Second near-infrared fluorescent Metal-Organic framework sensors for in vivo extracellular adenosine triphosphate monitoring.

Plant nanobionic sensors enable real-time monitoring of signaling molecules in plants by interfacing them with specifically designed nanoprobes, which have been acknowledged as species-independent analytical tools. In this study, we developed a plant nanobionic sensor for in vivo detection of extracellular adenosine triphosphate (eATP) in living plants by designing a novel second near-infrared (NIR-II) fluorescent metal-organic framework (MOF) nanoprobe. The NIR-II fluorescent nanoprobe (IR-1061 micelle@ZIF-90) with a sandwich structure was synthesized by successive encapsulation of the hydrophobic NIR-II dye IR-1061 with the amphipathic polymer DSPE-mPEG 2000 and MOF ZIF-90. Interestingly, coating ZIF-90 around IR-1061 micelles increased the NIR-II fluorescence 16.6-fold. Utilizing the ultrahigh NIR-II fluorescent emission of the designed nanoprobes and specific recognition of ZIF-90 to ATP, the nanoprobes were applied to spatial and temporal monitoring eATP in model and non-model plants under environmental stress.

Self-Illuminating NIR-II Chemiluminescence Nanosensor for In Vivo Tracking H2 O2 Fluctuation.

Chemiluminescence (CL) imaging, as an excitation-free technique, exhibits a markedly improved signal-to-noise ratio (SNR) owing to the absence of an excitation light source and autofluorescence interference. However, conventional chemiluminescence imaging generally focuses on the visible and first near-infrared (NIR-I) regions, which hinders high-performance biological imaging due to strong tissue scattering and absorption. To address the issue, self-luminescent NIR-II CL nanoprobes with a second near-infrared (NIR-II) luminescence in the presence of hydrogen peroxide are rationally designed. A cascade energy transfer, including chemiluminescence resonance energy transfer (CRET) from the chemiluminescent substrate to NIR-I organic molecules and Förster resonance energy transfer (FRET) from NIR-I organic molecules to NIR-II organic molecules, occurs in the nanoprobes, contributing to NIR-II light with great efficiency and good tissue penetration depth. Based on excellent selectivity, high sensitivity to hydrogen peroxide, and long-lasting luminescence performance, the NIR-II CL nanoprobes are applied to detect inflammation in mice, showing a 7.4-fold enhancement in SNR compared with that of fluorescence.

Crystal structure of MgK0.5[B6O10](OH)0.5·0.5H2O, poly[dimagnesium potassium bis(hexa-borate) hy-droxide monohydrate].

The solvothermal reaction of H3BO3, KCF3SO3, Mg(CF3SO3)2 and pyridine led to a new alkali- and alkaline-earth-metal borate, MgK0.5[B6O10](OH)0.5·0.5H2O. Its structure features an intricate three-dimensional framework built from [B6O13]8- clusters, thus resulting in a six-connected achiral net with high symmetry. Each [B6O13]8- building block is composed of three trigonal BO3 and three tetra-hedral BO4 units, with these BO4 units being further connected to neighboring BO3 units, giving rise to an oxoboron cluster of the general formula [B6O10]2-.

Crystal structure of Rb6[B12O18(OH)6]·2H2O.

The solvothermal reaction of H3BO3, sodium tert-butoxide, Rb2CO3 and pyridine led to a new alkaline metal borate hexa-rubidium hexa-hydroxy-dodeca-borate dihydrate, Rb6[B12O18(OH)6]·2H2O. Its structure contains a large cyclic dodeca-oxoboron cluster, [B12O18(OH)6]6-, formed by six {B3O3} rings. In the crystal, O-H⋯O hydrogen bonds between the components lead to the formation of a three-dimensional supra-molecular framework.

Crystal structure of 4,4'-(diazenediyl)dipyridinium nitrate perchlorate.

The title compound, C10H10N4 2+·NO3 -·ClO4 -, was obtained unexpectedly by the reaction of Co(ClO4)2·6H2O and cytidine-5'-monophosphate with 4,4'-azo-pyridine in an aqueous solution of nitric acid. The mol-ecular structure comprises two planar 4,4'-diazenediyldipyridinium dications lying on inversion centres and perchlorate and nitrate anions in general positions. In the crystal, N-H⋯O hydrogen bonds between dications and anions lead to the formation of [232] chains.

K2 Na3 [{B6 O10 (OH)}{B3 O4 (OH)3 }] ⋠H2 O: A Layered Borate Built by Mixed Oxoboron Clusters with Nonlinear-Optical Property.

A new acentric borate, K2 Na3 [{B6 O10 (OH)}-{B3 O4 (OH)3 }] ⋅ H2 O (1) has been made under solvothermal condition. 1 has layered structure made by B6 O13 (OH)-based chains and B3 O5 (OH)3 -bridging clusters. Second-harmonic generation (SHG) measurements reveal that 1 is a phase-matchable nonlinear optical (NLO) material, showing the SHG signal intensity of 1.8 times that of KDP (KH2 PO4 ). Besides, UV-Vis diffuse reflectance spectrum shows that 1 has the short deep UV (DUV) absorption cutoff edge of 198 nm. Thermogravimetric analysis reveals it has good thermal stability. Also 1 represents firstly mixed oxoboron clusters-made 2D layered borate with NLO property.

The Research of G-Motif Construction and Chirality in Deoxyguanosine Monophosphate Nucleotide Complexes.

A detailed understanding of the mismatched base-pairing interactions in DNA will help reveal genetic diseases and provide a theoretical basis for the development of targeted drugs. Here, we utilized mononucleotide fragment to simulate mismatch DNA interactions in a local hydrophobic microenvironment. The bipyridyl-type bridging ligands were employed as a mild stabilizer to stabilize the GG mismatch containing complexes, allowing mismatch to be visualized based on X-ray crystallography. Five single crystals of 2'-deoxyguanosine-5'-monophosphate (dGMP) metal complexes were designed and obtained via the process of self-assembly. Crystallographic studies clearly reveal the details of the supramolecular interaction between mononucleotides and guest intercalators. A novel guanine-guanine base mismatch pattern with unusual (high anti)-(high anti) type of arrangement around the glycosidic angle conformations was successfully constructed. The solution state 1H-NMR, ESI-MS spectrum studies, and UV titration experiments emphasize the robustness of this g-motif in solution. Additionally, we combined the methods of single-crystal and solution-, solid-state CD spectrum together to discuss the chirality of the complexes. The complexes containing the g-motif structure, which reduces the energy of the system, following the solid-state CD signals, generally move in the long-wave direction. These results provided a new mismatched base pairing, that is g-motif. The interaction mode and full characterizations of g-motif will contribute to the study of the mismatched DNA interaction.

Two new Cu-based borate catalysts with cubic supramolecular cages for efficient catalytic hydrogen evolution.

Focusing on renewable energy, we are devoted to developping efficient, robust and low cost water reduction catalysts (WRCs). Two new Cu-based borate catalysts, namely H2Na2K2[(µ4-O)Cu4@B20O32(OH)8]·21H2O (1) and H2Rb1.6K2.4[(µ4-O)Cu4@B20O32 (OH)8]·15H2O (2), with cubic supramolecular cages were synthesized under a hydrothermal condition. Moreover, new copper complexes were applied as water reduction catalysts (WRCs) in the presence of [Ir(ppy)2(dtbbpy)][PF6] as photosensitizer and triethanolamine (TEOA) as the sacrificial electron donor. Nevertheless, the main active place is attributed to the centre of Borates [(µ4-O)Cu4@B20O32(OH)8], and the atomic radius of the counter cation would be the critical factor of the photocatalytic activity. Increasing the atomic radius from the Na atom to the Rb atom, causes the photocatalytic activity to decrease efficiently. The experimental results match well with the density functional theory (DFT) conclusion. It is noteworthy to mention that our research not only enriches the Cu-based borate chemistry, but also investigates the photocatalytic activity of Cu-based borates. This would guide us through the borate synthesis and to develop their applications toward energy and the environment.

Shear Exfoliated Metal-Organic Framework Nanosheet-Enabled Flexible Sensor for Real-Time Monitoring of Superoxide Anion.

Recently, two-dimensional metal-organic framework (2D MOF) nanosheets have drawn a lot of attention on account of their various advantages, like ultrathin thickness, ultralarge specific surface area, abundant accessible active sites, favorable solution dispersion properties, and ease of designability. However, until now, it is still difficult to produce 2D MOF nanosheets in large scale, which hinders the practical applications of 2D MOF nanosheets. Here, for the first time, we introduced a novel shear exfoliation method to prepare scalable 2D MOF nanosheets by using a commercial blender. As a proof of concept, we used two kinds of layer-structured MOFs (ELM-12, Cu(bpy)2(OTf)2, bpy = 4,4-bipyridine, OTf = trifluoromethanesulfonate and Zn2(bim)4, bim = benzimidazole) as samples to prepare MOF nanosheets. The thickness of the two kinds of MOF nanosheets obtained is 3-5 nm. Notably, the exfoliated MOF nanosheet (ELM-12) shows improved electrochemical catalytic activity compared with its bulk counterpart. Based on this, an ELM-12 nanosheet-based flexible sensor was developed for detecting superoxide anions (O2•-) released from cancer cells. The fabricated flexible sensor displays excellent sensitivity, selectivity, flexibility, stability, and reproducibility.

Laser-induced noble metal nanoparticle-graphene composites enabled flexible biosensor for pathogen detection.

Noble metal nanoparticle-3D graphene hybrid nanocomposites possess the advantage of nanoparticles and graphene, which have attracted extensive interest. Here we developed a one-step laser induction method to prepare various noble metal nanoparticle-3D graphene nanocomposites. The nanocomposites were converted from polyimide film coated with the corresponding metal precursor-chitosan hydrogel ink. These nanoparticles including gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and platinum nanoparticles (PtNPs), were evenly distributed on the surface of porous 3D graphene. Furthermore, we prepared an AuNPs-3D graphene interdigitated array electrode using the one-step laser induction method, which was used to fabricate a flexible impedimetric immunosensor for the detection of Escherichia coli O157:H7. The immunosensor shows excellent performance including low detection limit, high selectivity, and great flexibility.

Simultaneous fluorometric determination of the DNAs of Salmonella enterica, Listeria monocytogenes and Vibrio parahemolyticus by using an ultrathin metal-organic framework (type Cu-TCPP).

Ultrathin (<10 nm) nanosheets of a metal-organic framework (MOF-NSs) were prepared in high-yield and scalable production by a surfactant-assisted one-step method. The MOF-NSs possess distinguished affinity for ssDNA but not for dsDNA. This causes the fluorescence of the labeled DNA to be quenched. On binding to the target DNA (shown here for Salmonella enterica, Listeria monocytogenes and Vibrio parahemolyticus), the labeled duplex is released and the fluorescence of the label is restored. The labels Texas Red, Cy3 and FAM were used and give red, red or green fluorescence depending on the kind of pathogen. The detection limits are 28 pM, 35 pM and 15 pM for the gene segments of Salmonella enterica, Listeria monocytogenes and Vibrio parahemolyticus, respectively. Graphical abstract Schematic of an ultrasensitive fluorescent biosensor for multiplex detection of pathogenic DNAs based on ultrathin MOF nanosheets (type Cu-TCPP).

Solution-Phase Synthesis of Platinum Nanoparticle-Decorated Metal-Organic Framework Hybrid Nanomaterials as Biomimetic Nanoenzymes for Biosensing Applications.

The synthesis of nanomaterials with specific properties and functions as biomimetic nanoenzymes has attracted extensive attention in the past decades due to their great potential to substitute natural enzymes. Herein, a facile and simple method for the preparation of platinum nanoparticle (PtNP)-decorated two-dimensional metal-organic framework (MOF) nanocomposites was developed. A ligand with heme-like structure, Fe(III) tetra(4-carboxyphenyl)porphine chloride (TCPP(Fe)), was applied to synthesize MOF nanosheets (denoted as Cu-TCPP(Fe) nanosheets) in high yield. Ultrathin Cu-TCPP(Fe) nanosheets with thickness less than 10 nm were used as a novel template for the growth of ultrasmall and uniform PtNPs. Significantly, the obtained hybrid nanomaterials (PtNPs/Cu-TCPP(Fe) hybrid nanosheets) exhibit enhanced peroxidase-like activity compared to PtNPs, Cu-TCPP(Fe) nanosheets, and the physical mixture of both due to the synergistic effect. On account of the excellent peroxidase-like activity of PtNPs/Cu-TCPP(Fe) hybrid nanosheets, we established a colorimetric method for sensitive and rapid detection of hydrogen peroxide. Furthermore, by combining with glucose oxidase, a cascade colorimetric method was established to further detect glucose with excellent sensitivity and selectivity.

Double layer zinc-UDP coordination polymers: structure and properties.

A homochiral Zn-UDP coordination polymer with an alternating parallel ABAB sequence was constructed and studied by X-ray single crystal diffraction analysis. Its crystal structure shows that there are potentially open sites in the 2D layers. The activation of the sites makes the coordination polymer a fluorescent sensor for novel heterogeneous detection of amino acids.

Cytosine-Cytosine Base-Pair Mismatch and Chirality in Nucleotide Supramolecular Coordination Complexes.

The base-pair sequences are the foundation for the biological processes of DNA or RNA, and base-pair mismatch is very important to reveal genetic diseases and DNA rearrangements. However, the lack of well-defined structural information about base-pair mismatch is obstructing the investigation of this issue. The challenge is to crystallize the materials containing the base-pair mismatch. Engineering the small-molecule mimics or model is an effective strategy to solve this issue. Here, six cytidine-5'-monophosphate (CMP) and 2'-deoxycytidine-5'-monophosphate (dCMP) coordination polymers were reported containing cytosine-cytosine base-pair mismatch (i-motif), and their single-crystal structures and chiralities were studied. The precise control over the formation of the i-motif was demonstrated, in which the regulating of supramolecular interactions was achieved based on molecular design. In addition, the chiralities of these coordination polymers were investigated according to their crystal structures and solution- and solid-state circular dichroism spectroscopy.

Controllable synthesis of nucleotide complex based on pH control: a small-molecule fluorescent probe as an auxiliary ligand to indicate the pre-organization of the nucleotide complex in solution.

Different CMP-bpe-M(ii) (CMP = cytidine monophosphate, bpe = bis(4-pyridyl)ethylene, M(ii) = Mn(2+) and Co(2+)) complexes are synthesized controllably based on pH control and well studied by X-ray single-crystal diffraction analysis. Interestingly, the suitable pH conditions are explored by considering the pre-organization modes of CMP, bpe, and M(2+) in aqueous solution by fluorescence spectroscopy based on acid/basic titration. The organic base bpe serves as a small-molecule fluorescent probe to indicate the changes of pre-organization modes along with the changes of the solution acidity. Furthermore, a perfect self-complementary sugar-base hydrogen bond is first reported based on the crystal structure analysis in this work, and different chiralities and SHG activities of CMP-bpe-Mn(ii) complexes obtained at different pH values are studied.

6-Nitro-1,3-benzothia-zole-2(3H)-thione.

In the title mol-ecule, C(7)H(4)N(2)O(2)S(2), the nitro group is twisted by 5.5 (1)° from the plane of the attached benzene ring. In the crystal, N-H⋯S hydrogen bonds link pairs of mol-ecules into inversion dimers, which are linked by weak C-H⋯O inter-actions into sheets parallel to (101). The crystal packing exhibits short inter-molecular S⋯O contacts of 3.054 (4) Šand π-π inter-actions of 3.588 (5) Šbetween the centroids of the five- and six-membered rings of neighbouring mol-ecules.

Iodido[5-methyl-1H-benzimidazole-2(3H)-thione-κS]bis-(triphenyl-phosphane-κP)copper(I) methanol monosolvate.

In the title compound, [CuI(C(8)H(8)N(2)S)(C(18)H(15)P)(2)]·CH(3)OH, the coordination environment around the Cu(I) atom is distorted tetra-hedral, defined by two P atoms of two triphenyl-phosphane ligands, one S atom of a 5-methyl-1H-benzimidazole-2(3H)-thione ligand and one I atom. The complex mol-ecules and the methanol solvent mol-ecules are connected via N-H⋯O and O-H⋯I hydrogen bonds, forming a chain along [010]. An intra-molecular N-H⋯I hydrogen bond is also observed.

3-Amino-1H-1,2,4-triazole-5(4H)-thione-4,4'-bipyridine (1/1).

The title two-component mol-ecular crystal, C(10)H(8)N(2)·C(2)H(4)N(4)S, was obtained unexpectedly by reaction of Zn(NO(3))(2)·6H(2)O, NH(4)BF(4) with 3-amino-1,2,4-triazole-5-thione (3-AMT) and 4,4'-bipyridine in water. The dihedral angle between the pyridine rings in the 4,4'-bipyridine molecule is 17.00 (13)°. In the crystal, N-H⋯N and N-H⋯S hydrogen bonds between the components lead to the formation of a three-dimensional network. Furthermore, the structure features face-to-face π-π stacking inter-actions between the 4,4'-bipyridine and triazole rings, with a centroid-centroid distance of 2.976 (2) Å.

catena-Poly[[[diaqua-(1,10-phenanthroline-κ(2)N,N')zinc]-µ-4,4'-bipyridine-κ(2)N:N'] dinitrate 4,4'-bipyridine hemisolvate monohydrate].

In the title compound, [Zn(C(10)H(8)N(2))(C(12)H(8)N(2))(H(2)O)(2)](NO(3))(2)·0.5C(10)H(8)N(2)·H(2)O, the Zn(II) atom is coordinated in a distorted octa-hedral geometry by two N atoms from two 4,4'-bipyridine (4,4'-bipy) ligands, two N atoms from a chelating 1,10-phenanthroline ligand and two O atoms from two mutually cis water mol-ecules. The 4,4'-bipy ligands bridge the Zn(II) atoms into a chain structure along [100]. The uncoordinated 4,4'-bipy mol-ecule lies on an inversion center. O-H⋯O and O-H⋯N hydrogen bonds connect the cationic chains, the nitrate anions, the uncoordinated 4,4'-bipy mol-ecules and the water mol-ecules into tow-dimensional networks.

Bis[µ-bis-(diphenyl-phosphan-yl)methane-κ(2)P:P']bis-[(isoquinoline-κN)silver(I)] bis-(trifluoro-methane-sulfonate)-isoquinoline (1/1).

The title complex, [Ag(2)(C(25)H(22)P(2))(2)(C(9)H(7)N)(2)](CF(3)SO(3))(2)·C(9)H(7)N, was prepared by the reaction of silver(I) trifluoro-methane-sulfonate with isoquinoline and bis-(diphenyl-phosphan-yl)methane (dppm). The dinuclear mol-ecule is located about a center of inversion and the Ag(I) atom is coordinated by two dppm P atoms and one isoquinoline N atom, forming an eight-membered metalla ring. In addition, in the asymmetric unit, there is a half-mol-ecule of isoquinoline located about a center of inversion. Since this mol-ecule does not possess this symmetry, for one position in the ring there is superposition of both a C atom of a C-H group and the isoquinoline N atom. In the structure, the Ag-P distances [2.4296 (9) and 2.4368 (9) Å] agree with the corresponding distances in related structures, while the Ag-N bond length [2.489 (3) Å] is slightly longer than that in related structures. On the other hand, the P-Ag-P angle [156.44 (3)°] is much larger than the corresponding angles in related structures. The trifluoro-methane-sulfonate anions do not coordinate to Ag(I) atoms. As is usually found for these anions, the -CF(3) group is disordered over two orientations [occupancies = 0.57 (12) and 0.43 (12)].