Reaction of thiones with dihalogens: comparison of the solid state structures of 4,5-bis(methylsulfanyl)-1,3-dithiole-2-thione-diiodine, -dibromine and -iodine monobromide

Reaction of 4,5-bis(methylsulfanyl)-1,3-dithiole-2-thione 1 with diiodine or iodine monobromide in CH2Cl2 resulted in the formation of molecular charge-transfer complexes 1 . I-2 and 1 . IBr respectively. Both complexes have been characterised crystallographically and contain a linear S-I-X (X = I or Br) moiety with the sulfur adopting a tetrahedral geometry taking into account the stereochemically active lone pairs. The S-I [2.716(3)] and I-I [2.808(3) Angstrom] bond lengths in 1 . I-2 are similar to those reported for diiodine complexes of related thione donors. The adduct 1 . IBr is the first crystallographically characterised thione-iodine monobromide charge-transfer complex. The S-I distance [2.589(2) Angstrom] is shorter than that in 1 . I-2, consistent with IBr being a stronger acceptor than I-2. The I-Br distance [2.7138(11) Angstrom] is lengthened with respect to that in unco-ordinated IBr, but within bonding distance when compared to the sum of the van der Waals radii for iodine and bromine (3.75 Angstrom). Treatment of 1 with dibromine under identical conditions resulted in the formation of the adduct 1 . Br-2 and the dithiolylium salt [C5H6S4Br][Br-3]. 1/2Br(2) 2. Treatment of 1 with Br-2 in toluene led to the isolation of 1 . Br-2 only. The crystal structure of 1 . Br-2 shows the compound to contain a linear Br-S-Br moiety with the sulfur in a T-shaped or Psi-trigonal bipyramidal environment (taking into account the stereochemically active lone pairs). The structure of 2 reveals a three component system consisting of the [C5H6S4Br](+) cation, the [Br-3](-) anion and a molecule of Br-2 in a 2:2:1 ratio. These components are held in the lattice by a series of weak intermolecular interactions which link the tribromide ions and dibromine molecules into zigzag chains

Novel transition metal complexes based on covalently linked DMIT systems

The synthesis of a novel series of transition metal ligands and complexes is reported; the materials are related to the well-studied DMIT systems, allowing greater versatility in terms of structural design and processability

Octahedral Cu-II and Ni-II complexes manifesting with N'-[1-(pyridin-2-yl)ethylidene] acetohydrazide: structural outlooks and spectral characteristics

A tridentate hydrazone precursor, N′-[1-(pyridin-2-yl)ethylidene] acetohydrazide (L) (1:1 refluxed product of acetichydrazide and 2-acetylpyridine), produced two octahedral Cu and Ni derivatives, [CuL ]·NO (1) and [NiL ]·ClO ·H O (2). Both are subjected to X-ray diffraction system, and structural investigation shows that the central metal atom (Cu or Ni ) adopts a distorted octahedral geometry with N O donor sets by coordination of a pair of independent hydrazone precursors. Besides X-ray study, IR and UV-vis spectra, thermal analysis and room temperature magnetic moments are utilized for establishing significant characteristics of both complexes. It is apparent that the M-N bonds are slightly longer than the M-N bonds, Cu1-N1 and Cu1-N4 [2.300(2) and 2.038(2) Å] for 1 and Ni1-N1 and Ni1-N4 [2.075(2) and 2.084(1) Å] for 2, Cu1-N2 and Cu1-N5 [2.062(1) and 1.932(1) Å] for 1 and Ni1-N2 and Ni1-N5 [2.008(2) and 1.975(2) Å] for 2, respectively. As per our observation, the effective magnetic moment value (μ ) is found to be 1.77 B.M. for 1 and 3.06 BM for 2, respectively