Trimeric Arrays Research Articles

Design and Functional Characterization of HIV-1 Envelope Protein-Coupled T Helper Liposomes.

Functionalization of experimental HIV-1 virus-like particle vaccines with heterologous T helper epitopes (T helper VLPs) can modulate the humoral immune response via intrastructural help (ISH). Current advances in the conjugation of native-like HIV-1 envelope trimers (Env) onto liposomes and encapsulation of peptide epitopes into these nanoparticles renders this GMP-scalable liposomal platform a feasible alternative to VLP-based vaccines. In this study, we designed and analyzed customizable Env-conjugated T helper liposomes. First, we passively encapsulated T helper peptides into a well-characterized liposome formulation displaying a dense array of Env trimers on the surface. We confirmed the closed pre-fusion state of the coupled Env trimers by immunogold staining with conformation-specific antibodies. These peptide-loaded Env-liposome conjugates efficiently activated Env-specific B cells, which further induced proliferation of CD4+ T cells by presentation of liposome-derived peptides on MHC-II molecules. The peptide encapsulation process was then quantitatively improved by an electrostatically driven approach using an overall anionic lipid formulation. We demonstrated that peptides delivered by liposomes were presented by DCs in secondary lymphoid organs after intramuscular immunization of mice. UFO (uncleaved prefusion optimized) Env trimers were covalently coupled to peptide-loaded anionic liposomes by His-tag/NTA(Ni) interactions and EDC/Sulfo-NHS crosslinking. EM imaging revealed a moderately dense array of well-folded Env trimers on the liposomal surface. The conformation was verified by liposomal surface FACS. Furthermore, anionic Env-coupled T helper liposomes effectively induced Env-specific B cell activation and proliferation in a comparable range to T helper VLPs. Taken together, we demonstrated that T helper VLPs can be substituted with customizable and GMP-scalable liposomal nanoparticles as a perspective for future preclinical and clinical HIV vaccine applications. The functional nanoparticle characterization assays shown in this study can be applied to other systems of synthetic nanoparticles delivering antigens derived from various pathogens.

Design of functionalised circular tandem repeat proteins with longer repeat topologies and enhanced subunit contact surfaces

Circular tandem repeat proteins (‘cTRPs’) are de novo designed protein scaffolds (in this and prior studies, based on antiparallel two-helix bundles) that contain repeated protein sequences and structural motifs and form closed circular structures. They can display significant stability and solubility, a wide range of sizes, and are useful as protein display particles for biotechnology applications. However, cTRPs also demonstrate inefficient self-assembly from smaller subunits. In this study, we describe a new generation of cTRPs, with longer repeats and increased interaction surfaces, which enhanced the self-assembly of two significantly different sizes of homotrimeric constructs. Finally, we demonstrated functionalization of these constructs with (1) a hexameric array of peptide-binding SH2 domains, and (2) a trimeric array of anti-SARS CoV-2 VHH domains. The latter proved capable of sub-nanomolar binding affinities towards the viral receptor binding domain and potent viral neutralization function.

Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet

The long-range order of noncoplanar magnetic textures with scalar spin chirality (SSC) can couple to conduction electrons to produce an additional (termed geometrical or topological) Hall effect. One such example is the Hall effect in the skyrmion lattice state with quantized SSC. An alternative route to attain a finite SSC is via the spin canting caused by thermal fluctuations in the vicinity of the ferromagnetic ordering transition. Here, we report that for a highly conducting ferromagnet with a two-dimensional array of spin trimers, the thermally generated SSC can give rise to a gigantic geometrical Hall conductivity even larger than the intrinsic anomalous Hall conductivity of the ground state. We also demonstrate that the SSC induced by thermal fluctuations leads to a strong response in the Nernst effect. A comparison of the sign and magnitude of fluctuation-Nernst and Hall responses in fundamental units indicates the need for a momentum-space picture to model these thermally induced signals.

Toroidic and antitoroidic orders in hexagonal arrays of dielectric trimers: Magnetic group approach

Herein, we investigate the symmetry-protected toroidal dipole resonances and conditions of their excitation in a new type of electromagnetic metamaterials. These metamaterials are all-dielectric planar periodic arrays of dielectric disks disposed on a dielectric substrate. The elementary building blocks of the array are trimers which are distributed in hexagonal unit supercells. The highest geometrical symmetry of the unit supercell is C6v. The analysis is fulfilled by using the representation theory of groups with the application of the magnetic group theory, which is a new approach in solving such problems. We have shown that to get access to the toroidal supermodes of the array, the unit supercell symmetry must be broken twice: firstly, the C3v symmetry of the trimer, and secondly, the C6v symmetry of the unit supercell needs to be reduced. Selection rules for the symmetric and antisymmetric orders of the toroidal dipole moments in the arrays are defined. In particular, we have shown that with the reduction of the unit supercell symmetry to the C2v group, the array exhibits the toroidal dipole resonance with an antitoroidic order. The arrays with the lower Cs symmetry can provide the resonances with both toroidic and antitoroidic orders. It is also shown that these arrays are always polarization sensitive. Full-wave simulations and experiments confirm the theoretical predictions. The suggested metamaterials can provide an enhanced light-matter interaction due to the spatially and temporally confined light in resonant systems with very high quality factors.

Orthogonally aligned cyclic BODIPY arrays with long-lived triplet excited states as efficient heavy-atom-free photosensitizers.

In photosensitizers, long triplet excited state lifetimes are key to their efficient electron transfer or energy transfer processes. Herein, we report a novel class of cyclic trimeric BODIPY arrays which were efficiently generated from easily accessible meso-mesityldipyrrinone and arylboronic acids in one pot. Arylboronic acid, for the first time, was used to provide a boron source for BODIPY derivatives. Due to the well-defined and orthogonally aligned BODIPY cores as verified by X-ray crystallography, these BODIPY arrays show strong exciton coupling effects and efficient intersystem crossings, and are novel heavy-atom-free photosensitizers with a long-lived triplet excited state (lifetime up to 257.5 μs) and good reactive oxygen species generation efficiency (up to 0.72) contributed by both 1O2 and O2−˙ under light irradiation.

Enhancing Spectral Reflection through Controlled Phase Distribution Using Doped Polar-Dielectric Metasurfaces.

Controlling the phase distribution of wavefronts using optical metasurfaces has led to interesting optical properties and applications. Here, we explore the control of phase distribution through polar-dielectric metasurfaces composed of doped SiC nanosphere arrays. We investigate the impact of doping concentration on the optical properties of SiC nano-spheres. Our results indicate that increasing the doping of SiC nanoparticles influenced electric dipolar resonances, whereas it did not change the dipolar resonances. Using this concept, we numerically studied the extension of this idea to form metasurface arrays of single, dimer and linear trimers of the doped SiC nano-spheres. Using different doping schemes, we studied the improvement of the reflectivity at frequencies greater than the longitudinal optical phonon frequency.

Impact of intra- and inter-unit cell symmetry breaking on the optical response of the arrays of nanotrimers.

Understanding the impact of geometric changes on the properties of otherwise symmetric nanostructures is of essential importance for nanophotonics. In this Letter, we show that intra- and inter-unit cell symmetry breaking can substantially modify the optical properties of nanotrimers from both the experimental and simulation aspect. Specifically, shifting the location of one nano-dot within the trimer unit cell leads to the formation of magnetic Fano resonances with loop-like polarization patterns that are not present in the symmetric configuration. We further unlock the impact of lattice modification on the optical response of square arrays of trimers with broken three-fold rotation symmetry and with intra-trimer distances as small as 25nm, showing distinctively different spectral evolutions of the electric and magnetic Fano resonances. The results achieved highlight the symmetry breaking as an essential tool to unlock and strengthen predefined resonances, which can have important applications, particularly in the field of sensing.

Electric field control of superexchange in multiple linear two-electron quantum dot arrays and mixed-valence molecules

This paper belongs to the area of electrical manipulation of spins in quantum dots and molecular spins for quantum technologies. We propose a theoretical analysis of the electric field controllable superexchange in the two-electron linear arrays of quantum dots (“physical” molecules) and linear mixed-valence molecules based on metal ions in different oxidation degrees (“chemical” molecules) of increasing length. In this view, we consider the kinetic magnetic exchange in trimeric and tetrameric linear arrays of quantum dots and the field dependence of the exchange interaction between electrons. An attainable electric field in these systems is able to essentially change the electronic distribution in the systems under consideration and subsequently to affect the exchange interaction. The numerical estimations demonstrate the feasibility of the revealed effects of the electric field. At a weak electric field, this control is shown to be more efficient for larger numbers of diamagnetic quantum dots mediating superexchange. The peculiarities of chemical analogs of such quantum dot arrays represented by the linear triferrocenium and tetraferrocenium complexes containing two mobile holes are discussed as well.

Symmetry-breaking induced magnetic Fano resonances in densely packed arrays of symmetric nanotrimers

Due to unique properties and great design flexibilities, Fano resonances represent one of the most promising optical features mediated by metallic nanostructures, while the excitation of some Fano modes is impossible due to symmetry reasons. The aim of this work is to show that dense lattice arrangements can have a profound impact on the optical properties of nanostructures and, in particular, can enable the excitation of otherwise dark modes. Here, we demonstrate this concept using the example of rectangular arrays of symmetric trimers packed so densely that the coupling between neighbouring unit cells imposes a symmetry break, enabling the excitation of magnetic Fano resonances. We found that in experiments as well as in simulations, electric and magnetic Fano resonances can be simultaneously formed in cases where the inter-trimer distances are sufficiently small. By analysing the transition from an isolated trimer mode into a regime of strong near-field coupling, we show that by modifying the rectangular unit cell lengths due to the symmetry mismatch between lattice and trimer, two types of Fano resonances can be found, especially magnetic Fano resonances with loop-type magnetic field distributions within the centre of each trimer, which can be either enhanced or suppressed. In addition, the influence of the refractive index environment was measured, showing sensitivity values of approximately 300 nm/RIU. Our work provides fundamental insights into the interaction of the lattice and nanostructure response and paves the way towards the observation of novel optical excitations.

Conditional quantum dynamics and nonlocal states in dimeric and trimeric arrays of organic molecules

Arrays of covalently bound organic molecules possess potential for light-harvesting and energy transfer applications due to the strong coherent dipole-dipole coupling between the transition dipole moments of the molecules involved. Here, we show that such molecular systems, based on perylene-molecules, can be considered as arrays of qubits that are amenable for laser-driven quantum coherent control. The perylene monomers exhibit dephasing times longer than four orders of magnitude a typical gating time, thus allowing for the execution of a large number of gate operations on the sub-picosecond timescale. Specifically, we demonstrate quantum logic gates and entanglement in bipartite (dimer) and tripartite (trimer) systems of perylene-based arrays. In dimers, naturally entangled states with a tailored degree of entanglement can be produced. The nonlocality of the molecular trimer entanglement is demonstrated by testing Mermin's (Bell-like) inequality violation.

Mechanism and Potential Inhibitors of GlmU: A Novel Target for Antimicrobial Drug Discovery.

Multidrug resistant Gram negative pathogens pose a persistent threat to the health care system and require investigation of new targets and molecules for the development of antibiotics to treat infections caused by MDR bacterial pathogens. It is essential to work on multidisciplinary approaches and diverse strategies for developing new compounds acting on novel antibacterial targets. N-acetylglucosamine-1-phosphateuridyltransferase/ glucosamine-1-phosphate-acetyltransferase (GlmU) is one such target which is involved in the synthesis of both peptidoglycan and Lipopolysaccharide in Gram negative and Gram positive bacteria making GlmU an attractive target for developing antibacterials. GlmU, as revealed by X- ray crystallographic studies, is made up of two domains connected by α helical arm; the N-terminal uridyltransferase domain resembles a dinucleotide Rossmann fold and the C- terminal acetyltransferase domain adopts a left handed parallel β helix structure. The GlmU molecules are arranged in a trimeric array, the acetyltransferase active site being formed at the junction of adjacent LβH domain. Many potent inhibitors of both the acetyltransferase and uridyltransferase activity of GlmU have been identified. Inhibitors of the acetyltransferase activity of GlmU include nonspecific thiol reactive agents, 2-phenylbenzofurans, arylamines and arylsulfonamides. A aminopiperidine based inhibitor has also been reported to inhibit uridyltransferase activity of hiGlmU. The present review provides an insight of the structure of GlmU and its reported inhibitors which make GlmU a potential target for drug designing. The GlmU is a promising target for drug discovery against Gram negative pathogens and future studies should focus on GlmU for the development of more potent compounds for treating Gram negative infections.

Covalent Linkage of HIV-1 Trimers to Synthetic Liposomes Elicits Improved B Cell and Antibody Responses.

We have demonstrated that a liposomal array of well-ordered trimers enhances B cell activation, germinal center formation, and the elicitation of tier-2 autologous neutralizing antibodies. Previously, we coupled well-ordered cleavage-independent NFL trimers via their C-terminal polyhistidine tails to nickel lipids integrated into the lipid bilayer. Despite favorable in vivo effects, concern remained over the potentially longer-term in vivo instability of noncovalent linkage of the trimers to the liposomes. Accordingly, we tested both cobalt coupling and covalent linkage of the trimers to the liposomes by reengineering the polyhistidine tail to include a free cysteine on each protomer of model BG505 NFL trimers to allow covalent linkage. Both cobalt and cysteine coupling resulted in a high-density array of NFL trimers that was stable in both 20% mouse serum and 100 mM EDTA, whereas the nickel-conjugated trimers were not stable under these conditions. Binding analysis and calcium flux with anti-Env-specific B cells confirmed that the trimers maintained conformational integrity following coupling. Following immunization of mice, serologic analysis demonstrated that the covalently coupled trimers elicited Env-directed antibodies in a manner statistically significantly improved compared to soluble trimers and nickel-conjugated trimers. Importantly, the covalent coupling not only enhanced gp120-directed responses compared to soluble trimers, it also completely eliminated antibodies directed to the C-terminal His tag located at the "bottom" of the spike. In contrast, soluble and noncovalent formats efficiently elicited anti-His tag antibodies. These data indicate that covalent linkage of well-ordered trimers to liposomes in high-density array displays multiple advantages in vitro and in vivoIMPORTANCE Enveloped viruses typically encode a surface-bound glycoprotein that mediates viral entry into host cells and is a primary target for vaccine design. Liposomes with modified lipid head groups have a unique feature of capturing and displaying antigens on their surfaces, mimicking the native pathogens. Our first-generation nickel-based liposomes captured HIV-1 Env glycoprotein trimers via a noncovalent linkage with improved efficacy over soluble glycoprotein in activating germinal center B cells and eliciting tier-2 autologous neutralizing antibodies. In this study, we report the development of second-generation cobalt- and maleimide-based liposomes that have improved in vitro stability over nickel-based liposomes. In particular, the maleimide liposomes captured HIV-1 Env trimers via a more stable covalent bond, resulting in enhanced germinal center B cell responses that generated higher antibody titers than the soluble trimers and liposome-bearing trimers via noncovalent linkages. We further demonstrate that covalent coupling prevents release of the trimers prior to recognition by B cells and masks a nonneutralizing determinant located at the bottom of the trimer.

Periodic array of regular Ag nanoparticle trimers: a reliable polarization-independent surface-enhanced Raman spectroscopy substrate

A large-area periodic array of regular Ag nanoparticle trimers was fabricated, it possesses polarization-independent SERS performance.

Reprint of “Ru(II)/Ag(I) mixed-metal complexes based on kinetically inert Ru(II) complexes with pendant binding sites as subcomponents”

The mononuclear complexes [Ru(LoPh)2](PF6)2 and fac-[Ru(L3-Py)3](PF6)2 have been prepared which contain different types of pendant binding site. In [Ru(LoPh)2](PF6)2, one ligand acts as a tetradentate chelate but the other is only bidentate such that there is one bidentate pyrazolyl-pyridine site pendant from the Ru(II) complex core. In fac-[Ru(L3-Py)3](PF6)2 in contrast there are three monodentate 3-pyridyl units pendant from the same face of the Ru(II) core. Two [Ru(LoPh)2](PF6)2 units assemble around an Ag(I) ion to give trinuclear [{Ru(LoPh)2}2Ag](PF6)5 in which the Ag(I) ion is four coordinate. In the solid state three of these associate into a triangular trimeric array via π-stacking and CH⋯F hydrogen-bonding interactions to give an assembly which contains two cup-shaped cavities either side of a central Ag3 face and pointing in opposite directions; these cavities contain H-bonded hexafluorophosphate anions. In MeCN solution at high concentrations (11mM), according to 1H NMR DOSY measurements the trinuclear complex [{Ru(LoPh)2}2Ag](PF6)5 remains intact but there is no evidence for further aggregation into the trimer. Two fac-[Ru(L3-Py)3](PF6)2 units combine with two {Ag(NCMe)}+ units and an additional Ag(I) ion to give a complex coordination network [{Ru(L3-Py)3}2{Ag(MeCN)2}2Ag](PF6)7. In this structure two fac-[Ru(L3-Py)3](PF6)2 and two {Ag(NCMe)}+ units form tetranuclear Ru2Ag2 rings via Ag–N(pyridyl) interactions; these rings are crosslinked into a one-dimensional chain by additional Ag–N(pyridyl) interactions. Argentophilic Ag⋯Ag interactions then connect the resulting chains into two-dimensional sheets. Both mixed-metal networks are based on initial formation of kinetically inert Ru(II) complexes which then associate in a separate step with Ag(I) ions, via pendant N-donor binding sites. However [{Ru(LoPh)2}2Ag](PF6)5 exploits π–π stacking and hydrogen-bonding interactions to form in the solid state a trimeric assembly which encapsulates anions; in contrast [{Ru(L3-Py)3}2{Ag(MeCN)2}2Ag](PF6)7 exploits argentophilic interactions to complete formation of the network.

Ru(II)/Ag(I) mixed-metal complexes based on kinetically inert Ru(II) complexes with pendant binding sites as subcomponents

The mononuclear complexes [Ru(LoPh)2](PF6)2 and fac-[Ru(L3-Py)3](PF6)2 have been prepared which contain different types of pendant binding site. In [Ru(LoPh)2](PF6)2, one ligand acts as a tetradentate chelate but the other is only bidentate such that there is one bidentate pyrazolyl-pyridine site pendant from the Ru(II) complex core. In fac-[Ru(L3-Py)3](PF6)2 in contrast there are three monodentate 3-pyridyl units pendant from the same face of the Ru(II) core. Two [Ru(LoPh)2](PF6)2 units assemble around an Ag(I) ion to give trinuclear [{Ru(LoPh)2}2Ag](PF6)5 in which the Ag(I) ion is four coordinate. In the solid state three of these associate into a triangular trimeric array via π-stacking and CH⋯F hydrogen-bonding interactions to give an assembly which contains two cup-shaped cavities either side of a central Ag3 face and pointing in opposite directions; these cavities contain H-bonded hexafluorophosphate anions. In MeCN solution at high concentrations (11mM), according to 1H NMR DOSY measurements the trinuclear complex [{Ru(LoPh)2}2Ag](PF6)5 remains intact but there is no evidence for further aggregation into the trimer. Two fac-[Ru(L3-Py)3](PF6)2 units combine with two {Ag(NCMe)}+ units and an additional Ag(I) ion to give a complex coordination network [{Ru(L3-Py)3}2{Ag(MeCN)2}2Ag](PF6)7. In this structure two fac-[Ru(L3-Py)3](PF6)2 and two {Ag(NCMe)}+ units form tetranuclear Ru2Ag2 rings via Ag–N(pyridyl) interactions; these rings are crosslinked into a one-dimensional chain by additional Ag–N(pyridyl) interactions. Argentophilic Ag⋯Ag interactions then connect the resulting chains into two-dimensional sheets. Both mixed-metal networks are based on initial formation of kinetically inert Ru(II) complexes which then associate in a separate step with Ag(I) ions, via pendant N-donor binding sites. However [{Ru(LoPh)2}2Ag](PF6)5 exploits π–π stacking and hydrogen-bonding interactions to form in the solid state a trimeric assembly which encapsulates anions; in contrast [{Ru(L3-Py)3}2{Ag(MeCN)2}2Ag](PF6)7 exploits argentophilic interactions to complete formation of the network.

Self-complementary double-stranded porphyrin arrays assembled from an alternating pyridyl-porphyrin sequence.

Oligomeric porphyrin arrays with an alternating pyridyl-porphyrin sequence were synthesized to explore double-strand formation through self-complementary pyridyl-to-zinc axial coordination bonds. Competitive titration experiments revealed the thermodynamic aspects involved in the zipper effect within double-strand formation. Multiple axial coordination bonds defined the stacked conformation, despite a marginal contribution to the stability of the double-strands. Thus, the zipper cooperativity was the dominant factor for the remarkable stability. Moreover, the dimeric and trimeric porphyrin arrays were independently assembled into double-strands by self-sorting from a binary mixture. Double-strand formation engineered discretely stacked π-systems. Successive slipped-cofacial stacks of the porphyrin rings progressively extended the π-system via exciton coupling over the double-strand while keeping a relatively high fluorescence quantum yield.

Magnetic and dielectric properties of one-dimensional array of S = 1/2 linear trimer system Na2Cu3Ge4O12

Magnetic susceptibility χ, specific heat C, capacitance Cp, and 23Na-NMR measurements have been carried out on polycrystalline samples of quantum spin linear trimer system Na2Cu3Ge4O12, which has the one-dimensional array of Cu3O8 trimers formed of edge-sharing three CuO4 square planes. The exchange interactions between the Cu2+ (S = 1/2) spins have been determined by analyzing χ-T and C-T curves. By employing the isolated S = 1/2 Heisenberg trimer model above 70 K, the nearest-neighbor exchange couplings J1 and the second-neighbor one J2 in trimer have been evaluated to J1/kB = 30 ± 20 K (antiferromagnetic) and J2/kB = 340 ± 20 K. At low temperature region, two spins of the edge in the Cu3O8 trimers form a nonmagnetic singlet by strong antiferromagnetic interaction J2, and the spin left in the center of the Cu3O8 trimer forms one-dimensional chains by the exchange interaction J3 between the trimers. By employing the S = 1/2 uniform Heisenberg chain model below 70 K, we have evaluated to J3/kB = 18 ± 1 K. The mechanism of multiferroic behavior at Tc = 2 K is discussed.

One-step purification of delipidated Bacteriorhodopsin by aqueous-three-phase system from purple membrane of Halobacterium

Bacteriorhodopsin (BR), the only protein in the purple membrane (PM) of certain extreme halophilic microorganisms, functions as a light-driven proton pump using light energy to generate transmembrane proton gradient for ATP synthesis. BR naturally aggregates in a highly ordered two-dimensional hexagonal array of trimers in the PM of Halobacterium. The BR in the isolated PM can be employed to generate a photocurrent in a photocell. However, delipidated BR (deBR) has been reported be more efficient than BR for photocurrent generation. In the present work, detergent CHAPS was included in anaqueous three-phase system (A3PS) to remove the lipids in the out layer of the BR trimer during the preparation of deBR. A3PS that consisted of polypropyleneglycol (PPG), polyethyleneglycol (PEG), and phosphate buffer purified deBR directly from the cell lysate of Halobacterium salinarum with a recovery yield of 89.7%. CHAPS along with the contaminant bacterioruberin pigment were partitioned into the top PPG-rich phase while deBR was mainly located at the interface between PEG-rich phase and the lower phosphate phase. After further purification by using ultrafiltration to remove PEG, the purified deBR when immobilized on indium tin oxide (ITO) glass was able to generate 60% higher photocurrent density.

Fano resonances in metasurfaces made of linear trimers of plasmonic nanoparticles

We investigate Fano resonances in planar two-dimensional periodic arrays of linear trimers of plasmonic nanoparticles that appear under plane wave incidence. The observed Fano resonances are associated to resonances belonging to the trimer (metamolecule) itself, where some are found to be strongly affected by the array periodicity. We observe that array-dependent resonances appearing for oblique incidence are resistant to losses, whereas narrow dipolar-like Fano resonances associated mainly to the metamolecule, which appear also under normal incidence, disappear when losses are too high. In particular, we prove the latter by theoretical (dipolar approximation) and full-wave simulations, in good agreement. We propose that the use of very low-loss plasmonic materials or the use of gain materials to mitigate plasmonic losses may lead to (high-quality factor) dipolar-like Fano resonances under normal incidence, exhibiting a certain degree of fabrication defect tolerance, which might be employed to improve sensors, lasing, switching, and nonlinear devices, for example.

Synthesis and ligand binding properties of triptycene-linked porphyrin arrays

Multiporphyrin arrays are a complex class of molecules with numerous potential applications in energy transfer, photomedicine, and light harvesting. We have developed a facile/versatile route to a class of triptycene-linked porphyrin arrays via both Suzuki and Sonogashira cross-coupling methods, which makes use of the rigid three-pronged orientation of triptycene to construct trimeric porphyrin arrays linked either in the meso or β-position with various linker groups. In order to understand the properties of these potential antenna systems and probe their potential applications, the coordination behavior of zinc(II) derivatives with mono- and bidentate N-donor ligands was investigated. Depending on ligand concentration, both one- and two-point binding was observed with a bidentate ligand. Also/in addition, different cavity sizes, obtained by the use of different linker groups, resulted in differences in the binding properties of each trimeric system.