C- and Z-Shaped Coordination Compounds. Synthesis, Structure, and Spectroelectrochemistry of cis- and trans-[Re(CO)3(L)]2-2,2‘-bisbenzimidizolate with L = 4-Phenylpyridine, 2,4‘-Bipyridine, or Pyridine

Self-Assembled Manganese(I)-Based Selenolato-Bridged Tetranuclear Metallorectangles: Host-Guest Interaction, Anticancer, and CO-Releasing Studies

Supramolecular one-step self-assembly of dimanganese decacarbonyl, diaryl diselenide, and linear dipyridyl ligands (L = pyrazine (pz), 4,4'-bipyridine (bpy), and trans-1,2-bis(4-pyridyl)ethylene (bpe)) has resulted in the formation of selenolato-bridged manganese(I)-based metallorectangles. The synthesis of tetranuclear Mn(I)-based metallorectangles [{(CO)₃Mn(μ-SeR)₂Mn(CO)₃}₂(μ-L)₂] (1-6) was facilitated by the oxidative addition of diaryl diselenide to dimanganese decacarbonyl with the simultaneous coordination of linear bidentate pyridyl linker in an orthogonal fashion. Formation of metallorectangles 1-6 was ascertained using IR, UV-vis, NMR spectroscopic techniques, and elemental analyses. The molecular mass of compounds 2, 4, and 6 were determined by ESI-mass spectrometry. Solid-state structural elucidation of 2, 3, and 6 by single-crystal X-ray diffraction methods revealed a rectangular framework wherein selenolato-bridges and pyridyl ligands define the shorter and longer edges, respectively. Also, the guest binding capability of metallorectangles 3 and 5 with different aromatic guests was studied using UV-vis absorption and emission spectrophotometric titration methods that affirmed strong host-guest binding interactions. The formation of the host-guest complex between metallorectangle 3 and pyrene has been explicitly corroborated by the single-crystal X-ray structure of 3•pyrene. Moreover, select metallorectangles 1-4 and 6 were studied to explore their anticancer activity, while CO-releasing ability of metallorectangle 2 was further appraised using equine heart myoglobin assay.

Unconventional DNA-relevant π-stacked hydrogen bonded arrays involving supramolecular guest benzoate dimers and cooperative anion–π/π–π/π–anion contacts in coordination compounds of Co(ii) and Zn(ii) phenanthroline: experimental and theoretical studies

Antiproliferative evaluation and supramolecular assemblies of Co(ii) and Zn(ii) coordination compounds involving cooperative anion–π and unconventional DNA-relevant π-stacked hydrogen bonded arrays.

Self-assembly of a fac-Mn(CO)3-core containing dinuclear metallacycles using flexible ditopic linkers

Flexible dimanganese metallacycles have been achieved using Mn(CO)₅Br and adaptable ditopic pyridyl linkers. The host–guest chemistry of Mn(i)-dinuclear metallacycles has been explored.

1,4-Bis(1H-benzimidazol-2-yl)benzene methanol monosolvate

The asymmetric unit of the title compound, C(20)H(14)N(4)·CH(4)O, contains two independent half-mol-ecules, each located on an inversion centre, and a methanol solvent mol-ecule. The benzimidazolyl groups form different dihedral angles [24.0 (1) and 11.6 (1)°] with the plane of the central benzene ring in the two mol-ecules. In the crystal, a two-dimensional network is formed through N-H⋯ N, N-H⋯O and O-H⋯N hydrogen-bonding inter-actions between the benzimidazole units and methanol solvent mol-ecules. π-π stacking inter-actions also occur between the benzimidazole rings of adjacent mol-ecules, with centroid-centroid distances of 3.720 (14) Å and inter-planar distances of 3.53 (1) Å .

Automated least-squares molecular overlay withouta prioriatomic correspondence or connectivity information

A method is described for automated least-squares molecular overlay withouta prioriatomic correspondence and without the requirement to establish connectivity information. The method is intended to be useful for automated structure comparison where it might be difficult to establish consistent descriptions of molecular connectivity, and for unconstrained molecular overlay. The general assignment algorithm of Munkres [J. Soc. Ind. Appl. Math.(1957),5, 32–38] is utilized to obtain the least-squares pairwise atomic correspondence for two molecules in a given relative orientation, and this step is alternated with analytical least-squares overlay using the established pairwise correspondence. Optional constraints for matching only atoms of the same type or same chemical connectivity can be applied by partitioning the molecule into corresponding groups during each Munkres match. The optimization cycle converges on a local minimum and a grid-search procedure is implemented to identify the global minimum. The method is validated and used to compare crystallographically distinct molecules in 18 941 single-component molecular crystal structures taken from the Cambridge Structural Database.

Synthesis of 4,4‘-Bisaryl-2,2‘-bisbenzimidazoles as Building Blocks for Supramolecular Structures

A series of 4,4'-bisaryl-2,2'-bisbenzimidazoles has been synthesized from the corresponding 4,4'-dibromo-2,2'-bisbenzimidazoles by Negishi coupling reactions. This procedure affords highly substituted bisbenzimidazoles. [reaction: see text]