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Abstract: The Group 5 pentahalides MX5 (M=Nb, Ta; X=Cl, Br), 1, react with a variety of epoxides (1,2-epoxybutane, styrene oxide, 2,3-dimethyl-2,3-epoxybutane, epoxycyclohexane, ethylene oxide) in a 1:3 molar ratio to afford the dinuclear dihalide-tris(2-haloalcoholato) complexes [MX2(OR)2(μ-OR)]2 [M=Nb, X=Cl, R=–CH(Et)CH2Cl, 2a; M=Nb, X=Cl, R=–CH2CH(Ph)Cl, 2b; M=Nb, X=Cl, R=–C(Me)2C(Me)2Cl, 2c; M=Nb, X=Br, R=–CH2CH(Ph)Br, 2d; M=Nb, X=Br, R=–C(Me)2C(Me)2Br, 2e; M=Ta, X=Cl, R=–CH(Et)CH2Cl, 2f; M=Ta, X=Cl, ▪, 2g; M=Ta, X=Br, R=–CH2CH2Br, 2h], in moderate to good yields. The products, 2a–h, result from multiple epoxide insertion into metal–halide bonds, and the reactions involving 1,2-epoxybutane and styrene oxide proceed with high regioselectivity. The molecular structure of 2h has been elucidated by X-ray diffraction. Differently, NbF5 adds one equivalent of 2,3-dimethyl-2,3-epoxybutane to give the monomer NbF5[Oce:italic> t )], 3, in high yield, as a result of epoxide to ketone isomerization. The reactions of MF5 (M=Nb, Ta) with other epoxides proceed non-selectively according to various pathways, including formation of C–O and C–F bonds and C–C and C–H cleavages. [Copyright &y& Elsevier]

Ionic platinum(II) complexes [PtCl(PPh 3 )(L∧L)][BF 4 ] {L∧L = 2,2′-bipyridyl ( 1 ) 1,10-phenanthroline ( 2 )} and [PtCl(PPh 3 )(L) 2 ][BF 4 ] {L = pyridine ( 3 ), dimethyl sulfoxide ( 4 )} were synthesized by dehalogenation of cis- [PtCl 2 (PPh 3 )(NCMe)], followed by reaction with the suitable ligand. Chelating nitrogen ligands L∧L afforded single products, which were structurally characterized. In the other cases mixtures of geometric (L = pyridine) and/or coordination (L = dimethyl sulfoxide) isomers were observed in solution. In these cases the structures of the less soluble isomers were obtained via single crystal X-ray diffraction. All the complexes were tested in vitro for their antiproliferative activity on three human tumor cell lines: MSTO-211H, HeLa and HepG2. [ABSTRACT FROM AUTHOR]

The coordination polymers [ Ln ( β - dik ) 3 bpy ] ∞ 1 ·C 7 H 8 (Ln = Eu, β-dik = dbm, tta, hfac; Ln = Tb; β-dik = dbm; Hdbm = dibenzoylmethane, Htta = thenoyltrifluoroacetone, Hhfac: hexafluoroacetylacetone) were easily assembled in mild conditions and high yields starting from the anhydrous lanthanide β-diketonates as nodes and 4,4′-bipyridine (bpy) as connector. X-ray single crystal studies have shown zigzag extended chains where lanthanide centres are 8-coordinated in a distorted square-antiprismatic geometry. Photoluminescence studies show bright red europium emission and spectral features dependent on the topology of the polymeric chains. [ABSTRACT FROM AUTHOR]

A series of neutral complexes of platinum(II) of general formula [PtCl 2 L(PPh 3 )] [L = Et 2 NC(Me)NH, SOMe 2 , CO, Et 2 NH, (HOCH 2 CH 2 ) 2 NH, Bz 2 NH, N-morpholine] was prepared starting from suitable precursors. The syntheses and spectroscopic characterizations of the two new complexes trans -[PtCl 2 (N-morpholine)(PPh 3 )] and cis -[PtCl 2 (SOMe 2 )(PPh 3 )] are described as well as their X-ray structures. The antiproliferative activity of all the available compounds was tested in vitro against HeLa, H460 and A549 human tumor cell lines. A brief discussion regarding the structure–activity correlation is presented. [ABSTRACT FROM AUTHOR]

Neodymium and terbium pentafluorophenolates, containing 1,10-phenanthroline as ancillary ligand, [Ln(OC 6 F 5 ) 3 (phen) 3 ], ( 1 Ln = Nd, 2 Ln = Tb) have been synthesized by reacting the N , N -dibutylcarbamato complexes, [Ln(O 2 CNBu 2 ) 3 ], easily obtained from aqueous solutions of lanthanide salts, with C 6 F 5 OH in the presence of 1,10-phenanthroline. The formation of the sparingly soluble hydrated compound [Tb(OC 6 F 5 ) 3 (phen) 2 (H 2 O)·phen], 3 , was observed, due to fortuitous presence of water. Single crystal X-ray diffraction studies on compounds 1 , 3 and 3 ·DME (DME = dimethoxyethane) showed coordination numbers (CN) 9 for neodymium in 1 and 8 for terbium in 3 and 3 ·DME, where only two 1,10-phenanthroline ligands are coordinated to terbium, the third forming two hydrogen bonds with the coordinated water. The structural characterisation of [NH 2 Bu 2 ][C 6 F 5 O], 4 , showed the organisation of the product in ionic quartets. The photoluminescence spectra of 1 and 2 displayed the typical emissions related to the lanthanide centre in the NIR and visible region, respectively. [ABSTRACT FROM AUTHOR]