The two-component phthalocyaninato copper-based heterojunctions fabricated from n-type CuPc(COOC₈H₁₇)₈ and p-type CuPc(OC₈H₁₇)₈ by a facile two-step solution-processing quasi-Langmuir–Shäfer method with both n/p- and p/n-bilayer structures are revealed to exhibit typical ambipolar air-stable organic thin-film transistor (OTFT) performance. The p/n-bilayer devices constructed by depositing CuPc(COOC₈H₁₇)₈ film on CuPc(OC₈H₁₇)₈ sub-layer show superior OTFT performance with hole and electron mobility of 0.11 and 0.02 cm² V⁻¹ s⁻¹, respectively, over the ones with n/p-bilayer heterojunction structure with the hole and electron mobility of 0.03 and 0.016 cm² V⁻¹ s⁻¹ due mainly to the more intense face-to-face π–π interaction in the CuPc(OC₈H₁₇)₈ sub-layer than that in CuPc(COOC₈H₁₇)₈ sub-layer, revealing the effect of different stacking sequence on tuning the OTFT performance of phthalocyanine-based bilayer heterojunctions. Furthermore, the chemiresistive devices fabricated from the p/n-bilayer heterojunction, with both Au and Indium tin oxide (ITO) interdigitated electrodes (IDEs), also display much better sensing properties to ethanol than those with n/p-bilayer heterojunction in terms of sensitivity and reversibility. Significantly, time-dependent current plot of the p/n-bilayer heterojunction with ITO IDEs reveals a detection limit as low as 100 ppm, nearly complete reversibility, and high selectivity to ethanol even at room temperature, rendering this novel two-component heterojunction device a great application potential in practical detecting ethanol.

A series of four porphyrin–alkaline earth metal– organic frameworks [Mg(HDCPP)₂(DMF)₂]_n⋅(H₂O)_7 n (1), [Ca(HDCPP)₂(H₂O)₂]_n(DMF)_1.5 n (2), [Sr(DCPP)(H₂O)(DMA)]_n (3), and [Ba(DCPP)(H₂O)(DMA)]_n (4) was isolated for the first time from solvothermal reaction between metal-free 5,15-di(4- carboxyphenyl)porphyrin (H₂DCPP) and alkaline earth ions. Single-crystal X-ray diffraction analysis reveals the 2D and 3D supramolecular network with periodic nanosized porosity for 1/2 and 3/4, respectively. The whole series of MOFs, in particular, compounds 1 and 2 with intrinsic low molecular formula weight, exhibit superior adsorption performance for methylene blue (MB) with excellent capture capacity as represented by the thus far highest adsorption amount of 952 mg g⁻¹ for 2 and good selectivity, opening a new way for the potential application of the main group metal-based MOFs.

Fluorescent [2]rotaxane BC12P5 is successfully constructed with 1,4-diethoxypillar[5]arene as wheel over a long alkyl axle with Bodipy chromophore as one stopper for the first time. NMR spectra clearly reveal its molecular shuttle nature triggered by multiple external stimuli including solvent polarity and temperature. In particular, the fluorescence nature introduced into [2]rotaxane BC12P5 renders it a good sensor for the external stimuli. Nevertheless, the supramolecular gel successfully fabricated from this novel rotaxane system via self-assembly in dimethyl sulfoxide (DMSO) also shows reversible gel–sol phase transition upon multiple external stimuli such as heating/cooling, shaking/resting, or the addition of different anions. Interestingly, exposure of the supramolecular gel film to HCl or ammonia vapor induces the change in the film fluorescence intensity, endowing this system with a potential application in gas detecting.

The periodic octupolar vibrational nature of the electron cloud in sandwich-type bis(phthalocyaninato) yttrium double-decker compounds has been revealed on the basis of coupled perturbed density functional theory. This in turn results in an intense hyper-Rayleigh scattering response and renders the double-decker skeletons excellent second-order hyperpolarizability with a maximum value as high as 5.55×10⁶ au (≈10⁵×10⁻³⁰ esu, theoretical prediction) achieved for the molecular conformation with a rotation angle between two phthalocyanine chromophores of approximately 70°.

The role of O₂ within the synthesis of phthalocyanines (Pcs) has remained unclear in the past century. Here, we demonstrate that O₂, in cooperation with the solvent n-pentanol, participates in the cyclic tetramerization of phthalonitriles over the half-sandwich complex template [Lu(Pc)(acac)] (acac=acetylacetonate) and terminates the reaction at the stage of uncyclized isoindole oligomeric derivatives rather than the phthalocyanine chromophores, resulting in the isolation of the heteroleptic (phthalocyaninato)(triisoindole-1-one) lutetium double-decker complexes [(Pc)Lu(TIO-I)] (TIO-I=3,4,7,8,11,12-sexi(2,6-diisopropylphenoxy)-15-[4,5-di(2,6-diisopropylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) and [(Pc)Lu(TIO-II)] (TIO-II=3,4,7,8,11,12-sexi(2,6-dimethylphenoxy)-15-[4,5-di(2,6-dimethylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) with the help of bulky substituents at the phthalonitrile periphery and an unsubstituted phthalocyanine ligand in the double-decker skeleton. Nevertheless, the cyclic tetramerization of the phthalonitriles was revealed to be sensitive to O₂ with the reaction progression also depending on the oxygen concentration/content, leading to the O₂-senstive and -dependent nature for the isolation of phthalocyanine derivatives.

Novel pyrene-fused unsymmetrical phthalocyanine derivatives 2,3,9,10,16,17-hexakis(2,6-dimethylphenoxy)-22,25-diaza(2,7-di-tert-butylpyrene)[4,5]phthalocyaninato zinc complex Zn[Pc(Pz-pyrene)(OC₈H₉)₆] (1) and 2,3,9,10-tra(2,6-dimethylphenoxy)-15,18,22,25-traza(2,7-di-tert-butylpyrene)[4,5]phthalocyaninato zinc compound Zn[Pc(Pz-pyrene)₂(OC₈H₉)₄] (2) were isolated for the first time. These unsymmetrical pyrene-fused phthalocyanine derivatives have been characterized by a wide range of spectroscopic and electrochemical methods. In particular, the pyrene-fused phthalocyanine structure was unambiguously revealed on the basis of single crystal X-ray diffraction analysis of 1, representing the first structurally characterized phthalocyanine derivative fused with an aromatic moiety larger than benzene.

The mixed cyclic tetramerization of 4,5-bis(hexylthio)phthalonitrile and bis(diiminoisoindoline) with [M(acac)₃]·nH₂O (M = Pr, Eu, Lu) as template in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol at reflux has provided binuclear phthalocyanine-containing sandwich-type rare-earth complexes [{Pc(SC₆H₁₃)₈}M{BiPc(SC₆H₁₃)₁₂}M(SC₆H₁₃)₈] (M = Pr, Eu, Lu; 1–3). These new binuclear phthalocyanine-containing sandwich compounds have been characterized by a series of spectroscopic methods including mass spectrometry and ¹H NMR, electronic absorption, and IR spectroscopy in addition to elemental analysis. Their electrochemical data have also been obtained by cyclic voltammetry. In addition, the third-order nonlinear optical properties of [{Pc(SC₆H₁₃)₈}Pr{BiPc(SC₆H₁₃)₁₂}Pr(SC₆H₁₃)₈] (1) and [Pr{Pc(SC₆H₁₃)₈}₂] in toluene solution were studied comparatively by using the Z-scan technique; effective imaginary third-order molecular hyperpolarizabilities of 1.86 × 10^–11 and 1.56 × 10^–11 esu, respectively, were obtained, which indicates their potential application in the optical-limiting field.

Two tri(benzo[b]thiopheno)subporphyrazine regioisomers with C₃ and C₁ molecular symmetry have been isolated from the cyclotrimerization of benzo[b]thiophene-2,3-dicarbonitrile as the first five-membered-heterocycle-fused subphthalocyanine analogues. Optical resolution of both regioisomers was achieved by using a chiral HPLC technique, affording the first chiral subphthalocyanine analogues.

Density functional theory method was employed to investigate the electronic properties of two series of subporphyrazine and subphthalocyanine derivatives, namely SubPz, SubPz-1H, SubPz-2H, SubPz-3H, SubPc, SubPc-1H, SubPc-2H, and SubPc-3H. Calculated results show that peripheral hydrogenation essentially changes the delocalized pattern from the common π₁₄¹⁴ to limited π₁₃¹⁴ or π₁₂¹⁴ for SubPz series, and substantially weakens the aromaticity for both SubPz and SubPc compounds. The unordinary delocalized circuit owns an unstable energy level, and thus gives rise to a notable transformation of geometric configuration, frontier molecular orbital topology, and absorption spectral bands.

The three-unit homoaromatic electron-delocalizing nature of the benzo-fused tetra(triptycene)porphyrins (TTPs) with a three-dimensional conjugated model is clarified using density functional theory studies. Due to the electron delocalization, the unidirectional photon-induced current of this kind of TTP molecular skeleton with a highest efficiency of about 90 % in the range between 350 and 500 nm gives them great potential as efficient solar antenna collectors. In addition, their active triptycene cups fused at the central porphyrin core render possible potential application in host–guest chemistry.

An optically active metal-free porphyrin (1) with four chiral binaphthyl units attached at the meso-phenyl substituents through crown ether moieties has been designed, synthesized, and characterized. Its self-assembly behavior in the absence and presence of K⁺ was comparatively investigated by electronic absorption and circular dichroism (CD) spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM), and energy-dispersive X-ray (EDX) spectroscopy. In the absence of K⁺, metal-free porphyrin self-assembles into nanoparticles depending mainly on the van der Waals interaction among neighboring metal-free molecules. In the presence of K⁺, additionally formed metal–ligand K–O_crown coordination bonds between K⁺ and crown units of (R)- and (S)-1 molecules, together with chiral discrimination of chiral side chains and intermolecular van der Waals interactions, induce a right-handed and left-handed helical arrangement in a stack of (R)- and (S)-1 molecules, respectively, with an ordered “head-to-tail” internal molecular arrangement. This then further hierarchically self-assembles into highly ordered fibrous nanostructures with a helicity opposite to that of the original porphyrin stack. This clearly reveals the effect of the metal–ligand coordination bonding interaction on the morphology and handedness of self-assembled nanostructures.

To investigate the effects of metal–ligand coordination on the molecular structure, internal structure, dimensions, and morphology of self-assembled nanostructures, two nonperipherally octa(alkoxyl)-substituted phthalocyanine compounds with good crystallinity, namely, metal-free 1,4,8,11,15,18,22,25-octa(butyloxy)phthalocyanine H₂Pc(α-OC₄H₉)₈ (1) and its lead complex Pb[Pc(α-OC₄H₉)₈] (2), were synthesized. Single-crystal X-ray diffraction analysis revealed the distorted molecular structure of metal-free phthalocyanine with a saddle conformation. In the crystal of 2, two monomeric molecules are linked by coordination of the Pb atom of one molecule with an aza-nitrogen atom and its two neighboring oxygen atoms from the butyloxy substituents of another molecule, thereby forming a Pb-connected pseudo-double-decker supramolecular structure with a domed conformation for the phthalocyanine ligand. The self-assembling properties of 1 and 2 in the absence and presence of sodium ions were comparatively investigated by scanning electronic microscopy (SEM), spectroscopy, and X-ray diffraction techniques. Intermolecular π–π interactions between metal-free phthalocyanine molecules led to the formation of nanoribbons several micrometers in length and with an average width of approximately 100 nm, whereas the phthalocyaninato lead complex self-assembles into nanostructures also with the ribbon morphology and micrometer length but with a different average width of approximately 150 nm depending on the π–π interactions between neighboring Pb-connected pseudo-double-decker building blocks. This revealed the effect of the molecular structure (conformation) associated with metal–ligand (PbN_isoindole, PbN_aza, and PbO_butyloxy) coordination on the dimensions of the nanostructures. In the presence of Na⁺, additional metal–ligand (NaN_aza and NaO_butyloxy) coordination bonds formed between sodium atoms and aza-nitrogen atoms and the neighboring butyloxy oxygen atoms of two metal-free phthalocyanine molecules cooperate with the intrinsic intermolecular π–π interactions, thereby resulting in an Na-connected pseudo-double-decker building block with a twisted structure for the phthalocyanine ligand, which self-assembles into twisted nanoribbons with an average width of approximately 50 nm depending on the intertetrapyrrole π–π interaction. This is evidenced by the X-ray diffraction analysis results for the resulting aggregates. Twisted nanoribbons with an average width of approximately 100 nm were also formed from the lead coordination compound 2 in the presence of Na⁺ with a Pb-connected pseudo-double-decker as the building block due to the formation of metal–ligand (NaN_aza and NaO_butyloxy) coordination bonds between additionally introduced sodium ions and two phthalocyanine ligands of neighboring pseudo-double-decker building blocks.