Search

Organic solvent nanofiltration (OSN) is an emerging membrane separation technology, which urgently requires robust, easily processed, OSN membranes possessing high permeance and small solutes-selectivity to facilitate enhanced industrial uptake. Herein, we describe the use of two 2,2′-biphenol (BIPOL) derivatives to fabricate hyper-crosslinked, microporous polymer nanofilms through IP. Ultra-thin, defect-free polyesteramide/polyester nanofilms (≈5 nm) could be obtained readily due to the relatively large molecular size and ionized nature of the BIPOL monomers retarding the rate of the IP. The enhanced microporosity arises from the hyper-crosslinked network structure and monomer rigidity. Specifically, the amino-BIPOL/PAN membrane exhibits extraordinary permselectivity performances with molecular weight cut-off as low as 233 Da and MeOH permeance of ≈13 LMH/bar. Precise separation of small dye mixtures with similar M.W. based on both their charge and molecular size are achieved.

Highly permeable organic solvent nanofiltration (OSN) membranes are desired to be used in an efficient and energy-saving chemical separation process. Herein, we fabricated a high-flux OSN membrane by synthesizing 7,7′-dihydroxy-2,2′-binaphthol (7,7′-OH-BINOL) as an aqueous phase monomer to react with trimesoyl chloride (TMC) via interfacial polymerization. The unique structures of 7,7′-OH-BINOL having a rotatable highly kinked unit and a rigid binaphthol ring endow the fabricated polyarylate membrane with very high microporosity and super-high Young's modulus. Both simulated and experimental results demonstrate that the BINOL-based polyarylate (PAR-BINOL) membrane has two types of micropores including cross-linked pores and stacked pores. Our results find that the PAR-BINOL membrane exhibits very high solvent permeance over a wide range of solvents with diverse polarity, and also possesses a long-term stable separation performance in solvents. Impressively, the membrane solvent permeance can reach up to 28.7 L m−2 h−1 bar−1, 9.2 L m−2 h−1 bar−1 and 6.7 L m−2 h−1 bar−1 for acetone, methanol, and dimethylformamide (DMF), respectively. The rejection of tetracycline (TC, Mw = 444 g mol−1) is 98.2%. Our work provides some insights into the molecular engineering of monomers with unique contorted and rigid structures for the fabrication of highly permeable OSN membranes.

It is known that the polyamide (PA) barrier layer's inherent microstructure and surface physicochemical properties of thin film composite nanofiltration membrane are crucial for its separation performance. Herein, we designed and synthesized a new zwitterionic aromatic diamine monomer 3-(4-(2-((4-aminophenyl)amino)ethyl)morpholino-4-ium)propane-1-sulfonate (PPD-MEPS) through a three steps reaction, and this hydrophilic molecule was incorporated into the active layer to tailor the poly(piperazine-amide)-based nanofiltration membranes with significantly improved water permeability and antifouling properties. As a p-phenylenediamine (PPD) derivative, PPD-MEPS possesses two active amine units, which can react with trimesoyl chloride in the organic phase during the interfacial polymerization reaction process. Thus, the super-hydrophilic zwitterions were not only on the membrane surface but also across the whole PA layer to facilitate water molecule transportation. The successful augmentation of zwitterions into the PA layer was well illustrated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results and X-ray photoelectron spectroscopy analysis. With increasing loading content of PPD-MEPS in PIP aqueous solution, the as-fabricated nanofiltration membranes (NFMs) exhibited higher hydrophilicity, increased active layer thickness, and molecular weight cut off. When the zwitterionic monomer reached 60% to PIP for NFM-4, the water permeability went up to 9.82 L m-2 h-1 bar-1, increasing by 45%; meanwhile, the Na2SO4/NaCl selectivity increased from 2.54 to 4.03. In addition, the fouling experiments illustrated that the fouling resistance of the zwitterion-modified NFMs to bovine serum albumin was significantly improved.

We describe here a novel targeting polyion complex (Tg-PIC) system for the delivery and intracellular release of cisplatin. Briefly, a guanidinium-pendant Pt(IV)-backboned poly-prodrug termed P(DSP-Gu) is prepared with excellent aqueous solubility, high drug-loading and high potency. To enable prolonged circulation and selective cellular internalization, P(DSP-Gu) is complexed with anisamide-end-capped poly(ethylene glycol)-block-poly(L-phosphotyrosine)-block-poly(L-leucine) (AA-PEG-PpY-PLeu) to yield Tg-PIC via electrostatic coacervation. Tg-PIC is stabilized by hydrogen bonding between phosphate and guanidinium, the PEG corona, and the helical poly(L-leucine) segment forming the hydrophobic core. The anisamide group, a high affinity ligand recognizing the sigma (σ) receptors that are overexpressed on many human malignancies including prostate cancer, is incorporated at the surface of the Tg-PIC for active targeting and efficient internalization. In vitro, the Tg-PICs show targeted and efficient internalization into sigma receptor-positive PC3 cells, and can release toxic Pt(II) species due to the degradation of P(DSP-Gu) under the intracellular reducing conditions. In vivo, the Tg-PICs exhibit superior antitumor efficacy with reduced toxicity. Thus, the system holds considerable promise towards more effective and safe nanomedicine.

The behaviour of drug/gene carriers in the blood stream under shear is still a puzzle. In this work, using the complexes formed by 21 bp DNA and poly(ethylene glycol)-b-poly(l-lysine) (PEG-PLL) of varying PEG lengths, we studied the dynamic behaviour of the complexes in the presence of fetal bovine serum (FBS) and under flow at different shear rates, a condition mimicking the internal physical environment of blood vessels. The PEG5k-PLL/DNA complex possesses a dense DNA/PLL core and a loose PEG5k protecting layer. The PEGylated DNA complexes exhibit multiple responses to external shear in the presence of FBS. The loose PEG5k layer is firstly disturbed at a shear rate below 30 s-1. The exposure of the charged core to the environment results in a secondary aggregation of the complex with FBS. The size of the aggregate is limited to a certain range as the shear rate increases to 50 s-1. The dense DNA/PLL core starts to withstand the shear force as the shear rate reaches 500 s-1. The reorganization of the core to accommodate more serum molecules leads to tertiary aggregation of the complexes. If PEG cannot form a valid layer around the complex, as in PEG2k-PLL/DNA, the complex forms an aggregate even without shear, and the first shear dependent region is missing. If the PEG layer is too stable around the complex, as in PEG10k-PLL/DNA, no tertiary aggregation occurs. The mechanism of shear on the behaviour of delivery particles in serum helps to design gene carriers with high efficacy.

Membrane fouling and degradation caused by free chlorine oxidation seriously hinder the long-term operation of aromatic polyamide (PA) thin-film-composite (TFC) membranes. In this study, sulfonamide monomers 4-aminobenzene sulfonamide (4-ABSA) and 2-aminoethanesulfonamide (2-AESA)) were facilely grafted onto the PA RO membranes surface via layer-by-layer interfacial polymerization (LbL-IP) method, endowing with much improved water flux, antifouling, and chlorine-resistance properties. The chemical compositions and surface properties of the RO membranes were systematically investigated by various techniques, as FTIR and XPS results clearly showed that sulfonamide groups were successfully grafted onto RO membranes’ surface. Compared to the pristine membrane, the water flux of the two modified membranes increased by 50.8% and 59.1%, reached 3.65 ± 0.15 L m−2 h−1 bar−1 and 3.85 ± 0.05 L m−2 h−1 bar−1, respectively, meanwhile their NaCl rejection remained above 99.25 ± 0.08%. Due to the improvement of surface hydrophilicity and decrease of surface roughness, the antifouling performance of the modified membranes was greatly improved. Moreover, the N–H moieties on sulfonamide can act as sacrificial units for free chloride attack to significantly improve the chlorine-resistance performances of the modified RO membranes compared to the pristine one, with NaCl rejection remain above 98.95 ± 0.09% after chlorination intensity of 8000 ppm⋅h under acidic condition of pH 4. This simple and efficient surface grafting strategy and modifying materials make it have great application potential in the field of water treatment.

We describe here the synthesis and cell-selective delivery of a cationic Pt(iv)-backboned prodrug-like polymer P(DSP-DAEP). P(DSP-DAEP) features excellent aqueous solubility, unusually high (44.5%) drug loading, can be rapidly reduced to release the active cisplatin, and is more potent than its small molecular Pt(iv) precursor DSP. P(DSP-DAEP) can be formulated with an oppositely charged methoxyl poly(ethylene glycol)-block-poly(l-phosphotyrosine) (mPEG-b-PpY) to afford a polyion micelle (Pt-PIC) by taking advantage of polyelectrolyte coacervation. Preliminary in vitro cellular uptake and cytotoxicity assays indicate that Pt-PIC exhibits receptor (surface alkaline phosphatase)-dependent uptake and cytotoxicity. Overall, our results suggest a new approach to the improved therapeutic index of platinum-based anticancer drugs via cell-selective delivery.

In this work, antifouling thin-film composite (TFC) nanofiltration (NF) membrane having zwitterionic PEI moieties was fabricated through the layer-by-layer interfacial polymerization (LbL-IP) via grafting hyperbranched polyethyleneimine (PEI) onto the polyamide surface, followed by in-situ N-methylation of PEI and then quaternization using 3-bromopropionic acid to form zwitterionic PEI. The successful surface modifications of TFC NF membrane with PEI and zwitterionic PEI were confirmed by XPS and ATR-FTIR results. Benefitting from the strong hydrophilicity and hyperbranched steric structure, the zwitterionic PEI-grafted TFC membrane (NF-ZPEI) exhibited a stronger hydration capacity and a thicker hydration layer than the PEI-grafted TFC membrane (NF-PEI) and the control sample (NF-PA). Meantime, the water permeability of NF-ZPEI membrane was enhanced by 11.6% higher than the control sample. The NF-ZPEI membrane also exhibited the improved ion selectivity of having a decreased rejection towards NaCl and maintaining a high rejection towards divalent ions. Dynamic fouling experiments were performed to demonstrate the impact of surface hydrophilicity and surface charge on the membrane fouling performances. Results illustrate that the zwitterionic PEI grafted on the TFC NF membrane mitigated the electrostatic attraction between the membrane surface and protein foulants, and exhibited the improved antifouling properties of having a low flux decline and a high flux recovery. Our work provides some insights on the zwitterionic surface modification of the TFC NF membrane with both the enhanced water permeability and the antifouling properties towards charged foulants.

As known, piperazine (PIP) and m-phenylenediamine (MPD) are popularly employed as aqueous monomer to interfacially polymerize with trimesoyl chloride (TMC) for the fabrication of TFC polyamide NF and RO membrane, respectively. In this work, we designed a novel amine monomer 4-(piperazin-1-yl)benzene-1,3-diamine (PMPD) having the combined PIP and MPD units in one molecule and employing it with TMC to prepare the pristine nanofiltration membrane. Subsequently, zwitterionic antifouling PA surface was constructed by modification with 3-bromopropionic acid (3-BPA). The resulting membrane (PMPD-PA) exhibited a smoother surface with enhanced surface hydrophilicity than the membrane made from MPD, and the thickness of the PA active layer was down to ~35 nm. Meanwhile, its pure water permeability was ~19 L m−2 h−1 bar−1, with Na2SO4 rejection of 98.4%, and NaCl rejection as low as 24.1%, performing as a novel selective NF membrane. Furthermore, fouling tests using model foulants BSA and SA well illustrated the good antifouling properties of membrane PMPD-PA with the mitigated flux decline and enhanced flux recovery upon physical cleaning. Thus, this work further demonstrates the fabrication of high-performance TFC NF membrane from the perspective of molecular design.

Zwitterions have been attracting great attention for researchers to tailor the separation membranes featuring enhanced water permeability and excellent antifouling property. Here we functionalized polyamide membrane surface with small-molecule zwitterions through sequential interfacial polymerization (SIP) technique to improve the performance of RO membranes. Zwitterionic molecules 3-(4-(2-((4-aminophenyl)amino)ethyl)morpholino-4-ium)propane-1-sulfonate (PPD-MEPS) and amino acid arginine were covalently bonded onto the PA surface via the amine groups of two zwitterions. Consequently, the surface hydrophilicity of both modified membranes were significantly improved with WCA decreased from ~60° to ~28°, and their surface negative charge also decreased to some extent at high pH values. The water permeability increased from 2.45 LMH/bar to 3.81–3.85 LMH/bar, increasing by about 57%, while maintained a NaCl rejection as high as 98.5%. In addition, the zwitterions-modified RO membranes exhibited much improved antibacterial attachment (E.coil) and fouling resistance to model foulants bovine serum albumin (BSA), lysozyme (LYZ) and humic acid (HA). Therefore, the facile zwitterions modified membranes possessing high water permeability and excellent antifouling performance, especially using amino acid Arg may find their potential promising application in water treatment.

Two novel OH-functionalized intrinsically microporous polymers were successfully synthesized from a tert-butyldimethylsilyl (TBS) protected 1,1′-binaphthalene-diamine monomer (NH2-BINOL-TBS). Interestingly, the polymerization and the removal of the TBS to form OH group happened at the same time. Polymers with 30% (PIM-HNTB-30) and 60% (PIM-HNTB-60) OH concentration were obtained by controlling the reaction time of 3.5 and 12 h, and confirmed by nuclear magnetic resonance spectroscopy (NMR). PIM-HNTB-30 exhibited higher Brunauer-Emmett-Teller (BET) surface area (432 vs 153 m2 g-1) and thermal stabilities (420 vs 385 °C) than PIM-HNTB-60. Both membranes showed modest gas permeabilities and selectivities, and PIM-HNTB-60 exhibited a relatively higher performance. After long-term aging or thermally annealed above glass transition temperature (Tg), both polymers exhibited a decreased permeabilities combined with a selectivity increase, and the 350 °C treated PIM-HNTB-60 exhibited O2 permeability of 89 Barrer and O2/N2 selectivity of 4.47. In all, the OH functionalization provided a good way to enhance the gas separation performance.

It is well known that the water flux and antifouling performance of polyamide (PA) membrane are strongly associated with their surface characters, especially for surface hydrophilicity, roughness, and charge. In this study, a zwitterionic surface TFC reverse osmosis (RO) membrane was fabricated by small molecule 3-bromopropionic (3-BPA) modification on the pristine membrane that fabricated through interfacial polymerization (IP) technique using a new aqueous monomer 4-morpholinobenzene-1,3-diamine (MpMPD) and trimesoyl chloride (TMC). The as-fabricated RO membranes were well analyzed by various techniques, that the zwitterionic MpMPD-PA membrane surface exhibited greatly enhanced hydrophilicity with water contact angle of 28.1° and surface roughness as low as 26.0 nm. The water permeability of membrane MpMPD-PA reached 1.65 L m−2 h−1 bar−1, which exhibited ~24% increase compared to our lab-made MPD membrane, meanwhile kept a high NaCl rejection of 97.8%. In addition, the dynamic fouling experiments illustrated that the zwitterionic surface RO membrane possess excellent fouling resistance to protein BSA, polysaccharides SA, and surfactant SDS. Therefore, this work provide a simple and convenient way to fabricate novel zwitterionic surface RO membrane with high performance from the molecular level design.

Electron-rich dioxynaphthalene (DNP) group bridged bifunctional ureidopyrimidinone (UPy) derivatives (L1, L2, and L3) were synthesized, which could form small cyclic monomers, oligomers, or linear supramolecular polymers at certain concentration in solution, to achieve a highly controllable ring–chain equilibrium self-assembling supramolecular system. The ring–chain equilibrium of these supramolecular monomers constructed by different lengths of oligo(ethylene oxide) (oligoEO) chain as spacers were investigated by a combination of techniques, such as 1H NMR, DOSY, single-crystal X-ray diffraction, and viscometry. The experiment results demonstrated that there exists intramolecular π–π stacking interaction between DNP group and intramolecularly dimerized UPy motif in the monomeric cyclic form of these supramolecular monomers, and the strength of this π–π stacking interaction directly depends on the length of the oligoEO chain. Furthermore, strong intramolecular π–π stacking interaction was found to promote...

A novel, bifunctional, quadruple hydrogen-bonding ureido-pyrimidinone (UPy) unit bridged by photochromic dithienylethene (1) has been synthesized, which affords linear assemblies in solution and undergoes concentration-dependent ring-opening polymerization. The two UPy functional groups of 1 can dimerize intramolecularly to form a cyclic monomer with the two thienyl rings fixed in a parallel conformation, which prohibits its photocyclization. We exploited the photochemical reactivity and resonance difference of the linker of the bis-UPy derivative as well as using the more typical (1)H NMR, DOSY, and Ubbelohde viscometry methods to investigate for the first time the ring-chain polymerization mechanism. Moreover, we fabricated a mixed polymer film with a fluorescent dye noncovalently endcapping the linear photochromic assemblies through quadruple hydrogen bonds, which showed nondestructive fluorescent read-out ability for data storage by fluorescence resonance energy transfer (FRET) from the fluorescent dye to the closed form of the diarylethene.

Two D–π–A organic dyes were employed as amphiphilic materials, and their fluorescent nanotubes were fabricated at the air/water interface by the Langmuir-Blodgett (LB) technique. The structural characteristics of the fluorescent nanotubes were investigated by means of transmission electron microscopy (TEM), atomic force microscopy (AFM), and small-angle x-ray diffraction (SAXRD).

Langmui-Blodgett (LB) monolayer films of two new amphiphilic D–π–A dyes were fabricated on both pure and acidic water subphases and transferred onto the ITO electrode by the LB) technique. The ultraviolet-visible absorption spectra and photocurrent properties of the ordered LB films were investigated.

To date, ∼700 microRNA (miRNA) molecules have been identified in humans. Accurate and sensitive quantification of miRNA levels will help unveil their biological functions. Here, we extend the isothermal ramification amplification (RAM) approach to a sensitive and specific real-time assay for quantitative analysis of miRNA. This RAM miRNA assay is based on the threshold cycle (CT) principle similar to that of real-time PCR. It has a dynamic range of at least seven orders of magnitude, allowing for the quantification of miRNA input from 103 to 1010 copies per reaction (10 nM to 1 fM). The capabilities of discriminating single-base mismatch and distinguishing mature miRNAs from their precursors are achieved by coupling the reverse-transcription of miRNA to the generation of a closed C-probe, rather than using expensive detection probes like in real-time PCR. Quantitative measurement of 5 miRNAs (mir-1, miR-122, mir-150, mir-143, and let-7a) across 12 mouse tissues is validated in total RNA samples without further purification. U6 snRNA, snoRNA 135, and miRNA-191 could be simultaneously quantified as endogenous controls. These results suggest that our RAM miRNA assay might provide a universal tool for miRNA detection and functional studies to meet the needs for bench examination, clinical diagnosis, and on-site detection.

MiRNAs (microRNAs) are a group of endogenous, small noncoding RNA with the length of 18-25 nucleotides, which have recently been demonstrated to play important roles in a wide range of biological processes. In this work, we developed a simple, sensitive, specific, and inexpensive assay through the combination of enzymatic probe ligation and real-time PCR amplification for the measurement of mature miRNAs. A couple of novel DNA probes with a stem-loop structure were implemented to reduce nonspecific ligation by at least 100-fold. The assay has several remarkable features including wide dynamic range, low total RNA input (0.02-0.2 ng), distinct anti-interference from precursor miRNAs (signal-to-noise ratio > 500), and single-base mismatch discrimination among miRNA sequences. In addition, a one-tube assay could be accomplished by designing a couple of universal probes, which makes it feasible to examine the expression of a whole family of miRNA (such as let-7) at one time. Finally, we validated the method for quantifying the expression of four mature miRNAs including miR-122, miR-1, miR-34a, and let-7a across 10 mouse tissues, where U6 snRNA could be simultaneously examined as an endogenous control. Thus, this method revealed a great potential for miRNA quantitation in ordinary laboratory studies and clinical diagnoses.

A series of new organic D−π−A dyes, coded as DS-1, DS-2, DS-3, and DS-4, was designed, synthesized, and characterized by 1H NMR, 13C NMR, infrared spectroscopy, mass spectrometry, and elemental analysis. These dyes consist of a di( p-tolyl)phenylamine moiety as an electron donor, a cyanoacetic acid moiety as an electron acceptor/anchoring group, and different types of conducting thiophene units as electron spacers to bridge the donor and acceptor. It was found that both the use of di( p-tolyl)phenylamine donor and the variation of electron spacers in the D−π−A dyes played an essential role in modifying and/or tuning physical properties of organic dyes. These dyes were developed as sensitizers for the application in dye-sensitized TiO 2 nanocrystalline solar cells (DSSCs), and their photophysical and electrochemical properties were investigated. The DSSCs based on the dyes gave good performance in terms of incident photon-to-current conversion efficiency (IPCE) in the range of 400−700 nm. A solar-energy-to...

Cu-W thin film with high W content was deposited by dual-target DC-magnetron co-sputtering technology. Effects of the substrates surface treating technique on the adhesive strength of Cu-W thin films were studied. It is found that the technique of ion beam assisting bombardment implanting of W particles can remarkably improve the adhesive property of Cu-W thin films. Indentation and scratching test show that, the critical load is doubled over than the sample only sputter-cleaned by ion beam. The enhancing mechanism of ion beam assisting bombardment implanting of Cu-W thin films was analyzed. With the help of mid-energy Ar+ ion beam, W atoms can diffuse into the Fe-substrate surface layer; Fe atoms in the substrate surface layer and W atoms interlace with one another; and microcosmic mechanical meshing and diffusing combination on atom-scale among the Fe and W atoms through the film/substrate interface can be formed. The wettability and thermal expansion properties of the W atoms diffusion zone containing plentiful W atoms are close to those of pure W or W-based Cu-W film.

Large aggregates, constructed by linking together monomer building blocks via non-covalent interactions with polymer properties, are regarded as supramolecular polymers. Many kinds of non-covalent interactions, such as metal–ligand coordination, hydrogen bonding, π–π stacking, ionic interaction, and host–guest interaction etc., can be involved in the binding interactions of monomer building blocks, as well as in the modification of the side chain for the construction of variable supramolecular polymers. In this tutorial review, we summarized the reported supramolecular polymers fully- or partially-created from the combination of multiple non-covalent binding interactions, mainly of two kinds, in the orthogonal way.

Large aggregates, constructed by linking together monomer building blocks via non-covalent interactions with polymer properties, are regarded as supramolecular polymers. Many kinds of non-covalent interactions, such as metal–ligand coordination, hydrogen bonding, π–π stacking, ionic interaction, and host–guest interaction etc., can be involved in the binding interactions of monomer building blocks, as well as in the modification of the side chain for the construction of variable supramolecular polymers. In this tutorial review, we summarized the reported supramolecular polymers fully- or partially-created from the combination of multiple non-covalent binding interactions, mainly of two kinds, in the orthogonal way.

Novel linear supramolecular polymers, based on the combination of two classical binding interactions: the quadruple hydrogen bonding ureidopyrimidinone units and crown ether–paraquat host–guest recognition motifs, have been constructed from two heteroditopic monomers.

Two novel metal-free organic dyes containing thienothiophene and thiophene segments have been synthesized. Nano-crystalline TiO2 dye-sensitized solar cells were fabricated using these dyes as light-harvesting sensitizers, and a high solar energy-to-electricity conversion efficiency of 6.23% was achieved.

A novel class of phthalocyanines substituted with azo group moieties on the periphery of phthalocyanine ring was synthesized, and they show obvious, broad uncommon absorption band in the visible re...

9-Aryl-fluorenes were synthesized conveniently from triarylcarbinols in the presence of TsOH. Notably, the orientation of the intramolecular aromatic substitution reaction was dictated by the nature of the substituents on the aryl rings of triarylcarbinols, owing to electronic and conjugated effects. In particular, triarylcarbinols with (3-methoxy)phenyl and naphthalenyl groups formed benzo[a]fluorenes selectively. Moreover, 9-methoxy-11-(naphthalen-1-yl)-11H-benzo[a] fluorene (2g), with a center of chirality, exists as a mixture of diastereoisomers, due to the restricted rotation of a C–C single bond. First-order rate constants for the enantiomerization of 2g in DMSO were obtained over the temperature from 297 K to 393 K, and thermodynamic parameters were determined as ΔH‡ = 99.7 kJ mol−1, ΔS‡373 K = 37.7 J mol−1 K−1, and ΔG‡373 K = 85.6 kJ mol−1 by Eyring plot analysis.

Novel dynamic [2]catenanes interlocked by the quadruple hydrogen bonding ureidopyrimidinone (UPy) motif have been developed. The dynamic catenation process was due to the selective cyclization of bifunctional UPy molecules over a wide concentration range with the assistance of the cyclobis(paraquat-p-phenylene) (CBPQT4+4+) macrocycle. The self-assembled [2]catenanes were stabilized by a combination of different non-covalent interactions comprising quadruple hydrogen bonding and host–guest interactions. This type of non-covalent bonded catenane is the first one interlocked by multiple hydrogen bonding interactions instead of metal–ligand interactions.

Three donor–(π-spacer)–acceptor dyes, coded as DS-3, DS-5 and DS-6, were designed and synthesized for dye-sensitized solar cells (DSSCs). These dyes possess the same donor (triarylamine) and acceptor/anchoring group (2-cyanoacrylic acid), but the varied π-spacers consisting of a combination of thiophene and/or 3,4-ethylenedioxythiophene (EDOT) units. They were evaluated by photophysical and electrochemical measurements as well as in nanocrystalline TiO2-based DSSCs fabricated using them as light-harvesting sensitizers. The results showed that incorporation of the EDOT moiety in the dye molecules strongly affected the molar extinction coefficient and photocurrent response. Among the three dyes, the DS-5-based DSSCs afforded the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 80%, a short-circuit photocurrent density (Jsc) of 14.6 mA cm−2, an open-circuit photovoltage (Voc) of 0.59 V and a fill factor (FF) of 0.70, corresponding to an overall conversion efficiency of 6.03% under 100 mW cm−2 irradiation, which reached 77% with respect to that of an N3-based device fabricated and measured under similar conditions. Further, a method of molecular orbital calculations was employed for the insight into the geometrical, electronic and optical properties of these dyes.