functionalized metalloporphyrin. Starting from an anthracene-based SAM, we demonstrate that subsequent addition of either a porphyrin layer or a graphene layer increases the Seebeck coefficient, and addition of both porphyrin and graphene leads to a further boost in their Seebeck coefficients. This demonstration of Seebeck-enhanced multi-component SAMs is the first of its kind and presents a new strategy towards the design of thin-film thermoelectric materials.

  • Journal article
    Sheppard SA, Bennett TLR, Long NJ, 2022,

    Development and Characterisation of Highly Conjugated Functionalised Ferrocenylene Macrocycles

    , EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Vol: 2022, ISSN: 1434-1948

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