Proceedings of the 24th Paediatric Rheumatology European Society Congress: Part three

From Springer Nature via Jisc Publications Router.Publication status: PublishedHistory: collection 2017-09, epub 2017-09-0

N-[1-Phenyl-2,5-bis(trimethylsilyl)pent-2-en-4-yn-1-yl]aniline

The molecular structure of the title compound, C23H31NSi2, reveals an acyclic conjugated enyne unit as the main feature. The central pent-2-en-4-yl fragment is essentially planar, with a maximum deviation of 0.0492 (7) Å from the mean plane defined by the C—C=C—C[triple-bond]C unit. The dihedral angle between the phenyl rings is 84.44 (5)°

Synthesis and crystallographic characterization of [2,2-bis(η5-pentamethylcyclopentadienyl)-3,4-bis(trimethylsilyl)-2-zirconafuran-5-one-κO5]triisobutylaluminium

The crystal structure of the title zwitterionic zirconocene complex containing a furanone unit, [AlZr(C10H15)2(C4H9)3(C9H18O2Si2)], is reported. On reacting a zirconafuranone with two equivalents of HAl(i-Bu)2, disproportionation of the Lewis acid results in the formation of a triisobutylaluminium fragment, Al(i-Bu)3, which coordinates to the exocyclic carbonyl O atom of the zirconafuranone ring. Single-crystal X-ray diffraction reveals that the zirconafuranone ring remains intact with coordination of the aluminium to the exocyclic O atom. One of the i-butyl groups is disordered over two sets of sites, with an occupancy ratio of 0.731 (3):0.269 (3)

(Table 1) Turbidity, temperature, and salinity in the hydrothermal plume and background waters above the northern part of the Mohn's Ridge at Station AMK36-3573-5

In July 1995 geological and biological studies in the axial zone of the northern part of the Mohn's Ridge (72°20'N) were carried out during Cruise 36 of R/V Akademik Mstislav Keldysh. Slopes of the neovolcanic zone, as well as a caldera on its crest were investigated with use of deep-sea manned submersibles Mir, geological and biological samples were also collected. Use of the Rosette sounding complex provided recognition of several major hydrothermal plumes. Bottom sediments of the marginal depression are enriched in metals characteristic for hydrothermal metalliferous sediments. Thus, a new unknown hydrothermal field was found

Thermal Isomerization of the Buchwald Seven-Membered Zirconacyclocumulene and Its Interaction with Acetylenes. Synthesis and Structures of Novel Seven-Membered Zirconacyclocumulene Complexes

On prolonged heating of the Buchwald seven-membered zirconacyclocumulene Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(C₂SiMe₃)CSiMe₃] (<b>1</b>) in toluene at 100 °C, the isomerization of <b>1</b> takes place with the formation of a seven-membered zirconacyclocumulene complex, Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(SiMe₃)C­(C₂SiMe₃)] (<b>8</b>), containing the Me₃SiCC group in α-position and the SiMe₃ group in β-position with respect to the Zr atom. A remarkable peculiarity of complex <b>8</b> is its ability to undergo a rapid degenerate rearrangement at room temperature in toluene solution, as a result of which only two rather than four singlets of the Me₃Si groups are observed in the ¹H NMR spectrum of <b>8</b> under such conditions. At temperatures below 200 K, the rate of this rearrangement decreases and, as a consequence, the ¹H NMR spectrum of <b>8</b> acquires the normal view. If <b>1</b> is heated at 100 °C in the presence of acetylenes such as 1,4-bis­(<i>tert</i>-butyl)­butadiyne (^<i>t</i>BuCC–CC^<i>t</i>Bu) and tolane, the corresponding seven-membered zirconacyclocumulenes, viz., Cp₂Zr­[η⁴-^<i>t</i>BuC₄(^<i>t</i>Bu)–C­(C₂SiMe₃)CSiMe₃] (<b>7</b>) and Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(Ph)CPh] (<b>14</b>), are formed along with free Me₃SiCC–CCSiMe₃. The interaction of <b>1</b> with 1,4-diphenylbutadiyne (PhCC–CCPh) at 100 °C leads to the formation of a mixture of products, from which a zirconacyclopentadiene metallacycle, Cp₂Zr­[η²-PhCC­(C₂Ph)–C­(C₂Ph)CPh] (<b>10</b>), as well as seven-membered zirconacyclocumulenes Cp₂Zr­[η⁴-PhC₄(Ph)–C­(C₂SiMe₃)CSiMe₃] (<b>11</b>), Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(C₂Ph)CPh] (<b>12</b>), and Cp₂Zr­[η⁴-PhC₄(Ph)–C­(C₂Ph)CPh] (<b>13</b>) were isolated. The structures of <b>8</b>, <b>9</b>, <b>10</b>, <b>12</b>, and <b>14</b> have been established by X-ray crystallography. The mechanism of the reactions found is discussed

Thermal Isomerization of the Buchwald Seven-Membered Zirconacyclocumulene and Its Interaction with Acetylenes. Synthesis and Structures of Novel Seven-Membered Zirconacyclocumulene Complexes

On prolonged heating of the Buchwald seven-membered zirconacyclocumulene Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(C₂SiMe₃)CSiMe₃] (<b>1</b>) in toluene at 100 °C, the isomerization of <b>1</b> takes place with the formation of a seven-membered zirconacyclocumulene complex, Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(SiMe₃)C­(C₂SiMe₃)] (<b>8</b>), containing the Me₃SiCC group in α-position and the SiMe₃ group in β-position with respect to the Zr atom. A remarkable peculiarity of complex <b>8</b> is its ability to undergo a rapid degenerate rearrangement at room temperature in toluene solution, as a result of which only two rather than four singlets of the Me₃Si groups are observed in the ¹H NMR spectrum of <b>8</b> under such conditions. At temperatures below 200 K, the rate of this rearrangement decreases and, as a consequence, the ¹H NMR spectrum of <b>8</b> acquires the normal view. If <b>1</b> is heated at 100 °C in the presence of acetylenes such as 1,4-bis­(<i>tert</i>-butyl)­butadiyne (^<i>t</i>BuCC–CC^<i>t</i>Bu) and tolane, the corresponding seven-membered zirconacyclocumulenes, viz., Cp₂Zr­[η⁴-^<i>t</i>BuC₄(^<i>t</i>Bu)–C­(C₂SiMe₃)CSiMe₃] (<b>7</b>) and Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(Ph)CPh] (<b>14</b>), are formed along with free Me₃SiCC–CCSiMe₃. The interaction of <b>1</b> with 1,4-diphenylbutadiyne (PhCC–CCPh) at 100 °C leads to the formation of a mixture of products, from which a zirconacyclopentadiene metallacycle, Cp₂Zr­[η²-PhCC­(C₂Ph)–C­(C₂Ph)CPh] (<b>10</b>), as well as seven-membered zirconacyclocumulenes Cp₂Zr­[η⁴-PhC₄(Ph)–C­(C₂SiMe₃)CSiMe₃] (<b>11</b>), Cp₂Zr­[η⁴-Me₃SiC₄(SiMe₃)–C­(C₂Ph)CPh] (<b>12</b>), and Cp₂Zr­[η⁴-PhC₄(Ph)–C­(C₂Ph)CPh] (<b>13</b>) were isolated. The structures of <b>8</b>, <b>9</b>, <b>10</b>, <b>12</b>, and <b>14</b> have been established by X-ray crystallography. The mechanism of the reactions found is discussed

Effect of Activator and Outgoing Ligand Nature on the Catalytic Behavior of Bis(phenoxy-imine) Ti(IV) Complexes in the Polymerization of Ethylene and Its Copolymerization with Higher Olefins

A series of bis(phenoxy-imine) (FI) titanium(IV) and zirconium(IV) complexes have been synthesized. The effect of the nature of the activator (MAO, combinations EtnAlCl3-n + Bu2Mg and iBu3Al + [Ph3C]+[B(C6F5)4]&minus;) on the catalytic activity and properties of the resulting polymers was studied. It was found that Ti-Fi complexes, despite the nature of the outgoing ligands (Cl or iPrO) in the presence of Al/Mg activators, effectively catalyze the polymerization of ethylene (with the formation of UHMWPE); copolymerization of ethylene with 1-octene (with the formation of ultra-high molecular weight copolymers); and the ternary copolymerization of ethylene, propylene and 5-vinyl-2-norbornene (with the formation of polyolefin elastomers). It has been shown that Zr-FI complexes are not activated by these Al/Mg compositions. The resulting UHMWPE can be processed by a solventless method into high-strength and high-modulus oriented films; however, their mechanical characteristics do not exceed those obtained using MAO