88,148 research outputs found
Macchi 202
No full textRight hand side view of the Macchi 202, a military aircraft, on the ground.https://corescholar.libraries.wright.edu/special_ms223_photographs/1336/thumbnail.jp
New Chiral Nitrogen Ligands Based on Amines Derived from -Pinene
No full textThe number of applications of bis-imines as ligands in homogeneous catalysis has much increased in recent years. Derivatives of acenaphthenequinone (R-BIAN) are especially useful for their chemical stability and rigidity. Until recently only Ar-BIAN ligands in which the aryl group contained electrondonating or moderately electronwithdrawing groups were known. We have recently expanded the available range of derivatives to ligands where the aryl group bears strongly electronwithdrawing substituents,1 two different aryl groups are present,2 and even to Alkyl-BIAN compounds.3,4 The latest had never been isolated before because an isomerization reaction occurred leading to their decomposition. We identified the cause of the decomposition in the ring strain of the five-membered ring of the acenaphthene moiety, which is partly released upon isomerization of the C=N double bond. The problem could be solved by employing ring-strained amines, for which this isomerization is thermodinamically unfavorable.3,4 Here we report the synthesis of a chiral cyclopropylamine derived from enantiomerically pure -pinene. The amine was obtained in good yields in four diastereomers. These can be separated by column chromatography. Two isomers are most abundant. One of them was employed in the synthesis of the corresponding BIAN derivative.
[1] Gasperini, M.; Ragaini, F.; Cenini, S. Organometallics, 2002, 21, 2950.
[2] Gasperini, M.; Ragaini, F.; Gazzola, E.; Caselli, A.; Macchi, P. Dalton Trans., 2004, 3376.
[3] Ragaini, F. ; Gasperini, M.;. Gallo, E.; Macchi, P. Chem. Commun., 2005, 1031.
[4] Ragaini, F.; Gasperini, M.; Parma, P.; Gallo, E.; Casati, N.; Macchi, P. New J. Chem. 2006, 30, 1046
Cesare Macchi Cassia, la forma della realtà
No full textCesare Macchi Cassia was a professor, thesis, and Ph.D. supervisor of Nicola Russi, who collaborated with him in developing research and project design between 1999 and 2005.
Nicola Russi was also a subject tutor at the "Laboratory of Urban Design I" (from AA 2001/02 to AA 2006/07) and the "Urban Planning and Contemporary Design" course (in AA A.A.2006/07) of Professor Cesare Macchi Cassia at the Faculty of Civil Architecture, Politecnico di Milano.
By describing selected cases, this text identifies themes and concepts underlying Cesare Macchi Cassia's design culture that moves along the boundary between the architectural, urban, and land scales, attempting to reconcile different worlds within an ethically and aesthetically coherent framework.
/ Cesare Macchi Cassia è stato professore, relatore di tesi e di dottorato di Nicola Russi, che ha collaborato con lui allo sviluppo di ricerche e all’elaborazione di progetti tra il 1999 e il 2005.
Nicola Russi è stato inoltre cultore della materia presso il “Laboratorio di Progettazione Urbanistica I” (dall’AA 2001/02 all’AA 2006/07) e il corso “Urbanistica e Progetto Contemporaneo” (nell’AA A.A.2006/07) del Professor Cesare Macchi Cassia, presso la Facoltà di Architettura Civile del Politecnico di Milano.
Attraverso la descrizione di casi selezionati, questo testo individua temi e concetti alla base della cultura progettuale di Cesare Macchi Cassia che si muove lungo il confine tra la scala architettonica, quella urbana e territoriale, tentando di conciliare mondi diversi all’interno di un quadro eticamente ed esteticamente coerente
Cesare Macchi Cassia, la forma della realtà
No full textCesare Macchi Cassia was a professor, thesis, and Ph.D. supervisor of Nicola Russi, who collaborated with him in developing research and project design between 1999 and 2005.
Nicola Russi was also a subject tutor at the "Laboratory of Urban Design I" (from AA 2001/02 to AA 2006/07) and the "Urban Planning and Contemporary Design" course (in AA A.A.2006/07) of Professor Cesare Macchi Cassia at the Faculty of Civil Architecture, Politecnico di Milano.
By describing selected cases, this text identifies themes and concepts underlying Cesare Macchi Cassia's design culture that moves along the boundary between the architectural, urban, and land scales, attempting to reconcile different worlds within an ethically and aesthetically coherent framework.
/ Cesare Macchi Cassia è stato professore, relatore di tesi e di dottorato di Nicola Russi, che ha collaborato con lui allo sviluppo di ricerche e all’elaborazione di progetti tra il 1999 e il 2005.
Nicola Russi è stato inoltre cultore della materia presso il “Laboratorio di Progettazione Urbanistica I” (dall’AA 2001/02 all’AA 2006/07) e il corso “Urbanistica e Progetto Contemporaneo” (nell’AA A.A.2006/07) del Professor Cesare Macchi Cassia, presso la Facoltà di Architettura Civile del Politecnico di Milano.
Attraverso la descrizione di casi selezionati, questo testo individua temi e concetti alla base della cultura progettuale di Cesare Macchi Cassia che si muove lungo il confine tra la scala architettonica, quella urbana e territoriale, tentando di conciliare mondi diversi all’interno di un quadro eticamente ed esteticamente coerente
A Chiral Ligand Accessible in One Step: Synthesis of bis-((R)-(+)-Bornyl)acenaphthenequinonediimine and of its Zinc and Nickel Complexes.
No full textA new neutral chiral nitrogen ligand was obtained in one step from commercially available acenaphthenequinone and (R)-(+)-bornylamine. Use of titanium tetraisopropoxide is the key to obtain good yields of the condensed product. Ring strain in the bicyclic system helps in stabilizing the otherwise unstable Alkyl-BIAN type derivative, but is not enough to render the free ligand indefinitely stable. However, complexes of the ligand with the ZnCl2and NiBr2fragment were prepared and are stable. The single crystal X-ray structure of ((R)-(+)-Bornyl-BIAN)NiBr2has been determined
Reaction of arylhydroxylamines with [Pd(Neoc)(NO3)2] (Neoc = neocuproine). Non-innocent behavior of the nitrate anion
No full textIn an effort to understand the first stages of the reduction of nitroarenes to anilines by palladium/phenanthroline complexes and suspecting that arylhydroxylaminato complexes may be intermediates in this process, we investigated the reactivity of [Pd(Neoc)(NO3)(2)] (Neoc = neocuproine = 2,9-dimethyl-1,10-phenanthroline) with 3,5-dichlorophenylhydroxylamine. Spectroscopic evidence indicates that the desired [Pd(Neoc)(ONHC6H3Cl2)(NO3)] is indeed formed, but the complex is not stable and decomposes within a few hours. Two of the decomposition products were characterized by single crystal X-ray diffraction. They are a N-aryl-N-nitrosohydroxylaminato complex, [Pd(Neoc)(ON(3,5-C6H3Cl2) NO)][NO3] (major decomposition product) and a nitro-nitrate complex [Pd(Neoc)(NO2)(NO3)]. The results indicate that the nitrate ion is not innocent in the starting complex and oxidize hydroxylamine, being reduced itself to NO2 and NO
Vitellogenesis in the stick insect Carausius morosus: I. Specific protein synthesis during ovarian development
No full textTratamientos dentinarios y adhesión de resinas reforzadas
No full textFactores que influyen en el logro y el mantenimiento de la continuidad resina/diente y posibilidades de éxito en la restauración.Fil: Abate, Pablo F. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Materiales Dentales. Buenos Aires, Argentina.Fil: Macchi, Ricardo L. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Materiales Dentales. Buenos Aires, Argentina
Schiff bases of the BIAN family and their metal complexes: recent advances from our group
No full textProgresses on studies on Schiff bases of the BIAN family and their metal complexes: recent advances from our group are described
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