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A double‐ligands enabled ruthenium catalyzed C(sp2)−H arylation of dialkyl phosphines is described, which provides a straight access to aryl‐substituted dialkyl phosphine ligands. The combination of 1,3‐diketone and amino acid ligands is essential for this transformation. An important six‐membered cycloruthenium intermediate was successfully isolated and characterized by X‐ray diffraction. Mechanistic studies showed that the 1,3‐diketone promoted the process of oxidative addition of cycloruthenium intermediate. Some of modified CyJohnPhos ligands exhibited highly catalytic activity in palladium catalyzed C−N bond formation. [ABSTRACT FROM AUTHOR]

An unexpected dominance of the coordination affinity of the sulfate anion over those of two organic chelating ligands, (1-methyl-1H-benzo[d]imidazol-2-yl)methanol (Hmbm) and pyridin-2-ylmethanamine (pma), was observed during the study of the solvothermal assembly of [Co11(mbm)6(pma)2(SO4)8(H2O)6(CH3OH)6]·5CH3OH (1), from CoSO4·7H2O at 100 °C in methanol. ESI-MS of solutions at different periods of the assembly reveal a hierarchical sequence, [Co1] → [Co2] → [Co3] → [Co4] → [Co5] → [Co9], where the lower nuclearity species are richer in Co2+ and SO42− before the inclusion of more mbm ligands at the last step. Its crystal structure consists of an almost symmetrical wheel of nine cobalt atoms, [Co9(mbm)6(SO4)8(H2O)6] in edge-sharing octahedral coordination arranged in triangles with two peripheral dangling [Co(pma)(CH3OH)3]. The sulfate ions exhibit three different coordination modes, two in μ6-, two in μ3- and four as μ2-bridging. Its thermal, optical and magnetic properties are also reported. [ABSTRACT FROM AUTHOR]

A new series of luminescent phosphine copper(I) complexes with cyano- and hydroxyl-substituted 2,2′-bipyridine ligands [CuI(bpy(CN)2)(P(PhX)3)2](ClO4) [X = H (1); Me (2); Cl (3)], [CuI(bpy(CN)2)(POP)](ClO4) (4), [CuI(bpy(OH)2)(PPh3)2](ClO4) (5) and [CuI(bpy(OH)2)(POP)](ClO4) (6) have been synthesized and characterized. Three of these complexes have been structurally characterized by using X-ray crystallography. The effect of the attaching –CN and –OH groups at the ortho-positions of bpy ligand was investigated. In CH2Cl2 solution, these complexes show yellow to orange phosphorescence, with the emission maxima not only sensitive to the electronic nature of the bipyridine ligands, but also considerably varied with the modification of phosphine ligands. In addition, these complexes show intense tunable green to yellow emissions in their solid state. To elucidate the electronic structures and transitions of these complexes, density functional theory (DFT) calculations on representative examples revealed that the lowest energy electronic transition associated with these complexes predominantly originates from metal-to-ligand charge transfer transitions (MLCT). [ABSTRACT FROM AUTHOR]

Abstract: Two heptanuclear discs, [Co7(L1)6(CH3O)6]2+ (Co7‐L1) and [Co7(L2)12](ClO4)2 (Co7‐L2), have been prepared by the reaction of [Co(H2O)6](ClO4)2 with Schiff base HL1 (HL1=2‐methoxy‐6‐[(methylimino)methyl]phenolate) or benzimidazole derivative HL2 (HL2=(1H‐benzo[d]imidazol‐2‐yl)methanolate), respectively, at room temperature. In contrast, the reaction of [Co(H2O)6](ClO4)2 with a mixture of the two ligands, having similar coordination ability but different shapes, resulted in the butterfly‐structured tetranuclear cobalt cluster [Co4(L1)2(L2)4](ClO4)2⋅2H2O (Co4). Electrospray ionization mass spectrometry (ESI‐MS) analysis in real time revealed the {Co1}→{Co2}→{Co4}→{Co7} stepwise assembly when a single ligand was employed, but when both ligands were used only {Co4} was obtained, an intermediate of the former reactions. Interestingly, ligand competition was evidenced in the assembly process of the reaction with two ligands; for example, [Co4(L1)4(L2)2]2+ and [Co4(L1)3(L2)3]2+ were the primary clusters observed at the beginning of the reaction, but [Co4(L1)2(L2)4]2+ was the final product. This observation suggests ligand exchange is taking place, and DFT calculations confirmed that these transformations were possible. By varying the ratio of ligands, the abundance of a certain species in the competitive reaction could be controlled. [ABSTRACT FROM AUTHOR]

Two polymorphs of supramolecular isomers, a discrete dimer and a zig-zag chain, having the same chemical composition, [Mn(Hbit)Cl2] (Hbit=1-methyl-2-(1H-1,2,3-triazol-4-yl)-1H-benzo[d]imidazole), were obtained solvothermally in a one-pot synthesis. The isomers differ in a number of ways: orange blocks versus pale-yellow needles, triclinic P1 versus orthorhombic Pbcn, double µ2-Cl versus alternate single and triple µ2-Cl, coordination number 5 versus 6, and antiparallel versus parallel near-neighbor orientation of Hbit. The packing in each case is driven by the supramolecular interactions, H-bonds (N--H…Cl, C--H…Cl) and π…π overlaps, calculated to be in the range 20-36 kcalmol-1. Calculations gave a difference of only 2 kcalmol-1 in favor of the dimer, which confirms with the observation of principally the dimer at short reaction time. ESI-MS spectra of the dissolved crystals reveal the same fragments with similar distributions. The presence of two fragments at m/z 286.96 [MnIV(Hbit)Cl-2H]+ and 323.94 [MnIII (Hbit)Cl2]+ indicates that [Mn(Hbit)Cl2] is the building unit in both cases; thus, the different orientations of the ligands lead to the two polymorphs stabilized by the respective supramolecular interactions. Importantly, the chain form represents the first example with alternate single and triple µ2-Cl bridges. The magnetic interactions are weakly antiferromagnetic in both cases, with J in the range 0.07-0.34 cm-1; however, high-field EPR analysis reveals moderate magneto-anisotropy with D=0.26(1) cm-1, E=0.06(1) cm-1 and D=0.17(1) cm-1, E=0.03(1) cm-1, respectively. [ABSTRACT FROM AUTHOR]

A series of highly connected metal-organic frameworks (MOFs), [Co8(O)(OH)4(H2O)4(ina)8](NO3)2 ⋅2 C2H5OH ⋅4 H2O ( 1), [Co8(O)(OH)4(H2O)4(pba)8](NO3)2 ⋅8 C2H5OH ⋅28 H2O ( 2), and [Co8(O)(OH)4(H2O)4(pbba)8](NO3)2 ⋅guest ( 3), in which ina=isonicotinate, pba=4-pyridylbenzoate, and pbba=4-(pyridine-4-yl)phenylbenzoate, is reported. These MOFs contain a new secondary building unit (SBU), with a square Co4(μ4-O) central unit having the rare μ4-O2− motif, which is decorated by the other four peripheral cobalt atoms through μ3-OH in a windmill-like shape. This SBU holds 16 divergent connecting organic ligands, pyridyl-carboxylates, to form three different frameworks. The high porosity of desolvated 2 is shown by the efficient gas absorption of N2, CO2, CH4, and H2. In addition, 1 and 2 exhibit unusual canted antiferromagnetic behavior with spin-glass-like relaxation, with blocking temperatures that are fairly high, 20 K ( 1) and 10 K ( 2), for cobalt materials. The relationship between the metal clusters and linkers has been studied, in which the size and rotational degrees of freedom of the ligands are found to control the topology, gas sorption, and magnetic properties. [ABSTRACT FROM AUTHOR]

The research on metal–organic frameworks (MOFs) has been developing at an extraordinary pace in its two decades of existence, as judged by the exponential growth of novel structures and the constant expansion of its applicability and research scope. A major part of the research and its success are due to the vital role of the concept of mixed organic ligands in the design, tuning and functions. This perspective, therefore, reviews the recent advances in MOFs based on this concept, which is generally based on employing a small polydentate ligand (here labelled as “nodal ligand”) to form either clusters, rods or layers, which are then connected by a second ditopic linker ligand to form the framework. The structures of the materials can be grouped into the following three categories: layer-spacer (usually known as pillared-layer), rod-spacer, and cluster-spacer based MOFs. Depending on the size and geometry of the spacer ligands, interpenetrations of frameworks are occasionally found. These MOFs show a wide range of properties such as (a) crystal-to-crystal transformations upon solvent modifications, post-synthetic metal exchange or ligand reactions, (b) gas sorption, solvent selectivity and purification, (c) specific catalysis, (d) optical properties including colour change, luminescence, non-linear optic, (e) short- and long range magnetic ordering, metamagnetism and reversible ground-state modifications and (f) drug and iodine carriers with controlled release. In the following, we will highlight the importance of the above concept in the design, tuning, and functions of a selection of existing MOFs having mixed organic ligands and their associated structures and properties. The results obtained so far using this concept look very promising for fine-tuning the pore size and shape for selective adsorption and specificity in catalytic reactions, which appears to be one way to propel the advances in the application and commercialization of MOFs. [ABSTRACT FROM AUTHOR]

Hydrothermal reaction of Co(ClO4)2·6H2O with 2-ethoxy-6-(iminomethyl)phenol (Heimp) or 3-ethoxysalicylaldoxime (H2eosa) leads to the formation of two completely different CoIIcomplexes [Co7(eimp)6(OMe)6]·2ClO4(1) and [Co13(eosao)8(Heosao)6(ClO4)4]·H2O (2). Compound 1is a disc-like heptanuclear CoIIcluster with all the eimp−ligands displaying the η1: η2: η1: μ2binding mode. Compound 2is a butterfly-like nano-tridecanuclear CoIIcluster and the oximation of iminomethyl group results in its complicated binding modes. Four of the six Heosao−ligands adopt the η1: η2: η1: μ2mode and the other two take the η1: η2: η1: η1: μ3fashion, while eight eosao2−ligands are in the η2: η1: η2: μ4, η1: η3: η1: η2: μ5manner. Microwave heating during the synthetic process will dramatically improve the reaction rate and yield of 1, which however, is not valid for the formation of 2. Electrospray ionization mass spectrometry (ESI-MS) solution analysis was performed, which reveals a ligand substitution reaction of the core bridge for 1. For 2, the result of ESI-MS indicates that the Co13cluster still exists in solution, and maintains a conformation similar to that observed in the crystal structure. Magnetic studies show that 1exhibits a dominated ferromagnetic coupling between the CoIIions below 30 K, while 2is a typical antiferromagnetic system. [ABSTRACT FROM AUTHOR]

Abstract: Two new 3D zinc carboxylates Zn2(suc)(ina)2 (1) (suc=succinate, ina=isonicotinate) and Zn2(fum)(ina)2 (2) (fum=fumarate) have been synthesized under the hydrothermal condition and characterized by the single crystal X-ray diffractions. Both complexes 1 and 2 featuring the [Zn2(CO2R)4] subunit (SBU) formed by mixed tetracarboxylate, interlinked by carboxylate-aromatic amine ligands (ina) to construct a 2D (4,4) sheet, which are further pillared by rigid or flexible dicarboxylates ligands (suc or fum) into 3D framework. The topology of 1 and 2 can be related to the cubic α-Po twofold interpenetrating lattice. Thermogravimetric analyses demonstrate the similar one-step thermal decomposition process with the tolerate temperature ca. 400°C of complexes 1 and 2 resulted from the parallel structure motifs and high stability of them. [Copyright &y& Elsevier]

Abstract: Four dimeric and polymeric coordination compounds [Zn2(bimb)2(pdc)2]·6H2O (1), [Cd2(bimb)2(tp)2]·H2O (2), [Cd(bimb)(ada)] (3) and [Co(bimb)(ada)] (4) (bimb, 4,4′-bis(imidazol-1-ylmethyl)biphenyl; pdc, pyridine-2,6-dicarboxylate; tp, terephthalate and ada, adipate) have been synthesized under hydrothermal conditions. Complex 1 is a discrete dinuclear metallomacrocycle featuring a 34-membered ring, in which the flexible bimb ligand acts as syn-conformation. While complexes 2–4 are 3D network structures connected by bimb and dicarboxylate ligands, the bimb ligand displays anti-confromation. [Copyright &y& Elsevier]

In the title compound, [Co(C19H12N5)2], each CoII atom occupies a position of high site symmetry, 222, and is coordinated by the six N atoms [Co—N = 2.085 (4)–2.157 (3) Å] from two tridentate 2-[6-(1 H-benzimidazol-2-yl)-2-pyrid­yl]­benz­imi­dazol­ide ligands in a distorted octa­hedral geometry. [ABSTRACT FROM AUTHOR]

Abstract: A chiral cluster-based 3D coordination polymer [Co2(ca)(ina)2(H2O)] n (1, ca= d-(+)-camphorate, ina=isonicotinate), containing mixed geometries cobalt(II) dimers as subunit, featuring unique rugate [Co2(ina)2] n 2 n + 2D layers pillared by the ca ligands has been studied. The bridge modes and their intermolecular interactions of the mixed rigid planar ina and flexible bulky ca ligands display an interesting example of shape recognition in packing style of 3D frameworks. The bulky antiferromagnetic behavior of 1, mainly arises from the cooperative magnetic effect of the interdimers arrangement in the chiral 3D network based on the nature of the exchange modes of mixed multi-carboxylate bridges within the mixed geometric Co(II) dimer. [Copyright &y& Elsevier]

The interest in metal-organic frameworks (MOFs) is rapidly expanding because of their fascinating architectures and intriguing topologies which allowed for potential applications in gas storage, separation, heterogeneous catalysis, and several other areas. As suitable chromatographic separation media, several MOFs have been employed as stationary phase for gas chromatography and high-performance liquid chromatography. In this work we report the use of a mixed ligands rod-spacer MOF [Mn 3 (HCOO) 2 ( D -cam) 2 (DMF) 2 ] n as coating material for capillary column of gas chromatographic separation of a series of biochemical important compounds having linear alkyl hydrocarbon (aldehyde, alcohol and ester), aromatic hydrocarbon with two phenyls (ether, ester and ester with alcohol) and aromatic hydrocarbon (ester, ester with amino and two esters). The mixture of functional ligands, good thermal and chemical stabilities and host-guest interaction sites of the MOF are attributes to the good efficiency in gas chromatographic separation. [ABSTRACT FROM AUTHOR]

Abstract: A unique [Co13(mosao)8(Hmosao)6]·(ClO4)4·3DMF·MeOH·3H2O (1, H2mosao=3-methoxysalicylaldoxime) supercluster has been synthesized by a method of solvothermal reaction. The [Co13(μ 2-O)8(μ 3-O)6(μ 2-O–N)2(μ 3-O–N)8]4+ core is highly conjugated butterfly-like disc, which can be considered as fourteen distorted defective cubes sharing the neighboring faces one another. The electrospray ionization mass spectrometry (ESI-MS) analysis of 1 strongly suggests that Co13 cluster also exists in solution and maintains a conformation similar to that in the crystal structure, indicating that the significant stability of 1 in solution. Magnetic measurements of 1 reveal antiferromagnetic behaviors resulting from the cooperative magnetic coupling through multiplicate monoatomic oxygen and –N–O– exchange bridges and the odd number of spins result in relatively effective noncompensated moments at very low temperature. [Copyright &y& Elsevier]

Abstract: A new 2D coordination polymer with the formula [Co4(μ3-OH)2(H2nip-2H)2(H2nip-H)2(bpe)2] n (1) (H2nip=5-nitro-isophthalic acid, bpe= trans-1,2-bis(4-pyridyl)ethylene), has been hydrothermally synthesized and structurally characterized. The structure of 1 is built around uncommon, rhombic {Co4} clusters with double T d and double O h Co(II) geometries, which are extended into 2D network by the rigid deprotonated H2nip and bpe bridges. Magnetic property study indicates there is weak antiferromagnetic coupling interaction between Co(II) ions, which mainly arises from the antiferromagnetic coupling interaction in the tetramer, based on the nature of the μ3-hydroxyl group and syn–syn carboxylate-bridged modes. [Copyright &y& Elsevier]

Abstract: The hydrothermal preparation via variations of dicarboxylate ligands (terephthalate (bdc) or d(+)-camphorate (ca)) with lead nitrate exhibits two new 3D coordination polymer. In complex 1 [Pb(bdc)2] n , linear rigid bdc ligands exhibit unique (μ 5-κO-μ 2:κO′:κO′′,O′′′:κO′′-μ 2) coordination mode. The carboxyl groups of bdc link adjacent lead(II) atoms to form a 2D infinite undulated [Pb(CO2)2] n layer, and further linked via the benzene ring of bdc to form a 3D pillared-layer compact framework. In contrast, complex 2 [Pb(ca)2·H2O] n exhibits a rod packing 3D sra (Al net in SrAl2) network with the combination of [Pb(CO2)2·H2O] n rods through (μ 4-κO,O′:κO′′,O′′′:κO′′-μ 2:κO′′′-μ 2) coordination mode of the bulky chiral ca linkers. Both in 1 and 2, the arrangement of donor atoms suggest the coordination around the lead(II) atoms is hemi-directed. The different steric hindrance of two bridged ligands, and lone pair electrons effect of lead(II) ion cooperatively influence bdc and ca displaying in diverse connecting modes and further result in different packing styles of two 3D motif. Two complexes exhibit an excellent thermal stability with the tolerate temperature ca. 410°C for 1 and 390°C for 2, respectively, attributed to the presence of abundant coordination bonds of dicarboxylate ligands and the infinite rod-shaped or layered building blocks in above 3D compact frameworks. [Copyright &y& Elsevier]

Abstract: A new Pb(II) coordination compound, namely [Pb(suc)(H2bbp)]2 (1) has been synthesized by treating succinic acid (H2suc), and 2,6-bis(2-benzimidazolyl) pyridine (H2bbp) with Pb(II) nitrate under hydrothermal conditions. Dicarboxylate as a bridging ligand is used to link adjacent metal centers forming dinuclear metal complex. The arrangement of the H2bbp ligand and carboxyl groups suggest a gap in the coordination around the Pb(II) ion, occupied possibly by a stereoactive lone-pair of electrons on Pb(II) where the coordination around the lead atoms is hemidirected. At room temperature, in the solid-state, the compound displays blue luminescence at 438nm, which is about 50nm red-shifted compared to the emission in DMF solution, resulting from long Pb···O interactions, a closer inspection of the pack reveals π–π stacking interactions that are crucial to lowering the HOMO–LUMO energy gaps. [Copyright &y& Elsevier]

Abstract: [Pb2(boa)(Hbbp)2] has been synthesized by treating 4-carboxylphenoxyacetic (H2boa) and 2,6-bis(benzimidazolyl)pyridine (H2bbp) with metal salts under hydrothermal conditions. Adjacent metal centers forms dinuclear metal complex through carboxylato groups as building blocks. The arrangement of the half deprotonated H2bbp ligand and carboxylate groups exhibits a coordination gap around the Pb(II) ion, occupied possibly by a stereoactive lone pair of electrons on Pb(II), with the coordination environment around the lead atoms is hemidirected. This system is a particularly clear example that coordination sphere of a unique dinuclear Pb(II) compound was controlled by lone pair activity, weak Pb···O interactions, π–π stacking and the hydrogen bonds. The above weak interactions influence differently strong red-shifted effect about the solution and solid-state photoluminescence of the compound, compared to the free ligand. [ABSTRACT FROM AUTHOR]