Reversible single-crystal to single-crystal transformations in a Hg(II) derivative. 1D-polymeric chain ⇋ 2D-networking as a function of temperature

Reactions of HgX2 (X = Cl-, Br-, l-) with the ligand hep-H (hep-H = 2-(2-hydroxyethyl)pyridine) in methanol at 298 K result in 1D-polymeric chains of [(X)Hg(μ-X)2(hep-H)]∞, 1-3, respectively, where hep-H binds to the Hg(II) ions in a monodentate fashion exclusively with the pyridine nitrogen donor and the suitably ortho-positioned -(CH2)2OH group of hep-H remains pendant. The packing diagrams of 1-3 exhibit extensive intramolecular and intermolecular hydrogen bonding interactions leading to hydrogen bonded 2D network arrangement in each case. Though the single crystal of either 2 (X = Br) or 3 (X = I) loses crystallinity upon heating, the single crystal of 1 selectively transforms to a 2D-polymeric network, 4 on heating at 383 K for 1.5 h. The polymeric 4 consists of central dimeric [Hg(μ3-Cl)(hep-H)Cl]2 units, which are covalently linked with the upper and lower layers of [-(μ-Cl)2-Hg-(μ-Cl)2-Hg(μ-Cl)2-]n. The packing diagram of 4 reveals the presence of O-H-Cl and C-H-Cl hydrogen bonding interactions which in effect yields hydrogen bonded 3D-network. Remarkably, the single crystals of 4 convert back to the single crystals of parent 1 on standing at 298 K for three days

Polyethersulfone supported titanium complexes as ethylene polymerization catalysts

Polyethersulfone has been used as the support to anchor TiCl4 or Cp2TiCl2 through dative 'O-Ti' bond. The supported complexes in combination with methylaluminoxane are effective ethylene polymerization catalysts. The polyethylene made by the supported catalysts, especially the titanocene-derived catalyst, has low polydispersity indicating single site character

Facile formation of hexahydroporphyrin complexes by reduction of octaethylisobacteriochlorinnickel(II)

Under extremely mild conditions (room temperature) the hexahydroporphyrin 2 isomerizes to its tautomer 3. Complex 2 is the first metal complex with a 2,3,7,8,15,23-hexahydroporphyrin as ligand and is synthesized from 1 by reduction with sodium amalgam

F430 model chemistry. Evidence for alkyl- and hydrido-nickel intermediates in the reactions of the nickel(I) octaethylisobacteriochlorin anion

The reactions of Ni<SUP>I</SUP>(OEiBC)- with alkyl (isomeric propyl, butyl, and hexyl) and aryl halides were investigated in acetonitrile, dimethylformamide, and tetrahydrofuran solutions. The principal products result from reduction or dehydrohalogenation of the alkyl or aryl halide. Alkene formation is favored by more polar solvents and by secondary vs primary substitution of the alkyl halide. Isomerization of alkenes occurs during the reaction, which strongly implies the intermediacy of hydrido-nickel intermediates. Coupling processes, which produce significant quantities of ethane from methyl iodide, become insignificant as the length or steric bulk of the alkyl group increases. No coupling products are observed for aryl or benzyl halides. The current observations provide strong support for the nonradical nickel-based mechanism previously proposed and suggest that the dehydrohalogenation processess in this system involve β -hydride elimination

F430 model chemistry. Mechanistic investigation of the reduction, coupling, and dehydrohalogenation of alkyl halides by the nickel(I) octaethylisobacteriochlorin anion

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Varying structural motifs in oxyanions (NO<SUB>3</SUB><SUP>−</SUP>, CO<SUB>3</SUB><SUP>2−</SUP>) and phenoxyacetate (PhOAc<SUP>−</SUP>) bridged coordination polymers derived from alkoxo-bridged dicopper building blocks with {Cu<SUB>2</SUB>O<SUB>2</SUB>} core

The oxyanions (NO3−, CO32−) and phenoxyacetate (PhOAc−) bridged three 1D-coordination polymeric chains, {[Cu2(μ-hep)2(μ-NO3)]2}n (1), {[Cu2(μ-hep)2(H2O)2]·2H2O(μ-CO3)}n (3) and {[Cu2(μ-hep)2(μ-PhOAc−)]2}n (2) (hep-H = 2-(2-hydroxyethyl)pyridine) have been synthesized. In 1-3 the alkoxide bridged dicopper building units, [Cu(μ-hep)]2 with Cu2O2 core, are linked via the respective anions. Detailed structural analysis reveals that in 1 or 2, two units of NO3− (1) or PhOAc− (2), respectively, bind with the four copper ions in two adjacent alkoxide bridged dimeric units in head-to-head and tail-to-tail fashion and the same binding mode continues along the polymeric chain. This in effect yields a 12-membered metallacyclic ring in between two dimeric core units. However, in 3 only one CO32− group bridges the two copper centres associated with the two neighbouring alkoxide bridged dimeric units in head-to-tail mode which in turn forms a zig-zag polymeric chain. Two coordinated and two lattice water molecules from two adjacent polymeric layers in the structure of 3 form water tetramers. Furthermore, the interaction of water tetramer with the uncoordinated -C=O group of the bridging CO32− develops an additional zig-zag chain which is being trapped between the two outer zig-zag coordination polymeric chains in 3. The polymeric chains in 1-3 further develop a 2D-network pattern via an extensive non-covalent hydrogen bonding as well as C-H···π and π···π interactions

Synthesis, structure, and electrochemistry of acetylide and oxo incorporated mixed Fe/Mo and Fe/W chalcogen-bridged clusters

Thermolysis of a benzene solution containing [Fe2Mo(CO)10(&#956;3-Se)2] (1) and [(&#951;5-C5Me5)W(CO)3C&#8801;CPh] (2) under an optimum concentration of oxygen in the reaction medium yields the cluster [(&#951;5-C5Me5)MoWFe2(O)(&#956;3-Se)(&#956;4-Se)(CO)8(CCPh)] (3), containing a monooxygenated metal center. Under an argon atmosphere, thermolysis of [Fe2Mo(CO)10(&#956;3-S)2] (4) with [(&#951;5-C5Me5)W(CO)3CCPh] (2) in benzene leads to an oxygen-free mixed metal cluster [(&#951;5-C5Me5)MoWFe4(&#956;3-S)3(&#956;4-S)(CO)14(CCPh)] (9). Interestingly, on reacting a benzene solution of 4 with 2 and [(&#951;5-C5Me5)Mo(CO)3C&#8801;CPh] (5) under an increased concentration of oxygen in the reaction medium gave way to clusters [(&#951;5-C5Me5)WMo2(&#956;-O)2(&#956;-S)(&#956;3-CCPh){Fe2(CO)6(&#956;3-S)2}2] (6), [(&#951;5-C5Me5)WMo(O)2(&#956;-O)(&#956;-CCPh){Fe2(CO)6(&#956;3-S)2}] (7), and [(&#951;5-C5Me5)Mo3(&#956;-O)2(&#956;-S)(&#956;3-CCPh){Fe2(CO)6(&#956;3-S)2}2] (8) with higher oxygen content. The structures of the newly formed clusters 3, 6, 7, 8, and 9 were established crystallographically and the oxo-containing Mo and W clusters investigated electrochemically

Synthesis, structure, and electrochemistry of [(&#951;<SUP>5</SUP>-C<SUB>5</SUB>H<SUB>5</SUB>)<SUB>2</SUB>Mo<SUB>2</SUB>WFe<SUB>2</SUB>(O)<SUB>2</SUB>(S)<SUB>2</SUB>(CO)<SUB>9</SUB>(CCPh)<SUB>2</SUB>]

Thermolysis of a toluene solution containing [Fe2W(CO)10(&#956; 3-S)2] (1) and [(&#951;5-C5H5)Mo(CO)3(CCPh)] (2) in the presence of air at 70 &#176;C yields the mixed-metal cluster [(&#951;5-C5H5)2Mo2WFe2(O)2(S)2(CO)9(CCPh)2] (3). The structure of 3 has been established crystallographically. It consists of a triangular Fe2W unit, each face of which is capped by a sulfido ligand. Each Fe atom bears three carbonyl groups, while the W atom is attached to two different Mo-containing moieties. It is &#960;-bonded to the C&#8801;C bond of a (&#951;5-C5H5)Mo(CO)3(C&#8801;CPh) unit, and it is also bonded to a second Mo atom, and this bond is bridged by an oxo group and a &#956;2,&#951;2-CCPh group. Also attached to this Mo atom is a terminal oxo group. Compound 3 has been investigated electrochemically

Synthesis, structure, electrochemistry and ROMP-activity of new ferrocenyl analog of Grubbs’ metathesis catalyst

Treatment of [(PCy3)2Cl2Ru=CH–Ph] (I) with vinylferrocene 1 and 1-ferrocenyl-1,3-butadiene 2 yielded solid products. These new complexes were characterized by 1H NMR, 31P NMR and 13C NMR spectroscopy. X-ray crystal structures of both the complexes have been solved. The crystal structure of II confirmed the assigned structure and revealed existence of two sets of intermolecular C–H–Cl(M) type interactions, viz. (Ru)Cl–H–C(ferrocene) and (Ru)Cl–H–CHCl2. The air-stable, dark solid II is an efficient catalyst for ring-opening metathesis polymerization (ROMP) of cyclopentene, norbornene and cycloocta-1,5-diene. Electrochemical behavior of the complexes clearly reflects electronic communication between two metal centers.© Elsevie