Search results for "sandwich"
showing 10 items of 62 documents
Ruthenium Metallodendrimers Based on Nitrile‐Functionalized Poly(alkylidene imine)s
2005
The preparation of the first- and second-generation of nitrile-functionalized poly(alkylidene imine) dendrimers with the organometallic ruthenium complex [Ru(η5-C5H5)(PPh3)2Cl] peripherally attached is described. The reaction of N,N′-bis(cyanomethyl)piperazine (1), N,N′-bis[N′′,N′′′-bis(cyanoethyl)aminoethyl]piperazine (2), or N,N,N′,N′-tetrakis(cyanoethyl)ethylenediamine (3) with [Ru(η5-C5H5)(PPh3)2Cl] (4) in the presence of TlPF6 gives the new air-stable ruthenium metallodendrimers 5, 6, and 7, respectively. These stable metallodendrimers are easily prepared and represent a novel quantitative method to solidify and chromatographically purify the otherwise semi-liquid nitrile-functionalize…
Preparation and Characterization of Novel Poly(alkylidenamine) Nitrile Ruthenium Metallodendrimers
2010
Complete functionalization of N,N,N',N'-[tetrakis(cyanoethyl)-hexamethylenediamine] [N≡C(CH 2 ) 2 ] 2 N(CH 2 ) 6 N[(CH 2 ) 2 -C≡N] 2 (4) and N,N,N',N'-(tetrakis(cyanoethoxypropyl)hexamethylenediamine] [N≡C(CH 2 ) 2 O(CH 2 ) 3 ] 2 N(CH 2 ) 6 N[(CH 2 ) 3 -O(CH 2 ) 2 C≡N] 2 (7) with the organometallic moiety [Ru(η 5 -C 5 H 5 )(PPh 3 ) 2 Cl] and the five-coordinate cis-[RuCl(dppe) 2 ]-[PF 6 ] [dppe = 1,2-bis(diphenylphosphanyl)ethane] was attained with good yield, respectively, by treating the metallo-fragment with the core in methanol (at room temperature and in presence of TIPF 6 as a chloride abstractor) and in 1,2-dichloroethane (under reflux). These novel nitrile-functionalized poly(alkyli…
Diastereoselective Synthesis of Dialkylated Bis(phosphino)ferrocenes: Their Use in Promoting Silver-Mediated Nucleophilic Fluorination of Chloroquino…
2017
International audience; The diastereoselective synthesis of dialkylated ferrocenyl bis(phosphane)s bearing aryl, alkyl, and hetero- or polycyclic substituents on the phosphino groups is reported, together with their characterization in the solid state by X-ray structure analysis and in solution by multinuclear NMR spectroscopy. Introduction of various alkyl groups on the ferrocene backbone, namely, tert-butyl, isopropyl, and trimethylsilyl, has a significant influence on the stereoselectivity of the ensuing lithiation/phosphination reactions. Only the introduction of the tert-butyl groups ensures both a high yield and perfect diastereoselectivity, which leads to the exclusive formation of t…
Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications
2018
Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Corr…
Interaction of half-sandwich alkylmolybdenum(III) complexes with B(C6F5)3. The X-ray structure of [CpMo(η4-C4H6)(μ-Cl)(μ-CH2)(O)MoCp][CH3B(C6F5)3]
2001
Abstract The reactions of the half-sandwich molybdenum(III) complexes CpMo(η 4 -C 4 H 4 R 2 )(CH 3 ) 2 , where Cpη 5 -C 5 H 5 and RH or CH 3 , with equimolar amounts of B(C 6 F 5 ) 3 have been investigated in toluene. EPR monitoring shows the formation of an addition product which does not readily react with Lewis bases such as ethylene, pyridine, or PMe 3 . The analysis of the EPR properties and the X-ray structure of a decomposition product obtained from dichloromethane, [CpMo(η 4 -C 4 H 6 )(μ-Cl)(μ-CH 2 )(O)MoCp][CH 3 B(C 6 F 5 ) 3 ], indicate that the borane attack has occurred at the methyl position.
Modal and Structural FEM Analysis of a 50 ft Pleasure Yacht
2012
In this paper a structural Finite Element analysis of a 50 ft pleasure vessel is presented. The study is performed under different loads conditions: modal analyses have been done in order to find the natural frequencies of the vessel, structural analyses to verify the strength of the vessel to design loads. The design loads for the vessel considered are computed according to RINA rules for the construction and classification of pleasure vessels [1]. Two different composites are used for the lamination: one is a monolithic sequence of short fibre and balanced glass lamina, used for the bottom of the vessel and for structural reinforcements, the other is a sandwich made of glass fibre composi…
Solid state joining of thin hybrid sandwiches made of steel and polymer: A feasibility study
2020
The growing demand for more environmentally friendly vehicles has led to an increased use of light materials in the transportation industry with the aim to reduce structural weight, fuel consumption, and gas emissions, thereby boosting cost-effectiveness and recyclable properties. Complex multi-material steel-based components would allow to improve mechanical properties and minimize weight even further. In particular, new sandwich materials made by steel outer skins and a polymeric internal layer seems very promising for obtaining mechanical performance and lightness at the same time. Unfortunately, traditional welding techniques, like arc welding, laser welding, and resistance spot welding…
Preparation and structure of the 17-electron (η5-C5R5)Mo(OH)2(dppe) (R=Me, Et) organometallic compounds containing two gem-terminal hydroxide ligands
2000
International audience; Oxidation of (η5-C5R5)MoH3(dppe) (R=Me, Et) by Cp2Fe+ in wet THF leads to the formation of the corresponding (η5-C5R5)Mo(OH)2(dppe). These compounds show a low-potential reversible oxidation wave. The structure of the C5Et5 complex has been confirmed by X-ray diffraction methods: triclinic; space group ; a=11.030(1); b=12.533(1); c=16.241 (1) Å; α=68.585(7); β=75.197(5); γ=83.991(7)°; V=2020.6(3) Å3; Z=2; Dcalc=1.324 g cm−3, μ(Mo–Kα)=0.441 mm−1; R1=0.0325; wR2=0.0875 for 415 parameters and 6823 independent reflections [Rint=0.0177] with I=2σ(I). The molecule shows a four-legged piano-stool geometry with two terminal OH ligands in a relative trans configuration. The c…
High oxidation state aqueous organometallics: synthesis and structure of a dinuclear oxo(pentamethylcyclopentadienyl)acetato complex of molybdenum(IV…
2003
International audience; The zinc reduction of Cp*2Mo2O5 in a MeOH–H2O mixture in the presence of acetic acid affords the diamagnetic dinuclear compound [Cp*MoO(O2CCH3)]2. An X-ray structural investigation reveals a novel dioxo- and diacetato-bridged structure, with a relatively strong metal–metal bond [2.5524(3) Å]. The compound exhibits a reversible one-electron oxidation process in the cyclic voltammogram. A comparison with other related structures reveals the effect of the electric charge on the mononuclear or dinuclear structural choice.Zinc reduction of Cp*2Mo2O5 in water–methanol in the presence of acetic acid affords compound Cp*2Mo2O2(O2CCH3)2, whose dinuclar tetrabridged structure …
Experimental and numerical evaluation of sandwich composite structures
2004
The main problem working with sandwich composite structures is their intrinsic anisotropy and non-homogeneity that does not allow their correct modelling. Nowadays the available data on mechanical properties of complex structures, necessary to allow a correct and reliable design, are not sufficient. The aim of the present work is to extend the knowledge of mechanical properties both on single components and on complete structures, focusing on the effects induced by different kind of skin arrangements (Kevlar, glass and carbon fibres). Compressive, shear and flexural tests were performed for a complete static mechanical characterisation of the sandwich structure both on each single component…