Bala. Manimaran

Diaqua­dichloridobis(pyridine-κN)manganese(II)

The molecular title compound, [MnCl2(C5H5N)2(H2O)2], lies about an inversion centre. The MnII atom is in an all-trans octahedral environment defined by two water molecules, two chloride anions and two pyridine ligands. An intermolecular hydrogen-bonding interaction between a water molecule and a chloride anion bonded to an adjacent MnII atom generates an eight-membered ring. The crystal packing exhibits two intermolecular π–π stacking interactions between the aromatic rings, with centroid–centroid distances of 3.485 (12) and 3.532 (12) Å.

Amide-Functionalized Chalcogen-Bridged Flexible Tetranuclear Rhenacycles: Synthesis, Characterization, Solvent Effect on the Structure, and Guest Binding

The synthesis of flexible rhenium(I)-based amide-functionalized chalcogen-bridged tetranuclear metallacycles of general formula [{(CO)3Re(μ-ER)2Re(CO)3}2(μ-L)2] (1–8) was achieved by treating rhenium carbonyl with dialkyl/diaryl chalcogenide (RE–ER; E = S and Se) in the presence of ditopic flexible or semiflexible pyridyl ligand with amide functionality (L = N,N′-bis(4-pyridylcarboxamide)-1,2-ethane (bpce) and N,N′-bis(4-(4-pyridylcarboxamide)phenyl)methane (bpcpm)). Compounds 1–8 were formed by multicomponent self-assembly under one-pot reaction conditions via oxidative addition of dialkyl/diaryl chalcogenide to rhenium carbonyl with pyridyl ligands. The resultant metallacyclophanes were characterized using elemental analyses, infrared, ultraviolet–visible, and NMR spectroscopic techniques. Metallacyclophanes 1–3 and 7 were structurally characterized by single-crystal X-ray diffraction methods. The solvent-induced structural change of flexible tetranuclear metallacyclophane 2 was demonstrated by crystallizing 2 in dichloroethane and dimethylformamide. Molecular recognition capabilities of 2 and 7 were studied with few aromatic compounds containing ethereal linkages.

2,2′-[Naphthalene-1,5-diylbis(nitrilo­methanylyl­idene)]diphenol

The title compound, C24H18N2O2, lies about an inversion centre and the asymmetric unit contains one half-molecule. An intramolecular O—H⋯N hydrogen bond generates a six-membered ring, producing an S(6) ring motif. The crystal packing exhibits intermolecular π–π stacking interactions between the aromatic rings with a centroid–centroid distance of 3.851 (2) Å.

Butane-1,4-diyl bis­(pyridine-4-carboxyl­ate)

The molecule of the title compound, C16H16N2O4, lies about an inversion centre; the butane chain adopts an extended zigzag conformation. The dihedral angle between the pyridine ring and the adjacent COO group is 3.52 (s14)°.

Bis(μ-phenyl­tellurido-κ2Te:Te)bis­[tetra­carbonyl­rhenium(I)]

The title compound, [Re2(C6H5Te)2(CO)8], crystallizes with two molecules in the asymmetric unit, in which two Re atoms are coordinated in a slightly distorted octahedral environment and are bridged by two Te atoms, which show a distorted trigonal-pyramidal geometry. The torsion angles for the Te—Re—Te—Re sequence of atoms are 19.29 (18) and 16.54 (16)° in the two molecules. Thus, the Re—Te four-membered rings in the two molecules deviate significantly from planarity. Two intramolecular C—H⋯O interactions occur in one of the molecules. Te—Te [4.0551 (10) Å] interactions between the two molecules and weak intermolecular C—H⋯O interactions stabilize the crystal packing.

Heptacarbonyl-1κ3C,2κ4C-(4-phenyl­pyridine-1κN)di-μ-phenyltellurido-1:2κ4Te:Te-dirhenium(I)

In the title complex, [Re2(C6H5Te)2(C11H9N)(CO)7], two Re atoms are coordinated in slightly distorted octahedral coordination environments and are bridged by two Te atoms, which are coordinated in trigonal-pyramidal environments. The torsion angle for the Te—Re—Te—Re sequence of atoms is 17.06 (3)°. The crystal structure is stabilized by weak C—H⋯O and C—H⋯π interactions. In addition, there are Te⋯Te distances [4.0392 (12) Å] and O⋯O distances [2.902 (19) Å] which are shorter than the sum of the van der Waals radii for these atoms. A short intermolecular lone pair⋯π distance [C O⋯Cg = 3.31 (2) Å] is also observed.