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Encapsulating enzymes within metal–organic frameworks has enhanced their structural stability and interface tunability for catalysis. However, the small apertures of the frameworks restrict their effectiveness to small organic molecules. Herein, we present a green strategy directed by visible linker micelles for the aqueous synthesis of MAF-6 that enables enzymes for the catalytic asymmetric synthesis of chiral molecules. Due to the large pore aperture (7.6 Å), double the aperture size of benchmark ZIF-8 (3.4 Å), MAF-6 allows encapsulated enzyme BCL to access larger substrates and do so faster. Through the optimization of surfactants’ effect during synthesis, BCL@MAF-6-SDS (SDS = sodium dodecyl sulfate) displayed a catalytic efficiency (Kcat/Km) that was 420 times greater than that of BCL@ZIF-8. This biocomposite efficiently catalyzed the synthesis of drug precursor molecules with 94–99% enantioselectivity and nearly quantitative yields. These findings represent a deeper understanding of de novo synthetic encapsulation of enzyme in MOFs, thereby unfolding the great potential of enzyme@MAF catalysts for asymmetric synthesis of organics and pharmaceuticals.

Reticular chemistry provides opportunities to design solid-state electrolytes (SSEs) with modular tunability. However, SSEs based on modularly designed crystalline metal–organic frameworks (MOFs) often require liquid electrolytes for interfacial contact. Monolithic glassy MOFs can have liquid processability and uniform lithium conduction, which is promising for the reticular design of SSE without liquid electrolytes. Here, we develop a generalizable strategy for the modular design of noncrystalline SSEs based on a bottom-up synthesis of glassy MOFs. We demonstrate such a strategy by linking polyethylene glycol (PEG) struts and nanosized titanium-oxo clusters into network structures termed titanium alkoxide networks (TANs). The modular design allows the incorporation of PEG linkers with different molecular weights, which give optimal chain flexibility for high ionic conductivity, and the reticular coordinative network provides a controlled degree of cross-linking that gives adequate mechanical strength. This research shows the power of reticular design in noncrystalline molecular framework materials for SSEs.

An anhydride-promoted traceless hydrazine–I/Br exchange strategy is reported, where hydrazine hydrate and cyclic/linear iodonium, including rarely explored cyclic bromonium, are converted to benzo[c]cinnolines/azobenzenes in one pot. The reaction proceeds through diacylation (first and second C─N formation), N,N′-diarylation (third and fourth C─N formation), and deacylation/oxidation (2 C─N cleavages and 1 N═N formation). The reaction mechanism is investigated by isolating multiple intermediates and kinetic studies. Furthermore, time-dependent electrospray ionization mass spectrometry (TD ESI-MS) was applied to track the process by detecting most intermediates. The complex [CuIII(iodobiphenyl)(bipy)I]+(Int-C) was detected for the first time, giving evidence for oxidative addition of cyclic iodonium to Cu catalyst. Another complex [CuI(PHA)(bipy)] (Int-B) via ligand-exchange between the hydrazide and Cu catalyst was also detected, indicating a two-path initial activation process.

The low-cost CuBr-promoted domino Biginelli reaction among readily available ketones, salicylaldehyde derivatives and 3-amino-1,2,4-triazole was studied under solvothermal conditions, giving the novel bridged polyheterocycles bearing two or three stereocenters depending on the starting ketones. This multicomponent reaction proceeded with high diastereoselectivity (dr > 20:1) based on a combined 1H NMR, crystallographic and supercritical fluid chromatographic (SFC) analysis of the product. Time-dependent high-resolution mass spectrometry (HRMS) was performed to track the reaction process, and several key intermediates were identified, leading to the drawing of a plausible reaction mechanism. Density functional theory (DFT) calculation was supplemented, and two reaction pathways were differentiated. Moreover, in vitroantitumor activity was evaluated using HeLa and HepG2 cell lines, and two of these polyheterocycles demonstrated promising activities against HepG2 cells with EC50 down to 10 µmol/L. Additionally, ESI-MS/MS studies on all the polyheterocycles suggest a common fragmentation pathway (loss of one molecule of amino-triazole) they shared, providing the first-hand fragmentation rules for future rapid structural identification of them. The multicomponent domino reaction presented here may offer prospects for future design of more efficient strategies to access medicinally important bridged polyheterocycles.

Metal–organic framework (MOF) glasses are a fascinating new class of materials, yet their prosperity has been impeded by the scarcity of known examples and limited vitrification methods. In the work described in this report, we applied synergistic stimuli of vapor hydration and thermal dehydration to introduce structural disorders in interpenetrated dia-net MOF, which facilitate the formation of stable super-cooled liquid and quenched glass. The material after stimulus has a glass transition temperature (Tg) of 560 K, far below the decomposition temperature of 695 K. When heated, the perturbed MOF enters a super-cooled liquid phase that is stable for a long period of time (>104s), across a broad temperature range (26 K), and has a large fragility index of 83. Quenching the super-cooled liquid gives rise to porous MOF glass with maintained framework connectivity, confirmed by EXAFS and PDF analysis. This method provides a fundamentally new route to obtain glassy materials from MOFs that cannot be melted without causing decomposition.

Conventional nanomaterials in electrochemical nonenzymatic sensing face huge challenge due to their complex size-, surface-, and composition-dependent catalytic properties and low active site density. In this work, we designed a single-atom Pt supported on Ni(OH)2nanoplates/nitrogen-doped graphene (Pt1/Ni(OH)2/NG) as the first example for constructing a single-atom catalyst based electrochemical nonenzymatic glucose sensor. The resulting Pt1/Ni(OH)2/NG exhibited a low anode peak potential of 0.48 V and high sensitivity of 220.75 μA mM–1cm–2toward glucose, which are 45 mV lower and 12 times higher than those of Ni(OH)2, respectively. The catalyst also showed excellent selectivity for several important interferences, short response time of 4.6 s, and high stability over 4 weeks. Experimental and density functional theory (DFT) calculated results reveal that the improved performance of Pt1/Ni(OH)2/NG could be attributed to stronger binding strength of glucose on single-atom Pt active centers and their surrounding Ni atoms, combined with fast electron transfer ability by the adding of the highly conductive NG. This research sheds light on the applications of SACs in the field of electrochemical nonenzymatic sensing.

Modification of commercially available biaryl monophosphine ligands via ruthenium(II)-catalyzed P(III)-directed-catalyzed ortho C–H secondary alkylation is described. The use of highly ring-strained norbornene as a secondary alkylating reagent is the key to this transformation. A series of highly bulky ligands with a norbornyl group were obtained in excellent yields. The modified ligands with secondary alkyl group outperformed common substituted phosphines in the Suzuki–Miyaura cross-coupling reaction at a ppm mole level of Pd catalyst.

Zona pellucida (ZP), which is composed of at most four extracellular glycoproteins (ZP1, ZP2, ZP3, and ZP4) in mammals, shelters the oocytes and is vital in female fertility. Several studies have identified the indispensable roles of ZP1–3 in maintaining normal female fertility. However, the understanding of ZP4 is still very poor because only one study on ZP4-associated infertility performed in rabbits has been reported up to date. Here we investigated the function of mammalian Zp4by creating a knockout (KO) rat strain (Zp4−/−rat) using CRISPR–Cas9-mediated DNA-editing method. The influence of Zp4KO on ZP morphology and some pivotal processes of reproduction, including oogenesis, ovulation, fertilization, and pup production, were studied using periodic acid–Schiff’s staining, superovulation, in vitro fertilization, and natural mating. The ZP morphology in Zp4−/−rats was normal, and none of these pivotal processes was affected. This study renewed the knowledge of mammalian Zp4by suggesting that Zp4was completely dispensable for female fertility.Zp4is completely dispensable for female fertility in rats.

An efficient and straightforward synthesis of aryl‐substituted biarylphosphines via unprotected amino acid‐accelerated ruthenium‐catalyzed P‐directed ortho‐C−H arylation reaction is described. This protocol utilized commercial and inexpensive (hetero)aryl chlorides as efficient arylating reagents under solvent‐free reaction conditions. Notably, diverse aryl bromides were also effective for this transformation. With the protocol, a wide variety of mono‐arylated biarylphosphines were obtained in moderate to high yields and excellent selectivity. Moreover, the aryl‐substituted phosphine exhibited higher catalytic performance than its precursor and other substituted phosphines in palladium‐catalyzed Suzuki coupling. The first solvent‐free ruthenium‐catalyzed P‐directed C−H arylationof tertiary phosphines and inactive aryl chlorides is described. This method utilizes commercial and inexpensive PhCl as arylating reagent and does not require additional organic solvent, it represents very economical and green method for the synthesis of arylated biarylphosphines.

We report the synthesis and structural characterization of a 2D metal–organic framework with AB-packing layers, [Co2(pybz)2(CH3COO)2]·DMF (Co2, pybz= 4-(4-pyridyl)benzoate), containing a stable (4,4)-grid network fabricated by paddle-wheel nodes, ditopic pybz, and acetate ligands. After removal of the guest, the layer structure is retained but reorganized into an ABCD packing mode in the activated phase (Co2a). Consequently, the intralayer square windows (7.2 × 5.0 Å2) close, while the interlayer separation is decreased slightly from 3.69 to 3.45 Å, leaving a narrow gap. Importantly, the dangling methyl group of the acetate with H-bonds to the adjacent layers and also the well-distributed π–π interactions between the aromatic rings of neighboring layers facilitate the structural stability. These weak supramolecular interactions further allow for favorable dynamic exfoliation of the layers, which promotes efficient adsorption of C2H2(41.6 cm3g–1) over CO2with an adsorption ratio of 6.3 (0.5 bar, 298 K). The effective separation performance of equimolar C2H2/CO2was verified by cycling breakthrough experiments and was even tolerable to moisture (R.H = 52%). DFT calculations, in situPXRD, and PDF characterization reveal that the favorable retention of C2H2rather than that of CO2is due to its H-bond formation with the paddle-wheel oxygen atoms that triggers the increase in interlayer separation during C2H2adsorption.

A new pillared-layer coordination polymer, [Co3(pybz)2(pico)2]n(1; pybz = 4-(pyridin-4-yl)benzoate, pico = 3-hydroxypicolinate), contains rare 2D [Co3(pico)2]n2n+layers formed by linear cobalt(II) trimers through the unusual μ4-κN,O:κO′-μ2:κO′′-μ2bridging mode of pico ligands, which are further cross-pillared by exotridentate bridging pybz ligands to form a three-dimensional structure with an unusual uninodal 8-connected body-centered-cubic topology. The bulk magnetic behavior of 1exhibits ferrimagnetic long-range ordering below 2.6 K, which mainly arises from the cooperative magnetic effect of the intra- and intertrimer arrangements in the 2D magnetic system based on the nature of the exchange modes of μ2-hydroxyl, μ2-carboxylate oxygen, and 1,1,3-μ3-carboxylate bridges.

Herein, we disclose a ruthenium-catalyzed meta-selective C–H activation of phosphines by using intrinsic P(III)as a directing group. 2,2,6,6-Tetramethylheptane-3,5-dione acts as the ligand and exhibits an excellent performance in boosting the meta-alkylation. The protocol allows an efficient and straightforward synthesis of meta-alkylated tertiary phosphines. Several meta-alkylated phosphines were evaluated for Pd-catalyzed Suzuki coupling and found to be superior to commercially available ortho-substituted phosphines. The practicability of this methodology is further demonstrated by the synthesis of difunctionalized phosphines.

Biphenylcarboxylic acid with two competing C(sp2)-H sites was designed for site selective C(sp2)-H functionalization by developing carboxylic acids assisted remote and selective olefination via 7-membered palladacycle. Mechanism investigation and DFT calculations reveal a kinetics-determined process, which could be utilized to explore a variety of remote site selectivity. The practicability of this method was highlighted by the precise construction of phenathrene under sequential site selectivity.

We have recently reported a strongly luminescent osmium(VI) nitrido complex [OsVI(N)(NO2-L)(CN)3]−[HNO2-L = 2-(2-hydroxy-5-nitrophenyl)benzoxazole]. The excited state of this complex readily activates the strong C–H bonds of alkanes and arenes (Commun. Chem.2019, 2, 40). In this work, we attempted to tune the excited-state properties of this complex by introducing various substituents on the bidentate L ligand. The series of nitrido complexes were characterized by IR, UV/vis, 1H NMR, and electrospray ionization mass spectrometry. The molecular structures of five of the nitrido compounds have been determined by X-ray crystallography. The photophysical and electrochemical properties of these complexes have been investigated. The luminescence of these nitrido complexes in the solid state, in a CH2Cl2solution, and in a CH2Cl2solid matrix at 77 K glassy medium clearly shows that these emissions are due to 3LML′CT [L ligand to Os≡N] phosphorescence. The presence of strongly electron-withdrawing substituents in these complexes enhances the LML′CT emission. Our result demonstrates that the excited-state properties of this novel class of luminescent osmium(VI) nitrido complexes can be fine-tuned by introducing various substituents on the bidentate L ligand.

Ru(II)-catalyzed direct alkylation of tertiary phosphines via hydroarylation of activated olefins promoted by mono-N-protected amino acid (MPAA) was achieved. This protocol provides a straightforward access to a large library of Buchwald-type bulky alkylated monophosphines from commercially available biaryl phosphine. Moreover, two ruthenacycle intermediates of tertiary phosphines via C–H bond cleavage were isolated to illustrate the mechanism of P(III)-directed C–H activation.

The flexible ligand 2-[(2-hydroxy-3-methoxy-benzylidene)-amino]-ethanesulfonate (L2–) uses five of its six donor atoms in coordination through meridian, chelate, and terminal modes with MIIX2to form chair-shaped tetranuclear clusters Zn4L2(OCH3)2(CH3OH)2X2[X = Cl (Zn4-Cl) and Br (Zn4-Br)] and solid solutions Zn4-xNix-Bror Zn4-xNix-Cl(x= 0–2). The structures contain butterfly tetramers that consist of segregated six-coordinated metals (Zn or Ni) at the center but only five-coordinated zinc at the ends. Syntheses using different proportions of metal salts (Zn and Ni) gave solid solutions with a substitution rate of two-third times the starting quantity of NiBr2up to a saturation content of 50%, Zn2Ni2L2(OCH3)2(CH3OH)2Br2(Zn2Ni2-Br). The elemental and powder X-ray diffraction follow Vegard’s law. The ferromagnetic coupling between nearest neighbors of 3.7 cm–1and the structural refinement for (Zn2Ni2-Br) confirms the Ni atoms are at the center. This segregation is assumed to be related to the size and coordination number and the softness difference of the metals. The electrospray ionization mass spectra display a series of positive ions ABnor CBn(A = {ZnBr} and B = {ZnL}, C = {Zn(OCH3)}, n= 0–4) and negative ions AxBy(x= 0–1, y= 1–2), but none corresponds to the parent cluster. The luminescence is enhanced from that of Li2Lupon coordination to the metals. Major dependence of the emission and the excitation profile intensity on the concentration in the range 5–500 μM has been observed for Li2Land its metal complexes.

The active lone pair electron effect and highly flexible coordination geometry of Pb2+prevented the rational construction of metal–organic frameworks (MOFs) but promoted excellent fluorescence tuning. The regulation on organic and alkali templates facilitated the assemblies of three new Pb-MOFs: [Pb2(pia)2(DMA)]·DMA (1), [Pb2(pia)2(DMF)]·1.5DMF (2), and [Pb2(pia)2(DMF)]·NEt3(3). They were rigid rod-spacer and double-walls frameworks, which possess defective dicubane [Pb4O6] based metal-carboxyl chains constructed from both semidirected and holodirected Pb2+ions. These MOFs exhibited thermal stability up to 370 °C and unprecedented chemical stability in H2O and acidic (pH 2) and alkaline (pH 12) aqueous solutions, found for the first time in Pb-MOFs. A single-phase and rare-earth-free white-emitting phosphor, 1, was screen out, which showed a near-sunlight and human-vision-friendly broadband spectrum covering the full visible region, possessing the close-to-pure-white chromaticity coordinates of (0.332, 0.347), a near-daylight color temperature of 5696 K, and a high color rendering index of 95. The replacement of DMF as apical ligand and guest in 2resulted in an intrinsic single and narrow emission at 562 nm with yellow color. The convenient yellow-and-blue color-tuning until white for 2was realized by either solution or solid blending with blue-emissive H2pia, benefited from their highly matched excitation spectra. Using large NEt3as template guest induced great framework distortion for 3and led to white emission with chromaticity coordinates of (0.302, 0.294), stemming from nonequivalent dual emission at 450 and 545 nm. In-depth structure analysis revealed intra-/interchain Pb···Pb interactions in the lead(II)-carboxyl chains greatly affected the photochemical output.

We report here the rare observation of a one-dimensional coordination polymer, {[Zn5(bit)4Cl6]·2(CH3CN)}n(1, Hbit= 1-methyl-2-(1H-1,2,3-triazol-4-yl)-1H-benzo[d]imidazole), having one mode of binding for the polytopic ligand and three different polyhedra, tetrahedron, square-base pyramid, and octahedron, for the metal node. The formation process of 1involves the in situ decarboxylation of Hbitc(5-(1-methyl-1H-benzo[d]imidazol-2-yl)-1H-1,2,3-triazole-4-carboxylic acid) to Hbit. Apart from one bridging μ2-Cl, all the other chlorine atoms act as a terminal ligand to complete the polyhedra. While 1is almost insoluble in most organic solvent, electrospray ionization mass spectrometry of its ultrasound-treated DMSO suspension found the two main species [Zn(bit)]+at 0 eV and [Zn2(bit)3]+at elevated in-source energies. Density functional theory calculation suggests a potential formation process involving the sequence: [Zn(bit)]+→ [Zn2(bit)3]++ [Zn2(bit)2Cl]+→ [Zn3(bit)4Cl2]+. The luminescence intensity enhancement and red shift of 1were compared with the ligand Hbit, which may be because the ligand coordinated to the metal center and increased the rigidity compared to the ligand and the interaction between the metal center and DMSO molecules. The lifetimes, 1(1.13 ns) < Hbit(1.64 ns), and the moderate quantum yields (5.88% Hbitand 4.48% 1), indicate fluorescence.

The photocatalysis process with high selectivity is a very important research forefront for the semiconductor photocatalytic decomposition of organic pollutants. However, the rational design of efficient photocatalysts with high selectivity is still a challenge. Here, we present an open-framework chalcogenide (Heta)8[In14Sn2Zn4Se33] (Heta = ethanolamine-H+) (compound 1) constructed from T4 supertetrahedral clusters [In14Sn2Zn4Se35]12–with visible-light-driven selectively photocatalytic degradation activity. Single-crystal XRD analysis shows that compound 1crystallizes in I41/acd(no. 142) space group, with a= b= 24.3462(2) Å, c= 45.0062(9) Å, V= 26676.9(7) Å3, and Z= 8. Under visible-light irradiation, the selectively photocatalytic activities of 1were evaluated by photodegradation of two kinds of cationic dye molecules, i.e., methylene blue (MB) and rhodamine B (RhB), against two anionic dyes, methyl orange (MO) and Kermes red (KR), with different sizes. We show that the adsorption capability and charge-matching between organic dyes and the supertetrahedral cluster together with a suitable band structure make it an excellent and selective photocatalyst. This is the first example of an open-framework chalcogenide based on supertetrahedral T4 for the selectively semiconductor photocatalytic decomposition of organic dyes.

On the basis of experimentally reported series of novel imide-functionalized ladder-type heteroarenes (fused bithiophene imide oligomers BTIn, n= 1–5), expanded BTInup to 24 rings with 8 imide groups (n= 6–8) as well as some heteroarenes derived from BTI are designed. Charge transfer and delocalization properties of BTIn(n= 1–8) are studied theoretically by non-empirically optimal tuned range-separated density functional theory (DFT) (LC-BLYP*), LC-BLYP* combining polarizable continuum model (PCM) [LC-BLYP* (PCM, solid)], and traditional B3LYP functional. LC-BLYP* provides a good balance between localized and delocalized effects and reduces the electron self-interaction error of the traditional DFT method, whereas combining PCM model with tuned range-separated DFT could accurately describe the properties of single crystals. The relationships between geometries, electronic properties, and semiconductor performances are explored. Because of the good planarity induced by the fused thienothiophene rings with the imide, BTI oligomers show better performance than their derivatives with a similar number of thiophene rings. It was found that the BTI oligomers have very good planarity, large conjugation extent, fully delocalized polaron (over 16T units), and good semiconductor properties for both p- and n-types. BTI8 is good potential ambipolar semiconductor with a very small charge-injection barrier and large hole and electron mobilities of 16.60 and 3.02 cm2V–1s–1, respectively. Different roles of thiophene and imide rings in making BTI series a good semiconductor are also revealed by comparing BTI2 and BTI3 with thiophene-containing derivatives.

Zona pellucida (ZP), which enwraps the oocyte during folliculogenesis, initially forms in the primary follicle and plays an important role in female fertility. Here, we investigated a mouse strain ("mutant mice" for short) carrying two types of ZP defects in folliculogenesis, i.e., ZP thinned (but intact) and ZP cracked, caused by targeted mutation in the Zp1 gene. Using this mutant mouse strain and wild-type mouse as control, we studied the effects of the ZP defects on the development of oocytes and granulosa cells during folliculogenesis. For each ZP defect, we examined the morphology of transzonal projections and apoptosis of granulosa cells in the corresponding growing follicles, as well as the morphology of corresponding ovulated eggs and their abilities to develop into viable individuals. Our results suggested that ZP integrity rather than thickness or porosity is crucial for preventing the ectopia of granulosa cells, maintaining adequate routine bilateral signaling between oocyte and surrounding granulosa cells, and thus for ensuring the survival of granulosa cells and the establishment of the full developmental competence of oocytes. This is the first study to elucidate the effects of different degrees of ZP defects caused by the same gene mutation, on the apoptosis of granulosa cells and developmental competence of oocytes, and to explore the potential mechanisms underlying these effects.

A ligand-promoted palladium(II)-catalyzed synthesis of arylalkynes and phthalides from benzoic acids and bromoalkynes via carboxylate-assisted ortho-C–H activation is reported. A series of phthalides with various functional groups are prepared via ortho-alkynylation and alkynylation–annulation. Moreover, the key ortho-alkynylated products are also obtained by controlling the reaction conditions. In addition, heteroaryl acids could react smoothly to form the corresponding alkynylation and cyclization products.

A tandem reaction of pyridin-2-ylmethanamine (L1′) with 8-hydroxyquinoline-2-carbaldehyde (HL1) assisted by FeCl3was observed to give the new nitrogen heterocycle HL3 (HL3=2-(imidazo[1,5-a]pyridin-3-yl)quinolin-8-ol) as its Fe(III) complex, [Fe(L3)Cl2] (Fel). Electrospray ionization mass spectrometry (ESI-MS) reveals its formation involves three steps: (1) coordination of both HL1and Ll′to Fe, (2) aldehyde-amine coupling, and (3) ring closure. The results of electronic absorption spectroscopy, cyclic voltammetry, and density functional theory (DFT) calculations show the proximity of the optical transition energy to that of the excitation of 3O2to 1O2, which prompted us to explore its application as a photosensitizer for photodynamic therapy (PDT). Photo-toxicity studies show that Felexhibits the highest anti-proliferation efficiency in human breast cancer MDA-MB-231 cells under light irradiation. Moreover, studies with orthotopic models of breast cancer further expounded the anti-tumor activity of Fe1with no significant toxicity to other organs and low retention in the body.

A way to understand kinetics and explore mechanism of reactions is to identify the intermediates and their relative energetics. In this respect, low-energy electrospray ionization mass spectrometry is providing information on possible intermediates that can be tandemly verified using crystallography of the products. This has been extended to the study of the formation of functional clusters of transition metals under varying conditions. The reaction of NiL2(L = 2-ethoxy-6-(N-methyliminomethyl)phenolate) with MII(H2O)6(ClO4)2in the presence of Et3N base leads to [NixM7-x(μ3-OH)6L6]2+according to NiL2→ [M2L3]+→ [M4(OH)2L4]2+→ [M7(OH)6L6]2+. In contrast, its reaction with MII(H2O)6(NO3)2in the absence of base leads to two crystallographic structural types [MII3L4(NO3)2(H2O)2]·CH3CN for M = Ni (I-Ni3) or Co (I-CoxNi3-x, x= 0–3) and [MIINiII2L4(NO3)2] for M = Zn (II-ZnNi2) or Co (II-CoNi2). Interestingly, ESI–MS suggests three slightly different formation processes: for I-Ni3, {NiL2→ [Ni2L(NO3)2]+→ [Ni2L2(NO3)]+→ [Ni2L3]+→ [Ni3L4(NO3)]+}; for II-ZnNi2, {NiL2→ [ZnNiL2(NO3)]+→ [ZnNi2L4(NO3)]+}; for II-CoNi2and I-CoxNi3-x, {NiL2→ [M2L2(NO3)]+→ [M2L3]+→ [M3L4(NO3)]+}. Magnetization measurements reveal the site of each metal ionin II-ZnNi2and the number of single electrons within different clusters. Without the base, there is an interplay between the weak coordinating nitrate and water stabilizing the two structural types via the different formation processes. The results indicate that not only the strength of the ligand matters but also the ionic sizes and possibly softness of the metals may be implicated.

The solvothermal reaction of cobalt(II) sulfate with S,S-1,2-bis(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol, (H2L), neutralized with triethylamine (Et3N) in a mixture of methanol and water (2:1), resulted in triangular red crystals of [CoII7(L)3(SO4)3(OH)2(H2O)9]·4H2O·3CH3OH (Co7). It is formed of chiral and polar clusters crystallizing in the R3space group. Co7consists of apex-shared asymmetric dicubane units where all of the metals adopt an octahedral coordination and the three ligands wrap diagonally around the unit. One end of the cluster is bonded by six water molecules and the other end by three monodentate sulfates. The head-to-tail packing through extended H-bonds leads to polar chains. The ligand has lost two protons, adopts a cis-conformation, and is coordinated to five metals around the waist of the dicubane. Electrospray ionization mass spectrometry (ESI-MS) of solutions of the reaction as a function of time reveals the possible step-by-step assembly process of the cluster: the initial product [CoII(HL)(SO4)]2–combines with CoSO4, forming [CoII2(HL)(SO4)2]2–, and then, upon addition of Et3N, dimerizes through a [OH]−bridge to [CoII4(HL)2(OH)(CH3OH)2(SO4)3]−followed by capture of one Co2+and one CoSO4to form [CoII6(L)2(OH)(CH3O)(SO4)4]2–before eventually binding to CoL to form [CoII7(L)3(OH)2(SO4)4]2–. These results allow us to propose a possible process for the formation of Co7, which is a good example for chiral multidentate chelating ligand-controlled assembly of clusters. Magnetization measurements as a function of the temperature, field, and ac-frequency reveal ferromagnetic coupled moments and single-molecule magnetism (SMM).

An original Pd(II)-catalyzed domino two C–H activations strategy has been designed to synthesize pyrano[4,3-b]indol-1(5H)-one motifs from inexpensive and commercially available olefins and heteroaromatic acids by carboxylate-directed sequential ortho-C–H alkenylation and remote C–H lactonization. Importantly, this protocol overcomes the selectivity for carboxylic acids with acrylates of the conventional Michael addition-type process. Preliminary studies of mechanism indicate that both aryl and olefinlic C–H activations may participate in this catalytic system.

A general protocol for site-preferential mono-C–H arylation of tertiary phosphine ligands catalyzed by a ruthenium(II) complex was devised. This protocol gives access to a series of modified Buchwald–biaryl monophosphines on a gram scale in moderate to excellent yields. A catalytic cycle is proposed derived from knowledge of the intermediates observed by ESI-MS. Importantly, these monoarylated products could be further transformed into dibenzophosphole derivatives.

A weakly carboxylate-directed palladium(II)-catalyzed ortho-C–H alkynylation of diverse phenylacetic acids promoted by monoprotected amino acid ligand enabled is reported. The reaction has a broad substrate scope including α-secondary, tertiary, and quaternary phenylacetic acids. Notably, the direct ortho-C–H alkynylation of α-quaternary phenylacetic acids and chiral α-tertiary phenylacetic acids was achieved for the first time. Moreover, this method could be used for simple and efficient gram-scale synthesis and diversification of an anti-inflammatory drug.

Crystal transformation between two polymorphs (green, 1-G, and red, 1-R) of the square-planar nickel complex NiL2(L = 2-ethoxy-6-(N-methyliminomethyl)phenolate) and their tuning effect to semiconductor properties were studied both experimentally and theoretically. When 1-Gis heated to 413 K, it converts to 1-R, whereas soaking 1-Rin several kinds of solvents causes it to revert to 1-G. Crystallographic and PXRD studies reveal the dramatic changes in crystal dimensions due to the changes of packing models. Heating device made from 1-G(D-1-G(298)) at 413 K significantly increases the electrical conductivity from 6.55 × 10–4S cm–1for D-1-G(298)to 1.11 × 10–3S cm–1for D-1-G(413), showing significant crystal form dependence. Heat-treating D-1-Gand D-1-Rdevices at different temperatures clearly reveals the reason for the conductivity tuning. Thus, the conductivity of NiL2-based devices could be well tuned through crystal transformation by heating or by soaking in solvent. Theoretical calculations clearly revealed the reason for such conductivity changes and also predicted that both polymorphs are good p-type semiconductors with hole mobilities of 1.63 × 10–2(1-G) and 2.11 × 10–1cm2V–1s–1(1-R).

A clear dependence on the ligand has been observed for the magnetic properties of a closely related series of Co(II) cubane structures, viz. [Co4(mbmor bm)4(ROH)4Br4] (1-MeOH, 1-EtOH, 2-MeOH, and 2-EtOH, where 1= [Co4(mbm)4Br4], 2= [Co4(bm)4Br4], bm= (1H-benzo[d]imidazol-2-yl)methanolate. and mbm= 1-Me-bm.) The [Co4(OR)4] cubane core consists of an octahedral CoIIcenter chelated by the alkoxide oxygen and imidazole nitrogen atoms from monoanionic bmor mbmand coordinated by methanol/alcohol and bromine. Interestingly, electrospray ionization mass spectrometry (ESI-MS) indicates that 1-MeOHand 2-MeOHare unstable in methanol and transformed to the butterfly [Co4L6]2+but that 1-EtOHand 2-EtOHare stable in ethanol. Their magnetic susceptibilities suggest ferromagnetic coupling between the nearest cobalt centers to give a theoretical S= 4 × 3/2 ground state with considerable magneto-crystalline behavior. The packing and intermolecular interactions appear to influence the geometry of the cubes and thus the anisotropy of cobalt, which leads to different blocking temperatures (TB). Consequently, the compounds with mbm, 1-MeOHand 1-EtOH, exhibit TB> 2 K as shown by the relaxation of magnetization in zero applied dc field where the barriers Ueff/kBare respectively 27 and 21 K and relaxation times are τ0= 1.3 × 10–9and 9.7 × 10–9s. However, the compounds with bm, 2-MeOHand 2-EtOH, remain paramagnetic above 2 K and do not show nonlinear response of the ac susceptibilities. These findings reaffirm the subtle dependence of single-molecule magnetism on coordination geometry and intermolecular interaction.

Information of solid-state and solution structures is crucial in the characterization of molecular clusters and in advancing the understanding of their diverse properties. [Et3NH]2[Zn14(hmq)8(OH)4X10] [X = Cl and Br; H2hmq = 2-(hydroxymethyl)quinolin-8-ol] consist of a peanut-shaped Zn10O12core, in which the Zn atoms occupy the faces and corners of an octahedron and are protected by bonded halogen atoms and bulky organic ligands. Observation of the [Zn14(hmq)8(OH)4X10]2–fragment in electrospray ionization mass spectrometry (ESI-MS) suggests that the cluster is stable in solution. ESI-MS analyses from dissolved crystals and mother liquors reveal that Zn(hmq) self-assembles to Zn5(hmq)4Cl, then dimerizes through four [OH]−bridges to Zn10(hmq)8(OH)4Cl2, and progressively captures four ZnCl2one-by-one to [Zn14(hmq)8(OH)4Cl10]2–. Because the supramolecular interactions between the anion and cation in the solid suppress the rotation/vibration of the halogen atoms and confine the movable organic ligands on the rigid Zn–O core, both crystal phases exhibit intense photoluminescence, much stronger than that in solution. This is the first coordination cluster to exhibit “aggregation-induced enhanced emission”. In addition, preliminary tests indicate that these coordination clusters are promising for organic-light-emitting-diode applications.

The wide diversity in the structure, pore size, high surface area, adsorption affinity, and selective penetration renders metal–organic frameworks (MOF) attractive as highly efficient adsorbents for chromatographic separation. We report the results of chromatographic separation of four families of biochemically important compounds, viz., linear alkyl hydrocarbons (aldehyde, acid, and ketone), aromatic hydrocarbons (aldehyde, acid, and alcohol), cyclic hydrocarbons (ketone, alcohol, and ester) and aromatic hydrocarbons (ether, ester, and ester with alcohol) with two phenyls, employing the porous MOF [Zn2(bdc)(l-lac)] (l-lac = l-lactate; bdc = 1,4-benzenedicarboxylate) as the retention material of the capillary column. Its good performance relies on the robustness and chemical and thermal stability of the framework, the permanent porosity, and, most importantly, the host–guest interaction sites. The results from this work will also help in understanding the intermolecular forces based on host–guest interaction between the MOF and analytes.

Atom economic in situ domino N-alkylation reactions of triethylamine/ammonia with 2-(hydroxymethyl)quinolin-8-ol (HL-OH) assisted by FeSO4·7H2O were realized under mild solvothermal conditions at 120 °C in acetonitrile. The resulting tripodal 2,2′,2″-[nitrilotris(methylene)]tris(quinolin-8-ol) (H3L3-N) forms a linear trimer [Fe3(L3-N)2] (1). Electrospray ionization mass spectrometry of the reaction solution provides evidence for the intermediates of three steps, while crystallography and X-ray photoelectron spectroscopy characterize the trimer. Shortening the time of the reaction allowed for the organic intermediates to be isolated, which led to a proposed mechanism. The method provides a facile way to produce symmetric tertiary amine from widely used NEt3and NH3. The results represent an example of the in situ Fe2+-catalyzed domino reaction in which Fe2+is coordinated by the generated ligands and is involved in each step until the final cluster 1.