Nano/Micro-Structural Supramolecular Biopolymers: Innovative Networks with the Boundless Potential in Sustainable Agriculture

Sustainable agriculture plays a crucial role in meeting the growing global demand for food while minimizing adverse environmental impacts from the overuse of synthetic pesticides and conventional fertilizers.In this context,renewable biopolymers being more sustainable offer a viable solution to improve agricultural sustainability and production.Nano/micro-structural supramolecular biopolymers are among these innovative biopolymers that are much sought after for their unique features.These biomaterials have complex hierarchical structures,great stability,adjustable mechanical strength,stimuli-responsiveness,and self-healing attributes.Functional molecules may be added to their flexible structure,for enabling novel agricultural uses.This overview scrutinizes how nano/micro-structural supramolecular biopolymers may radically alter farming practices and solve lingering problems in agricultural sector namely improve agricultural production,soil health,and resource efficiency.Controlled bioactive ingredient released from biopolymers allows the tailored administration of agrochemicals,bioactive agents,and biostimulators as they enhance nutrient absorption,moisture retention,and root growth.Nano/micro-structural supramolecular biopolymers may protect crops by appending antimicrobials and biosensing entities while their eco-friendliness supports sustainable agriculture.Despite their potential,further studies are warranted to understand and optimize their usage in agricultural domain.This effort seeks to bridge the knowledge gap by investigating their applications,challenges,and future prospects in the agricultural sector.Through experimental investigations and theoretical modeling,this overview aims to provide valuable insights into the practical implementation and optimization of supramolecular biopolymers in sustainable agriculture,ultimately contributing to the development of innovative and eco-friendly solutions to enhance agricultural productivity while minimizing environmental impact.

Luminescent terpyridine-based metallo-supramolecular systems:from design to applications

Luminescent metallo-supramolecules have received tremendous attention in recent years owing to their diverse yet well-defined structures,tunable luminescent properties,and broad applications.In this context,the development of terpyridine(tpy)-based luminescent metallo-supramolecular systems has seen rapid growth.This review aims to summarize the recent progress of luminescent metallo-supramolecular assemblies from tpy ligands with metal ions,with a focus on discrete metallo-supramolecular architectures and metallo-supramolecular polymers.The design strategies and common approaches for tuning the luminescence properties are detailed along with representative applications.Finally,the pitfalls and unmet challenges regarding the structural characterization and practical applications of tpy-based metallo-supramolecules are discussed followed by our perspectives on the future directions of this field.

Supramolecular polymer-based gel fracturing fluid with a double network applied in ultra-deep hydraulic fracturing

A gel based on polyacrylamide,exhibiting delayed crosslinking characteristics,emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong wellbores.High viscosity/viscoelasticity of the fracturing fluid was required to maintain excellent proppant suspension properties before gelling.Taking into account both the cost and the potential damage to reservoirs,polymers with lower concentrations and molecular weights are generally preferred.In this work,the supramolecular action was integrated into the polymer,resulting in significant increases in the viscosity and viscoelasticity of the synthesized supramolecular polymer system.The double network gel,which is formed by the combination of the supramolecular polymer system and a small quantity of Zr-crosslinker,effectively resists temperature while minimizing permeability damage to the reservoir.The results indicate that the supramolecular polymer system with a molecular weight of(268—380)×10^(4)g/mol can achieve the same viscosity and viscoelasticity at 0.4 wt%due to the supramolecular interaction between polymers,compared to the 0.6 wt%traditional polymer(hydrolyzed polyacrylamide,molecular weight of 1078×10^(4)g/mol).The supramolecular polymer system possessed excellent proppant suspension properties with a 0.55 cm/min sedimentation rate at 0.4 wt%,whereas the0.6 wt%traditional polymer had a rate of 0.57 cm/min.In comparison to the traditional gel with a Zrcrosslinker concentration of 0.6 wt%and an elastic modulus of 7.77 Pa,the double network gel with a higher elastic modulus(9.00 Pa)could be formed only at 0.1 wt%Zr-crosslinker,which greatly reduced the amount of residue of the fluid after gel-breaking.The viscosity of the double network gel was66 m Pa s after 2 h shearing,whereas the traditional gel only reached 27 m Pa s.

Application of supramolecular hydrogel in supercapacitors: Opportunities and challenges

Supercapacitors(SCs)are studied and used in variousfields due to their high power density,fast charging/discharging rate,as well as long cycle life.Compared to other traditional electrode and electrolyte materials,supramolecular hydrogels have great advantages in the application of SCs due to their excellent properties.Unlike covalent bonds,supramolecular systems are assembled through dynamic reversible bonds,including host–guest interactions,ion interactions,electrostatic interactions,hydrogen bonding,coordination interactions,etc.The resulting supramolecular hydrogels show some special functions,such as stretching,compression,adhesion,self-healing,stimulus responsiveness,etc.,making them strong candidates for the next generation of energy storage devices.This paper reviews the representative progress of electrodes,electrolytes,and SCs based on supramolecular hydrogels.Besides,the properties of supramolecular hydrogels,such as conductivity,exten-sibility,compressibility and elasticity,self-healing,frost resistance,adhesion,andflexibility,are also reviewed to highlight the key role of excellent properties of hydro-gel materials in SCs.In addition,this article also discusses the challenges faced by current technologies,hoping to continue promoting future research in thisfield.

Enhanced Ion-Selective Diffusion Achieved by Supramolecular Interaction for High Thermovoltage and Thermal Stability

Thermoelectric(TE)generators capable of converting thermal energy into applicable electricity have gained great popularity among emerging energy conversion technologies.Biopolymer-based ionic thermoelectric(i-TE)materials are promising candidates for energy conversion systems because of their wide sources,innocuity,and low manufacturing cost.However,common physically crosslinked biopolymer gels induced by single hydrogen bonding or hydrophobic interaction suffer from low differential thermal voltage and poor thermodynamic stability.Here,we develop a novel i-TE gel with supramolecular structures through multiple noncovalent interactions between ionic liquids(ILs)and gelatin molecular chains.The thermopower and thermoelectric power factor of the ionic gels are as high as 2.83 mV K-1 and 18.33μW m^(-1)K^(-2),respectively.The quasi-solid-state gelatin-[EMIM]DCA i-TE cells achieve ultrahigh 2 h output energy density(E_(2h)=9.9 mJ m^(-2))under an optimal temperature range.Meanwhile,the remarkable stability of the supramolecular structure provides the i-TE hydrogels with a thermal stability of up to 80℃.It breaks the limitation that biopolymer-based i-TE gels can only be applied in the low temperature range and enables biopolymer-based i-TE materials to pursue better performance in a higher temperature range.

A clusteroluminescent supramolecular polymer network constructed by pillararene and its application in information encryption

Clusterization-triggered emissive(CTE)materials have attracted great attention in recent years.The regulation of the emission property of materials with CTE property through supramolecular interactions is an excellent strategy for the construction of smartfluorescent materials.In this work,we have pre-pared a regulatable supramolecular polymer network with CTE properties through pillararene-based host-guest interactions.The pillar[5]arene-grafted poly(methyl methacrylate)(PMMA)showed a classic CTE character.After adding Brooker’s merocyanine-grafted polymer to the solution of the pillar[5]arene-containing PMMA,the supramolecular polymer network gel formed by the host-guest inter-actions between pillararene and Brooker’s merocyanine guest.This supramolecular network showed brighterfluorescence than the pillar[5]arene-grafted PMMA in the solid state.In addition,thefluorescence emission of the supramolecular network can be further regulated by pH conditions.After adding an acid,the Brooker’s merocyanine-containing guest polymer was protonated,and the supramolecular net-work changed to a protonated network through host-guest interactions between protonated Brooker’s merocyanine guest and pillararene.Interestingly,thefluores-cence was quenched when the supramolecular network turned into the protonated network.After adding a base,the protonated network can convert back to the origi-nal network,along with recovery of thefluorescence.Therefore,the regulation of thefluorescence of the supramolecular polymer materials with CTE was successfully realized by pillararene-based host-guest interactions.Furthermore,this tailorablefluorescent supramolecular polymer network system was applied as an information encryption material.

Construction and Properties of the Me_(10)Q[5]/2,7-diaminofluorenedihydrochloride Supramolecular Hydrogel

Compared to traditional polymer hydrogels,supramolecular hydrogels exhibits superior reversibility and stimulus response due to the instantaneous and reversible nature of non-covalent bonds.In this paper,we utilized the host-guest exclusion interaction between Decamethylcucurbit[5]uril(Me_(10)Q[5])and the 2,7-diaminofluorenedihydrochloride(DAF·HCl)to construct a Q[n]-based hydrogel system.The composition,structure,and properties of the hydrogel were compre-hensively characterized using rheometer,nuclear magnetic resonance,scanning electron microscope.This cost-effective and straightforward hydrogel synthesis method paves the way for the scalable production of practical and commercially viable Q[n]-based hydrogels.

Preparation and Properties of Vegetable-Oil-Based Thioether Polyol and Ethyl Cellulose Supramolecular Composite Films

Ethyl cellulose(EC),an important biomass-based material,has excellent film-forming properties.Nevertheless,the high interchain hydrogen bond interaction leads to a high glass transition temperature of EC,which makes it too brittle to be used widely.The hydroxyl group on EC can form a supramolecular system in the form of a non-covalent bond with an effective plasticizer.In this study,an important vegetable-oil-based derivative named dimer fatty acid was used to prepare a novel special plasticizer for EC.Dimer-fatty-acid-based thioether polyol(DATP)was synthesized and used to modify ethyl cellulose films.The supramolecular composite films of DATP and ethyl cellulose were designed using the newly-formed van der Waals force.The thermal stability,morphology,hydrophilicity,and mechanical properties of the composite films were all tested.Pure EC is fragile,and the addition of DATP makes the ethyl cellulose films more flexible.The elongation at the break of EC supramolecular films increased and the tensile strength decreased with the increasing DATP content.The elongation at the break of EC/DATP(60/40)and EC/DATP(50/50)was up to 40.3%and 43.4%,respectively.Noticeably,the thermal initial degradation temperature of the film with 10%DATP is higher than that of pure EC,which may be attributed to the formation of a better supramolecular system in this composite film.The application of bio-based material(EC)is environmentally friendly,and the novel DATP can be used as a special and effective plasticizer to prepare flexible EC films,making it more widely used in energy,chemical industry,materials,agriculture,medicine,and other fields.

A pH-sensitive supramolecular nanosystem with chlorin e6 and triptolide co-delivery for chemo-photodynamic combination therapy

The combination of Ce6,an acknowledged photosensitizer,and TPL,a natural anticancer agent,has been demonstrated as a useful strategy to reinforce the tumor growth suppression,as well as decrease the systemic side effects compared with their monotherapy.However,in view of the optimal chemo-photodynamic combination efficiency,there is still short of the feasible nanovehicle to steadily co-deliver Ce6 and TPL,and stimuli-responsively burst release drugs in tumor site.Herein,we described the synergistic antitumor performance of a pH-sensitive supramolecular nanosystem,mediated by the host–guest complexing betweenβ-CD and acid pH-responsive amphiphilic co-polymer mPEG-PBAE-mPEG,showing the shell–core structural micelles with the tightβ-CD layer coating.Both Ce6 and TPLwere facilely co-loaded into the spherical supramolecular NPs(TPL+Ce6/NPs)by one-step nanoprecipitation method,with an ideal particle size(156.0 nm),acid pH-responsive drug release profile,and enhanced cellular internalization capacity.In view of the combination benefit of photodynamic therapy and chemotherapy,as well as co-encapsulation in the fabricated pH-sensitive supramolecular NPs,TPL+Ce6/NPs exhibited significant efficacy to suppress cellular proliferation,boost ROS level,lower MMP,and promote cellular apoptosis in vitro.Particularly,fluorescence imaging revealed that TPL+Ce6/NPs preferentially accumulated in the tumor tissue area,with higher intensity than that of free Ce6.As expected,upon 650-nm laser irradiation,TPL+Ce6/NPs exhibited a cascade of amplified synergistic chemo-photodynamic therapeutic benefits to suppress tumor progression in both hepatoma H22 tumor-bearingmice and B16 tumor-bearingmice.More importantly,lower systemic toxicitywas found in the tumor-bearingmice treated with TPL+Ce6/NPs.Overall,the designed supramolecular TPL+Ce6/NPs provided a promising alternative approach for chemo-photodynamic therapy in tumor treatment.

Preparation and characterization of supramolecular gel suitable for fractured formations

The excellent mechanical properties of supramolecular gel could adapt to the complex reservoir environment and had broad application prospects in the field of oil and gas drilling and production engineering.In this paper,a supramolecular gel based on hydrophobic association and hydrogen bonding was prepared by micellar copolymerization,which could be used to plug fractures and pores in formations.Supramolecular gel was a gel network system with high performance characteristics formed by self-assembly of non-covalent bond interaction.The rheological properties,mechanical mechanics,temperature resistance and swelling ability of supramolecular gel were studied.The results showed that the supramolecular gel had a dense three-dimensional network structure with open and interconnected pore structures,which could exhibit good rheological properties and strong viscoelastic recovery ability.The mechanical properties of the supramolecular gel were excellent,it had a tensile stress of 0.703 MPa and an elongation at break of 1803%.When the compressive strain was 96%,the compressive stress could reach 14.5 MPa.Supramolecular gel also showed good temperature resistance and swelling properties.At the aging temperature of 135℃,supramolecular gels still maintained good gel strength,and it only took 12 h to reach the equilibrium swelling ratio of 35.87 in 1%NaCl solution.It was also found that supramolecular gel in low concentration saline(1%NaCl solution)showed relatively faster swelling than high concentration saline(25%NaCl solution).The swelling process of the supramolecular gel was non-Fick diffusion(typeⅡ).This indicated that the organic/inorganic permeability network was well formed.Therefore,the diffusion rate of small molecules could be guaranteed to be equal to the relaxation rate of large molecules before and after the phase transition temperature.In addition to the diffusion of water molecules,the swelling process of the supramolecular gel was also affected by the relaxation of gel network and polymer chain segment,the interaction between water molecules and polymer network and the groups of polymer network and other factors.Supramolecular gel particles could be used as plugging materials for drilling fluids,which had excellent ability to plug formation fractures and pores.The plugging ability of the supramolecular gel was up to 6.7 MPa for 0.5 mm fracture width,and 9.6 MPa for porous media with 5 mD permeability.Compared with HT-PPG gel particles commonly used in oil fields,supramolecular gel particles had better plugging ability on fractures and porous media.The development and application of supramolecular gel had far-reaching significance for promoting the functional application of polymer materials in drilling and production engineering.

Skin‑Inspired Ultra‑Tough Supramolecular Multifunctional Hydrogel Electronic Skin for Human–Machine Interaction

Multifunctional supramolecular ultra-tough bionic e-skin with unique durability for human–machine interaction in complex scenarios still remains challenging.Herein,we develop a skininspired ultra-tough e-skin with tunable mechanical properties by a physical cross-linking salting-freezing-thawing method.The gelling agent(β-Glycerophosphate sodium:Gp)induces the aggregation and binding of PVA molecular chains and thereby toughens them(stress up to 5.79 MPa,toughness up to 13.96 MJ m^(−3)).Notably,due to molecular self-assembly,hydrogels can be fully recycled and reprocessed by direct heating(100°C for a few seconds),and the tensile strength can still be maintained at about 100%after six recoveries.The hydrogel integrates transparency(>60%),super toughness(up to 13.96 MJ m^(−3),bearing 1500 times of its own tensile weight),good antibacterial properties(E.coli and S.aureus),UV protection(Filtration:80%–90%),high electrical conductivity(4.72 S m^(−1)),anti-swelling and recyclability.The hydrogel can not only monitor daily physiological activities,but also be used for complex activities underwater and message encryption/decryption.We also used it to create a complete finger joint rehabilitation system with an interactive interface that dynamically presents the user’s health status.Our multifunctional electronic skin will have a profound impact on the future of new rehabilitation medical,human–machine interaction,VR/AR and the metaverse fields.

A novel strategy of constructing 2D supramolecular organic framework sensor for the identification of toxic metal ions

Two novel two-dimensional(2D)supramolecular organic frameworks were fabricated in water based on the encapsulation-enhanced donor-acceptor interaction between the methyl viologen(MV)units,methoxy naphthyl(MN)units,and CB[8].The tetraphenylethylene(TPE)derivatives 1 with four MV units were employed as rigid building blocks and the two MN units modified oligoethylene glycol derivatives 2 and 3 served as flexible edges,respectively.The obtained two SOFs have obvious sheet-like structures and exhibit fluorescence emission at 350-500 nm.In addition,these two SOFs were employed for the luminescent detection of Cr(Ⅵ)and Mn(Ⅶ)in aqueous solutions,and the detection limits of CrO_(4)^(2-),Cr_(2)_(O)_(7)^(2-),and MnO_(4)
were calculated in a very low concentration range,indicating that these two SOFs can serve as a potential sensor for Cr(Ⅵ)and Mn(Ⅶ)detection in water.This work constructs two SOFs in an aqueous solution through a facile method and further enriches the applications of SOFs.

Supramolecular Self-assembly and Functionalization of Porphyrin-based Systems

Porphyrins are abundant in nature. They have been frequently employed as building blocks in the construction of nanoarchitectures and functional supramolecular systems. Recently, a series of novel porphyrin molecules including small molecules and polymers have been originally designed and synthesized with the aim of producing nanostructures with controllable-growth and materials with high-performance. Literature coverage is through 2004-2012. This review gives a full summary of related studies in our group.

Dimensional effects of organic anion templates in modulating the assembly of water clusters in cucurbit[6]uril supramolecular systems

Two new supramolecular architectures {（HC2O4）2^2- [C6H（18）N2^2＋ C（36）H（36）N（24）O（12）]} 12H2O（1） and{（C6H5SO3）22 [C6H（18）N22＋ C（36）H（36）N（24）O（12）]} 12H2O（2） were synthesized and characterized by singlecrystal X-ray diffraction, thermogravimetric analysis and X-ray powder diffraction. Compound 1contains infinite two dimensional（2D） L18（8）14（8）8（4） type anion–water aggregates [（HC2O4）4（H2O）（22）]^4- and results in the construction of sandwich-like three dimensional（3D） networks. In compound 2, honeycomb-like three dimensional（3D） networks are fabricated by one dimensional（1D）＂W＂-like T5（0）A2 type anion–water clusters [（C6H5SO3）（H2O）6]^-. These results indicate that anionic groups play a crucial role in modulating the structures of water clusters with their spatial structure and binding sites. In these two structures, the majority of interactions are O...H and H...H interactions on the Hirshfeld surface, which means that hydrogen bonding and hydrophobic interactions are the dominate drive forces in forming these supramolecular systems.

Some Topological Values of Supramolecular Chain of Different Complexes of N-Salicylidene-L-Valine

L-valine is a glycogen-type amino acid regarded among the necessary mammalian amino acids.This is an amino acid that is essential for protein synthesis.N-salicylidene-L-valine is gaining a lot of attention because of its unique structure and increased catalytic and cytotoxic activity.We explore the chain of supramolecular dialkyltin N-salicylidene-L-valine complexes 2,3,and 4 to learn more about this structure and its features regarding topological indices.We computed the first and second Randi′c index,harmonic index,sum-connectivity index,atom-bond-connectivity index,geometric arithmetic index and reduced reciprocal Randi′c index of Supramolecular Chain of Different Complexes of N-Salicylidene-L-Valine.Furthermore,we present an analysis of such structures using specific examples,as well as a comparison of topological indices.

Curative Effect of 30% Supramolecular Salicylic Acid Combined with Yufa Spray Dressing on Moderate to Severe Scalp Seborrheic Dermatitis

Objective:To observe the clinical efficacy of 30%supramolecular salicylic acid combined with Yufa spray dressing in the treatment of moderate to severe seborrheic dermatitis(seborrheic dermatitis of the scalp,SDS).Methods:From January 2020 to December 2021,150 patients with SDS,who were treated in the Dermatology Clinic of the First Affiliated Hospital of Xi’an Medical University,were randomly divided into two groups,a treatment group and a control group,with 75 cases in each group.The treatment group was given 30%supramolecular salicylic acid combined with Yufa spray dressing on the basis of external medicine given to the control group,while the control group was given oral medicine combined with external medicine.Results:The difference in scores of erythema,scales,pruritus,and folliculitis of the treatment group before and after treatment was significant(P<0.01),indicating that supramolecular salicylic acid combined with Yufa spray dressing can relieve the symptoms of SDS.The difference in scores of erythema of the control group before and after treatment was significant as well(P<0.05),indicating that traditional antibiotics are also effective in treating SDS;however,there was no significant difference(P>0.05)in the scores of other signs and symptoms,such as scales,pruritus,and folliculitis,before and after treatment,indicating that traditional antibiotics have no obvious curative effect on SDS.After 12 weeks of treatment,the improvement in erythema,scaling,and folliculitis was significantly greater in the treatment group compared with the control group(P<0.05).Curative effect comparison showed that the total effective rate of the treatment group was 80.00%,compared with 25.67%of the control group,and the difference was statistically significant(P<0.05).Conclusion:30%supramolecular salicylic acid combined with Yufa spray dressing can significantly improve the therapeutic effect in moderate to severe SDS;the recurrence rate is lower,the course of treatment is shorted,and patients generally feel better;thus,it is a new option for the treatment of dermatitis.

Solid-state room-temperature phosphorescence activated by the end-capping strategy of cyano groups

Avoiding the tedious process of crystal cultivation and directly obtaining organic crystals with desirable phosphorescent performance is of great significance for studying their structure and properties.Herein,a set of benzophenone-cored phos-phors with bright green afterglow are obtained on a large scale through in-situ generation via an end-capping strategy to suppress non-radiative triplet excitons and reinforce the intermolecular interactions.The ordered arrangement of phosphors with alkyl-cyano groups as regulators is crucial for the enhancement of room-temperature phosphorescence(RTP)emission,which has been further verified by the attenuated lifetimes in isolated states through the formation of inclusion complexes upon binding with pillar[5]arenes.Moreover,the hierarchical interactions of phos-phors,including hydrogen bonding,π-πstacking interactions,and van der Waals forces,are quantified by crystal structures and theoretical calculation to deeply inter-pret the origins of RTP emission.With this study,we provide a potential strategy for the direct acquisition of crystalline organic phosphors and modulation of RTP.

Catalytic epoxidation of olefin over supramolecular compounds of molybdenum oxide clusters and a copper complex

The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.

Effects of Doubled_CO_2 Concentration on Ultrastructure, Supramolecular Architecture and Spectral Characteristics of Chloroplasts from Wheat

Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architecture, absorption spectrum and low temperature (77 K) fluorescence emission spectrum of the chloroplasts from wheat leaves. The results were briefly summarized as follows: (1) The wheat leaves possessed normally developed chloroplasts with intact grana and stroma thylakoid membranes; The grana intertwined with stroma thylakoid membranes and increased slightly in stacking degree and the width of granum, in spite of more accumulated starch grains within the chloroplasts than those in control; (2) The particle density in the stacked region of the endoplasmic fracture face (EFs) and protoplasmic fracture face (PFs) and in the unstacked region the endoplasmic fracture face (EFu) and the protoplasmic fracture face (PFu) was significantly higher than that of control. Furthermore, in some cases many more particles on EFs faces of thylakoid membranes appeared as a paracrystalline particle array; (3) The variations in the structure of chloroplasts were consistent with the absorption spectra and the low temperature (77 K) fluorescence emission spectra of the chloroplasts developed under the doubled_CO 2 concentration. Results indicate that the capability of light energy absorption of chloroplasts and regulative capability of excitation energy distribution between PSⅡ and PSⅠ were raised by doubled_CO 2 concentration. This is very favorable for final productivity of wheat.

Luminescence of Nanosized Supramolecular Material of Mesoporous Molecular Sieve and Samarium (Ⅲ) Complex

The solutions of rare earth complexes Sm(Phen) 2(TTA)(Bipy)(NO 3) 3 and Sm(L) x (TTA) 4-x (NO 3) 3 [L=Phen (1,10-phenanthroline) or Bipy(2,2′-bipyridine), x =4, 3, 2, 1, 0; TTA is 2-thenoyltrifluoacetone] in EtOH(1×10 -3 mol/L) were prepared. The coefficients of antenna effect are 31 5, 18 2 and 5 6 for Phen, Bipy and TTA, respectively, when the electron configuration of the excited state of the samarium atom in the complexes is 4 D 1/2 . The fluorescent intensity and the lifetime of the supramolecular encapsulation products of (CH 3) 3Si-MCM-41 and Sm 3+ complexes are stronger and longer than those of the encapsulation products of MCM-41 and Sm 3+ complexes respectively. The results show that the host with lipophilic channels is more favourable to the fluorescence of the rare earth complexes than the hydrophilic mesoporous molecular sieve. The fluorescent intensity of (CH 3) 3Si-MCM-41-Sm(Phen) 3(TTA)(NO 3) 3 is the strongest \{among\} the encapsulation series of Sm 3+ complexes, which is assumed to result from the greatly reduction of SiO-H vibration relaxation in host (CH 3) 3Si-MCM-41 and the presence of the discrete strong luminescent centres of the guest molecules associated with the nanosized material′s structure. The luminescent decay halftime of the supramolecular materials is much shorter than that of the powder of the samarium complexes. The result shows that the ligand transferring energy from the triplet state to the singlet state of Sm 3+ ( T 1→S , intersystem crossing) becomes higher. The fluorescent experimental results indicate that the interaction between the host and the guest influences the luminescent properties of the nanostructured supramolecular materials.