scholarly journals Prediction of favorable isomeric structures for the C100 to C120 giant fullerenes. An application of the phason line criteria

2001 ◽  
Vol 1 (1) ◽  
pp. 163-171 ◽  
Author(s):  
M. Yoshida ◽  
H. Gotō ◽  
Y. Hirose ◽  
X. Zhao ◽  
E. Ōsawa
Keyword(s):  
Isomeric Structures

Cyclisierung von Di(tert-butyl-methyl)ketazin zu 1,2-Diaza-3-bora- und 1,2-Diaza-3-sila-cyclopent-5-enen / Cyclization of Di(tert-butyl-methyl)ketazine to 1,2-Diaza-3-bora- and 1,2-Diaza-3-sila-cyclopent-5-enes

2006 ◽  
Vol 61 (10) ◽  
pp. 1261-1274 ◽  
Author(s):  
Florian Armbruster ◽  
Nina Armbruster ◽  
Uwe Klingebiel ◽  
Mathias Noltemeyer ◽  
Stefan Schmatz
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Chlorine Atom ◽  
Quantum Chemical ◽  
Membered Ring ◽  
Substitution Product ◽  
Tert Butyl ◽  
Isomeric Structures

The results of quantum chemical calculations on lithium ketazides suggest mainly four isomeric structures with different modes of lithium coordination (A-D). A monolithium ketazide thf-adduct (1) was isolated supporting the results of the quantum chemical calculations. In reactions of the lithiated di(tert-butyl-methyl)ketazine with BCl3 and Cl2BPh, 1,2-aza-azonia-3-borata-cyclopent-5-enes (2, 3) were isolated. Substitution of a chlorine atom of 2 and 3 with t-BuLi leads to the formation of derivatives 4 and 5. HCl elimination from 2 with Et3N gives - via a diazaboracyclopentene (6) - a bicyclus 7. In the reaction of the dilithiated ketazine with F2BN(SiMe3)2, the diaza-boracyclopentene 8 is obtained while with Cl4Si, F3SiN(SiMe3)2, and Cl2SiMe2 the diazasilacyclopentenes 9 - 11 are generated. SiF4 reacts with the dilithium ketazide to give a spirocyclus (12). The monolithium ketazide and Cl2SiMe2 react at 30 °C to give a four-membered ring isomer of the substitution product which is formed via a 1,3-chlorine shift from silicon to carbon (13). A tetrameric silanolate was isolated as a by-product in this reaction. It gives evidence for the structure of lithium ketazide A. Crystal structures of 5, 7, 10, and 14 are reported.

Ion chemistry of transition metals in hydrocarbon flames. II. Cations of Sc, Ti, V, Cr, and Mn

1988 ◽  
Vol 66 (9) ◽  
pp. 2219-2228 ◽  
Author(s):  
John M. Goodings ◽  
Quang Tran ◽  
Nicholas S. Karellas
Keyword(s):  
Transition Metals ◽  
Metal Atom ◽  
Chemical Ionization ◽  
Metallic Ions ◽  
Ion Chemistry ◽  
Hydrocarbon Flames ◽  
Basic Series ◽  
First Time ◽  
Isomeric Structures

The same fuel-rich, premixed, conical, methane–oxygen flame at 2200 K and atmospheric pressure used for studies of Fe, Co, Ni, Cu, and Zn in Part I (1) is doped with the same concentration (~1 ppm) of Sc, Ti, V, Cr, and Mn to complete the first row of ten transition metals. Metallic ions of these metals and their compounds formed by chemical ionization reactions with H3O+ are observed by sampling the flame through a nozzle into a quadrupole mass spectrometer. Concentration profiles of individual and total cations are measured as a function of distance along the flame axis, and also mass spectra at a fixed point in the burnt gas. If A is the metal atom, the observed ions can be represented by four hydrate series including (a) A+•nH2O, (b) AOH+•nH2O, (c) AO+•nH2O, and (d) AO2H+•nH2O with n = 0–3 or 4, giving a maximum of four ligands around the metal atom. However, alternative isomeric structures are possible for each of the four basic series (e.g. AO+•2H2O ~ A(OH)2+•H2O ~ A(OH)3H+). The ions observed with Cr and Mn, in common with those of Fe, Co, Ni, and Cu, strongly favour series (a). On the other hand, Sc is completely different; the ions of series (c) are dominant. All four series are observed with each of Ti and V. Series (b) dominates for Ti and series (c) for V; ions from series (d) were observed for the first time. The ion chemistry of these metals is discussed in detail with emphasis on the probable chemical ionization reactions responsible for metallic ion formation. The pre-eminent role of proton transfer processes is apparent.

Formation and Decay of Fluorobenzene Radical Anions Affected by Their Isomeric Structures and the Number of Fluorine Atoms

2010 ◽  
Vol 114 (31) ◽  
pp. 8069-8074 ◽  
Author(s):  
Saki Higashino ◽  
Akinori Saeki ◽  
Kazumasa Okamoto ◽  
Seiichi Tagawa ◽  
Takahiro Kozawa
Keyword(s):  
Radical Anions ◽  
Isomeric Structures

scholarly journals Categorization of Boranes Into Clan Series

2020 ◽  
Vol 12 (1) ◽  
pp. 107
Author(s):  
Enos Masheija Rwantale Kiremire ◽  
Ivan Lule
Keyword(s):  
Skeletal Element ◽  
Cluster Number ◽  
Inherent Characteristic ◽  
Valence Electrons ◽  
Whole Number ◽  
Fundamental Equations ◽  
Isomeric Structures ◽  
Cluster Series

Boranes, despite their instability in nature, can be regarded as hydrocarbon relatives since a [BH] fragment corresponds to a carbon [C] skeletal element in terms of the number of valence electrons. The borane formula which can be expressed as BnHm usually appears in such a way that when (n) is even, then (m) is even and when (n) is odd, (m) is odd as well. Through the study of cluster series, it appears that the cluster number K which represents skeletal linkages is usually a whole number. This inherent characteristic confers unique order within borane clusters with nodal connectivity of 5 and the polyhedral nature of the borane clusters. The orderliness of the borane clusters is reflected by the ease of their categorization into clan series and their readily constructed geometrical isomeric structures. The cluster valence electrons can easily be calculated using one of the six recently discovered fundamental equations.

A 14N NMR study of the isomeric structures of urea and its analogues

Tetrahedron ◽  
1976 ◽  
Vol 32 (17) ◽  
pp. 2127-2129 ◽  
Author(s):  
M. Witanowski ◽  
L. Stefaniak ◽  
S. Szymański ◽  
G.A. Webb
Keyword(s):  
Nmr Study ◽  
Isomeric Structures ◽  
14N Nmr
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