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The new ligand bis(4-pyridylthio)methane (4-bpytm) (1) and its complexes [CuX 2 (4-bpytm)] and [CuX 2 (4-bpytm) 2 ] (X ϭ Cl and Br) (2 Ϫ 5) have been prepared and characterized by elemental analysis, IR-Raman, UV/Vis spectroscopy. The structures of (4-bpytm) (1), [CuCl 2 (4-bpytm) 2 ] (3) and [CuBr 2 (4-bpytm) 2 ] (4) were determined by single-crystal X-ray diffraction analysis. X-ray analysis of the 1:2 derivatives reveals that the copper atom has a distorted (4 ϩ 2) octahedral environment. The copper atom is coordinated by four nitrogen atoms from four bridging 4-bpytm ligands 2241 and two halogen atoms. The axial CuϪN bonds are considerably longer than the equatorial CuϪN bonds owing to JahnϪTeller distortion. CuX 2 units are linked to each other through bridging 4bpytm ligands to form a 2D interpenetrated coordination polymer. The structural parameters of the 4-bpytm ligand in these complexes were compared with those of the free ligand.

The reactions of methylacetoacetate and ethyl 2-methylacetoacetate thiosemicarbazones (H(2)L(A) and H(2)L(B), respectively) with [ReX(CO)(5)] and [ReX(CO)(3)(CH(3)CN)(2)] (X = Cl, Br) were explored under various experimental conditions. Besides the adducts fac-[ReX(CO)(3)(H(2)L)], in which the rhenium is coordinated to three carbonyl groups, the X anion, and the N,S-bidentate thiosemicarbazone ligand, the following complexes were also isolated: fac-[ReBr(CO)(3)(Hpyz(B))], the tetrameric complexes fac-[Re(pyz(A))(CO)(3)](4) and fac-[Re(pyz(B))(CO)(3)](4), and fac-[Re(pyz(B))(CO)(3)(H(2)O)] (where Hpyz(A) and Hpyz(B) are pyrazolones derived by cyclization of H(2)L(A) and H(2)L(B), respectively). The cyclization reactions were monitored by (1)H NMR spectroscopy and the complexes isolated were identified by elemental analysis, mass spectrometry, IR and (1)H NMR spectroscopy, and in some cases by X-ray diffractometry. The isolation and the full structural identification of the rather unusual fac-[ReBr(CO)(3)(Hpyz(B))], which contains the enol form of the pyrazolone ligand, affords new insight into the cyclization of thiosemicarbazones derived from beta-keto esters.

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We report herein a novel infinite two-dimensional water morphology, found in a metallo-organic host, made up of discrete cyclic water hexamers and which contains large circular holes defined by 18 molecules of water.

Two new mixed-ligand complexes [Fe(HG) 2 (dipyam)] (1) (HG ϭ glycolato and dipyam ϭ 2,2Ј-dipyridylamine) and [Cu(HB) 2 (im) 2 ]·2H 2 O (2) (HB ϭ benzilato and im ϭ imidazole) have been hydrothermally synthesized and structurally characterised by X-ray diffraction. In both cases the metallic centre is in an octahedral environment, strongly distorted in 2 (4ϩ2 coordination). The α-hydroxycarboxylato ligands (glycolato or benzilato) present different coordinative behaviour, bidentade chelate through the hydroxyl oxygen and one carboxy oxygen in 1 and through the two oxygen atoms of the carboxylate group in 2. The complexes are extended into 2D frameworks through hydrogen bonding and π···π or C-H···π interactions. The complexes were also characterized by elemental analysis, FT-IR and UV-vis spectroscopy and room temperature magnetic measurements.

) (where SS ) 4,4′-dipyridyldisulfide, SCS ) bis(4-pyridylthio)methane, L 1 ) 2-methyllactate, and L 2 ) glycolate), have been synthesized by the reaction of the SS and SCS ligands with the corresponding copper(II) R-hydroxycarboxylates (2-methyllactate and glycolate). The structures of the mononuclear compounds 1 and 1w 1 , which could be considered as pseudo-polymorphs, show that the solvent molecules are not innocent partners and play a key role in the supramolecular association. Compound 2w 1 is a discrete dinuclear molecule in which the SCS ligand acts as bridge between the two copper(II) ions. In these three compounds it seems that the presence of the 2-methyllactate ligand prevents the formation of the expected coordination polymers through the twisted SS and SCS ligands. Compounds 3w 1D and 4w 1D , which both contain the glycolate ligand, are one-and two-dimensional (1D and 2D) coordination polymers, respectively. In the crystal lattices of the two compounds, two 1D water morphologies are hosted: a treelike chain for 3w 1D and a staircase T4(2) tape for 4w 1D . In both cases, the dehydration-rehydration processes are investigated.

Compounds of type [MX 2 (Hpben)] [M ϭ Pd (X ϭ Cl), Pt (X ϭ Cl, I); Hpben ϭ 2-(2Ј-pyridyl)benzimidazole] were prepared and characterized, and the structures of the Pt derivatives were determined by X-ray crystallography. The crystals of [PtI 2 (Hpben)] consist of discrete units in which the Pt atom is coordinated to two iodine atoms and to pyridine and imidazole N atoms in a distorted square planar arrangement. The structure of the chloro derivative is similar, except that the [PtCl 2 (Hpben)] monomers are hydrogenbonded in zig-zag chains. In assays of the interactions of the Pd