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(1-methyl-1H-benzo[d]imidazol-2-yl) methanol (Hmbm) reacts with Mn(ClO4)2·6H2O to form heptanuclear disks [Mn7(mbm)12]·2(ClO4) (1) under ambient conditions. The heptanuclear cluster was previously described as a double calix unit with the hydroxides in the middle. The seven Mn(II) ions are essentially coplanar as expected for all edge-sharing octahedra, which can be intituled as a segment of Mg(OH)2 layer of brucite, so it is a symmetric disk. ESI–MS of crystals showed its stability in solution. Time-dependent mass spectrometry (MS) from solutions at different period of the assembly reveal a hierarchical sequence, [MnIII(mbm)2]+ → [MnII2(mbm)3]+ → [MnII4(mbm)6(ClO4)]+ → [MnIIIMnII6(mbm)12(ClO4)2]+. [ABSTRACT FROM AUTHOR]

Herein, the reaction of (1‐methyl‐1 H‐benzo[d]imidazol‐2‐yl)methanamine (L1) with Co(H2O)6Cl2, in CH3CN at 120 °C, leading to the 2,3,5,6‐tetrakis(1‐methyl‐1 H‐benzo[d]imidazol‐2‐yl)pyrazine (3), isolated as a dimeric cluster {[CoII2(3)Cl4]⋅2 CH3CN} (2), is reported. When O2 and H2O are present, (1‐methyl‐1 H‐benzo[d]imidazole‐2‐carbonyl)amide (HL1′) is first formed and crystallized as [CoIII(L1)2(L1′)]Cl2⋅2 H2O (4) before fusion of HL1′ with L1, giving 1‐methyl‐N‐(1‐methyl‐1 H‐benzo[d]imidazol‐2‐carbonyl)‐1 H‐benzo[d]imidazol‐2‐carboxamide (HL2′′) forming a one‐dimensional (1D) chain of [CoII3(L2′′)2Cl4]n (5). The combination of crystallography and mass spectrometry (ESI‐MS) of isolated crystals and the solutions taken from the reaction as a function time reveal seven intermediate steps leading to 2, but six steps for 5, for which a different sequence takes place. Control and isotope labeling experiments confirm the two carbonyl oxygen atoms in 5 originate from both air and water. The dependence on the metals, compared with FeCl3⋅6 H2O leading to a stable triheteroarylmethyl radical, is quite astounding, which could be attributed to the different oxidation states of the metals and coordination modes confirmed by DFT calculations. This metal and valence dependent process is a very useful way for selectively obtaining these large molecules, which are unachievable by common organic synthesis. [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]

Dehydration of (S,S)‐1,2‐bis(1H‐benzo[d]imidazol‐2‐yl)ethane‐1,2‐diol (H4L) to (Z)‐1,2‐bis(1H‐benzo[d]imidazol‐2‐yl)ethenol) (H3L′) was found to be metal‐assisted, occurs under solvothermal conditions (H2O/CH3OH), and leads to [MnII4(H3L)4Cl2]Cl2⋅5 H2O⋅5 CH3OH (Mn4L4) and [MnII4(H2L′)6(μ3‐OH)]Cl⋅4 CH3OH⋅H2O (Mn4L′6), respectively. Their structures were determined by single‐crystal XRD. Extensive ESI‐MS studies on solutions and solids of the reaction led to the proposal consisting of an initial stepwise assembly of Mn4L4 from the reactants via [MnL] and [Mn2L2] below 80 °C, and then disassembly to [MnL] and [MnL2] followed by ligand modification before reassembly to Mn4L′6 via [MnL′], [MnL′2], and [Mn2L′3] with increasing solvothermal temperature up to 140 °C. Identification of intermediates [Mn4LxL′6−x] (x=5, 4, 3, 2, 1) in the process further suggested an assembly/disassembly/in situ reaction/reassembly transformation mechanism. These results not only reveal that multiple phase transformations are possible even though they were not realized in the crystalline state, but also help to better understand the complex transformation process between coordination clusters during "black‐box" reactions. [ABSTRACT FROM AUTHOR]

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Two zinc clusters Zn4(H3L)4(NO3)4⋅5H2O (Zn4, H4L=(1,2‐bis(1H‐benzo[d]imidazol‐2‐yl)ethane‐1,2‐diol) and [Zn5(H2L′)6](NO3)4]⋅8H2O⋅2CH3OH (Zn5, H3L′=(1,2‐bis(benzo[d] imidazol‐2‐yl)‐ethenol) have been obtained by the reaction of Zn(NO3)2⋅6H2O with H4L at 80 °C or 140 °C under solvothermal condition. Powder X‐ray Diffraction (PXRD) of precipitate and Electrospray Ionization Mass Spectrometry (ESI‐MS) of reaction solution revealed the existence of transformation behavior from Zn4 to Zn5 by increasing the temperature from 80 °C to 140 °C, or directly heating Zn4 at 140 °C via solvothermal reaction. Here we proposed a possible mechanism involves split process of Zn4 and reassembly to form Zn5. ESI‐MS for single crystals revealed [Zn4(H3L)4−3H]+ splits to [Zn(H3L)]+ via [Zn2(H3L)2−H]+. Time dependent ESI‐MS of reaction solution revealed the [Zn(H2L′)]+→[Zn2(H2L′)2−H]+→[Zn5(H2L′)6−H]3+ stepwise assembly. It also has been captured the in situ reaction mainly occurs in the step of [Zn(H3L)]+ to [Zn(H2L′)]+. [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]

The square-planar monomer NiL2 ( Ni1), L=2-ethoxy-6-( N-methyl-iminomethyl)phenolate, reacts with M(H2O)6(ClO4)2, M=Ni or Co, to form heptanuclear disks [Co xNi7− x(OH)6(L)6](ClO4)2 ⋅2 CH3CN ( Co x Ni7− x, x=0-7) and the co-crystal [Co xNi7− x(OH)6L6][NiL2](ClO4)2 ⋅2 CH3CN ( Co x Ni7− x -Ni1) under ambient conditions. It has proved possible to explore the bottom-up assembly process of Co x Ni7− x and Co x Ni7− x -Ni1 in real time. The final products have been characterized by thermogravimetric analysis, IR, elemental analysis, ICP-MS, and single-crystal X-ray diffraction. Time-dependent mass spectrometry (MS) revealed the following reaction steps: Ni1→[M2L3]+→[M4(OH)2L4]2+→[M7(OH)6L6]2+. In contrast, the reaction of Ni1 with Zn2+ only reaches halfway, and crystallographic evidence indicates a butterfly structure for [Zn2Ni2(OH)2Cl2] ( Zn2Ni2), an intermediate that is difficult to isolate in the above Ni-Co series. A summation method has been used to analyze the MS of bimetallic clusters with very similar atomic masses, as is the case for Co and Ni. The results provide ample information on the distribution of Co and Ni within each cluster and their statistical distribution within selected crystals. [ABSTRACT FROM AUTHOR]

In the title compound, C16H11NO3, the quinolin-8-yl­oxy and 2-carboxy­phenyl groups are linked through an ether O atom, the angle at this atom being 116.4 (1)° in one mol­ecule and 114.8 (1)° in the other independent mol­ecule. In both mol­ecules, the carboxylic acid group inter­acts with the heterocyclic moiety through an intra­molecular hydrogen bond. [ABSTRACT FROM AUTHOR]

A cadmium (II) coordination polymer, namely {[Cd5(Ln)6Cl4]·2H2O}n (1, HLn =1-methyl-2-(3H-[1–3]triazol-4-yl)-1H-benzoimidazole), has been constructed from in situ generated HLn under hydrothermal condition. The unsuccessful synthesis of 1 under similar synthesis condition using HLn as reactant suggests the in situ reaction is crucial for the assembly of the compound. Crystallography study reveals that 1 processes layer structure in which chains of [Cd3(Ln)4Cl4]2− were connected by a pair of Cd ions. These layers further stack in an AAA model to form a 3D supramolecular framework and hydrogen bonding as well as π–π interaction were formed between adjacent layers to stabilize the framework. TGA indicates that 1 is highly thermally stable up to about 380°C. The luminescence of 1 in the solid state which may be assigned to intraligand transition shows a blue shift of 16nm compared to that of HLn·HCl. [ABSTRACT FROM AUTHOR]