Inorganic Chemistry最新文献

{"title":"Chiral Ligand-Induced Second-Harmonic Generation Response in Helical One-Dimensional Hybrid Lead Bromides","authors":"Qiao-Feng Huang, Shu-Fang Yan, Yi-Fan Fu, Wenlong Liu, Jiajing Wu, Sheng-Ping Guo","doi":"10.1021/acs.inorgchem.5c01893","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01893","url":null,"abstract":"Chiral hybrid organic–inorganic metal halides have garnered broad attention due to their unique optoelectronic properties. Here, a pair of chiral helical lead halides, (<span>d</span>-/<span>l</span>-<i>pro</i>)PbBr₃·H₂O (<i>pro</i> = proline), with centimeter-size has been successfully synthesized via integrating three types of functional building units including chiral amino acid ligand, ns² metal cations, and halide anion. Their structures are composed of one-dimensional helical {[Pb₂Br₆]^2–}_∞ chains formed by face-sharing distorted [PbBr₆]^4– octahedra, which are separated by chiral cations and crystallize into the space group <i>P</i>2₁. They present a phase-matchable second-harmonic-generation (SHG) response and moderate birefringence. First-principles calculations elucidate that the effective SHG performances originate from the synergetic contribution of chiral cations and distorted [PbBr₆]^4– octahedra. This work not only enriches the structural chemistry of lead-based hybrid halides but also provides an important reference for the development of chiral metal halides.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"44 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144193265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[C(NH2)3]Y(HCOO)4: Constructing 3D Framework for Guanidine-Based UV Nonlinear Optical Crystals with Good Performance","authors":"Jiayin Tang, Xin Wen, Huili Zhang, Yuchen Yan, Jindong Chen, Shihui Ma, Min Luo, Chensheng Lin, Ning Ye, Guang Peng","doi":"10.1021/acs.inorgchem.5c01629","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01629","url":null,"abstract":"The guanidine group, [C(NH₂)₃]⁺, is a promising π-conjugated unit for nonlinear optical (NLO) materials. However, its saturated amino coordination typically leads to weak hydrogen bond interaction and zero-dimensional structures, limiting the stability and mechanical strength. Herein, we propose a design strategy that constructs a non-centrosymmetric (NCS) three-dimensional (3D) framework for [C(NH₂)₃]⁺ by utilizing (HCOO)⁻ and rare-earth cations and successfully synthesizes a novel 3D guanidine-based compound, [C(NH₂)₃]Y(HCOO)₄, which not only effectively immobilizes the [C(NH₂)₃]⁺ but also induces an NCS arrangement. This crystal exhibits a strong second-harmonic generation response of 1.7 × KH₂PO₄, a short UV cutoff edge of 236 nm, an appropriate birefringence of 0.099@546 nm, and good thermal stability, fulfilling critical requirements for UV NLO applications. This work provides a new strategy for developing high-performance guanidine-based UV NLO materials.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"41 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144193264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reimagining Pt(II) Anticancer Agents: The Role of Ferrocene in Monofunctional Chemotherapeutic Compounds","authors":"Selma Miguel, Javier Ortín-Fernández, Silvia Gómez-Pastor, María Ángeles Moliné, Pedro A. Sánchez-Murcia, Inés Corral, Francisco Sanz-Rodríguez, Ana María González-Vadillo","doi":"10.1021/acs.inorgchem.5c00704","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c00704","url":null,"abstract":"The side effects and resistance to treatments associated with platinum compounds, such as cisplatin, underscore the present need for novel anticancer agents with improved properties. The development of hybrid drugs, combining two bioactive units, offers a promising approach by synergistically enhancing the biological activity of the two fragments while reducing the resistance of classic drugs. This work presents the synthesis of a novel family of heterobimetallic compounds, featuring a monofunctional Pt(II) complex with amino groups and a <i>p</i>-ferrocenylaniline ligand. Cytotoxic assays reveal that the derivatives with methylated and isopropylated substituted amines exhibit remarkably higher activity against several tumor cell lines compared with cisplatin and the unsubstituted diamino complex. Notably, these methylated and isopropylated complexes demonstrate high selectivity and present high antitumor activity in cell lines where cisplatin is ineffective. Classical molecular dynamics simulations targeting DNA reveal a consistent relation between the extent of distortion of the duplex upon complex coordination and the cytotoxic activity observed in biological assays. According to our simulations, coordination of the heterometallic complexes can produce a significant disruption of the H-bond pattern of the platinated guanine. Moreover, the distortion mechanism induced by the voluminous substituents of the amino ligands entails either the intercalation of the ferrocene moiety, facilitating new hydrogen bonds between originally non-interacting base pairs and new weak attractive stacking interactions between the Pt(II) complex and neighboring nucleobases, or the displacement of adjacent nucleotides from the pairing region toward the solvent environment.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"7 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144193339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of the π-System in Fe-Porphyrins for CO2 Reduction Catalysis","authors":"Vasilis Nikolaou, Zhi-Mei Luo, Marcos Gil-Sepulcre, Jia-Wei Wang, Olaf Rüdiger, Ignacio Funes-Ardoiz, Marco Nicaso, Jordi Benet-Buchholz, Antoni Llobet","doi":"10.1021/acs.inorgchem.5c01499","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01499","url":null,"abstract":"Iron porphyrins are extensively utilized as molecular catalysts in the electrocatalytic CO₂ reduction reaction (CO₂RR). While current research primarily investigates the impact of peripheral substitution and second coordination sphere effects, the role of the π-system in governing Fe-porphyrins’ redox and catalytic properties in CO₂RR has received limited systematic investigation. To that end, we have prepared and thoroughly characterized, both spectroscopically and electrochemically, a series of Fe-porphyrins with varying numbers of π-orbitals involved in conjugation. We have observed a correlation between thermodynamics and kinetics with the number of atomic orbitals involved in their π-system. Notably, bicycloporphyrins with the lowest number of atomic orbitals involved in the π-system, [<b>FeCl(TbcTPP</b>)] and [<b>FeCl(TbcP</b>)], exhibit lower rate constants and TOF_max values than the <b>[FeCl(TPP)]</b> reference catalyst. Interestingly, benzoporphyrins <b>[FeCl(TBP)]</b> and <b>[FeCl(TBTPP)]</b>, with more atomic orbitals involved in the π-system, display two different catalytic cycles, depending on the applied potential.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"12 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144193266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Primary Alkyl Amine-Mediated ZnSe@ZnS QDs from Giant Flowers to Nanorods","authors":"Jiada Fan, Haorong Jiao, Hui Cai, Jialiang Xu, Jiabin Cui","doi":"10.1021/acs.inorgchem.5c01870","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01870","url":null,"abstract":"Understanding the relationship between surface ligands and colloidal quantum dots (QDs) is crucial for precisely controlling their size, morphology, and composition. Compared to traditional Cd- or Pb-based II–VI QDs, the precise synthesis of zinc-based colloidal ZnSe@ZnS QDs remains challenging due to zinc’s high oxytropism and diffusion tendencies. Herein, we introduce a primary alkyl amine-mediated surface engineering strategy that enables morphology control: from giant flowers and clovers to branches and nanorods (NRs). Fine structural analysis and theoretical calculations reveal that ligand affinity and low adsorption energy promote rod-shaped growth. From both fundamental and industrial perspectives, it is essential to explore the underlying mechanisms and inherent properties that influence these processes. Such insights will enhance the potential applications of these materials in photocatalysis, sensing, and illumination.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"44 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144183842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controllable Photoluminescence Modulation of 2D Hybrid Perovskite Single-Phase Derivatives via Inorganic Skeleton Thickness Regulation","authors":"Zihao Zhao, Yi Liu, Qingshun Fan, Hao Rong, Haojie Xu, Huaimin Ni, Jingtian Zhang, Xianmei Zhao, Junhua Luo, Zhihua Sun","doi":"10.1021/acs.inorgchem.5c00774","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c00774","url":null,"abstract":"The modulation of photoluminescence (PL) properties has great application prospects in the optical and photoelectric fields. Two-dimensional hybrid perovskites exhibit exceptional structural tunability and superior optoelectronic properties, making them promising for advanced photoluminescent applications. However, synthesizing pure multilayer single crystals remains challenging, hindering precise PL modulation. Herein, a series of two-dimensional hybrid perovskite single crystals (<i>i</i>-BA)₂MA_<i>n</i>–1Pb_nBr_3<i>n</i>+1 (where <i>i</i>-BA = isobutylammonium, MA = methylammonium, and <i>n</i> = 1–4 expressed as <b>n1</b>–<b>n4</b>) with varying inorganic framework thicknesses were synthesized. Interestingly, a red shift of PL in these homologues was observed with the change in color from white (<i>n</i> = 1) to green (<i>n</i> = 4); the emission wavelengths were tuned from 430 to 528 nm. Notably, the PL quantum yields increased as the inorganic layer thickness increased from <i>n</i> = 2 to <i>n</i> = 4. Furthermore, we developed green light-emitting devices and polydimethylsiloxane (PDMS)-based flexible luminescent patterns through employing the pure <b>n4</b> phase. These findings highlight the pivotal role of structural tuning in modulating PL and demonstrate the potential of these single-phase derivatives for advancing solid-state lighting applications.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"1 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144183724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and Characterization of Copper Complexes Featuring a Redox-Active ONO Ligand in Three Molecular Oxidation States","authors":"David D. Hebert, Ankita Puri, Daniel Ye, Allison McAninch, Amanda Chisholm, Maxime A. Siegler, Marcel Swart, Isaac Garcia-Bosch","doi":"10.1021/acs.inorgchem.5c01578","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01578","url":null,"abstract":"In this research article, we report the synthesis, characterization, and reactivity of a family of Cu complexes bearing a tridentate iminosemiquinone ligand and ancillary amine ligands ((^sqONO)Cu^II(L)<i>_n</i>, <i>n</i>: 1 or 2). The complexes were obtained following a one-pot synthetic protocol by mixing Cu^II, 3,5-di-<i>tert</i>-butylcatechol, and aqueous ammonia in the presence of an amine base. The Cu complexes were structurally characterized by single-crystal X-ray diffraction analysis (SC-XRD). Cyclic voltammetry measurements showed that the Cu complexes reached three molecular oxidation states in a reversible fashion. The reaction between the Cu-iminosemiquinone complex (^sqONO)Cu^II(L) with cobaltocene (1e^– donor) and ferrocenium (1e^– acceptor) produced the corresponding reduced and oxidized complexes. Structural and spectroscopic characterization (SC-XRD, UV–vis, and EPR) of the Cu complexes in the three oxidation states, namely, [(^catONO)Cu^II(L)]⁻, (^sqONO)Cu^II(L), and [(^bqONO)Cu^II(L)]⁺, suggest that the redox events are ligand-based. DFT computations also formulated the complexes as Cu^II species with the ONO ligand in different oxidation states. For the Cu^II-iminosemiquinone complexes, we calculated small energetic differences between their singlet and triplet states (<i>S</i> = 0 vs <i>S</i> = 1), which explain their magnetic behavior in solution. Our results provide evidence of how Cu-radical metalloenzymes might tune their electronic structure to modulate their reactivity.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"48 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144177248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Irradiation-Assisted Functionalization of Hierarchically Porous Boron Nitride for Ultrafast Uranium Removal from Radioactive Sewage","authors":"Peng Zhang, Yifan Li, Ziwen Tang, Weichao Feng, Zengyuan Li, Mingzhang Lin, Fuyou Fan, Guirong Cao, Duoqiang Pan, Wangsuo Wu","doi":"10.1021/acs.inorgchem.5c00143","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c00143","url":null,"abstract":"Decontamination of uranium (U) from radioactive sewage is crucial for sustainable development of the nuclear industry and human health. In order to develop a high-performance adsorbent for efficient U removal from radioactive sewage, terpyridine (TPy)-functionalized hierarchically porous boron nitride (HPBN-TPy) was prepared by feasible irradiation-assisted functionalization. The pretreatment of HPBN by γ irradiation is the key of functionalization for introducing active defect sites in inert boron nitride (BN). On this basis, amino and terpyridine functionalization was carried out successively. Large specific surface area and TPy groups with strong affinity for U resulted in high adsorption amount; the investigation of mechanism confirmed that TPy groups adsorbed U through the chelation of three pyridine moieties to one UOuman health. In order to develop a high-performance adsorbent for efficient U removal from radioactive sewage, terpyridine (TPy)-functionalized hierarchically porous boron nitride (HPBN-TPy) was prepared by feasible irradiation-assisted functionalization. The pretreatment of HPBN by γ irradiation is the key of functionalization for introducing active defect sites in inert boron nitride (BN). On this basis, amino and terpyridine functionalization was carried out successively. Large specific surface area and TPy groups with strong affinity for U resulted in high adsorption amount; the investigation of mechanism confirmed that TPy groups adsorbed U through the chelation of three pyridine moieties to one UO₂²⁺ ion. Abundant hierarchical mesopores provided a sufficient mass transfer channel for U, which together with low mass transfer resistance from the small size of TPy groups caused the ultrafast adsorption kinetics for U, and adsorption reached equilibrium within 30 s. Moreover, HPBN-TPy displayed outstanding adsorption selectivity, irradiation resistance, and reusability, which endowed HPBN-TPy with great prospects for industrial removal of U from radioactive sewage. This study offered an efficient method for the efficient functionalization of inert BN materials and provided new insight for U removal from radioactive sewage.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"34 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144177156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic Anisotropy and Jahn–Teller Distortion of Itinerant Ferromagnets with Cubic Structures","authors":"Changhoon Lee, Taesu Park, Hyun-Joo Koo, Jae-Hoon Park, Ji Hoon Shim, Myung-Hwan Whangbo","doi":"10.1021/acs.inorgchem.5c01136","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01136","url":null,"abstract":"An itinerant ferromagnet with a cubic structure such as α-Fe has no uniaxial magnetism, while uranium monosulfide US has the strongest-known uniaxial magnetism despite its cubic structure. We probed the cause for this difference by density functional theory (DFT) calculations for α-Fe, FeNi, and US to determine their magnetocrystalline anisotropy energies (MAEs), partial density of states (PDOS) plots, and pair polarization indexes (i.e., the strengths of the pair polarizations), Δ<i>p</i>. By comparing these results with those already reported for MnAl and SmCo₅, we find that the MAEs of these itinerant ferromagnets increase in the order, α-Fe &lt; FeNi &lt; MnAl &lt; SmCo₅ &lt; US, and so do their Δ<i>p</i> values, revealing that US and α-Fe differ in their uniaxial magnetism due to the large difference in their pair polarizations. We also investigated the possibility for pair polarization to induce Jahn–Teller instability by analyzing the weak cubic-to-rhombohedral distortion of US that accompanies its ferromagnetic transition at 177 K to show that this is indeed a weak Jahn–Teller distortion. The absence of such a Jahn–Teller instability in other permanent magnets was ascribed to the weak covalent character of their interatomic bonds.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"14 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144177157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stepwise Structural Transformations of Coordination Polymers Caused by Ligands Replacements and Solid-State Photoreaction","authors":"Jun-Feng Wang, Shen-Shen Wang, Qi-Meng Liu, Xiao-Yan Tang, Dong Liu","doi":"10.1021/acs.inorgchem.5c01464","DOIUrl":"https://doi.org/10.1021/acs.inorgchem.5c01464","url":null,"abstract":"The structural transformations of coordination polymers not only contribute to structural diversity but also provide design strategies at the molecular level for developing a new generation of smart materials. In this work, a photoinert olefin-containing coordination chain {[Zn(H₂O)(5-NO₂-1,3-BDC)(3,3′-dpe)]₂·H₂O}<i>_n</i> (<b>1</b>) was prepared by the hydrothermal reaction between Zn(NO₃)₂·6H₂O, 1,2-di(pyridin-3-yl)ethene (3,3′-dpe), and 5-nitro-1,3-benzenedicarboxylic acid (5-NO₂-1,3-H₂BDC). After replacing the 5-NO₂-1,3-H₂BDC ligand in the solution of <b>1</b> with 5-methyl-1,3-benzenedicarboxylic acid (5-Me-1,3-H₂BDC), a unique two-dimensional photoreactive coordination network [Zn(5-Me-1,3-BDC)(3,3′-dpe)]<i>_n</i> (<b>2</b>) was formed. When exposed to UV light, <b>2</b> can undergo a [2 + 2] photocycloaddition reaction to produce [Zn(5-Me-1,3-BDC)(<i>rctt</i>-3,3′-tpcb)_0.5]<i>_n</i> (<b>3</b>, 3,3′-tpcb = 1,2,3,4-tetra(pyridin-3-yl)cyclobutane) via single-crystal-to-single-crystal (SCSC) transformation. By replacing the 5-Me-1,3-BDC ligand in the solution of <b>3</b> with 5-NO₂-1,3-H₂BDC, a three-dimensional framework of {[Zn₂(5-NO₂-1,3-BDC)₂(<i>rtct</i>-3,3′-tpcb)]·2H₂O}<i>_n</i> (<b>4</b>) can be obtained. Accompanied by the in situ solid-state photoreaction, <b>2</b> exhibits intriguing photocontrolled fluorescence behavior, making it a promising smart material for applications in fluorescence sensors, super-resolution imaging, and optical anticounterfeiting.","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":"37 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144183786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}