Dimeric Complex Research Articles

When Molecular Dimerization Induces Magnetic Bi‐Stability at the Metal–Organic Interface

Abstract2D metal–organic frameworks have been recently proposed as a flexible platform for realizing new functional materials including quantum phases. Here, we present a method to create metal‐organic dimer complexes by on‐surface assembly on a metal substrate using low‐temperature scanning tunneling microscopy (STM) and spectroscopy (STS). We demonstrate that a dimer of Mn‐Phthalocyanine (MnPc)2 on a Ag(111) surface can be switched between two stable configurations upon a small conformational change controlled by STM manipulation. By means of density‐functional theory calculations, it is found that the two conformations correspond to an antiferromagnetic (AFM) and a ferromagnetic (FM) state respectively. Directly coordinated Mn atoms of the dimer lead to an AFM‐coupling whereas indirectly coordinated (shifted) Mn atoms lead to a FM‐coupling. Rarely seen in a molecular‐dimers with transition‐metal atoms, the FM‐AFM‐FM transition is thus readily on‐surface accessible. Furthermore, the two configurations of the switch are easily identified by their Kondo states, opening interesting routes in terms of both, writing (FM versus AFM states) and reading. These results pave the experimental route toward dimer‐based materials with complex magnetic structures of potential interest for application in spintronics, logics and computing.

Charge Transfer Chromophores Derived from 3d-Row Transition Metal Complexes

A series of new charge transfer (CT) chromophores of "α-diimine-MII-catecholate" type (where M is 3d-row transition metals-Cu, Ni, Co) were derived from 4,4'-di-tert-butyl-2,2'-bipyridyl and 3,6-di-tert-butyl-o-benzoquinone (3,6-DTBQ) in accordance with three modified synthetic approaches, which provide high yields of products. A square-planar molecular structure is inherent for monomeric [CuII(3,6-Cat)(bipytBu)]∙THF (1) and NiII(3,6-Cat)(bipytBu) (2) chromophores, while dimeric complex [CoII(3,6-Cat)(bipytBu)]2∙toluene (3) units two substantially distorted heteroleptic D-MII-A (where D, M, A are donor, metal and acceptor, respectively) parts through a donation of oxygen atoms from catecholate dianions. Chromophores 1-3 undergo an effective photoinduced intramolecular charge transfer (λ = 500-715 nm, extinction coefficient up to 104 M-1·cm-1) with a concomitant generation of a less polar excited species, the energy of which is a finely sensitive towards solvent polarity, ensuring a pronounced negative solvatochromic effect. Special attention was paid to energetic characteristics for CT and interacting HOMO/LUMO orbitals that were explored by a synergy of UV-vis-NIR spectroscopy, cyclic voltammetry, and DFT study. The current work sheds light on the dependence of CT peculiarities on the nature of metal centers from various groups of the periodic law. Moreover, the "α-diimine-MII-catecholate" CT chromophores on the base of "late" transition elements with differences in d-level's electronic structure were compared for the first time.

Molecular stacking pattern effects in heterojunction of D18:Y6 organic solar cell

AbstractMolecular stacking modes that determine morphology of bulk‐heterojunctions are important because of their effects on photovoltaic performance of organic solar cells (OSCs). Here, in order to investigate how molecular stacking pattern in OSCs heterojunction impact on electronic structures and properties, and then influence photovoltaic performance, this work selected D18:Y6 OSC as a representative system. On the basis of semi‐empirical quantum chemistry and density functional theory calculations, we studied the geometries, electronic structures and excitation properties, as well as electron and hole couplings of D18 and Y6 molecules, Y6 dimers, D18/Y6 and D18/Y6‐dimer complexes which are heterojunction interface models. The results indicate that the molecular stacking effects on open‐circuit voltage (VOC) can be attributed to the influences on charge transfer (CT) excitation energies because molecular stacking modes at donor/acceptor heterojunction interface can significantly change excitation energies. Furthermore, the molecular stacking modes can cause drastically different electron and hole couplings, and then affect charge transfer/transport rates. Hence, the molecular stacking effects on short‐circuit current density (JSC) can be understood from the effects on electron and hole couplings. The molecular stacking modes that are favorable to improving VOC and JSC of D18:Y6 OSC were also discussed.

Isolation and Reactivity of Stannylenoids Stabilized by Amido/Imino Ligands.

The reaction of the lithium aryl(silyl)amide Dipp(i Pr3 Si)NLi (Dipp=2,6-i Pr2 C6 H3 ) with one equivalent of SnCl2 in THF gave a novel stannylenoid Dipp(i Pr3 Si)NSnCl⋅LiCl(THF)2 . Heating the solution of amidostannylenoid in toluene to 80 °C resulted in dimeric amido(chloro)stannylene [Dipp(i Pr3 Si)NSnCl]2 , which can be converted to bis(amido)stannylene Sn[N(Dipp)(i Pr3 Si)]2 and amido(imino)stannylene Sn[N(Dipp)(i Pr3 Si)][IPrN] (IPrN=bis(2,6-diisopropylphenyl)imidazolin-2-imino). Treatment of bis(imino)stannylenoid [IPrN]2 Sn(Cl)Li with N2 O resulted in the dimeric complex [IPrNSn(Cl)OLi]2 . All compounds were characterized by NMR, elementary analysis, and X-ray structural determination.

Calcium Hydride Cation Dimer Catalyzed Hydrogenation of Unactivated 1-Alkenes and H2 Isotope Exchange: Competitive Ca-H-Ca Bridges and Terminal Ca-H Bonds.

Recently, it was shown that the double Ca-H-Ca bridged calcium hydride cation dimer complex [LCaH2 CaL]2+ (macrocyclic ligand L=NNNN-tetradentate Me4 TACD) exhibited remarkable activity in catalyzing the hydrogenation of unactivated 1-alkenes as well as the H2 isotope exchange under mild conditions, tentatively via the terminal Ca-H bond of cation monomer LCaH+ . In this DFT mechanistic work, a novel substrate-dependent catalytic mechanism is disclosed involving cooperative Ca-H-Ca bridges for H2 isotope exchange, competitive Ca-H-Ca bridges and terminal Ca-H bonds for anti-Markovnikov addition of unactivated 1-alkenes, and terminal Ca-H bonds for Markovnikov addition of conjugation-activated styrene. THF-coordination plays a key role in favoring the anti-Markovnikov addition while strong cation-π interactions direct the Markovnikov addition to terminal Ca-H bonds.

Flexible Coordination of the Bis(amino-oxazoline) Ligand in Rare-Earth Metal Complexes: Synthesis, Structure, and Their Reactivity and Polymerization Performance.

Mononuclear rare-earth metal alkyl complexes supported by tetradentate dianionic bis(amino-oxazoline) ligands have been synthesized, and their reactivity toward small molecules and catalytic performance on ring-opening polymerization have been studied. Treatment of Ln(CH2SiMe3)3(THF)2 (Ln = Sc, Y; THF = tetrahydrofuran) with the bis(amino-oxazoline) proligand H2L afforded the corresponding rare-earth metal monoalkyl complexes L-Ln(CH2SiMe3)(THF)x (Ln = Sc, x = 0 (1); Ln = Y, x = 1 (2)). The isopropyl-substituted Sc alkyl complex L'-Sc(CH2SiMe3) (3) and the analogue Y silylamide complex L-Y[N(SiHMe2)2] (4) have been prepared by a similar method. Complexes 1 and 2 were stable in solution at room temperature but transformed gradually at elevated temperature to give a nucleophilic addition product for Sc (5) and an oxazoline ring-opened dimeric complex for Y (6). Reactions of 1 with elemental sulfur and selenium each led to insertion of one chalcogen into the Sc-C bond, and the corresponding six-coordinate mononuclear chalcogenolate complexes L-Sc(ECH2SiMe3)(THF) (E = S (7), Se (8)) were isolated. Treatment of 1 with an equimolar amount of aniline yielded the Sc anilide complex L-Sc(NHC6H5) (9), whereas the reaction of 1 with [NHEt3][BPh4] afforded the Sc ion-pair [L-Sc][BPh4] (10), which upon recrystallization led to formation of a THF-solvated product [L-Sc(THF)][BPh4] (11). Single-crystal X-ray diffraction analyses of complexes 1-3, 7-9, and 11 revealed the flexible coordination capability of the tetradentate bis(amino-oxazoline) ligand of upholding a mononuclear metal center via a torsion of the diaminobiphenyl axis. Complexes 1-4 were active catalysts for initiating the ring-opening polymerization of rac-lactide with good activity (TOF up to 3204 h-1) and heteroselectivity (Pr = 0.65-0.71). This study highlights the applicability of the well-defined tetradentate bis(amino-oxazoline) ligands for mononuclear rare-earth metal complexation and shed light on the new potential of rare-earth metal catalysts bearing this type of easily derivatizable polydentate ligand.

Physico-chemical Characterization of Some Metal Complexes Formed by Substituted Thiourea

In view of unique physico-chemical observations affecting the geometry and various properties of the substituted thiourea complexes in literature along with several biological activities, N-(hydroxy)-N,N-diphenyl thiourea was taken up for study. Complexes with geometries of high spin octahedral for iron(II), cobalt(II); tetrahedral & square planar for nickel(II); and dimeric square planar for copper chloride, copper perchlorate, copper acetate and distorted octahedral for copper nitrate were synthesized and characterized based on magnetic moments, visible spectra, diffuse reflectance spectra, electron spin resonance, infrared spectral studies, and thermal analysis.
 Interestingly, the nature of anion influenced the geometry, the complex from copper nitrate salt resulted in a distorted octahedral structure and complexes formed from copper chloride, copper perchlorate, copper acetate exhibited sub-normal magnetic moments, highly insoluble in the most common organic solvents and water. Based on these and spectral data, polymeric or square-planar dimeric geometry with sulfur bridging between copper atoms is proposed. It was confirmed by the application of Bleaney-Bower’s equation for magnetic susceptibility, applicable to dimeric copper complexes.
 The overall thermal behavior of the ligand and complexes were observed and the detailed calculations interestingly lead to confirmation of the above proposed geometrical structures.

Selective light-up of dimeric G-quadruplex forming aptamers for efficient VEGF165 detection

To develop efficient anticancer theranostic systems, we studied the interaction between a cyanine dye, analogue of thiazole orange (named CyOH), and two G-quadruplex-forming aptamers, V7t1 and 3R02, recognizing the Vascular Endothelial Growth Factor 165 (VEGF165) - an angiogenic protein overexpressed in cancer cells, responsible for the rapid growth and metastases of solid tumours. We demonstrated, by exploiting different biophysical techniques - i.e. gel electrophoresis, circular dichroism (CD), UV–vis and fluorescence spectroscopy - that this cyanine interacted with both aptamers giving a marked fluorescence light-up only when bound to their dimeric forms. Interestingly, both oligonucleotides recognized VEGF165 with higher affinity when adopting dimeric G-quadruplexes, largely prevalent over their monomeric forms in pseudo-physiological conditions. Notably, the fluorescence light-up produced by the probe was maintained when the dimeric aptamer-CyOH complexes bound to the target protein. These complexes, tested on MCF-7 cancer cells using non-tumorigenic MCF-10A cells as control, were effectively internalized in cells and colocalized with a fluorescently-labelled anti-VEGF-A antibody, allowing both recognition and detection of the target. Our experiments showed that the studied systems are promising tools for anticancer theranostic strategies, combining the therapeutic potential of the G4-forming anti-VEGF aptamers with the diagnostic efficacy of the cyanine selective fluorescence light-up.

Np(V) dicyanamide complexes with electroneutral N-donor ligands

Abstract Three new complexes of Np(V) dicyanamide with electroneutral N-donor ligands have been synthesized and structurally characterized: two with terpyridine derivatives: [(NpO2)(Cl-Terpy)(DMA)(N(CN)2)]·0.5DMA (1), [(NpO2)(TPTZ)(N(CN)2)(H2O)]·2H2O·CH3OH (2) and a dimeric complex with bipyridine [(NpO2)(Bipy)(N(CN)2)(H2O)]2·2(CH3OH) (3). In compounds 1–3, the coordination polyhedra of Np atoms are pentagonal bipyramids with “yl” oxygen atoms in apical positions. The equatorial plane of the bipyramids is formed by nitrogen atoms of the anions [N(CN)2]− and N-donor electroneutral ligands (Cl-Terpy, TPTZ, Bipy) and the oxygen atom of water molecule (1, 3) or DMA (2). In compounds 1 and 2, the [N(CN)2]− anions manifest themselves as monodentate ligands, and in compound 3 dicyanamide is a bidentate-bridging ligand.

Quantifying the Influence of Covalent Metal‐Ligand Bonding on Differing Reactivity of Trivalent Uranium and Lanthanide Complexes

AbstractQualitative differences in the reactivity of trivalent lanthanide and actinide complexes have long been attributed to differences in covalent metal‐ligand bonding, but there are few examples where thermodynamic aspects of this relationship have been quantified, especially with U3+ and in the absence of competing variables. Here we report a series of dimeric phosphinodiboranate complexes with trivalent f‐metals that show how shorter‐than‐expected U−B distances indicative of increased covalency give rise to measurable differences in solution deoligomerization reactivity when compared to isostructural complexes with similarly sized lanthanides. These results, which are in excellent agreement with supporting DFT and QTAIM calculations, afford rare experimental evidence concerning the measured effect of variations in metal‐ligand covalency on the reactivity of trivalent uranium and lanthanide complexes.

Quantifying the Influence of Covalent Metal-Ligand Bonding on Differing Reactivity of Trivalent Uranium and Lanthanide Complexes.

Qualitative differences in the reactivity of trivalent lanthanide and actinide complexes have long been attributed to differences in covalent metal-ligand bonding, but there are few examples where thermodynamic aspects of this relationship have been quantified, especially with U3+ and in the absence of competing variables. Here we report a series of dimeric phosphinodiboranate complexes with trivalent f-metals that show how shorter-than-expected U-B distances indicative of increased covalency give rise to measurable differences in solution deoligomerization reactivity when compared to isostructural complexes with similarly sized lanthanides. These results, which are in excellent agreement with supporting DFT and QTAIM calculations, afford rare experimental evidence concerning the measured effect of variations in metal-ligand covalency on the reactivity of trivalent uranium and lanthanide complexes.

Modulating the Inclusive and Coordinating Ability of Thiacalix[4]arene and Its Antenna Effect on Yb3-Luminescence via Upper-Rim Substitution.

The present work introduces the series of thiacalix[4]arenes (H4L) bearing different upper-rim substituents (R = H, Br, NO2) for rational design of ligands providing an antenna-effect on the NIR Yb3+-centered luminescence of their Yb3+ complexes. The unusual inclusive self-assembly of H3L− (Br) through Br…π interactions is revealed through single-crystal XRD analysis. Thermodynamically favorable formation of dimeric complexes [2Yb3+:2HL3−] leads to efficient sensitizing of the Yb3+ luminescence for H4L (Br, NO2), while poor sensitizing is observed for ligand H4L (H). X-ray analysis of the single crystal separated from the basified DMF solutions of YbCl3 and H4L(NO2) has revealed the transformation of the dimeric complexes into [4Yb3+:2L4−] ones with a cubane-like cluster structure. The luminescence characteristics of the complexes in the solutions reveal the peculiar antenna effect of H4L(R = NO2), where the triplet level at 567 nm (17,637 cm−1) arisen from ILCT provides efficient sensitizing of the Yb3+ luminescence.

Mono(imidazolin-2-iminato) Hafnium Complexes: Synthesis and Application in the Ring-Opening Polymerization of ε-Caprolactone and rac-Lactide

Mono-substituted imidazolinX-2-iminato hafnium(IV) complexes (X = iPr, tBu, Mesityl, Dipp) were synthesized and fully characterized, including solid-state X-ray diffraction analysis. When the X group is small (iPr), a dimeric structure is obtained. In all the monomeric complexes, the Hf-N bond can be regarded as a double bond with similar electronic properties. The main difference among the monomeric complexes is the cone angle of the ligand, which induces varying steric hindrances around the metal center. When the monomeric complex of mono(bis(diisopropylphenyl)imidazolin-2-iminato) hafnium tribenzyl was reacted with three equivalents (equiv) of iPrOH, the benzyl groups were easily replaced, forming the corresponding tri-isopropoxide complex. However, when BnOH was used, dimeric complexes were obtained. When five equivalents of the corresponding alcohols (BnOH, iPrOH) were reacted with the monomeric complex, different dimeric complexes were obtained. Regardless of the high oxophilicity of the hafnium complexes, all complexes were active catalysts for the ring-opening polymerization (ROP) of ε-caprolactone. Dimeric complexes 5 and 6 were found to be the most active catalysts, enabling polymerization to occur in a living, immortal fashion, as well as the copolymerization of ε-caprolactone with rac-lactide, producing block copolymer PCL-b-LAC. The introduction of imidazolin-2-iminato ligands enables the tailoring of the oxophilicity of the complexes, allowing them to be active in catalytic processes with oxygen-containing substrates.

Pd-Mediated Light-Controlled Living Radical Polymerization of Methyl Acrylate

Abstract The radical polymerization of methyl acrylate in the presence of a palladium dimer complex and ethyl iodoacetate as an initiator under photoirradiation conditions led to the formation of poly(methyl acrylate) having good Ð values. The polymerization could be controlled by switching the light on and off, exhibiting living characteristics. We propose that such α-Pd polyesters could function as dormant species, which would allow a pair of transient α-keto radicals and persistent Pd radicals to be generated upon photoirradiation.

Algal photosystem I dimer and high-resolution model of PSI-plastocyanin complex

Photosystem I (PSI) enables photo-electron transfer and regulates photosynthesis in the bioenergetic membranes of cyanobacteria and chloroplasts. Being a multi-subunit complex, its macromolecular organization affects the dynamics of photosynthetic membranes. Here we reveal a chloroplast PSI from the green alga Chlamydomonas reinhardtii that is organized as a homodimer, comprising 40 protein subunits with 118 transmembrane helices that provide scaffold for 568 pigments. Cryogenic electron microscopy identified that the absence of PsaH and Lhca2 gives rise to a head-to-head relative orientation of the PSI–light-harvesting complex I monomers in a way that is essentially different from the oligomer formation in cyanobacteria. The light-harvesting protein Lhca9 is the key element for mediating this dimerization. The interface between the monomers is lacking PsaH and thus partially overlaps with the surface area that would bind one of the light-harvesting complex II complexes in state transitions. We also define the most accurate available PSI–light-harvesting complex I model at 2.3 Å resolution, including a flexibly bound electron donor plastocyanin, and assign correct identities and orientations to all the pigments, as well as 621 water molecules that affect energy transfer pathways.

The Unprecedented [S4 N2 O10 ]2- Anion in the Molecular Gold Complexes [Au2 Br2 (S4 N2 O10 )2 ] and [Au2 Cl2 (S4 N2 O10 )2 ](S2 O5 Cl2 ).

The reaction of hexachlorophosphazene, P3 N3 Cl6 , with SO3 and the gold halides AuCl3 and AuBr3 , respectively, leads to the new cyclic anionic tetramer, [S4 N2 O10 ]2- , which is coordinated to Au3+ in the dimeric complexes [Au2 X2 (S4 N2 O10 )2 ] (X=Cl, Br). The [S4 N2 O10 ]2- anion can be seen as the condensation product of two sulfate anions, [SO4 ]2- , and two amidosulfate anions, [NH2 SO3 ]- .

Electromigration Dispersion in Sodium Dodecyl Sulfate Capillary Gel Electrophoresis of Proteins

The electromigration dispersion of the light- and heavy-chain subunit peaks of the therapeutic monoclonal antibody omalizumab was investigated in sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE) using borate cross-linked dextran sieving matrices. Increasing boric acid content (340-640 mM) caused electromigration dispersion shifts for both low (2%)- and high (10%)-dextran-concentration gels in all gel-buffer compositions. In case of the heavy-chain fragment, elevated borate concentrations resulted in decreasing tailing and increasing fronting with the use of higher- and lower-dextran-concentration gels, respectively. The light-chain fragment, on the other hand, exhibited increased fronting with increasing borate concentration for both dextran concentrations examined in this study. Increase of the glycerol ingredient level in the gel-buffer system caused the same effect as the increasing borate concentration in both dextran concentrations. The detected electromigration dispersion was considered as the result of the formation of monomeric and dimeric glycerol-borate complexes as co-ionic constituents, migrating slower than that of the unconjugated tetrahydroxyborate. In addition, complexation of the tetrahydroxyborate anion with the glucose building blocks of the dextran polymer decreased its mobility to practically zero, contributing to further decrease in the resultant effective mobility of the co-ionic species. We suggest that the observed fronting and/or tailing peak shapes of the monoclonal antibody fragments in SDS-CGE at increasing boric acid concentrations can be considered as the result of multiple effects including changes in pH, sieving matrix pore size, viscosity, and the mobility variation of the co-ionic borate adducts with the gel-buffer ingredients. While electromigration dispersion-mediated band broadening, in general, can be minimized via matching the effective mobility of the co-ionic species to the analyte molecules of interest, in case of borate cross-linked dextran gels, optimization of the boric acid concentration required special consideration of its gel cross-linking function. For the light- and heavy-chain fragments of the IgG analyte, best peak shapes were attained with the use of 10% dextran/340 mM boric acid and 10% dextran/640 mM boric acid-containing gel-buffer systems, respectively. Based on this observation, here we introduce the concept of borate-gradient-mediated transient mobility matching in SDS-CGE of proteins. This novel approach resulted in close to optimal peak shapes for the distantly migrating IgG subunits within a single run, as well as unraveled the long-sought possible solution to perform capillary pore-size-gradient gel electrophoresis.

CEP19-RABL2-IFT-B axis controls BBSome-mediated ciliary GPCR export.

The intraflagellar transport (IFT) machinery mediates the import and export of ciliary proteins across the ciliary gate, as well as bidirectional protein trafficking within cilia. In addition to ciliary anterograde protein trafficking, the IFT-B complex participates in the export of membrane proteins together with the BBSome, which consists of eight subunits encoded by the causative genes of Bardet-Biedl syndrome (BBS). The IFT25-IFT27/BBS19 dimer in the IFT-B complex constitutes its interface with the BBSome. We show here that IFT25-IFT27 and the RABL2 GTPase bind the IFT74/BBS22-IFT81 dimer of the IFT-B complex in a mutually exclusive manner. Cells expressing GTP-locked RABL2 [RABL2(Q80L)], but not wild-type RABL2, phenocopied IFT27-knockout cells, that is, they demonstrated BBS-associated ciliary defects, including accumulation of LZTFL1/BBS17 and the BBSome within cilia and the suppression of export of the ciliary GPCRs GPR161 and Smoothened. RABL2(Q80L) enters cilia in a manner dependent on the basal body protein CEP19, but its entry into cilia is not necessary for causing BBS-associated ciliary defects. These observations suggest that GTP-bound RABL2 is likely to be required for recruitment of the IFT-B complex to the ciliary base, where it is replaced with IFT25-IFT27.

Synthesis and photophysical studies on cyclometalated iridium complexes containing various monodentate phenyl-azole ancillary ligands

In this study, five cyclometalated iridium complexes containing phenyl-azole ancillary ligands were synthesized and characterized by X-ray crystallography, and their photophysical properties were studied. The reaction of [Ir(ppy)2(μ-Cl)]2 (ppy: 2-phenylpyridine) with pim (4-phenylimidazole), ptr4h (4-phenyl-4H-1,2,4-triazole), and ptr1h (1-phenyl-1H-1,2,4-triazole) ligands furnished mononuclear [Ir(ppy)2ClL] complexes (1–3; L = pim, ptr4h, ptr1h) featuring monodentate neutral N → Ir coordination. In contrast, the corresponding reaction with ptz (5-phenyl-1H-tetrazole) ligand yielded a hetero-bridged dimeric iridium complex, [Ir(ppy)2(μ-Cl)(μ-ptz)Ir(ppy)2] (4). Notably, adding dimethylsulfoxide (DMSO) solvent to complex 4 resulted in its division to [Ir(ppy)2(ptz)(DMSO)] (5) and [Ir(ppy)2Cl(DMSO)]. Complexes 1–4 exhibited blue-green phosphorescence in solution with marginal shifts in the emission wavelengths. Complex 1, having a pim ligand, exhibited a significantly higher phosphorescence quantum efficiency (ΦPL = 31%) than those of complexes 2–4 (ΦPL = 4–9%), which was attributed to the relatively small non-radiative decay rate constant in 1. Density functional theory calculations confirmed that the phosphorescence has originated from both the metal–ligand charge transfer (3MLppyCT) and the ligand-centered (3LCppy) states. An increased LC character was observed in the phosphorescence of the dinuclear complex 4.

Naked-Eye-Detectable Supramolecular Sensing System for Glutaric Acid and Isophthalic Acid

Abstract We report a molecular sensor, comprising a porphyrin core and four 2-aminoquinolyl groups at meso positions, for the naked-eye detection of glutaric acid and isophthalic acid, both featuring a C3 spacer between two CO2H groups. In the presence of the C3 dicarboxylic acids, solutions of the porphyrin sensor underwent significant changes in color and absorption spectra. NMR spectroscopy and X-ray crystallography revealed that the porphyrin derivative bound to two molecules of the C3 dicarboxylic acids selectively to form 1:2 complexes, which dimerized through strong π-stacking interactions. Magnetic circular dichroism (MCD) spectroscopy and density functional theory (DFT) calculations suggested that the red-shifting of the Q-bands in the absorption spectra of the porphyrin derivative arose from tilted quinolyl rings in the dimeric complexes. In addition, we found that a test strip containing the porphyrin sensor could also be used to efficiently detect glutaric acid and isophthalic acid.