Supramolecular Framework Research Articles

Supramolecular polynuclear clusters sustained cubic hydrogen bonded frameworks with octahedral cages for reversible photochromism

Developing supramolecular porous crystalline frameworks with tailor-made architectures from advanced secondary building units (SBUs) remains a pivotal challenge in reticular chemistry. Particularly for hydrogen-bonded organic frameworks (HOFs), construction of geometrical cavities through secondary units has been rarely achieved. Herein, a body-centered cubic HOF (TCA_NH4) with octahedral cages was constructed by a C3-symmetric building block and NH4+ node-assembled cluster (NH4)4(COOH)8(H2O)2 that served as supramolecular secondary building units (SSBUs), akin to the polynuclear SBUs in reticular chemistry. Specifically, the octahedral cages could encapsulate four homogenous haloforms including CHCl3, CHBr3, and CHI3 with truncated octahedron configuration. Crystallographic evidence revealed the cages served as spatially-confined nanoreactors, enabling fast, broadband photochromic effect associated with the reversible photo/thermal transformation between encapsulated CHI3 and I2. Overall, this work provides a strategy by shaping SSBUs to expand the framework topology of HOFs and a prototype of hydrogen-bonded nanoreactors to accommodate reversible photochromic reactions.

Exploring the synthesis, structure, and properties of two 2D transition metal polymers based on 4, 4’-bistriazole 3, 3’-biphenyldicarboxylic acid

Two coordination polymers {[Zn(BTBPA)(H2O)2]·0·5H2O}n (Zn-1), and {[Mn(BTBPA)(H2O)2]·0·5H2O}n (Mn-2) were synthesized solvothermally by the combination of organic linker 4,4′-bistriazole 3,3′-biphenyldicarboxylic acid (H2BTBPA) and Zn(NO3)2·6H2O or MnCl2·4H2O. Both of the polymers 1–2 are as 4,4-linked two-dimensional layered structures, which constitute into three dimensional supramolecular frameworks with porous channels via O − H⋅⋅⋅O hydrogen bonds. Zn-1 exhibits recognition abilities to antibiotics (PCL, NFT and NFZ) with high sensitivity via luminescence “turn-off” mechanism. In addition, the static magnetic performance of Mn-2 was investigated.

In Situ Grown Coordination-Supramolecular Layer Holding 3D Charged Channels for Highly Reversible Zn Anodes.

Dynamic reversible noncovalent interactions make supramolecular framework (SF) structures flexible and designable. A three-dimensional (3D) growth of such frameworks is beneficial to improve the structure stability while maintaining unique properties. Here, through the ionic interaction of the polyoxometalate cluster, coordination of zinc ions with cationic terpyridine, and hydrogen bonding of grafted carboxyl groups, the construction of a 3D SF at a well-crystallized state is realized. The framework can grow in situ on the Zn surface, further extending laterally into a full covering without defects. Relying on the dissolution and the postcoordination effects, the 3D SF layer is used as an artificial solid electrolyte interphase to improve the Zn-anode performance. The uniformly distributed clusters within nanosized pores create a negatively charged nanochannel, accelerating zinc ion transfer and homogenizing zinc deposition. The 3D SF/Zn symmetric cells demonstrate high stability for over 3000 h at a current density of 5 mA cm-2.

Synthesis, molecular self-assembly and anti-carcinogenic study of 2-pyridone molecules

4H-pyrans obtained from the multicomponent reactions of aromatic aldehyde, malononitrile, and ethyl acetoacetate were used as a starting scaffold for synthesizing 2-pyridone derivatives (1–3). Two catalytic methods were reported for the conversion of 4H-pyrans to 3,4-dihydropyridones. The non-aromatic 3,4-dihydropyridones obtained were then oxidized to give the final desired 2-pyridone derivatives (1–3). Crystals of the synthesized compounds were prepared and subjected to single-crystal X-ray crystallography (SCXRD) to acquire their structural parameters. Non-covalent interactions in the supramolecular systems 1–3 were studied, and it found that NH∙∙∙O interactions between the lactam groups are the most dominant hydrogen bonds. It is also observed that the aromatic rings are involved in lone pair∙∙∙π, CH∙∙∙π, and weak π∙∙∙π interactions in assisting the supramolecular framework. Hirshfeld surface studies are also performed to validate the interactions within the supramolecular crystals. The 2-pyridone derivatives (1–3) were also analyzed by in vitro techniques to evaluate their cytotoxic activities using human lung adenocarcinoma (A549). It is also found that ethyl 5-cyano-2-methyl-4-(3-nitrophenyl)-6-oxo-1,6-dihydropyridine-3-carboxylate (1) has shown the highest cytotoxic potency amongst the synthesized compound.

Visible light-mediated supramolecular framework for tunable CO2 adsorption

In the pursuit of creating azobenzene-functionalized photo-responsive supramolecular frameworks (PSMFs) activated by the visible spectrum, an endeavor traditionally relied on ultraviolet activation, we report the successful fabrication of a visible light-mediated metal–organic cage-based PSMF, designated as NUT-104. This achievement was realized by the hierarchical self-assembly process of Zr-metal–organic cages featuring ortho-fluoroazobenzene functional terephthalic acid and tri-nuclear Zr-clusters. NUT-104 displays permanent porosity coupled with reversible responsiveness to visible light. This remarkable behavior emerges as a consequence of the σ-electron-withdrawing effect induced by the presence of fluorine substituents. Visible light-regulated CO2 adsorption capacity can be achieved and the change value can reach 61 %, while the change for CH4 and N2 is only 7 % and 3 %, respectively. In response to irradiation at wavelengths of 520 and 420 nm, respectively, the azobenzene moieties within the NUT-104 structure exhibit a remarkable capacity for visible light-controlled reversible conformational changes. Grand Canonical Monte Carlo simulations unveiled that the dynamic reorganization of the NUT-104 proficiently governs the accessibility of CO2 adsorption sites positioned within the interstitial regions of proximate cages. The advent of NUT-104, underpinned by its visible light responsiveness and versatile tunability, paves the way for avenues of exploration in controlled gas separation and storage applications.

Pt(II)/Pd(II)-Based Metallosupramolecular Architectures as Light Harvesting Systems and their Applications.

The development of artificial light-harvesting systems mimicking the natural photosynthesis method is an ever-growing field of research. Numerous systems such as polymers, metal complexes, POFs, COFs, supramolecular frameworks etc. have been fabricated to accomplish more efficient energy transfer and storage. Among them, the supramolecular coordination complexes (SCCs) formed by non-covalent metal-ligand interaction, have shown the capacity to not only undergo single and multistep energy migration but also to utilize the harvested energy for a wide variety of applications such as photocatalysis, tunable emissive systems, encrypted anti-counterfeiting materials, white light emitters etc. This review sheds light on the light-harvesting behavior of both the 2D metallacycles and 3D metallacages where design ingenuity has been executed to afford energy harvesting by both donor ligands as well as metal acceptors.

Pt(II)/Pd(II)‐Based Metallosupramolecular Architectures as Light Harvesting Systems and their Applications

AbstractThe development of artificial light‐harvesting systems mimicking the natural photosynthesis method is an ever‐growing field of research. Numerous systems such as polymers, metal complexes, POFs, COFs, supramolecular frameworks etc. have been fabricated to accomplish more efficient energy transfer and storage. Among them, the supramolecular coordination complexes (SCCs) formed by non‐covalent metal‐ligand interaction, have shown the capacity to not only undergo single and multistep energy migration but also to utilize the harvested energy for a wide variety of applications such as photocatalysis, tunable emissive systems, encrypted anti‐counterfeiting materials, white light emitters etc. This review sheds light on the light‐harvesting behavior of both the 2D metallacycles and 3D metallacages where design ingenuity has been executed to afford energy harvesting by both donor ligands as well as metal acceptors.

Proton Conductivity in a Metal-Organic Cube-Based Framework and Derived Hydrogel with Tubular Morphology.

The hydrogels, formed by self-assembly of predesigned, discrete metal-organic cubes (MOCs), have emerged as a new type of functional soft material whose diverse properties are yet to be explored. Here, we explore the proton conductivity of a MOC-based supramolecular porous framework {(Me2NH2)12[Ga8(ImDC)12]·DMF·29H2O} (1) (ImDC = 4,5-imidazole dicarboxylate) and derived hydrogel (MOC-G1). The intrinsic charge-assisted H-bonded (between anionic MOC {[Ga8(ImDC)12]12-} and dimethylammonium cations) framework 1 exhibits an ambient condition proton conductivity value of 2.3 × 10-5 S cm-1 (@40% RH) which increases with increasing temperature (8.2 × 10-4 S cm-1 at 120 °C and 40% RH) and follows the Grotthuss type of mechanism of proton conduction. Self-assembly of the MOCs in the presence of ammonium cations, as molecular binders, resulted in a hydrogel (MOC-G1) that shows directional H-bonded 1D nanotubular morphology. While guest water molecules are immensely important in deciding the proton conductivity of both 1 and MOC-G1, the presence of additional proton carriers, such as DMA and ammonium cations, resulted in at least 1 order increment in the proton conductivity of the latter (1.8 × 10-2 S cm-1) than the former (1.4 × 10-3 S cm-1) under 25 °C and 98% RH condition. The values of proton conductivity of 1 and MOC-G1 are comparable with those of the best proton conduction reports in the literature. This work may pave the way for the development of proton conductors with unique architecture and conductivity requisite for the state-of-the-art technologies by selecting appropriate MOC and molecular binders.

Synthesis of novel supramolecular selenomolybdate as anticancer agents: An experimental and DFT computational analysis

A novel organic–inorganic material based on three-dimensional (3D) Strandberg-type polyoxoselenomolybdate, (C6H14N2)2[Se2Mo5O21]·2·6H2O (I, where C6H14N2 = DABCO cation) was successfully synthesized by solution process and characterized by scanning electron microscopy (SEM), infrared (FT-IR) and ultraviolet (UV–vis) spectroscopies, thermogravimetric analysis (TGA), cyclic voltammetry (CV) measurement. The electronic and electrochemical behavior of the compound was further evaluated as a function of pH and time via UV–vis spectroscopy and CV. Single crystal X-Ray diffraction (XRD) technique was used for complete structure elucidation. The title compound crystallizes in the non-centrosymmetric orthorhombic space group P212121, thus resulting in non-linear optical properties. The supramolecular framework exhibits a periodic arrangement of Strandberg clusters anions [Se2Mo5O21]4– connected to each other with water molecules and dabconium cations, through a network of hydrogen bonds and van der Waals interactions. The occurrence of intermolecular interactions, ensuring the cohesion between different entities, was assessed by density functional theory (DFT) calculations and Hirshfeld surface analysis. DFT calculations with different functionals have been used to better understand several properties like as RDG, QTAIMs, ELF, MEP and NLO.A good agreement was indeed found between the experimental and computational results. Furthermore, the (C6H14N2)2[Se2Mo5O21]·2·6H2O compound was tested for its biological activity. This selenomolybdate displayed a significant inhibitory effect on the growth of human ovarian cancer cells A2780, with an IC50 value of 4.05 ± 0.55 μM, being thus the first Strandberg-type polyoxometalate to show a significant anticancer activity.

Superprotonic Conductivity in a Metalloporphyrin-Based SMOF (Supramolecular Metal-Organic Framework).

Metal-organic frameworks and supramolecular metal-organic frameworks (SMOFs) exhibit great potential for a broad range of applications taking advantage of the high surface area and pore sizes and tunable chemistry. In particular, metalloporphyrin-based MOFs and SMOFs are becoming of great importance in many fields due to the bioessential functions of these macrocycles that are being mimicked. On the other hand, during the last years, proton-conducting materials have aroused much interest, and those presenting high conductivity values are potential candidates to play a key role in some solid-state electrochemical devices such as batteries and fuel cells. In this way, using metalloporphyrins as building units we have obtained a new crystalline material with formula [H(bipy)]2[(MnTPPS)(H2O)2]·2bipy·14H2O, where bipy is 4,4'-bipyidine and TPPS4- is the meso-tetra(4-sulfonatephenyl) porphyrin. The crystal structure shows a zig-zag water chain along the [100] direction located between the sulfonate groups of the porphyrin. Taking into account those structural features, the compound was tested for proton conduction by complex electrochemical impedance spectroscopy (EIS). The as-obtained conductivity is 1 × 10-2 S·cm-1 at 40 °C and 98% relative humidity, which is a remarkably high value.

Luminescent Supramolecular Ionic Frameworks based on Organic Fluorescent Polycations and Polyanionic Phosphorescent Metal Clusters.

Emissive ionic supramolecular frameworks are designed by associating tetraphenylethylene-based tetra-cationic units and di-anionic molybdenum or tetra-anionic rhenium octahedral clusters. Obtained structures were characterized by single-crystal X-ray diffraction. The emission properties of the hybrids were investigated as dry powders or in various solvents by one photon and two photon absorption leading to a O2 concentration dependent luminescence color for the Mo based hybrid.

Iodine Adsorption-Desorption-Induced Structural Transformation and Improved Ag+ Turn-On Luminescent Sensing Performance of a Nonporous Eu(III) Metal-Organic Framework.

Posttreatment of pristine metal-organic frameworks (MOFs) with suitable vapor may be an effective way to regulate their structures and properties but has been less explored. Herein, we report an interesting example in which a crystalline nonporous Eu(III)-MOF was transferred to a porous amorphous MOF (aMOF) via iodine vapor adsorption-desorption posttreatment, and the resulting aMOF showed improved turn-on sensing properties with respect to Ag+ ions. The crystalline Eu-MOF, namely, Eu-IPDA, was assembled from Eu(III) and 4,4'-{4-[4-(1H-imidazol-1-yl)phenyl]pyridine-2,6-diyl}dibenzoic acid (H2IPDA) and exhibited a two-dimensional (2D) coordination network based on one-dimensional secondary building blocks. The close packing of the 2D networks gives rise to a three-dimensional supramolecular framework without any significant pores. Interestingly, the nonporous Eu-IPDA could absorb iodine molecules when Eu-IPDA crystals were placed in iodine vapor at 85 °C, and the adsorption capacity was 1.90 g/g, which is comparable to those of many MOFs with large BET surfaces. The adsorption of iodine is attributed to the strong interactions among the iodine molecule, the carboxy group, and the N-containing group and leads to the amorphization of the framework. After immersion of the iodine-loaded Eu-IPDA in EtOH, approximately 89.7% of the iodine was removed, resulting in a porous amorphous MOF, denoted as a-Eu-IPDA. In addition, the remaining iodine in the a-Eu-IPDA framework causes strong luminescent quenching in the fluorescence emission region of the Eu(III) center when compared with that in Eu-IPDA. The luminescence intensity of a-Eu-IPDA in water suspensions was significantly enhanced when Ag+ ions were added, with a detection limit of 4.76 × 10-6 M, which is 1000 times that of pristine Eu-IPDA. It also showed strong anti-interference ability over many common competitive metal ions and has the potential to sense Ag+ in natural water bodies and traditional Chinese medicine preparations. A mechanistic study showed that the interactions between Ag+ and the absorbed iodine, the carboxylate group, and the N atoms all contribute to the sensing performance of a-Eu-IPDA.

Crystal Engineering and Self-Assembled Nanoring Formation with Purine-CdII/HgII Supramolecular Frameworks.

We report three complexes of CdII and HgII with two purine rare tautomers, N9-(pyridin-2-ylmethyl)-N6-methoxyadenine, L1 and N7-(pyridin-2-ylmethyl)-N6-methoxyadenine, L2, highlighting diverse crystallographic signatures exhibited by them. Influence of substituents, binding sites, steric effects and metal salts on the different modes of binding enabled an insight into metal-nucleobase interactions. L1 interacted with two and three equivalents of Cd(NO3)2.4H2O and HgCl2, respectively, while L2 interacted with two equivalents of HgCl2, altogether leading to three different complexes (1 [C48H48Cd6N34O50], 2 [C12H12Cl4Hg2N6O] and 3 [C12H12Cl2HgN6O]) possessing varied dimensionality and stabilising interactions. The photoluminescent properties of these coordination frameworks have also been probed. Notably, nanoring-like structures were obtained, as a result of self-assembly of 3 when investigated by transmission electron microscopy, additionally supported by molecular dynamics simulations.

Seed‐Induced Living Two‐Dimensional (2D) Supramolecular Polymerization in Water: Implications on Protein Adsorption and Enzyme Inhibition

AbstractIn biological systems, programmable supramolecular frameworks characterized by coordinated directional non‐covalent interactions are widespread. However, only a small number of reports involve pure water‐based dynamic supramolecular assembly of artificial π‐amphiphiles, primarily due to the formidable challenge of counteracting the strong hydrophobic dominance of the π‐surface in water, leading to undesired kinetic traps. This study reveals the pathway complexity in hydrogen‐bonding‐mediated supramolecular polymerization of an amide‐functionalized naphthalene monoimide (NMI) building block with a hydrophilic oligo‐oxyethylene (OE) wedge. O‐NMI‐2 initially produced entropically driven, collapsed spherical particles in water (Agg‐1); however, over a span of 72 h, these metastable Agg‐1 gradually transformed into two‐dimensional (2D) nanosheets (Agg‐2), favoured by both entropy and enthalpy contributions. The intricate self‐assembly pathways in O‐NMI‐2 enable us to explore seed‐induced living supramolecular polymerization (LSP) in water for controlled synthesis of monolayered 2D assemblies. Furthermore, we demonstrated the nonspecific surface adsorption of a model enzyme, serine protease α‐Chymotrypsin (α‐ChT), and consequently the enzyme activity, which could be regulated by controlling the morphological transformation of O‐NMI‐2 from Agg‐1 to Agg‐2. We delve into the thermodynamic aspects of such shape‐dependent protein‐surface interactions and unravel the impact of seed‐induced LSP on temporally controlling the catalytic activity of α‐ChT.

Seed-Induced Living Two-Dimensional (2D) Supramolecular Polymerization in Water: Implications on Protein Adsorption and Enzyme Inhibition.

In biological systems, programmable supramolecular frameworks characterized by coordinated directional non-covalent interactions are widespread. However, only a small number of reports involve pure water-based dynamic supramolecular assembly of artificial π-amphiphiles, primarily due to the formidable challenge of counteracting the strong hydrophobic dominance of the π-surface in water, leading to undesired kinetic traps. This study reveals the pathway complexity in hydrogen-bonding-mediated supramolecular polymerization of an amide-functionalized naphthalene monoimide (NMI) building block with a hydrophilic oligo-oxyethylene (OE) wedge. O-NMI-2 initially produced entropically driven, collapsed spherical particles in water (Agg-1); however, over a span of 72 h, these metastable Agg-1 gradually transformed into two-dimensional (2D) nanosheets (Agg-2), favoured by both entropy and enthalpy contributions. The intricate self-assembly pathways in O-NMI-2 enable us to explore seed-induced living supramolecular polymerization (LSP) in water for controlled synthesis of monolayered 2D assemblies. Furthermore, we demonstrated the nonspecific surface adsorption of a model enzyme, serine protease α-Chymotrypsin (α-ChT), and consequently the enzyme activity, which could be regulated by controlling the morphological transformation of O-NMI-2 from Agg-1 to Agg-2. We delve into the thermodynamic aspects of such shape-dependent protein-surface interactions and unravel the impact of seed-induced LSP on temporally controlling the catalytic activity of α-ChT.

Hybrid 2D Supramolecular Organic Frameworks (SOFs) Assembled by the Cooperative Action of Hydrogen and Halogen Bonding and π⋯π Stacking Interactions.

The cis- and trans-isomers of 6-(3-(3,4-dichlorophenyl)-1,2,4-oxadiazol-5-yl)cyclohex-3-ene-1-carboxylic acid (cis-A and trans-A) were obtained by the reaction of 3,4-dichloro-N'-hydroxybenzimidamide and cis-1,2,3,6-tetrahydrophthalic anhydride. Cocrystals of cis-A with appropriate solvents (cis-A‧½(1,2-DCE), cis-A‧½(1,2-DBE), and cis-A‧½C6H14) were grown from 1,2-dichloroethane (1,2-DCE), 1,2-dibromoethane (1,2-DBE), and a n-hexane/CHCl3 mixture and then characterized by X-ray crystallography. In their structures, cis-A is self-assembled to give a hybrid 2D supramolecular organic framework (SOF) formed by the cooperative action of O-H⋯O hydrogen bonding, Cl⋯O halogen bonding, and π⋯π stacking. The self-assembled cis-A divides the space between the 2D SOF layers into infinite hollow tunnels incorporating solvent molecules. The energy contribution of each noncovalent interaction to the occurrence of the 2D SOF was verified by several theoretical approaches, including MEP and combined QTAIM and NCIplot analyses. The consideration of the theoretical data proved that hydrogen bonding (approx. -15.2 kcal/mol) is the most important interaction, followed by π⋯π stacking (approx. -11.1 kcal/mol); meanwhile, the contribution of halogen bonding (approx. -3.6 kcal/mol) is the smallest among these interactions. The structure of the isomeric compound trans-A does not exhibit a 2D SOF architecture. It is assembled by the combined action of hydrogen bonding and π⋯π stacking, without the involvement of halogen bonds. A comparison of the cis-A structures with that of trans-A indicated that halogen bonding, although it has the lowest energy in cis-A-based cocrystals, plays a significant role in the crystal design of the hybrid 2D SOF. The majority of the reported porous halogen-bonded organic frameworks were assembled via iodine and bromine-based contacts, while chlorine-based systems-which, in our case, are structure-directing-were unknown before this study.

Two new polyoxomolybdate-based organic–inorganic hybrid compounds with copper ions and bridging ligands

Two new polyoxomolybdate-based organic–inorganic hybrid compounds with copper ions and bridging ligands were prepared in a hydrothermal reaction system, and the chemical formulas are [Cu2(L1)4S][Mo6O19] (1) and [CuIICuI 2(L2)5][β-Mo8O26] (2) (L1 = 1,2-bis(iminazole-1-ylmethyl)benzene, L2 = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene). Complexes 1 and 2 were characterized by elemental analysis, IR spectra, TG analyses and single-crystal X-ray diffraction analyses. Compound 1 exhibits 2-D layers with honeycomb-like cavities, further stacking into a 3-D supramolecular framework with the [Mo6O19]2- polyoxoanions as guest templates in the honeycomb-like cavities. Compound 2 possesses an overall 3D(2D/3D) framework constituted by the undulating 2-D motifs and the 3D sqp framework. The photocatalytic activities of 1 and 2 under UV light were investigated based on the degradation of methylene blue (MB). Both compounds exhibit efficient catalytic activity for the degradation of MB.

Transformation of reactive oxygen species caused by assembly of excitation modules into supramolecular organic frameworks for photocatalysis

Transformation of reactive oxygen species caused by assembly of excitation modules into supramolecular organic frameworks for photocatalysis

Crystal structure and characterization of a new lanthanide coordination polymer, [Pr2(pydc)(phth)2(H2O)3]·H2O

A new lanthanide coordination polymer, poly[[triaquabis(μ4-phthalato)(μ3-pyridine-2,5-dicarboxylato)dipraseodymium] monohydrate], {[Pr2(C7H3NO4)2(C8H4O4)(H2O)3]·H2O} n or {[Pr2(phth)2(pydc)(H2O)3]·H2O} n , (pydc2− = pyridine-2,5-dicarboxylate and phth2− = phthalate) was synthesized and characterized, revealing the structure to be an assembly of di-periodic {Pr2(pydc)(phth)2(H2O)3} n layers. Each layer is built up by edge-sharing {Pr2N2O14} and {Pr2O16} dimers, which are connected through a new coordination mode of pydc2− and phth2−. These layers are stabilized by internal hydrogen bonds and π–π interactions. In addition, a three-dimensional supramolecular framework is built by interlayer hydrogen-bonding interactions involving the non-coordinated water molecule. Thermogravimetric analysis shows that the title compound is thermally stable up to 400°C.

Anticancer Drug Extraction from Plasma Samples Using Three-Dimensional Polyoxometalate-Based Supramolecular Frameworks as Sorbents.

Four self-assembled inorganic-organic hybrid materials, namely, H{Na(H2O)3[Gd(PDA)(H2O)2]3[BW12O40]}·4H2O (1), H{Na(H2O)3[Tb(PDA)(H2O)2]3[BW12O40]}·3H2O (2), H{Na(H2O)3[Er(PDA)(H2O)3]3[BW12O40]}·H2O (3) (PDA = 1,10-phenanthroline-2,9-dicarboxylate), and [Pr3(H2O)13(pydc-OH)2][BW12O40]·12H2O (4) (pydc-OH = 4-hydroxy-2,6-pyridinedicarboxylate), were hydrothermally synthesized and structurally characterized. Hybrids 1-3 are isostructural and contain a Keggin unit, which is linked to lanthanoids to produce distinct trinuclear lanthanoid building blocks. The fragments are connected by anion-π and hydrogen bonding interactions to create 3D networks. In hybrid 4, a trimeric Pr-organic species bearing a Keggin unit forms a 2D coordination polymer, and then hydrogen bonding interactions between 2D layers lead to the formation of a 3D structure. These polyoxometalate-based frameworks were used as sorbents for the dispersive microsolid-phase extraction (D-μSPE) of two anticancer drugs (doxorubicin and epirubicin) in human plasma samples. Analytes were quantified and separated using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The method's linearity was between 0.8-500 ng mL-1 and 1.0-500 ng mL-1 for the antineoplastic drugs doxorubicin and epirubicin, respectively. The limits of detection (S/N = 3) were in the range of 0.2-0.3 ng mL-1, while the precision was in the range of 3.5-4.3%. Finally, human plasma samples from patients treated with doxorubicin or epirubicin were analyzed by using the D-μSPE-HPLC-FLD method.