Bromhexine and its fumarate salt: Crystal structures, Hirshfeld surfaces and dissolution study.

Bromhexine is an expectorant drug repurposing as a TMPRSS2 inhibitor, which has also been proposed for potential treatment in COVID-19 infection. Multicomponent crystal strategy has been applied in bromhexine to improve its poor solubility, which limits its bioavailability and efficacy. A new bromhexine crystal and its fumarate salt crystal have been successfully obtained by slow evaporation technique.

Build 3D Nanoparticles by Using Ultrathin 2D MOF Nanosheets for NIR Light-Triggered Molecular Switching.

The coordination interactions between transition-metal ions (Cu, Ag) and sulfur atoms on ultrathin two-dimensional (2D) nanosheets of spin-crossover (SCO) metal-organic frameworks {[Fe(1,3-bpp)(NCS)]} (1,3-bpp = 1,3-di(4-pyridyl)propane), which constructed the ultrathin 2D nanosheets into three-dimensional (3D) nanoparticles, have made a profound effect on the SCO performance. Compared with 2D nanosheets, both the intraligand π-π* transition band and the metal-to-ligand charge transition band from the d(Fe) + π(NCS) to π*(1,3-bpp), for the 3D nanoparticles, have shown dramatic blue-shifts; meanwhile, the d-d transition band for the high-spin (HS) state Fe(II) ions has been generated, suggesting significantly the influence of 3D assemble-caused dimensional changes on the solid-state SCO performance of ultrathin 2D nanosheets. More importantly, by loading on the ytterbium ion (Yb)-sensitized hexagonal phase upconverting nanoparticles in the aqueous colloidal suspension, the near infrared (NIR) light (980 nm) triggered HS (high spin) to LS (low spin) state transitions have been observed, demonstrating the achievement of challenging target of NIR light-triggered molecular conversion under environment conditions.

Unraveling the Mechanisms of the Excited-State Intermolecular Proton Transfer (ESPT) for a D-π-A Molecular Architecture.

Precise revealing the mechanisms of excited-state intermolecular proton transfer (ESPT) and the corresponding geometrical relaxation upon photoexcitation and photoionization remains a formidable challenge. In this work, the compound (E)-4-(((4H-1,2,4-triazol-4-yl)imino)methyl)-2,6-dimethoxyphenol (TIMDP) adopting a D-π-A molecular architecture featuring a significant intramolecular charge transfer (ICT) effect has been designed. With the presence of perchloric acid (35 %), TIMDP can be dissolved through the formation of a HClO -H O-OH(TIMDP)-N(TIMDP) hydrogen-bonding bridge.

Porous High-Valence Metal-Organic Framework Featuring Open Coordination Sites for Effective Water Adsorption.

The design and preparation of a porous high-valence metal-organic framework (MOF) featuring open coordination sites are of utmost importance for the development of adsorbent materials. Here in this work, the three-dimensional (3D) high-valence MOF [Er(dcbp)(DMF)(HO)]·2HO (HV-MOF-1; Hdcbp = 4,4'-dicarboxy-2,2'-bipyridine, DMF = N,N-dimethylformamide), which possesses permanent porosity and two open coordination sites, has been prepared and characterized. In the 3D framework, the dcbp molecules display two different bridging styles, resulting in ordered diamondlike pores with bared carboxyl oxygen and pyridine nitrogen atoms on dcbp exposed directly to the pores, generating hydrophilic characteristics and high water affinity.

Ultralarge Dielectric Relaxation and Self-Recovery Triggered by Hydrogen-Bonded Polar Components.

Subtle integration of rotatable polar components into dielectric crystals can contribute significantly to adjustable switching temperatures ( T) and dielectric relaxation behaviors. Currently, one of the biggest challenges lies in the design of optimal polar components with moderate motion resistance in a crystalline system. In this work, we demonstrate that under refrigerator conditions, rotatable hydrogen-bonded one-dimensional (1D) cationic chains, {[CHN]} (CHN = 3,5-diamino-1,2,4-triazolinium), and two-dimensional (2D) anionic layers, {[(HO)·SO]} , can be generated in an organic salt, 3 ([CHN]·[(HO)·SO]).

Enhanced treatment effect of nanoparticles containing cisplatin and a GSH-reactive probe compound.

Cisplatin is a highly effective antitumor drug, which can kill cancer cells by crossing-linking DNA and inhibiting transcription, but this process is limited by the combination of cisplatin and many endogenous nucleophiles, such as glutathione (GSH). Thus, when cisplatin enter cells, it is potentially vulnerable to cytoplasmic inactivation by GSH. To settle this bottleneck, we designed and synthesized a probe compound (Probe 1) and fabricated pH-responsed cisplatin, Probe 1-loaded lipid-polymer hybrid NanoParticles (CPNPs) using a single-step sonication method.

Atomically Thin Two-Dimensional Nanosheets with Tunable Spin-Crossover Properties.

Combining the fascinating advantages of ultrathin two-dimensional (2D) nanosheets with the nanostructuration of spin-crossover (SCO) materials represents an attractive target of controlled fabrication of SCO nano-objects at the device level. Here, we demonstrate that through facile-operating ultrasonic force-assisted liquid exfoliation technology the three-dimensional (3D) van der Waals SCO bulk precursor {[Fe(1,3-bpp)(NCS)] (1, 1,3-bpp = 1,3-di(4-pyridyl)-propane)} can be exfoliated into single-layered 2D nanosheets (NS-1). As a consequence, the magnetism has been tuned from complete paramagnetic (bulk precursors) to SCO transition at around 250 K (2D nanosheets).

Subcellular co-delivery of two different site-oriented payloads based on multistage targeted polymeric nanoparticles for enhanced cancer therapy.

The co-delivery of two or more anti-tumor agents using nanocarriers has shown great promise in cancer therapy, but more work is needed to selectively target drugs to specific subcellular organelles. To this end, our research has reported on "smart" polymeric nanoparticles that can encapsulate two different site-oriented pro-drug molecules, allowing them to reach their targeted subcellular organelles based on NIR-mediated controlled release, allowing for targeted modifications in the nucleus or the mitochondria. Specially, an all-trans retinoic acid (RA) conjugated cisplatin derivative (RA-Pt) can be delivered with high affinity to the nucleus of target cells, facilitating the binding of cisplatin to double-stranded DNA.

Single-Layered Two-Dimensional Metal-Organic Framework Nanosheets as an in Situ Visual Test Paper for Solvents.

Through a facile-operating ultrasonic force-assisted liquid exfoliation technology, the single-layered two-dimensional (2D) [Co(CNS)(pyz)] (pyz = pyrazine) nanosheets, with a thickness of sub-1.0 nm, have been prepared from the bulk precursors. The atomically thickness and the presence of abundant sulfur atoms with high electronegativity arrayed on the double surfaces of the sheets are making this kind of 2D MOF (metal-organic framework) nanosheets highly sensitive to intermolecular interactions.

Bidirectional Photoswitching via Alternating NIR and UV Irradiation on a Core-Shell UCNP-SCO Nanosphere.

Bidirectional photoswitching of molecular materials under ambient condition is of significant importance. Herein, we present for the first time that a core-shell UCNP-SCO nanosphere (UCNP = upconversion nanophosphor, SCO = spin crossover), which was composed of a UCNP core (NaYF: 20 mol % Yb, 1 mol % Er) and an SCO iron(II) shell ([Fe(HBpz)(bipy-COOH)], HBpz = dihydrobis(1-pyrazolyl)borate, bipy-COOH = 4,4'-dicarboxy-2,2'-bipyridine), can be reversibly photoswitched between the high-spin and low-spin states at room temperature in the solid state, via alternating irradiation with near-infrared (λ = 980 nm) and ultraviolet (λ = 310 nm) light. What's more, this reversible spin-state switching was accompanied by a variation of fluorescent spectrum and dielectric constants.

Thermal-Induced Dielectric Switching with 40K Wide Hysteresis Loop Near Room Temperature.

A thermal-induced dielectric switching has been realized in two ion-pair crystal [CHN]·[HPO] (1, CHN = 3,5-diamino-1,2,4-triazolinium) through single-crystal-to-single-crystal phase transition (SCSC-PT). Upon cooling from room temperature, the 1D cation stripes that are composed of [CHN] cations have undergone a 90° sharp rotation around the c axis, accompanied by the transition of crystal stacking from loose unparallel (dynamic state) to compression parallel (static state) and reorientation of dipoles on the [CHN] cation, which thus resulted in high dielectric state to low dielectric state transformation. While on the warming run, the reverse process was rather sluggish, resulting in a reversible dielectric switching with ultralarge (about 40K wide) hysteresis loop near room temperature.

Binding CO from Air by a Bulky Organometallic Cation Containing Primary Amines.

The organometallic cation 1 (Fe(bipy-NH), bipy-NH = 4,4'-diamino-2,2'-bipyridine), which was constructed in situ in solution, can bind CO from air effectively with a stoichiometric ratio of 1:4 (1/CO), through the formation of "H-bonded CO" species: [CO-OH-CO] and [CO-CO-OH]. These two species, along with the captured individual CO molecules, connected 1 into a novel 3D (three-dimensional) architecture, that was crystal 1·2(OH)·4(CO). The adsorption isotherms, recycling investigations, and the heat capacity of 1 have been investigated; the results revealed that the organometallic cation 1 can be recycled at least 10 times for the real-world CO capture applications.

Ambient-Temperature Spin-State Switching Achieved by Protonation of the Amino Group in [Fe(H2Bpz2)2(bipy-NH2)].

Magnetism of a complex [Fe(H2Bpz2)2(bipy-NH2)] (H2Bpz2 = dihydrobis(1-pyrazolyl)borate, bipy-NH2 = 4,4'-diamino-2,2'-bipyridine) has been altered from paramagnetic to spin-crossover (SCO) behavior, through protonation of one amino group of bipy-NH2 with CF3SO3H. Complete SCO transition, both in solid state and in solution, occurs at ambient temperature.

Complexation of different transition metals with 4,4'-dimethyl-2,2'-bipyridine: Crystal structure, UV spectra and Hirshfeld surfaces.

Four new complexes, [Co(dmbpy)2(dca)2]·CH3OH (1), [Ni(dmbpy)2(dca)2]·CH3OH (2), [Zn(dmbpy)2(dca)2]·(3) and [Cu(dmbpy)2(OH)2]·5H2O (4) (dca=dicyanamide), derived from 4,4'-dimethyl-2,2'-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1-3 were mainly supported by OH⋯N, CH⋯N and π⋯π intermolecular interactions, and for complex 4, the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306nm.

[Advances in the study of site-specific antibody-drug conjugates].

Antibody drug conjugates (ADCs) are an emerging class of targeted therapeutics with the potential to improve therapeutic index over the traditional chemotherapy. However, it is difficult to control the site and stoichiometry of conjugation in mAb, typically resulting in heterogeneous mixtures of ADCs that are difficult to optimize. New methods for site-specific drug attachment allow development of more homogeneous conjugates and control of the site of drug attachment.

Biological evaluation of a novel Herceptin-platinum (II) conjugate for efficient and cancer cell specific delivery.

Platinum-based drugs have been widely used for the treatment of malignant tumors. However, their applications are limited by severe side effects for their lack of selectivity for cancer cells. The development of antibody drug conjugates (ADCs) have provided a platform to reduce drug toxicity and improve drug efficacy.

DNA-caged gold nanoparticles for controlled release of doxorubicin triggered by a DNA enzyme and pH.

DNA polyhedron-caged gold nanoparticles (AuNP) were self-assembled using four-point-star DNAs, with three strands hybridizing to each other and the fourth strand attaching to the AuNPs. The DNA-caged AuNPs can work as nanocarriers for doxorubicin, and controlled release behaviour can be triggered by both a DNA enzyme and by the pH value.

Lattice water molecules tuned spin-crossover for an iron(II) complex with thermal hysteresis.

A new iron(II) complex based on the 4,4'-dimethyl-2,2'-bipyridine ligand [Fe(4,4'-dmbpy)3(ClO4)(SCN)·3H2O (1·3H2O)] has been prepared and characterized. Structural studies and Hirshfeld surface analysis for complex 1·3H2O at three different temperatures (300, 240 and 130 K) are described. The UV-vis absorption spectrum of a water-free sample (1) in methanol solution and magnetic susceptibility measurements for solid-state samples 1·3H2O and 1 revealed that the removal of lattice water molecules from complex 1·3H2O changed the magnetic properties from the low-spin state (1·3H2O) to the complete spin-crossover (1) between 350-220 K with a thermal hysteresis of 7 K, and was accompanied by a colour change from brown to red.

Crystal structure, Hirshfeld surfaces and DNA cleavage investigation of two copper(II) complexes containing polypyridine and salicylide ligands.

Two copper complexes 1 [Cu2(phen)2(salicylaldehyde)2(ClO4)2] and 2 [Cu2 (2,2'-dipyridyl)2(salicylaldehyde)2(ClO4)2] have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes were display binuclear structure with Cu(II) ions in distorted octahedral environment but antipodal orientation of the binuclear units between them. Molecular Hirshfeld surfaces revealed that the crystal structures of 1 and 2 were supported mainly by H-H, C-H⋯π, π⋯π (C-C), and C-H⋯O intermolecular interactions.

Two new metastable forms of 6-chloroquinolin-2(1H)-one: crystal structure, Hirshfeld surfaces and spectroscopic studies.

Two new metastable crystalline forms of 6-chloroquinolin-2(1H)-one (forms II and III), which were induced by two kinds of 3D inorganic anions (ClO4- and BF4-), have been prepared and characterized in this work. We performed single-crystal diffraction, X-ray powder diffraction (XRPD), Hirshfeld surfaces, solid-state vibrational spectroscopy (IR) and thermal analysis (DSC, TGA) to these two new forms as well as the original one (form I). Form I featured with 1D chain, while form II and III featured with dimeric unit with stronger π⋯π and hydrogen bonds interactions.

Co-crystallization of pyridine-2-carboxamide with a series of alkyl dicarboxylic acids with different carbon chain: crystal structure, spectroscopy and Hirshfeld analysis.

Three new co-crystals: pyridine-2-carboxamide-succinic acid (1), pyridine-2-carboxamide-glutaric acid (2) and pyridine-2-carboxamide-adipic acid (3) have been synthesized and characterized by single-crystal X-ray diffraction, TGA/DSC measurements, solid-state vibrational spectroscopy (IR and Raman) in this work. The investigation revealed that the carbon chain length of these alkyl acids changed the connecting motif of co-crystals 1-3 from trimer to 1D chain, and the formation of hydrogen bond interaction of pyridine-2-carboxamide with these alkyl acids lead to red shift of stretching vibration of NH2 and OH groups in IR and Raman spectra. We also studied Hirshfeld surface and UV properties of co-crystals 1-3, and we found that the carbon chain length lead to decrease of close intermolecular interactions, and the formation of hydrogen bond interaction lead to red shift of UV spectra.

Antibody-drug conjugates as targeted cancer therapeutics.

Traditional chemotherapy has become one of the essential treatments of cancer. However, cytotoxic agents are not tumor specific, which would cause serious side effects. Antibody-drug conjugates (ADCs), also called immunoconjugates, belong to the "targeted chemotherapeutics" category of anti-cancer drugs.

Aqua-(1,10-phenanthroline-κN,N')bis-(trimethyl-acetato)-κO,O';κO-cobalt(II).

In the title compound, [Co(C(5)H(9)O(2))(2)(C(12)H(8)N(2))(H(2)O)], the Co(II) atom is coordinated in a distorted octahedral environment by three carboxyl O atoms of two trimethyl-acetate ligands, one aqua O atom and two N atoms from 1,10-phen-anthroline. The crystal structure is stabilized by O-H⋯O hydrogen bonds and π-π stacking inter-actions [inter-planar distance between inter-digitating 1,10-phenanthroline ligands = 3.378 (2) Å].

Di-μ-chlorido-bis-[aqua-(2,2'-bipyridine-κN,N')chloridocobalt(II)].

The title complex, [Co(2)Cl(4)(C(10)H(8)N(2))(2)(H(2)O)(2)], is composed of two Co(II) atoms, each hexa-coordinated by three Cl atoms, one 2,2'-bipyridine (bpy) ligand and one water mol-ecule in a distorted octa-hedral geometry. Neighboring Co(II) atoms are linked together by two Cl bridges, forming a dinuclear Co(II) complex with inversion symmetry. There are inter-molecular O-H⋯Cl hydrogen bonds and inter-molecular π-π stacking inter-actions between adjacent bpy ligands [centroid-centroid distance = 3.

Bis{μ-2-[1-(2-Pyridylmethyl-imino)eth-yl]phenolato}bis-[azido-copper(II)].

The title compound, [Cu(2)(C(14)H(13)N(2)O)(2)(N(3))(2)], was synthesized by the reaction of Cu(NO(3))(2)·3H(2)O with the Schiff base 2-[1-(2-pyridylmethyl-imino)eth-yl]phenol (HL) in methanol-water solution, adding NaN(3) as the bridging ligand. The asymmetric unit contains one half-mol-ecule, the other half being generated by the inversion center. Each Cu(II) atom shows a slightly distorted trigonal-pyramidal geometry formed by two N atoms and one O atom from one Schiff base ligand, by another O atom of a second Schiff base ligand and by an azide N atom.