Syntheses of Iminophosphomamido Chlorogermylenes and Their Complexation with a Rhodium(I) Complex.

Three-coordinated chlorogermylenes of the type [Ph P(RN) ]GeCl (3: R= Bu; 4: R=Dip=2,6- Pr C H ), which bear an N,N-substituted iminophosphonamide ligand, were synthesized. The coordination behavior of 3 and 4 toward rhodium(I) complex was investigated. When 3 was treated with 1/2 of an equivalent of [RhCl(cod)] (cod=1,5-cyclooctadiene), the corresponding chlorogermylene-Rh(I) complex 5 was obtained as orange crystals.

Synthesis of a homoleptic tris(silylene)-palladium(0) complex and a silylyne-bridged tetranuclear palladium cluster.

We report the reactions of an iminophosphonamido-silylene (1) with different palladium complexes. The reaction of 1 with [Pd(PPh)] furnished a homoleptic tris(silylene)-palladium(0) complex. In contrast, treatment of 1 with [PdMe(tmeda)] led to the unprecedented formation of a non-planar -silylyne-bridged tetranuclear palladium cluster that contains palladium atoms in different oxidation states.

Niobium Complexes Supported by Chalcogen-Bridged [OEO]-Type Bis(phenolate) Ligands (E = S, Se): Synthesis, Characterization, and Phenylacetylene Polymerization.

Trichloro niobium(V) complexes and with the sulfur- or selenium-bridged [OEO]-type bis(phenolate) ligands (E = S, Se) were synthesized and fully characterized on the basis of their NMR spectroscopic data and X-ray crystallographic analysis. In the crystalline state of , the [OSeO]-core of the ligand was coordinated to the niobium center in a -fashion. The corresponding tribenzyl niobium(V) complexes and were also prepared by the reactions of and with 3 equivalents of PhCHMgCl in toluene.

Iminophosphonamido-Supported Plumbylenes and Plumbyliumylidenes: Synthesis and Properties.

A series of low-valent lead(II) species, i.e., plumbylenes and plumbyliumylidenes supported by an ,'-di--butyliminophosphonamide ligand, have been synthesized.

Halogen-Exchange Reactions of Iminophosphonamido-Chlorosilylenes with Alkali Halides: Convenient Synthesis of Heavier Halosilylenes.

Halogen-substituted silylenes are an important building block for synthesizing silicon-based low-valent and multiple-bond species. However, the number of reports on heavier halosilylenes that contain bromine and iodine is still limited. Here, we present a convenient synthesis for bromo- and iodosilylenes supported by an iminophosphonamide ligand.

Novel [FeFe]-Hydrogenase Mimics: Unexpected Course of the Reaction of Ferrocenyl α-Thienyl Thioketone with Fe(CO).

The influence of the substitution pattern in ferrocenyl α-thienyl thioketone used as a proligand in complexation reactions with Fe(CO) was investigated. As a result, two new sulfur-iron complexes, considered [FeFe]-hydrogenase mimics, were obtained and characterized by spectroscopic techniques (H, C{H} NMR, IR, MS), as well as by elemental analysis and X-ray single crystal diffraction methods. The electrochemical properties of both complexes were studied and compared using cyclic voltammetry in the absence and in presence of acetic acid as a proton source.

Hydroboration of carbonyls and imines by an iminophosphonamido tin(II) precatalyst.

A novel three-coordinated tin(II) chloride [PhP(NBu)]SnCl (1) supported by an ,'-di--butyliminophosphonamide having two phenyl groups on the phosphorus atom was synthesized by the reaction of the starting lithium iminophosphonamide [PhP(NBu)]Li with SnCl·(dioxane) in toluene. The molecular structure of 1 was established by X-ray diffraction analysis. Tin(II) chloride 1 can act as an efficient precatalyst for the hydroboration of a wide variety of aldehydes, ketones, and imines at -10 °C.

Formation of silaimines from a sterically demanding iminophosphonamido chlorosilylene intramolecular N-P bond cleavage.

The sterically demanding iminophosphonamido chlorosilylene [Ph2P(DipN)2]SiCl (Dip = 2,6-diisopropylphenyl) was synthesized and fully characterized using NMR spectroscopy and X-ray crystallography. Substitution reactions of [Ph2P(DipN)2]SiCl with N- and Fe-nucleophiles led to the unexpected formation of the corresponding silaimine derivatives. This process involves the ring-opening rearrangement of three-coordinated silylene intermediates that proceeds via intramolecular N-P bond cleavage.

Interconversion between a silaimine and an aminosilylene supported by an iminophosphonamide ligand.

The reaction of a chlorosilylene, supported by an iminophosphonamide ligand, with KN(SiMe) resulted in the formation of a silaimine instead of the expected aminosilylene. However, this silaimine exists in equilibrium with the corresponding aminosilylene, which was experimentally demonstrated using variable-temperature NMR spectroscopy and a trapping reaction with elemental selenium to give a silaselenourea.

An Iminophosphonamido-Chlorosilylene as a Strong σ-Donating NHSi Ligand: Synthesis and Coordination Chemistry.

The N-heterocyclic silylene (NHSi) [Ph P( BuN) ]SiCl (1), supported by an iminophosphonamide ligand, was obtained from the dehydrochlorination of [Ph P( BuN) ]SiHCl (2) with LiN(SiMe ) . NHSi 1 contains an extremely high-energy HOMO level and consequently displays unique coordination behavior toward Rh complexes. When 1 was treated with 1/4 of an equivalent of [RhCl(cod)] (cod=1,5-cyclooctadiene), the 14-electron Y-shaped bis(chlorosilylene) Rh complex 5 was obtained as dark purple crystals.

Chlorogermylenes and -stannylenes stabilized by diimidosulfinate ligands: synthesis, structures, and reactivity.

The reaction of the lithium salt of N,N'-di-tert-butyldiimidosulfinate ([PhS(NBu)]Li) having a phenyl group on the sulphur atom with ECl·(dioxane) (E = Ge, Sn) afforded the corresponding chlorogermylene [PhS(NBu)]GeCl 1 and -stannylene [PhS(NBu)]SnCl 2, respectively. In contrast, treatment of the N,N'-bis(trimethylsilyl)diimidosulfinate ion ([PhS(NSiMe)]) with ECl·(dioxane) resulted in the unexpected formations of six-membered 1,3-bis(chlorogermylene) [PhS(NSiMe)(η-η-GeCl)[μ-NSPh(NHSiMe)] 7 and -stannylene [PhS(NSiMe)(η-η-SnCl)[μ-NSPh(NHSiMe)] 8. The structures of these chlorometallylene derivatives were fully characterized on the basis of their NMR spectroscopic data and X-ray diffraction.

Enantio- and Stereoselective Cyclopolymerization of Hexa-1,5-diene Catalyzed by Zirconium Complexes Possessing Optically Active Bis(phenolato) Ligands.

Enantio- and stereoselective cyclopolymerization of hexa-1,5-diene was achieved by enantiomerically pure dichloro zirconium(IV) pre-catalysts 2 possessing chiral [OSSO]-type bis(phenolate) ligands (-)-1 and (+)-1 in combination with dried methylaluminoxane (dMAO) as an activator. The corresponding activities were recorded with quite high values up to 1,960 g mmol(2) h , which are extremely larger than those of the related complexes. The microstructure analysis for the PMCPs furnished by pre-catalysts (Λ,S,S)-2 and (Δ,R,R)-2 showed good isotacticity factors (α = 75-78%) and relatively high proportions of trans-cyclopentane rings (σ = 14-21%).

Macromol. Rapid Commun. 12/2016.

Back Cover: Highly isospecific polymerization of silyl-protected ω-alkenols, using a combination of [OSSO]-type bis(phenolato) dichloro zirconium(IV) complex and dMAO as the precatalyst and the activator, respectively, is established. This method represents the first example for a stereoselective polymerization of polar functional α-olefins ([mmmm] > 95%). Subsequently, the obtained terminal siloxy-substituted isotactic polymer could be readily transformed by a macromolecular desilylation/acetylation reaction sequence to afford the corresponding terminal acetyl-enriched polymer.

Highly Isospecific Polymerization of Silyl-Protected ω-Alkenols Using an [OSSO]-Type Bis(phenolato) Dichloro Zirconium(IV) Precatalyst.

The coordination polymerization of silyl-protected ω-alkenols such as ω-alken-α-oxytriisopropylsilanes 1 provides poly(ω-alkenyl-α-oxytriisopropylsilalne)s with a highly isospecific microstructure ([mmmm] > 95%) when a combination of [OSSO]-type bis(phenolato) dichloro zirconium(IV) complex 2 and dried methylaluminoxane is used as the precatalyst and activator, respectively. The resulting siloxy-substituted polymers could be efficiently transformed into the corresponding functionalized polyolefins, which contained up to 90% acetyl groups and ≈7% hydroxy groups in the terminal side chains.

Highly Active and Isospecific Styrene Polymerization Catalyzed by Zirconium Complexes Bearing Aryl-substituted [OSSO]-Type Bis(phenolate) Ligands.

[OSSO]-type dibenzyl zirconium(IV) complexes and possessing aryl substituents ortho to the phenoxide moieties (ortho substituents, phenyl and 2,6-dimethylphenyl (Dmp)) were synthesized and characterized. Upon activation with dMAO (dried methylaluminoxane), complex was found to promote highly isospecific styrene polymerizations ([] = 97.5%⁻99%) with high molecular weights up to 181,000 g·mmol.

Red and Near-Infrared Photoluminescence of D-π-A-Type Compounds Based on a 1,4-Diaryl-1-thio-1,3-butadiene Conjugated System in a Dibenzobarrelene Skeleton.

1,4-Diaryl-1-thio-1,3-butadiene derivatives having a π-donor dimethylamino group and several π-acceptor substituents at both terminals of the conjugated system were synthesized by intramolecular [4 + 2] cycloaddition of 1-thio-enynes and subsequent chemical transformations. They displayed largely red-shifted absorption and emission spectra in solution, the powder state, and in polymer films. The derivatives with a 2,2-dicyanoethenyl group as the π-acceptor exhibited inverted solvatochromism in both optical absorption and fluorescence spectroscopies.

Cationic dinuclear platinum and palladium complexes with bridging hydrogermylene and hydrido ligands.

Hydride-abstraction reactions of hydrido(dihydrogermyl) complexes [MH(GeH2Trip)(dcpe)] [M = Pt, Pd, Trip = 9-triptycyl, dcpe = 1,2-bis(dicyclohexylphosphino)ethane] with B(C6F5)3 led to the unexpected formation of new cationic (μ-germyl)(μ-hydrido) dinuclear platinum and palladium complexes, [{M(dcpe)}2(μ-GeHTrip)(μ-H)](+).

Synthesis of 4-chalcogeno-1-aza-1,3-butadiene derivatives by intramolecular cyano-Diels-Alder reaction and borane-coordination-induced fluorescence enhancement.

4-Thio-1-aza-1,3-butadiene derivatives 3 incorporating a rigid dibenzobarrelene skeleton were synthesized by the intramolecular cyano-Diels-Alder reaction of 9-anthryl cyanoethenyl sulfides 6. The thermal reaction of 6 afforded an equilibrium mixture of 3 and 6, but the cyclization was effectively promoted by the addition of BF3·Et2O or B(C6F5)3 to yield imine-borane adducts 8 and 9. The imine-borane adducts emit intense blue fluorescence both in solution and in the crystalline state.

Titanium complexes supported by an [OSSO]-type bis(phenolato) ligand based on a trans-cyclooctanediyl platform: synthesis, structures, and 1-hexene polymerization.

trans-Cyclooctanediyl-bridged [OSSO]-type ligand 4 reacts with TiCl(4)(thf)(2) in toluene to produce the corresponding titanium(IV) dichloro complexes as an inseparable mixture of cis-α isomer 6a and cis-β isomer 6b in a ratio of 2:1, whereas treatment of dilithio salt of 4 with TiCl(3)(thf)(3) in Et(2)O afforded chloride-bridged dimeric titanium(III) complex 8, which indicated the antiferromagnetic character in a nonpolar solvent solution. Di(isopropoxy) titanium(IV) complex 10 having a C(2)-symmetric cis-α configuration was synthesized by the reaction of 4 with Ti(O(i)Pr)(4) in toluene as yellow crystals. Moreover, the reaction of 4 with Ti(NEt(2))(4) in toluene resulted in the unexpected formation of [OSSO]-type bis(phenolato)-bridged dinuclear diamido titanium(IV) complex 11, which adopted a distorted tetrahedral geometry on the titanium center.

Confluent two-balloon technique: an alternative method for subintimal recanalization of peripheral arterial occlusion.

The present report describes a technique of simultaneous confluent balloon inflation in cases in which conventional subintimal angioplasty failed. Eight patients with peripheral vascular occlusive disease (n = 4 each with iliac arterial lesions and superficial femoral arterial lesions) of clinical category 3-5 received treatment with the confluent two-balloon technique. Recanalization was successfully completed with this technique in all eight patients, without any major complications.

Fluorescent 3-methylene-2,3-dihydrochalcogenophenes incorporated in a rigid dibenzobarrelene skeleton.

The fluorescent 3-methylene-2,3-dihydroselenophene derivative (Φ(F) = 0.86 in CH(2)Cl(2)) incorporated in a dibenzobarrelene skeleton was synthesized by the reaction of a four-membered selenaplatinacycle with dimethyl acetylenedicarboxylate (DMAD) or reaction of bis(dibenzobarrelenyl) diselenide with DMAD in the presence of Pd(PPh(3))(4) and PPh(3). A fluorescent sulfur homologue (Φ(F) = 1.

Empiric transcatheter arterial embolization for massive bleeding from duodenal ulcers: efficacy and complications.

Purpose: To evaluate the efficacy and safety of empiric transcatheter arterial embolization (TAE) for patients with massive bleeding from duodenal ulcers.

Materials And Methods: During January 2000 and December 2009, 59 patients with duodenal ulcer bleeding in whom TAE was attempted after endoscopic therapy failed were retrospectively analyzed. The patients were divided into empiric TAE (n = 36) and identifiable TAE (n = 23) groups according to angiographic findings with or without identification of the bleeding sites.

Syntheses of selenolato-bridged dinuclear hydridoplatinum complexes [Pt2H2(mu-Se(t)Bu)2(PPh3)2] and [Pt2H(Se(t)Bu)(mu-Se(t)Bu)2(PPh3)2]: unusual thermal reaction of hydrido(1,1-dimethylethaneselenolato) platinum complex cis-[PtH(Se(t)Bu)(PPh3)2].

Novel selenolato-bridged dinuclear hydridoplatinum complexes, cis-[Pt(2)H(2)(mu-Se(t)Bu)(2)(PPh(3))(2)] (2) and cis-[Pt(2)H(Se(t)Bu)(mu-Se(t)Bu)(2)(PPh(3))(2)] (3) were synthesized in 30% and 57% yields, respectively, by the thermolysis of hydrido(1,1-dimethylethaneselenolato) Pt(II) complex cis-[PtH(Se(t)Bu)(PPh(3))(2)] (1) in toluene at 80 degrees C for 3 h. The structures of dinuclear complexes 2 and 3 were fully characterized on the basis of their NMR and IR spectroscopic data and X-ray crystallography. The two distorted square planar Pt atoms in 2 and 3 are held together by two bridged selenolato ligands, (t)Bu groups of which adopt a trans configuration with respect to the four-membered Pt(2)Se(2) ring.