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Supertetrahedral chalcogenido (semi)metalate cluster-based frameworks possess high selectivity for alkali metal cations, matching the specific charge density of their inner surfaces, which enables their use as ion-exchange materials. Aggregates of the supertetrahedral chalcogenido metalate cluster offer even new perspectives for metal ion capture and separation. Herein, we report on ionothermal preparation of two corresponding model compounds, (C$_2$C$_1$Im)$_7$[Cs@Ge$^{II}$$_4$(Ge$^{IV}$$_4$Se$_{10}$)$_4$] (1) and (C$_2$C$_1$Im)$_{10}$[Na$_5$(CN)$_6$@Cu$_6$(Ge$_4$Se$_{10}$)$_4$(Cu)] (2). Their formation is reliant on one specific cation type each, Cs$^+$ for 1 and Na$^+$ for 2, thus providing promising separation potential during crystallization. Compound 1 is based on the largest discrete binary selenido germanate cluster reported to date and the first mixed-valent chalcogenido germanate(II/IV) supertetrahedron. Moreover, it adds to the few examples of chalcogenides capable of capturing Cs$^+$ ions. Its high selectivity for Cs$^+$ compared to that of Li$^+$, Na$^+$, K$^+$, and Rb$^+$ was confirmed by single-crystal X-ray diffraction, energy-dispersive X-ray spectroscopy, and electrospray ionization mass spectrometry. Quantum chemical studies indicate that smaller ions, K$^+$ and Rb$^+$, could also be embedded in an isolated cluster assembly, but as the cluster aggregate slightly distorts for crystallization, the selectivity for Cs$^+$ becomes exclusive in the salt. The anionic substructure of compound 2 is based on a two-dimensional network of supramolecular assemblies and exhibits an exclusive preference for Na$^+$. This work thus provides the first comprehensive insight into the selective incorporation of specific alkali metal ions into supramolecular aggregates of supertetrahedral chalcogenide clusters, as a promising basis for new ion trapping techniques─especially for heavy alkali metal ions that pose environmental challenges.

The synthetic access to macrocyclic molecular topologies with interesting photophysical properties has greatly improved thanks to the successful implementation of organic and inorganic corner units. Based on recent reports, we realized pseudo- meta [2.2]para­cyclo­phanes (PCPs) might serve as optimal corner units for constructing 3D functional materials, owing to their efficient electronic communication, angled substituents and planar chirality. Herein, we report the synthesis, characterization and optical properties of four novel all-carbon enantiopure macrocycles bearing three to six pseudo- meta PCPs linked by 1,3-butadiyne units. The macrocycles were obtained by a single step from enantiopure literature known dialkyne pseudo- meta PCP and were unambiguously identified and characterized by state of the art spectroscopic methods and in part even by x-ray crystallography. By comparing the optical properties to relevant reference compounds, we show that the pseudo- meta PCP subunit effectively elongates the conjugated system throughout the macrocyclic backbone, such that already the smallest macrocycle consisting of only three subunits reaches an astounding polymer-like conjugation length. Additionally, we show that the chiral pseudo- meta PCPs induce remarkable chiroptical response in the respective macrocycles, reaching unprecedented high molar dichroism values for all-carbon macrocycles of up to 1307 L mol -1 cm -1 .

Orthogonal joints, understood as connections with an angle of 90°, were introduced in the design of the “Geländer” model compounds 1 and 2. The banister, consisting of a conjugated carbazole dimer linked by either 1,3-butadiyne (2) or a single thiophene (1), wraps around an axis composed of a phthalimide dimer due to the dimensional mismatch of both subunits, which are interconnected by phenylene rungs. The “Geländer” structure was assembled from a monomer comprising the 1,4-diaminobenzene rung with one amino substituent as part of a 4-bromo phthalimide subunit forming the orthogonal junction to the axis, andthe other as part of a masked 2-ethynyl carbazole as orthogonal joint to the banister. The macrocycle was obtained by two sequential homocoupling steps. A first dimerization by a reductive homocoupling assembled the axis, while an oxidative acetylene coupling served as ring closing reaction. The formed butadiyne was further derivatized to a thiophene, rendering all carbons of the model compound sp2 hybridized. Both helical structures were fully characterized and chirally resolved. Assignment of the enantiomers was achieved by simulation of chiroptical properties and enantiopure synthesis.

Porphyrin cyclophane 1, consisting of two rigidly fixed but still movable cofacial porphyrins and exposing acetate-masked thiols in opposed directions of the macrocycle, is designed, synthesized, and characterized. The functional cyclophane 1, as pioneer of mechanosensitive 3D materials, forms stable single-molecule junctions in a mechanically controlled break-junction setup. Its reliable integration in a single-molecule junction is a fundamental prerequisite to explore the potential of these structures as mechanically triggered functional units and devices.

Five [PSiP]-pincer iron hydrides 1-5, [(2-Ph2PC6H4)2HSiFe(H)(PMe3)2 (1), (2-Ph2PC6H4)2MeSiFe(H)(PMe3)2 (2), (2-Ph2PC6H4)2PhSiFe(H)(PMe3)2 (3), (2-(iPr)2PC6H4)2HSiFe(H)(PMe3) (4), and (2-(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (5)], were used as catalysts to study the effects of pyridine N-oxide and the electronic properties of [PSiP]-ligands on the catalytic hydrosilylation of carbonyl compounds. It was proved for the first time that this catalytic process could be promoted with pyridine N-oxide as the initiator at 30 °C because the addition of pyridine N-oxide is beneficial for the formation of an unsaturated hydrido iron complex, which is the key intermediate in the catalytic mechanism. Complex 4 as the best catalyst shows excellent catalytic performance. Among the five complexes, complex 3 was new and the molecular structure of complex 3 was determined by single crystal X-ray diffraction. A proposed mechanism was discussed.

The synthetic access to macrocyclic molecular topologies with interesting photophysical properties has greatly improved thanks to the successful implementation of organic and inorganic corner units. Based on recent reports, we realized that pseudo-meta [2.2]paracyclophanes (PCPs) might serve as optimal corner units for constructing 3D functional materials, owing to their efficient electronic communication, angled substituents and planar chirality. Herein, we report the synthesis, characterization and optical properties of four novel all-carbon enantiopure macrocycles bearing three to six pseudo-meta PCPs linked by 1,3-butadiyne units. The macrocycles were obtained by a single step from enantiopure, literature-known dialkyne pseudo-meta PCP and were unambiguously identified and characterized by state of the art spectroscopic methods and in part even by x-ray crystallography. By comparing the optical properties to relevant reference compounds, it is shown that the pseudo-meta PCP subunit effectively elongates the conjugated system throughout the macrocyclic backbone, such that already the smallest macrocycle consisting of only three subunits reaches a polymer-like conjugation length. Additionally, it is shown that the chiral pseudo-meta PCPs induce a remarkable chiroptical response in the respective macrocycles, reaching unprecedented high molar circular dichroism values for all-carbon macrocycles of up to 1307 L mol$^{−1}$ cm$^{−1}$.

Thiol- and solvent-coordinated cation exchange kinetics have been applied to engineer the composition and crystallinity of novel nanocrystals. The detailed thermodynamics and kinetics of the reactions were explored by NMR spectroscopy, time-dependent photoluminescence (PL) characterizations and theoretical simulations. The fine structure of the colloidal semiconductor nanocrystals (CSNCs) was investigated by X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). In this way, high-quality p-type Ag-doped ZnS quantum dots (QDs) and Au@ZnS hetero-nanocrystals with a cubic phase ZnS shell were synthesized successfully.The unprecedented dominant Ag+ -dopant-induced fluorescence and p-type conductivity in the zinc-blende ZnS are reported.

The bidentate phosphine bis(diphenylphosphino)-N-phenyl-maleimide (L1) is used to synthesize a series of complexes from coinage metals and palladium. Some of them are mononuclear species where one metal atom is coordinated by two phosphine ligands. Three of these complexes have been investigated in detail because they contain the initial ligand in an anionic, radical form (L1') i.e. [Cu(L1L1')] (1), [Ag(L1L1')] (7), [Pd(L1')2] (11). L1' in 1, 7 and 11 shows significant differences in its bonding parameters compared to free or coordinating L1. By magnetic measurements the radical nature of these three compounds could be verified. Quantum chemical calculations prove the existence of either one (1 and 7) or two (11) unpaired electrons localized on the ligand. Furthermore these calculations can explain that 1 and 7 show an asymmetric structure in solid state where one can clearly differ L1 from L1'.

[Pb{Mn(CO)5}3][AlCl4] containing a trigonal planar PbMn3 cluster was obtained by the reaction of PbCl2 and Mn2(CO)10 in the ionic liquid [BMIm][AlCl4]. The title compound is composed of [Pb{Mn(CO)5}3]+ carbonyl cations and [AlCl4]− anions that are connected to infinite zig-zag chains. The [Pb{Mn(CO)5}3]+ cation exhibits a central PbMn3 cluster with three equal Pb–Mn single bonds, resulting in an almost equilateral triangle of three manganese atoms with a formal Pb+I in its center. Such a cluster and compound were identified for the first time. In addition to single-crystal structure analysis, the composition, structure and properties were further characterized by density functional theory (DFT) calculations, energy dispersive X-ray spectroscopy (EDXS), and Fourier-transform infrared spectroscopy (FT-IR), as well as optical spectroscopy (UV-Vis).

Three novel iron dinitrogen hydrides, [FeH(iPr-PSiMeP)(N2)(PMe3)] (1), [FeH(iPr-PSiPhP)(N2)(PMe3)] (2), and [FeH(iPr-PSiPh)(N2)(PMe3)] (3), supported by a silyl ligand are synthesized for the first time by changing the electronic effect and steric hindrance of the ligands through the reaction of ligands L1-L3 with Fe(PMe3)4 in a nitrogen atmosphere. The ligands containing an electron-donating group with large steric hindrance on the phosphorus atom are beneficial for the formation of dinitrogen complexes. A penta-coordinate iron hydride [FeH(iPr-PSiPh)(PMe3)2] (4) was formed through the reaction of ligand L3 with Fe(PMe3)4 in an argon atmosphere under the same conditions. The reactions between complexes 1-3 with an atmospheric pressure of dihydrogen gas resulted in Fe(II) dihydrides, [(iPr-PSiMe(μ-H)P)Fe(H)2(PMe3)] (5), [(iPr-PSiPh(μ-H)P)Fe(H)2(PMe3)] (6) and [(iPr-PSiPh(μ-H))Fe(H)2(PMe3)2] (7), with an η2-(Si-H) coordination. The isolation of dihydrides 5-7 demonstrates the ability of the dinitrogen complexes 1-3 to realize the activation of dihydrogen under ambient temperature and pressure. The molecular structures of complexes 1-7 were elucidated by single crystal X-ray diffraction analysis. The iron dinitrogen hydrides 1-3 are effective catalysts for the silylation of dinitrogen under ambient conditions and among them 3 is the best catalyst.

In this paper, two [PCP] pincer silylene cobalt(I) complexes [((Ph2POCH2)2CH)Co(PMe3)(SiCl((NtBu)2CAr)))] (Ar = Ph (2) and 4-MePh (3)) were synthesized through the substitution reaction of [PCP] pincer cobalt(I) complex [((Ph2POCH2)2CH)Co(PMe3)2] (1) with silylene ligands :SiCl((NtBu)2CAr) (Ar = Ph (L1) and 4-MePh (L2)). The reaction of complex 2 with CO afforded the carbonyl silylene cobalt(I) complex [((Ph2POCH2)2CH)Co(CO)(SiCl((NtBu)2CPh)))] (4) while complex 2 reacted with CH3I to give rise to the cobalt(II) iodide [((Ph2POCH2)2CH)Co(I)(PMe3)] (6). With a catalyst loading of 2 mol%, complex 6 displayed the efficent catalytic activity for hydrosilylation of alkenes by using Ph2SiH2 as the hydrogen source under mild conditions. The molecular structures of complexes 2, 3, 4 and 6 were determined by single crystal X-ray diffraction analysis.

A solvent-free cobalt-catalyzed highly selective hydrosilylation of alkenes has been developed. It was found that both Co(PMe3)4 and CoCl(PMe3)3 are highly active catalysts for hydrosilylation of a...

The two nickel chlorides 1 and 2 with [P,S] and [P,Se] bidentate ligands, respectively, were synthesized and used as catalysts for Sonogashira coupling reaction. Both 1 and 2 are efficient catalyst...

Six silyl cobalt(III) hydrides 1-6 with [PSiP] pincer ligands having different substituents at the P and Si atoms ([(2-Ph2PC6H4)2MeSiCo(H)(Cl)(PMe3)] (1), [(2-Ph2PC6H4)2HSiCo(H)(Cl)(PMe3)] (2), [(2-Ph2PC6H4)2PhSiCo(H)(Cl)(PMe3)] (3), [(2-iPr2PC6H4)2HSiCo(H)(Cl)(PMe3)] (4), [(2-iPr2PC6H4)2MeSiCo(H)(Cl)(PMe3)] (5), and [(2-iPr2PC6H4)2PhSiCo(H)(Cl)(PMe3)] (6)) were synthesized through the reactions of the ligands (L1-L6) with CoCl(PMe3)3 via Si-H bond cleavage. Compounds 1-6 have catalytic activity for alkene hydrosilylation, and among them, complex 3 is the best catalyst with excellent anti-Markovnikov regioselectivity. A silyl dihydrido cobalt(III) complex 7 from the reaction of 3 with Ph2SiH2 was isolated, and its catalytic activity is equivalent to that of complex 3. Complex 7 and its derivatives 10-12 could also be obtained through the reactions of complexes 3, 1, 4, and 5 with NaBHEt3. The molecular structure of 7 was indirectly verified by the structures of 10-12. To our delight, the addition of pyridine N-oxide reversed the selectivity of the reaction, from anti-Markovnikov to Markovnikov addition. At the same time, the reaction temperature was reduced from 70 to 30 °C on the premise of high yield and excellent selectivity. However, this catalytic system is only applicable to aromatic alkenes. On the basis of the experimental information, two reaction mechanisms are proposed. The molecular structures of cobalt(III) complexes 3-6 and 10-12 were determined by single crystal X-ray diffraction analysis.

The reaction of mixed-ligands 1,2,4,5-benzene tetracarboxylic acid (H4btec) and 1,2-bis(4-amino-5-methylmercapto-1,2,4-triazole-3-yl)ethane (bamte) with zinc(II) nitrate hexahydrate under hydrothermal conditions led to the formation of the coordination polymer [Zn2 (bamte) (btec)]n (CP1), whereas the reaction of the same organic tetraacid with 4-amino-5-(pyridine-4-yl)-4H-1,2,4-triazole-3-thiol (Haptt) and cadmium (II) nitrate tetrahydrate under solvothermal conditions gave the coordination polymer [Cd3 (aptt)2 (btec)]n (CP2). Both CPs have been characterized by elemental analysis, FT−IR, powder X-ray diffraction as well as single-crystal X-ray diffraction. Both complexes possess three-dimensional (3D) networks based on two-dimensional MII-btec4-- layers connected by multidentate triazole moieties. CP1 shows a rarely observed binodal (4,6)-connected ‘‘fsc’’ coordination network with (44.610.8) (44.62) topology, whereas CP2 presents a new tetranodal (4,4,5,6)-connected 3D net with (43.62.8)2 (44.62) (44.66)2 (46.66.83) point symbol. Furthermore, the morphology, thermal stability, and solid-state luminescent property of both coordination polymers have been investigated.

Four different [PSiP]-pincer ligands L1-L4 ((2-Ph2PC6H4)2SiHR (R = H (L1) and Ph (L2)) and (2-iPr2PC6H4)2SiHR' (R' = Ph (L3) and H (L4)) were used to investigate the effect of substituents at P and/or Si atom of the [PSiP] pincer ligands on the formation of silyl cobalt(I) complexes by the reactions with CoMe(PMe3)4 via Si-H cleavage. Two penta-coordinated silyl cobalt(I) complexes, (2-Ph2PC6H4)2HSiCo(PMe3)2 (1) and (2-Ph2PC6H4)2PhSiCo(PMe3)2 (2), were obtained from the reactions of L1 and L2 with CoMe(PMe3)4, respectively. Under similar reaction conditions, a tetra-coordinated cobalt(I) complex (2-iPr2PC6H4)2PhSiCo(PMe3) (3) was isolated from the interaction of L3 with CoMe(PMe3)4. It was found that, only in the case of ligand L4, silyl dinitrogen cobalt(I) complex 4, [(2-iPr2PC6H4)2HSiCo(N2)(PMe3)], was formed. Our results indicate that the increasing of electron cloud density at the Co center is beneficial for the formation of a dinitrogen cobalt complex because the large electron density at Co center leads to the enhancement of the π-backbonding from cobalt to the coordinated N2. It was found that silyl dinitrogen cobalt(I) complex 4 is an effective catalyst for catalytic transformation of dinitrogen into silylamine. Among these four silyl cobalt(I) complexes, complex 1 is the best catalyst for hydrosilylation of alkenes with excellent regioselectivity. For aromatic alkenes, catalyst 1 provided Markovnikov products, while for aliphatic alkenes, anti-Markovnikov products could be obtained. Both catalytic reaction mechanisms were proposed and discussed. The molecular structures of complexes 1-4 were confirmed by single-crystal X-ray diffraction.

The historical roots, the discovery and the modern relevance of Dmitri Mendeleev's remarkable advance have been the subject of numerous scholarly works. Here, with a brief overview, we hope to provide a link into the contents of this special issue honouring the great scientist. Mendeleev's advance, announced in March 1869, as he put it in 1889, to the ‘…then youthful Russian Chemical Society…’, first set out the very basis of the periodic law of the chemical elements, the natural relation between the properties of the elements and their atomic weights. This was, and still is, the centrepiece of a historical journey for chemistry to today's position as a pre-eminent science. This article is part of the theme issue ‘Mendeleev and the periodic table'.

Herewith, we report on a method that allows to simultaneously protect both the ∆14,15 bond and the carbonyl group of the symmetrical bis-steroidal diketone 2. We found that environmentally friendly and gas-free chlorination is ideally suited to achieve this goal. This method was discovered during our efforts to methoxylate 2 in a solution of dichloromethane and basic methanol in the presence of diacetoxy iodobenzene. Unexpectedly, the ∆14,15 bonds were chlorinated once as well as twice in a statistical manner. Interestingly, the singly dichlorinated desymmetrized product is an ideal precursor for conduction a series of position selective transformations. Importantly, the carbonyl group present in the nonchlorinated hemisphere can be selectively reduced, olefinated or oximated, while the other carbonyl group stays unaltered. A structurally related “monomeric” steroid derivative undergoes ∆14,15 chlorination and 11-position methoxylation under same conditions. These findings represent a powerful entry for preparing new nonsymmetrical cephalostatin derivatives., Natural product chemistry; Organic chemistry; Biochemistry; Cancer research, Cephalostatin 1; Chemo and regioselective transformations.; Gas-free chlorination method; Double-functional protection.

The reactions of unsymmetrical N-heterocyclic carbene (NHC) [CNC]-pincer preligands with CoMe(PMe3)4 gave rise to NHC [CNC]-pincer cobalt(III) hydrides, [(CcarbeneNaminoCnaphthyl)Co(H)(PMe3)2] (3a)...

A novel mononuclear palladium(II) complex, [Pd(L)Cl2]·DMF (1·DMF, L = 1,4-bis(5-amino-1,3,4-thiadiazol-2-sulfanyl-methyl)benzene), has been synthesized and characterized by elemental analysis, FT-IR and 1H NMR spectroscopy and single-crystal X-ray diffraction. On the basis of the molecular structure, in 1·DMF, a ligand acts as a bidentate chelating one using its endocyclic nitrogen atoms. The biological activities of the free ligand and its palladium complex including cytotoxic activity towards the human colon cancer cell line (HCT-116) and antibacterial activity against one Gram-negative strain (Escherichia coli (ATCC 25922)) and one Gram-positive strain (Staphylococcus aureus (ATCC 6538)) have been examined. The IC50 value of 1·DMF against HCT-116 was 500 μM, which is much higher than that reported for cisplatin, and hence, the compound exhibited low anticancer efficacy compared to cisplatin. However, it exhibited excellent antibacterial activities against both Gram-negative as well as Gram-positive bacterial microorganisms. Furthermore, the thermal stability of complex 1·DMF was studied by thermal gravimetric analysis (TGA). The resulting product was characterized as highly pure PdO nanoparticles (mean crystallite size: 39 nm) by using a series of techniques including powder XRD, EDAX, and SEM.

Exploring efficient photocatalysts for water oxidation is highly demanded because of their significant role in artificial photosynthesis. The research of metal-organic frameworks (MOFs) based photoelectrochemical (PEC) water splitting is promising but still in its infancy due to the challenge to fabricate high-quality MOFs photoelectrode. Here an Fe2O3/Fe-based MOF core/shell nanorod is prepared for efficient PEC water oxidation via a facile surfactant-assisted solvothermal method. With polyvinylpyrrolidone (PVP) molecules as intermedia, an ultrathin MOF shell of several nanometers thick can be controllably grown on the surface of Fe2O3 nanorod. Charge dynamical behaviors study by ultrafast transient absorption spectroscopy (TAS) and photoelectrochemical impedance spectroscopy (PEIS), reveal that the ultrathin MOF shell is crucial to promote the charge separation by providing a cascade band level, but also accelerate the hole injection efficiency via exposing more accessible Fe-oxo cluster active sites. Accompanied with good visible-light response, the Ti-doped Fe2O3/NH2-MIL-101(Fe) photoanode delivers a boosted photocurrent density of 2.27 mA cm−2 at 1.23 V vs. RHE, which is about 2.3 folds of that of pristine Fe2O3. This study provides new insights into the rational design of semiconductor/MOFs hybrid materials for photo/photoelectrochemical catalysis.

Three novel η 3 -2-azaallyl iron(I) complexes, [(2-PPh 2 )C 6 H 4 ](CH=N-CH)C 6 H 4 (4-R)]Fe(PMe 3 ) 2 ( 4 - 6 ) (R = H ( 4 ), Cl ( 5 ) and OMe ( 6 )), were prepared through the reactions of Schiff base preligands [(2-PPh 2 )C 6 H 4 ](CH=NCH 2 )C 6 H 4 (4-R)] ( 1 - 3 ) (R = H ( 1 ), Cl ( 2 ) and OMe ( 3 )) with Fe(PMe 3 ) 4 via sp 3 C-H bond activation under mild reaction conditions. Compared with the reported 2-azaallyl cobalt complexes, these are the first 2-azaallyl iron(I) complexes obtained via Csp 3 -H bond activation. Complex [(2-PPh 2 )C 6 H 4 ](CH=N-CH) (C 6 H 4 )FeBr(PMe 3 ) 2 ( 7 ) was obtained through the reaction of 4 with EtBr. The ligand replacement reaction of complex 4 with CO delivered the dicarbonyl iron(I) complex [(2-PPh 2 )C 6 H 4 ](CH-N=CH) (C 6 H 5 )Fe(CO) 2 (PMe 3 ) ( 8 ). The molecular structures of complexes 4 and 6 were determined by single crystal X-ray diffraction.

A novel Co(III) complex ( o -(Ph 2 P)C 6 H 4 ) 3 SiCoHCl ( 2 ) was synthesized by reaction of tris(phosphino)silyl ligand ( o -(Ph 2 P)C 6 H 4 ) 3 SiH ( 1 ) and CoCl(PMe 3 ) 3 with Si–H bond activation. Complex 2 was very stable to CO or CH 3 I. Co(I) complex ( o -(Ph 2 P)C 6 H 4 ) 3 SiCo(PMe 3 ) ( 3 ) could be isolated in a yield of 72% when treatment of 2 with one equivalent of CH 3 Li in the presence of one equivalent of PMe 3 with the formation of LiCl and the escape of one molecule of methane. Complex 3 could also be obtained by the reaction of 1 with Co(PMe 3 ) 4 or CoMe(PMe 3 ) 4 via elimination of H 2 or CH 4 . The molecular structures of complexes 2 and 3 were determined by single crystal X-ray diffraction. Complex 2 has catalytic reactivity to the Kumada cross-cupling reactions.

The C(carbene)N(amino)N(amine)-pincer nickel(II) bromides 1a–c were hydrogenated to the corresponding nickel(II) hydrides 2a–c by (EtO)3SiH/NaOtBu or NaBH4. These nickel(II) hydrides 2a–c were characterized by NMR and IR spectroscopy as well as X-ray diffraction. The catalytic performance of complex 2b for hydrodehalogenation reactions was explored. With a combination of 3 mol % catalyst loading, (EtO)3SiH/NaOtBu/toluene/80 °C and different reaction times, organic halides were successfully reduced to the related alkanes. A catalytic radical mechanism is proposed and partially verified by experiments.

The reaction between 2-pyridinetetramethyldisilazane 1 and CoMe(PMe3)4 led to the formation of the novel bissilyl cobalt(III) hydride CoH((C5H4N)-N(SiMe2)2)(PMe3)3 (2) via the cleavage of two Si-H bonds with the elimination of methane. The reaction of phenyltetramethyldisilazane 3 with CoMe(PMe3)4 could directly provide the hydrido cobalt(III) complex CoH((C6H5)-N(SiMe2)2)(PMe3)3 4. Complex 4 is an analogue to complex 2. This result indicates that a pre-coordination of the nitrogen atom in pyridine to the cobalt center before Si-H bond activation can be excluded in the formation mechanism of 2. This exclusion is further supported by the in situ 1H NMR spectra of the reaction mixtures between 2-pyridinetetramethyldisilazane 1 with CoMe(PMe3)4 in C6D6 in different reaction times. A new bissilyl iron hydride FeH((C5H4N)-N(SiMe2)2)(PMe3)3 (5) was obtained through the reaction of Fe(PMe3)4 with 1. Complexes 2, 4 and 5 with two metal-Si bonds are very stable and did not react with MeI, EtBr, acetylacetone, CO or CO2. The molecular structures of complexes 2, 4 and 5 were determined by single crystal X-ray diffraction.

The reaction of the bis(dichlorogold) complex of 2,3-bis(diphenylphosphino)maleic anhydride (L1) with S(SiMe3)2 in the presence of NaBPh4 yields the ionic dodecanuclear cluster compound [Au12(PPh2)2S4(L2)4](BPh4)2 (1). During the formation of 1, the initial ligand L1 is transformed into the doubly sylilated derivative, 3,4-bis(diphenylphosphino)-2,5-bis(trimethylsilyloxy)-furan (L2). The presence of bridging PPh2 groups is a result of the transformation of L1 in the coordination sphere of Au(i). Compound 1 was characterized by single crystal X-ray diffraction and electrospray-ionization (ESI) mass spectrometry.

The synthesis and characterization of a series of silyl hydrido iron complexes bearing a pincer-type [PSiP] ligand (2-R2PC6H4)2SiH2 (R = Ph (1) and iPr (5)) or (2-Ph2PC6H4)2SiMeH (2) were reported. Preligand 1 reacted with Fe(PMe3)4 to afford complex ((2-Ph2PC6H4)SiH)Fe(H)(PMe3)2 (3) in toluene, which was structurally characterized by X-ray diffraction. ((2-iPr2PC6H4)SiH)Fe(H)(PMe3) (6) could be obtained from the reaction of preligand 5 with Fe(PMe3)4 in toluene. Furthermore, complex ((2-iPr2PC6H4)Si(OMe))Fe(H)(PMe3) (7) was isolated by the reaction of complex 6 with 2 equiv. MeOH in THF. The molecular structure of complex 7 was also determined by single-crystal X-ray analysis. Complexes 3, 4, 6 and 7 showed good to excellent catalytic activity for transfer hydrogenation of aldehydes under mild conditions, using 2-propanol as both solvent and hydrogen donor. α,β-Unsaturated aldehydes could be selectively reduced to corresponding α,β-unsaturated alcohols. The catalytic activity of penta-coordinate complex 6 or 7 is stronger than that of hexa-coordinate complex 3 or 4.

Polyfluorinated aryl imines 2,4,5-R1,R2,R3-C6H2-HCN-1-C10H7 (R1 = F, R2 = F, R3 = H (1); R1 = F, R2 = H, R3 = F (2) and R1 = F, R2 = F, R3 = F (3)) and F5C6-HCN-1-C10H7 (7) reacted with CoMe(PMe3)4 to give rise to hydrido [CNC]-pincer cobalt(III) complexes (2,4,5-R1,R2,R3-C6H-HCN-1-C10H6)Co(H)(PMe3)2 (R1 = F, R2 = F, R3 = H (4); R1 = F, R2 = H, R3 = F (5); R1 = F, R2 = F, R3 = F (6)) and (F4C6-HCN-1-C10H6)Co(H)(PMe3)2 (8) via selective C–F/C–H bond activation. Penta-coordinate dicarbonyl cobalt(I) complexes (2,4,5-R1,R2,R3-C6H-HCN-1-C10H7)Co(CO)2(PMe3) (R1 = F, R2 = H, R3 = F (9); R1 = F, R2 = F, R3 = F (10)) were obtained from reactions of hexa-coordinate cobalt(III) complexes 5 and 6 with carbon monoxide through reductive elimination. Cobalt(III) halides (2,4,5-R1,R2,R3-C6H-HCN-1-C10H6)Co(I)(PMe3)2 (R1 = F, R2 = F, R3 = H (11); R1 = F, R2 = H, R3 = F (12); R1 = F, R2 = F, R3 = F (13)) and (2,4,5-R1,R2,R3-C6H-HCN-1-C10H6)Co(Br)(PMe3)2 (R1 = F, R2 = F, R3 = H (14); R1 = F, R2 = H, R3 = F (15); R1 = F, R2 = F, R3 = F (16)) were prepared by the interaction between hydrido cobalt(III) complexes 4–6 and MeI or EtBr. The molecular configurations of complexes 4, 8, and 11 were determined by single crystal X-ray diffraction. We then confirmed that the four hydrido cobalt(III) complexes 4–6 and 8 could be used as catalysts for reduction of aldehydes and ketones. Complex 8 is the best catalyst among the four complexes and can selectively catalyze the carbonyl groups of α,β-unsaturated aldehydes and ketones.

The hydrido silyl iron complex (o-Ph2PC6H4SiMe2)Fe(PMe3)3H (2) was obtained via the activation of the Si–H bond of the bidentate silyl ligand o-Ph2P(C6H4)SiMe2H (1) by Fe(PMe3)4. 2 showed good to excellent catalytic activity in both the reduction of aldehydes/ketones and the dehydration of benzamide. In addition, with complex 2 as a catalyst, α,β-unsaturated carbonyls could be selectively reduced to the corresponding α,β-unsaturated alcohols. The mechanisms of the formation of 2 and the catalytic dehydration process are proposed and partly experimentally verified.

The electron-rich silylene Co(I) chloride 5 was obtained through the reaction of CoCl(PMe3)3 with chlorosilylene. Complex 5 reacted with 1,3-siladiazole HSiMe(NCH2PPh2)2C6H4 to give the silylene Co(III) hydride 6 through chelate-assisted Si–H activation. To the best of our knowledge, complex 6 is the first example of Co(III) hydride supported by N-heterocyclic silylene. Complexes 5 and 6 were fully characterized by spectroscopic methods and X-ray diffraction analysis. Complex 6 was used as an efficient precatalyst for Kumada cross-coupling reactions. Compared with the related complex 3 supported by only trimethylphosphine, complex 6 as a catalyst supported by both chlorosilylene and trimethylphosphine exhibits a more efficient performance for the Kumada cross-coupling reactions. A novel catalytic radical mechanism was suggested and experimentally verified. As an intermediate silylene cobalt(II) chloride 6d was isolated and structurally characterized.

C(carbene)N(amido)N(amine)-pincer nickel(II) complexes [iPrCNN-Ni-Br] (6), [nBuCNN-Ni-Br] (7) and [BnCNN-Ni-Cl] (8) were synthesized. The catalytic performance of complexes 6–8 for Sonogashira cross-coupling reactions was explored. In a combination of 5 mol% catalyst loading of 6 and CuI/Cs2CO3/NaI/DMSO at different temperatures for the coupling reactions between alkyl iodides, bromides, chlorides and terminal alkynes, the corresponding coupling products were obtained in moderate to excellent yields. The mechanism of these catalytic reactions was discussed and partially supported by experiments. The phenylethynyl CNN pincer nickel complex 9 as a catalytically active complex was isolated and structurally characterized using X-ray diffraction.

Two novel cobalt Schiff base complexes 3 and 4, ((2-PPh2)C6H4)CN(C10H7)Co(PMe3)2 (3) and ((2-PPh2)C6H4)CHN(C6H5)Co(PMe3)2 (4) with η2(C–H) coordination, were synthesized by the reactions of Schiff base preligands ((2-PPh2)C6H4)CHN(C10H7) (1) and ((2-PPh2)C6H4)CHN(C6H5) (2) with CoMe(PMe3)4via sp2 C–H bond activation. Under similar reaction conditions, the reactions of Co(PMe3)4 with 1 and 2 gave rise to the simple π-(CN)-coordinated cobalt(0) complexes ((2-PPh2)C6H4)CHN(C10H7)Co(PMe3)2 (5) and ((2-PPh2)C6H4)CHN(C6H5)Co(PMe3)2 (6). Complex ((2-PPh2)C6H4)CN(C10H6)CoI(PMe3)2 (7) was obtained through the reaction of 3 with iodomethane via the activation of the second C–H bond in 1. The substitution reaction of complex 3 with carbon monoxide afforded the dicarbonyl cobalt(I) complex ((2-PPh2)C6H4)CN(C10H7)Co(CO)2(PMe3) (8). The molecular structures of 4, 5, 7 and 8 were determined by single-crystal X-ray diffraction.

The synthesis and reactivity of a novel iron hydride supported by [P, Se]-chelate ligand have been explored. Iron hydride o-(Ph2P)C6H4SeFeH(PMe3)3 (1) was obtained via the reaction of (o-PPh2)PhSeH with Fe(PMe3)4. Complex 1 reacted with HCl or acetylacetone delivered a bis-chelated iron complex (o-(Ph2P)C6H4Se)2Fe(PMe3) (2). Through the substitution reaction of PMe3 ligand of complex 1 by CO, monocarbonyl iron(II) hydride o-(Ph2P)C6H4SeFeH(CO) (PMe3)2 (3) with two isomers 3A and 3B was obtained. The molecular structures of complexes 1 and 2 were determined by single crystal X-ray diffraction.

Three η4-(C=C–C=O) coordination cobalt(I) complexes 1–3 were synthesized by the reactions of cinnamaldehyde, p-fluorocinnamaldehyde, and p-chlorocinnamaldehyde with CoMe(PMe3)4. Complex 4 as η2-(C=C) coordination was prepared by the reaction of chalcone with Co(PMe3)4. The structures of complexes 1–4 were confirmed by single-crystal X-ray diffraction. Although the reactions didn't undergo C–H bond activation and decarbonylation, the formation of complexes 1–4 deepens our understanding of the reactions between α,β-unsaturated aldehyde or ketone with low-valent central cobalt atom.

In this paper the reactions of iron(II) hydrides 6 – 10 formed by selective C F/C H bond activation in fluoroaryl-imines were reported. Iron hydrides 6 and 7 reacted with haloalkane to give rise to the corresponding iron halides 11 and 12 with the mer -rearrangement of the three trimethylphosphine ligands. The related trifluoromethylcarboxyl iron complexes 13 and 14 with the carboxyl group as monodentate ligand were obtained from the reactions of hydrides 8 and 9 with F 3 CCOOH. The reaction of iron hydride 6 with Lewis acid LiBF 4 delivered ionic iron complex 15 . Both the reaction of iron hydride 10 with Me 3 SiC C H and the reaction of iron bromide 11 with Me 3 SiC CLi could provide the derivative trimethylsilylacetylenyl iron(II) complexes 16 and 17 respectively. The molecular structures of complexes 12 , 13 and 17 were determined by single crystal X-ray diffraction.

The hydrosilylation of aldehydes and ketones under mild conditions with hydrido thiophenolato iron(II) complexes [ cis –Fe(H)(SAr)(PMe 3 ) 4 ] ( 1–4 ) as catalysts is reported using (EtO) 3 SiH as an efficient reducing agent in the yields up to 95%. Among them complex 1 is the best catalyst. Complex 1 could also be used as catalyst to reduce the α,β-unsaturated carbonyl compounds selectively to the α,β-unsaturated alcohols in high yields.

A three-dimensional functional metal–organic framework (LIFM-38) has been successfully synthesized with a fluorinated bicarboxylate ligand. LIFM-38 exhibits good stability and a surface area of 803 m2 g–1. Owing to the synergistic effect of different functional groups, cocrystallized amine active sites, and suitable pore space, LIFM-38 shows good selective CO2 and C2+ hydrocarbons adsorption over CH4 and N2; in addition, LIFM-38 exhibits good selective C3 hydrocarbons adsorption over C2 hydrocarbons.

A 3D porous perchlorinated metal–organic framework (MOF), LIFM-26, featuring dual functionality, that is, functional polar groups and open metal sites, has been synthesized using perchlorinated linear dicarboxylate to link trigonal prismatic Fe3(μ3-O) units. LIFM-26 exhibits good thermal and chemical stability, and possesses high porosity with a BET surface area of 1513 m2 g−1, compared with isoreticular MOF-235 and Fe3O(F4BDC)3(H2O)3 (F4BDC=2,3,5,6-tetrafluorobenzene-1,4-dicarboxylate). Most strikingly, LIFM-26 features good gas sorption/separation performance at 298 K and 1 atm with IAST selectivity values reaching up to 36, 93, 23, 11, 46, and 202 for CO2/CH4, CO2/N2, C2H4/CH4, C2H6/CH4, C3H8/CH4, and R22/N2 (R22=CHClF2), respectively, showing potential for use in biogas/natural gas purification and CO2/R22 capture.

Three novel unsymmetrical η3-2-azaallyl cobalt(I) complexes, [(2-PPh2)C6H4]CH═N[CHC6H4(4-R)]Co(PMe3)2 (4–6) (R = H (4); Cl (5); and OMe (6)), were synthesized by the reactions of Schiff base ligands [(2-PPh2)C6H4]CH═N[CH2C6H4(4-R)] (1–3) (R = H (1); Cl (2); and OMe (3)) with CoMe(PMe3)4 via sp3 C–H bond activation under mild reaction conditions. Complex {[(2-PPh2)C6H4]CH═NCH3[CHC6H4(4-R)]Co(PMe3)2}I (7) as an 18e cobalt(III) salt was obtained through the reaction of 4 with iodomethane. The substitution reaction of complex 4 with carbon monoxide afforded the dicarbonyl cobalt(I) complex [(2-PPh2)C6H4]CH[N═CHC6H4(4-R)]Co(CO)2(PMe3) (8). The molecular structures of complexes 4–8 were determined by single crystal X-ray diffraction.

Two analogous M4 L4 -type tetrahedral cages (smaller: MOC-19; larger: MOC-22) were synthesized and investigated for their interactions with the anticancer drug 5-fluoracil (5-FU) by NMR spectroscopy, high-resolution electrospray-ionization mass spectrometry (HR-ESI-MS), and molecular simulation. The cage's size and window are of importance for the host-guest binding, and consequently the smaller MOC-19 with a more suitable size of cavity window was found to have much stronger hydrogen-bond interactions with 5-FU. The porous nanoparticles of MOC-19 exhibited outstanding behavior for the controlled release of 5-FU in a simulated human body with liquid phosphate-buffered saline solution.

With the aim to synthesize soluble cluster molecules, the silver salt of (4-(tert-butyl)phenyl)methanethiol [AgSCH2C6H4tBu] was applied as a suitable precursor for the formation of a nanoscale silver sulfide cluster. In the presence of 1,6-(diphenylphosphino)hexane (dpph), the 115 nuclear silver cluster [Ag115S34(SCH2C6H4tBu)47(dpph)6] was obtained. The molecular structure of this compound was elucidated by single crystal X-ray analysis and fully characterized by spectroscopic techniques. In contrast to most of the previously published cluster compounds with more than a hundred heavy atoms, this nanoscale inorganic molecule is soluble in organic solvents, which allowed a comprehensive investigation in solution by UV-Vis spectroscopy and one- and two-dimensional NMR spectroscopy including 31P/109Ag-HSQC and DOSY experiments. These are the first heteronuclear NMR investigations on coinage metal chalcogenides. They give some first insight into the behavior of nanoscale silver sulfide clusters in solution. Additionally, molecular weight determinations were performed by 2D analytical ultracentrifugation and HR-TEM investigations confirm the presence of size-homogeneous nanoparticles present in solution.