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Reactions of [NH 4 ] 2 [PdCl 4 ] with N -protonated or N -alkyl-1,3,5-triaza-7-phosphaadamantane iodide salts [PTA-R]I (R = H, Me, Et, n Pr, n Bu) give the water-soluble palladium(II) complexes of type [PdI 3 (PTA-R)] in isolated yields of 62–81%. All these compounds have been fully characterized by IR and NMR spectroscopies and elemental analyses. Their molecular structures were confirmed by single crystal X-ray diffraction analysis. The complexes belong to the relatively unusual zwitterionic, coordination compounds. Moreover, they constitute, as far as we are aware, the first reported examples of palladium compounds bearing N -alkyl-1,3,5-triaza-7-phosphaadamantane ligands. The complexes catalyze efficiently Heck reaction of iodobenzene and n -butyl acrylate as well as iodobenzene and substituted styrenes, under mild conditions in water as a solvent. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of the hydrospirophosphorane HP(OCMe2CMe2O)2 ligand or the five-membered cyclic hydrogen phosphonate HP(O)(OCMe2CMe2O) ligand with the ReOCl3(OPPh3)(SMe2) precursor under controlled reaction conditions led to the isolation of dimeric oxo-rhenium(V) complexes containing P(O)(OCMe2CMe2O)− moieties, represented by [ReOCl2{μ-OP(OCMe2CMe2O)}3ReOCl(OPPh3)] (1) and [ReOCl2(SMe2){μ-OP(OCMe2CMe2O)}]2 (2). The chemical composition of these complexes was established by means of NMR, IR spectroscopic methods, and based on analytical data. The relative stereochemistry of 1 and 2 was unambiguously determined by single X-ray diffraction studies. The crystal structure of 1 comprises two crystallographically independent molecules in an asymmetric unit and co-crystallised molecules of both dichloromethane and acetonitrile. Two different six-coordinated monomeric subunits, ReOCl2 and ReOCl(OPPh3), connected by three phosphonate bridges, build up the dinuclear complex 1. It exhibits an uncommon feature, a cis disposition of the triphenylphosphine oxide molecule relative to the terminal Rehe crystal structure of 2 includes four molecules, in which two equivalent rhenium subunits ReOCl2(SMe2) are linked by two P(O)(OCMe2CMe2O)− bridges. [Copyright &y& Elsevier]

Abstract: The treatment of ReOCl3(OPPh3)(SMe2) with an appropriate amount of [1,3]- and [1,4]-diaza heterocyclic ligands N∼N (were N∼N=pyrimidine (pym) and pyrazine (pyz)) in boiling acetonitrile under different reaction conditions yielded either the mononuclear ReOCl3(OPPh3)(pym) (1), ReOCl3(OPPh3)(pyz) (2) or dinuclear compounds [ReOCl3(OPPh3)]2(μ-pym) (3), [ReOCl3(OPPh3)]2(μ-pyz) (4). The new complexes were characterized in solution by means of NMR, IR, FIR, and UV–Vis spectroscopic methods. The molecular and crystal structures of 1, 3 and 4 were also determined by X-ray crystallography. All complexes adopt distorted octahedral geometries, with similar donor atoms arrangement, were axial positions are taken by terminal oxygen and triphenylphosphine oxide molecules. The equatorial planes are occupied by three chloride ligands and one nitrogen atom of the diaza ligand. The dinuclear complexes 3 and 4 comprise two equivalent six-coordinated monomeric units. Two halves of the dimer molecule are rotated about the Re–N∼N–Re fragment: thus, an N-heterocyclic ring is stacked with two adjacent phenyl rings belonging to two triphenylphosphine oxide ligands. The preliminary results concerning the reactivity of the dimeric complexes point to their relative inertness in attempted further substitution towards synthesis of polynuclear complexes. [Copyright &y& Elsevier]

The 2nd generation Grubbs-Hoveyda complex in the presence of triphenylphosphine is efficient catalyst for the synthesis of 1,4-disubstituted enynes with preference for Z -selectivity. The experimental and theoretical results revealed that its activity is related with σ-donor ability and bulkiness of added phosphine combined with small size alkyne bearing electron-withdrawing group. [Display omitted] The 2nd generation Grubbs-Hoveyda complex in the presence of slight excess of triphenylphosphine was found as an efficient catalyst for the synthesis of 1,4-disubstituted enynes with preference for head-to-head coupling and Z -selectivity form in the dimerization of various terminal aryl alkynes. Selective product formation was affected by the steric and the electronic properties of the phosphine used as well as the substituents of the alkynes. In order to shed some light on the properties of the alkynes that may affect the yield of desired products a set of 14 alkyne derivatives was characterized on the basis of Density Functional Theory (DFT) using ωB97XD functional and 6-311++G(d,p) basis set. The Atoms in Molecules (AIM) theory was employed for electronic structure and topological analyses of the investigated compounds. The quantitative description of the substituent effect was carried out with assistance of the Harmonic Oscillator Model of Aromaticity (HOMA), charge of the Substituent Active Region (cSAR(X)) and Substituent Effect Stabilization Energy (SESE). It was found that substituents in the phenyl ring are able to affect the geometric and electronic structure of the alkynyl moiety. The experimental and theoretical results revealed that high activity of the investigated ruthenium complex towards dimerization of alkynes is related with σ-donor ability and bulkiness of added phosphine combined with small size aryl alkyne bearing electron-withdrawing group. However, the influence of the structure of aryl alkyne on the catalyst activity could not be easily explained only on the basis of steric and electronic factors. [ABSTRACT FROM AUTHOR]

The origin of oxygen atoms in oxido-bridged cubo-octahedral hexanuclear rhenium clusters [Re 6 (μ-O) 12 L 6 ] + (L – aromatic amine) has been investigated thoroughly. We confirmed that water is a crucial agent in the creation of the Re 6 (μ-O) 12 core. The reaction of ReI 3 with H 2 18 O and 3-methylpyridine was carried out resulting in the formation of [Re 6 (μ- 18 O) 12 (3-Mepy) 6 ]I complex. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigated reactivity of ReCl3 and ReI3 in excess of N-heterocyclic compounds. [•] Two kinds of complexes rhenium(III) and rhenium(V) were synthesized. [•] Single crystal X-ray diffraction and spectroscopic studies were performed. [Copyright &y& Elsevier]

Abstract: We investigated the coordination properties of H-spirophosphoranes towards rhodium ion. Symmetrical phosphorus ligands: HP(OCH2CH2NH)2 L1, HP(OCH2CMe2NH)2 L2, HP(OCMe2CMe2O)2 L3, HP(OC6H4NH)2 L4, and unsymmetrical phosphorus ligands: HP(OCMe2CMe2O)(OCH2CMe2NH) L5, HP(OCMe2CMe2O)(OC6H4NH) L6 were found to coordinate to rhodium precursor [Rh(CO)2Cl]2 exclusively in protonated κ 2-P,E (E = N, O) bidentate fashion, yielding complexes [Rh(CO)ClL] 1–6. The complexes were characterised by spectroscopic methods. The molecular structures of the ligand L6 complexes 3, 5 and 6 were determined by single-crystal X-ray diffraction. The catalytic activity of the complexes was determined in hydroformylation reaction of 1-hexene. Complexes 1 and 2 appeared to be active in isomerisation reactions yielding 76 and 62% of 2-hexene. When used with six-fold excess of triphenylphosphite P(OPh)3 as a modified ligand, the most active catalyst 1 in hydroformylation reaction produced 66% of aldehydes and 22% of 2-hexene. [Copyright &y& Elsevier]

Abstract: New preparative methods have been developed for the synthesis of the rhenium(I) carbonyl complexes [Re(CO)2(OAc)(PPh3)2] (1) and [ReCl(CO)3(PPh3)2] (2). Acetic anhydride was decarbonylated during the course of its reaction with [ReOCl3(PPh3)2], resulting in the formation of the rhenium(I) carbonyl complex [Re(CO)2(OAc)(PPh3)2] (1), which was subsequently converted almost quantitatively to [ReCl(CO)3(PPh3)2] (2) via the decarbonylation of its acetate group under acidic conditions. [Copyright &y& Elsevier]