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[PdI(TePy-2)(I2TePy-2)2] is obtained via a rare oxidation reaction of palladium powder by the in situ generated diiodine adduct of bis-2-pyridylditelluride at room temperature. An X-ray diffraction study reveals the molecular structure of [PdI(TePy-2)(I2TePy-2)2], where the palladium atom is surrounded by an iodide and three tellurium atoms (two [I2TePy-2] and one [TePy-2] groups). The oxidation states for the tellurium atoms were analysed using calculated atomic charges and electron localization function (ELF). The optical bang gap for [PdI(TePy-2)(I2TePy-2)2] was determined through theoretical (DFT) and experimental (diffuse reflectance UV–Visible) studies and the electrochemical behavior for the compound was examined by cyclic voltammetry.

N-(diethylthiocarbamoyl)benzimidoyl chloride reacts with o-aminoacetophenone 4-methylthiosemicarbazone under formation of a novel N2S2 benzamidine/thiosemicarbazone ligand (H2L). The reaction of H2L with [ReNCl2(PPh3)2] yields a red complex of the composition [ReN(L)]. The molecular structure of [ReN(L)] reveals a square-pyramidal environment around the Re atom, in which the organic ligand occupies all four positions of the equatorial plane. The reaction of H2L with [TcNCl2(PPh3)2] results in a mixture of [TcN(L)] and a side-product of the composition [TcN(PPh3){Et2NC(S)NH}(L′)] (L′ = 1,10b-dimethyl-5-phenyl-1,10b-dihydro-[1,2,4]triazolo[1,5-c]quinazoline-2-thiolate). The formation of diethylthiourea and HL′ is the result of a metal-driven decomposition of H2L followed by cyclization.

Tetrameric complexes of the composition [MO(L1)]4 (M = Tc, Re), where (L1)3– represents an asymmetric, trianionic cyclisation product with thiocarbamoylbenzamidinato and mercaptotriazolato donor sites, were formed during reactions of [TcOCl4]– or [ReOCl4]– with a potentially multidentate ligand derived from thiocarbohydrazide and N-[N',N'-diethylamino(thiocarbonyl)]benzimidoyl chloride.

Bis(2-pyridyl) diselenide (2-py2Se2, 1) reacts with [ReOCl3(PPh3)2] under the formation of the unusual oxidorhenium(V) complex [ReOSe(2-pySe)3], which was isolated in crystalline form and studied by spectroscopic methods and X-ray diffraction. The oxidorhenium(V) core is bonded to three 2-pyridineselenolato ligands together with a selenium(0) atom. While the rhenium atom is coordinated in a common distorted octahedral coordination sphere, the selenium(0) atom shows a bent T-shaped coordination with Se N bonds of 2.13 (1) and 2.28 (1) A and a Se Re bond of 2.387 (1) A. The oxidation state of the Se(0) atom has been analyzed using calculated atomic charges and the electron localization function (ELF).

[ReNCl2(PPhMe2)3] reacts with the glycine ethylester derivative Et2NC(S)NC(Ph)NHCH2COOEt, HL(GlyEt), in methanol under hydrolysis of the ester and formation of the tetrameric, nitrido-bridged rhenium(V) compound [{ReN{fac-L(Gly)}(PMe2Ph)}{ReN{mer-L(Gly)}(H2O)}]2. Both facial and meridional coordination has been found for the tridentate {L(Gly)}2− ligand in the building blocks of the tetramer. Syn and anti isomers with respect to the PPhMe2 ligands have been isolated and characterized by X-ray diffraction.

N-[N′,N′-Methylphenylamino(thiocarbonyl)]benzimidoyl chloride (1) reacts with in situ-prepared arylselenolates or aryltellurolates under formation of the first representatives of the corresponding iminoselenides or -tellurides. The products are air-stable solids, which have been studied spectroscopically and by single-crystal X-ray diffraction.

[ReOCl3(PPh3)2] reacts with phenylbis(2-pyridyl)phosphine (PPhpy2) in boiling THF under the formation of the rhenium(III) compound [ReCl3(PPh3)(OPPhpy2-O,N)]. Reduction of the metal can be avoided by milder reaction conditions, and an asymmetric, oxo-bridged rhenium(V) dimer of the composition (NBu4)[Re2O2Cl5(μ-PPhpy2-P,N,N′)(μ-O)] is obtained from the reaction of PPhpy2 and (NBu4)[ReOCl4] in THF at room temperature. The products have been characterized spectroscopically and by X-ray structure analyses.

(NBu4)[ReOCl4] reacts with N-picolyl-N′-benzoylthiourea (H2picbtu) in acetone under formation of the deep-green oxorhenium(V) complex (NBu4)2[{Re2O2Cl5(Hpicbtu)}2O], which was studied by X-ray diffraction. Two dimeric units with each one bridging, singly deprotonated thiourea ligand are connected by an oxo ligand. Inside the subunits, Hpicbtu− coordinates as S,O chelate with a six-membered chelate ring to one rhenium atom, while a five-membered chelate ring is established with the second Re atom and the nitrogen atoms of the picolylamine building block. The compound represents one of the very rare examples of anionic μ-oxorhenium(V) complexes.

The reaction of (NBu4) [ReNBr4] with BBr3 in CH2Cl2 gives purple crystals of (NBu4)2[(OH2)Br4ReNReBr4NReBr 4(OH2)]. The centrosymmetric complex anion is formed by three ReBr4 units which are linked by two asymmetric nitrido bridges with ReN distances of 1.69(2) and 2.00(2) A. The coordination spheres of the terminal Re atoms are completed by water ligands. The EPR spectra of the trimer suggest a d2-d1-d2 sequence for the Re atoms. The g, AReand ABr tensor components deviate from those of [ReNBr4] − and indicate an increase in the ReBr covalency.

A technetium(IV) complex of the composition trans-[TcCl4(tht)2] (tht = tetrahydrothiophene) is formed during heating of K2TcCl6 in a mixture of tht and aqueous HCl. The thioether ligands are only weakly bonded and the red crystals slowly decompose under release of tht. The weak technetium–sulphur bonds are confirmed by Tc–S distances of 2.494(1) A. The anionic thioether technetium(IV) complex [TcBr5(tht)]− is formed by the reaction of (NBu4)2[TcBr6] with neat tht. The tetrabutylammonium salt of the complex is indefinitely stable in air.

(MesTe)2 reacts with equivalent amounts of iodine to produce a crystalline powder. Attempts to crystallize mesityltellurenyl monoiodide (MesTeI) were unsuccessful and we always obtained Mes(I)Te(TeMes2) from the recrystallization of the crude solid. The structure of the new organotellurium(II) halide has been studied by means of single crystal X-ray diffractometry. The three-centre system Te2–Te1–I1 is approximately linear, suggesting the occurrence of a charge transfer complex. The geometry about the Te1 atom is a distorted T-shape, indicating the presence of a stereochemically active lone pair.

2-Pyridineformamide thiosemicarbazone (HL1) reacts with UO2(NO3)2 · 6H2O or [NBu4]2[UO2Cl4] under deprotonation and formation of neutral uranyl complexes. The composition of the products is dependent on the solvents used: [UO2(L1)(OH)]2 is formed when acetonitrile is used, whereas the hydrogen-bonded dimer [UO2(L1)(MeO)(MeOH)]2 is the product in methanol. Both products have been studied by X-ray crystallography showing uranium–uranium distances of 3.750 and 5.385 A.

Azomethine ligands with electron-withdrawing groups such as bis{N,N′-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-1,2-diaminobenzene (H2L1) or N-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-2-aminophenol (H2L2) react with uranyl nitrate under deprotonation and formation of chelate complexes. The composition of the products can be controlled by the reaction conditions and the denticity of the ligands. Structure determinations have been performed on [NEt3H][UO2(L1)(OMe)], [UO2(L1)(DMSO)] and [NEt3H]2[{UO2(L2)}3(μ3-O)].

The potentially five-dentate ligand diacetylpyridinebis(benzoylhydrazone), H2ac2py(benzhyd)2, reacts with Th(NO3)4·5H2O in methanol under formation of the neutral bis-chelate [Th{ac2py(benzhyd)2}2)]. The co-ordination polyhedron of the 10-coordinate metal ion can best be described to be intermediate between a bicapped cube and a bicapped square antiprism. Bond length between 2.390(3) and 2.398(3) A have been found for the Th–O bonds, whereas the Th–N distances are in the range between 2.644(3) and 2.781(4) A.

The title compound is formed during the reaction of [ReN(Me2PhP)(Et2dtc)2] (Me2PhP=dimethylphenylphosphine, Et2dtc−=diethyldithiocarbamate) with excess BH3 in tetrahydrofurane. Two ReV atoms are linked by two (NBH2SBH3)4− units which act as three-dentate ligands via N, S and H forming an eight-membered metallacycle with additional coordination of an hydrido H atom trans to the nitrogen atom. The ReN multiple bond length is 1.70(1) A which is only slightly longer than in the starting compound [ReN(Me2PhP)(Et2dtc)2] (1.666(6) A).

The reaction of the organometallic complex [AuIII(damp-CI,N)Cl2] (damp-C,N− = dimethylaminomethylphenyl) with PhP(C6H3SH-2-SiMe3-3) 2, H2L, results in cleavage of the AuC bond and the formation of [AuIIILCl] and [AuIL2AuIII] complexes. The square coordination environment of gold in [AuLCl] is noticeably distorted (maximum deviation from planarity: 0.326(1) A) by the steric requirements of the tridentate chelating ligand, but the oxidation state ‘+3’ of the metal is retained. [AuIL2AuIII] contains gold atoms in both square-planar (AuIII) and linear (AuI) coordination environments. The square-planar AuIII is bound by two trans-chelated PS units, and the two remaining thiolate groups provide the linear coordination of AuI. The Au-Au distance is 2.919(1) A, indicative of a weak bonding interaction.

X-band and Q-band EPR spectra of the cationic 5d5 ‘low-spin’ ( S= 1 2 ) nitrosylrhenium(II) complex [ReII(NO)Cl2(OPPh3)3] [ReO4] show a well resolved 185' 187Re hyperfine pattern characterized by slightly rhombic g and ARe tensors. The hyperfine parameters are discussed in terms of spin-density distribution and compared with the result obtained from extended Huckel theory molecular orbital (EHT-MO) calculations.

The reaction between dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], and the thiosemicarbazones of 2-acetylpyridine (HAPTSC) or 4-hydroxy-3-methoxybenzaldehyde, vanilline (HVTSC) leads to the formation of the first gold(III) thiosemicarbazone complexes. The reactions occur under cleavage of the AuN bond and protonation of the amino group. The heterocyclic tridentate ligand HAPTSC binds to gold by formation of two five-membered rings, the bidentate ligand HVTSC by formation of one five-membered ring. Crystal structures and spectroscopical data of the novel complexes are discussed.

The EPR detection of the formation of two tetrahalogeno ReVI (5d1) complexes containing a nitrogen bridge ‘Re-N-E’ (E = ⊕C(C6H5)3) is described. Their EPR parameters are compared to those of the [ReNX4]− (X = Cl, Br) parent complexes; spin-density changes are discussed.

The existence of [ReNF4]− as a product of the reaction of [ReNX4]− (X=Cl, Br) with (n-Bu4N)F was confirmed by EPR. The EPR data are used to get information about the bonding properties of [ReNF4]−.