scholarly journals Syntheses and Structures of Novel λ3,λ3-Phosphanylalumanes Fully Bearing Carbon Substituents and Their Substituent Effects

Inorganics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 132 ◽  
Author(s):  
Tatsuya Yanagisawa ◽  
Yoshiyuki Mizuhata ◽  
Norihiro Tokitoh
Keyword(s):  
Bond Length ◽  
Theoretical Calculations ◽  
Substituent Effects ◽  
The Other ◽  
Protecting Groups ◽  
Large Contribution ◽  
The Novel ◽  
Single Bond ◽  
Bond Lengths ◽  
Theoretical Results

The novel phosphanylalumanes, Al–P single-bond species, fully bearing carbon protecting groups on aluminum and phosphorus atoms, are synthesized by the reactions of aluminum monohalides [(t-Bu)2AlBr and (C6F5)2AlCl·0.5(toluene)] with Mes2PLi. Regarding the t-Bu system, λ3,λ3-phosphanylalumane is obtained. Concerning the C6F5 system, on the other hand, the corresponding LiCl complex, λ4,λ4-phosphanylalumane, is obtained. The Al–P bond lengths of C6F5-substituted λ3,λ4-, and λ4,λ4-derivatives are much shorter than those of the reported λ3,λ4-phosphanylalumane derivatives and comparable to that observed for the previously reported λ3,λ3-phosphanylalumanes. Theoretical calculations reveal that the binding of the C6F5 groups to Al results in a large contribution of Al and a large s-character in the Al–P bond of phosphanylalumanes. Considering t-Bu-substituted phosphanylalumanes, the Al–P bond lengths reflect the coordination number of Al, showing a longer Al–P bond length in the case of λ4-Al as compared with that of λ3-Al. Combining the structural, spectroscopic, and theoretical results, the t-Bu-substituted λ3,λ3-phosphanylalumane has well separated vacant p orbital and lone pairs, which is suitable for reactivity studies.

Use of a Lowest Intensity 241Am Compton Spectrometer for the Measurement of Directional Compton Profiles of ZnSe

2006 ◽  
Vol 61 (7-8) ◽  
pp. 364-370 ◽  
Author(s):  
Babu Lal Ahuja ◽  
Narayan Lal Heda
Keyword(s):  
Bond Length ◽  
Theoretical Calculations ◽  
The Other ◽  
Energy Bands ◽  
Electron Momentum ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Self Consistent ◽  
Scattering Technique ◽  
Small Disc

In this paper we report on electron momentum densities in ZnSe using Compton scattering technique. For the directional measurements we have employed a newly developed 100 mCi 241Am Compton spectrometer which is based on a small disc source with shortest geometry. For the theoretical calculations we have employed a self-consistent Hartree-Fock linear combination of atomic orbitals (HF-LCAO) approach. It is seen that the anisotropy in the measured Compton profiles is well reproduced by our HF-LCAOcalculation and the other available pseudopotential data. The anisotropy in the Compton profiles is explained in terms of energy bands and bond length. - PACS numbers: 13.60.Fz, 78.70. Ck, 78.70.-g

scholarly journals Substituent effects on the basicity (pKa) of aryl guanidines and 2-(arylimino)imidazolidines: correlations of pH-metric and UV-metric values with predictions from gas-phase ab initio bond lengths

2017 ◽  
Vol 41 (19) ◽  
pp. 11016-11028 ◽  
Author(s):  
Christophe Dardonville ◽  
Beth A. Caine ◽  
Marta Navarro de la Fuente ◽  
Guillermo Martín Herranz ◽  
Beatriz Corrales Mariblanca ◽  
...  
Keyword(s):  
Ab Initio ◽  
Bond Length ◽  
Gas Phase ◽  
Substituent Effects ◽  
Bond Lengths

The AIBLHiCoS method accurately predicts the pKa values of 2-(arylimino)imidazolidines using only a single ab initio bond length.

The duodecet rule: Part 3. Fluoro species of the third period elements

1992 ◽  
Vol 70 (6) ◽  
pp. 1696-1705 ◽  
Author(s):  
E. A. Robinson
Keyword(s):  
Bond Length ◽  
Molecular Species ◽  
Central Atom ◽  
Covalent Radius ◽  
Valence Shell ◽  
Single Bond ◽  
Electron Pairs ◽  
Bond Lengths ◽  
The Third

On the basis of the suggested new value of 54 pm for the single bond covalent radius of fluorine, the previously established duodecetrule for period 3 elements in molecular species with highly electronegative ligands is extended to fluorides. It is shown, for species such as SiF4, (F3Si)2O, F3SiNH2, F3PO, and PF5, that the observed bond lengths are consistent with significant partial double bonding involving all the ligands, including fluorine, and with a total of six electron pairs in the valence shell of the central atom. Empirical rules based on d/d1, the ratio of an observed bond length to the corresponding single bond length calculated from the sum of covalent radii, are developed as a simple approximate guide to the extent of partial double bonding in bonds to third period elements. It is also shown that bond lengths in species such as Al2F5, AlO45−, and Al(NH2)4− are consistent with a duodecet rule.

scholarly journals Crystal structure of 2-bromo-3-dimethylamino-N,N,N′,N′,4-pentamethyl-4-(trimethylsilyloxy)pent-2-eneamidinium bromide

2015 ◽  
Vol 71 (12) ◽  
pp. o1061-o1062
Author(s):  
Ioannis Tiritiris ◽  
Ralf Kress ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Bond Length ◽  
Single Bond ◽  
Charge Delocalization ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Bromide Ions ◽  
Bond Character

The reaction of the orthoamide 1,1,1-tris(dimethylamino)-4-methyl-4-(trimethylsilyloxy)pent-2-yne with bromine in benzene, yields the title salt, C15H33BrN3OSi+·Br−. The C—N bond lengths in the amidinium unit are 1.319 (6) and 1.333 (6) Å, indicating double-bond character, pointing towards charge delocalization within the NCN plane. The C—Br bond length of 1.926 (5) Å is characteristic for a C—Br single bond. Additionally, there is a bromine–bromine interaction [3.229 (3) Å] present involving the anion and cation. In the crystal, weak C—H...Br interactions between the methyl H atoms of the cation and the bromide ions are present.

A Correlation between Bond Length and Ionic Bond Order. Application to the Ylide–Ylene Problem

1975 ◽  
Vol 53 (20) ◽  
pp. 3040-3043 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe ◽  
Fernando Bernardi
Keyword(s):  
Bond Length ◽  
Bond Order ◽  
The Other ◽  
Atomic Charges ◽  
Bond Orders ◽  
Ionic Bond ◽  
Molecular Systems ◽  
Bond Lengths ◽  
Coulombic Repulsion ◽  
Overlap Population

The C—O and C—S bond lengths of the cations, radicals, and anions CH3O, CH3S, CH2OH, and CH2SH have been found not to correlate with the overlap populations of the C—X bonds. On the other hand, very satisfactory linear relations are observed with the ionic bond orders of the C—X bonds. It is suggested that, in certain molecular systems, it may be more meaningful to associate shortening of a bond A—B with greater coulombic attraction (or smaller coulombic repulsion) between the two point charges represented by the net atomic charges on the atoms A and B than with an increase in the overlap population between these atoms. It is noted that such an interpretation can account for the short C—P bond in a phosphonium ylide without resort to (p → d)π conjugation.

The crystal and molecular structure of the copper(II) bis(dialyldithiocarbamate) complex

1984 ◽  
Vol 49 (10) ◽  
pp. 2210-2221 ◽  
Author(s):  
Eleonóra Kellö ◽  
Victor Kettmann ◽  
Ján Garaj
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
The Other ◽  
Tetragonal Pyramid ◽  
X Ray ◽  
Bond Lengths ◽  
Triclinic System ◽  
Bond Character

The crystal structure of {Cu[S2CN(C3H5)2]2}2 was solved by the single crystal method of X-ray structural analysis. The substance crystallized as a dimer in the triclinic system with space group of PI and latice parameters a = 1.0161 (4), b =0.9294(4), c = 1.0518(3) nm, α = 77.46(3), β = 77.10(3), γ = 89.02(3)°. The structure was refined by the least squares method to a final value of R = 4.9% using all the 1 713 observed reflections. The crystal structure consists of dimeric molecules, where each pair of centrosymmetrically dependent Cu atoms lies at a distance of 0.3742 nm. The coordination polyhedron of the Cu atom is a tetragonal pyramid, where the four sulphur atoms lie at distances of Cu-S1 0.2314, Cu-S2 0.2309, Cu-S3 0.2324, Cu-S4 0.2328 and are approximately in a place from which the Cu atoms lies at a distance of 0.026 nm. The fifth, longer bond, Cu-S'4 0.2888 nm forms the apex of the tetragonal pyramid. In the streochemistry of the dithiocarbamate ligands of the studied substances there are no marked differences in the bond lengths and corresponding angles compared with the values for the solvent structures of the other dialkyl-dtc complexes. The lengths of the sulphur-carbon bonds lie in the range from 0.170 to 0.173 nm and both lengths of the C(sp)2 - N(sp2) bonds equal to 0.134 and 0.133 nm indicate marked double bond character of the C-N bond. The S2CN ligand fragment is planar. In the alyl part of the ligand, the N-C bond lengths lie in the range 0.147-0.149 nm, the average C-C bond length is 0.149 nm and C=C bond length is 0.132 nm.

Crystal and Molecular Structure of Tris(Ethane-1,2-Diamine)Osmium(III) Trifluoromethanesulfonate Monohydrate

1987 ◽  
Vol 40 (7) ◽  
pp. 1267 ◽  
Author(s):  
PA Lay ◽  
GM Mclaughlin ◽  
AM Sargeson
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Oxidation State ◽  
Bond Order ◽  
Crystal And Molecular Structure ◽  
Single Bond ◽  
Bond Lengths ◽  
Formal Oxidation State ◽  
Bite Angle ◽  
Diamine Ligands

The crystal and molecular structure of racemic [Os(en)3] (CF3SO3)3.H2O has been determined. The [Os(en)3]3+ ion adopts a le ξob configuration and has approximate C2 symmetry with an Os-N(av.) bond length of 2.11 � and a bite angle for the chelate of - 82�. The previously recorded structure of the [Os(en-H)2(en)]2+ ion in which two deprotonated ethane-1,2-diamine ligands adoptoa cis configuration of the two amido donors, and in which the OsIV -N( amido ) bonds (1.90 �) are much shorter than the Os-N(amine) bonds, 2.11 ( cis ), 2.19 (trans), along with the present structure indicates a bond order > 1 for the osmiumo amido bond. The normal Os-N bond lengths fall into well defined ranges OS-NR3 (2.11-2.14 �), Os=NR2- (~1.90 �),Os=NR2 (- 1.70 �) and Os=N3-(- 1.58-1.63 �). These single bond lengths are more affected by trans effects than the formal oxidation state of the osmium centre.

scholarly journals 3-Methyl-4,5-dihydrooxazolium tetraphenylborate

2014 ◽  
Vol 70 (3) ◽  
pp. o325-o325
Author(s):  
Ioannis Tiritiris ◽  
Stefan Saur ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Bond Length ◽  
Phenyl Ring ◽  
Single Bond ◽  
Charge Delocalization ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Bond Character

In the cation of the title salt, C4H8NO+·C24H20B−, the C—N bond lengths are 1.272 (2), 1.4557 (19) and 1.4638 (19) Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.3098 (19) Å shows that double-bond character and charge delocalization occurs within the NCO plane of the cation. In the crystal, a C—H...π interaction is present between the methylene H atom of the cation and one phenyl ring of the tetraphenylborate ion. The latter forms an aromatic pocket in which the cation is embedded.

scholarly journals Multivaluedness in Networks: Theory

2020 ◽  
Author(s):  
Anton van Wyk
Keyword(s):  
Structural Complexity ◽  
The Other ◽  
Sufficient Condition ◽  
The Novel ◽  
Necessary And Sufficient Condition ◽  
Cascaded Systems ◽  
The Right ◽  
Necessary And Sufficient ◽  
Theoretical Results

<div>An unexpected and somewhat surprising observation is that two counter-cascaded systems,12 satisfying the right conditions, implicitly exhibit multivaluedness from one of the outputs to the other. Based on the novel notions of immanence and transcendence, the main result presented here, gives a necessary and sufficient condition for multivaluedness to be exhibited by counter-cascaded systems. Subsequent corollaries provide further characterization of multivaluedness under specific conditions.</div><div><br></div><div>As an application of these theoretical results, we demonstrate how these aid in the structural complexity reduction of directed complex networks.</div>

Margaret Mahy: An Adlerian Reading

2008 ◽  
Vol 1 (2) ◽  
pp. 187-199
Author(s):  
KATHRYN WALLS
Keyword(s):  
Young Female ◽  
The Other ◽  
Individual Psychology ◽  
The Novel ◽  
Alfred Adler ◽  
Female Protagonists ◽  
Magical Power ◽  
Margaret Mahy ◽  
The Individual

According to the ‘Individual Psychology’ of Alfred Adler (1870–1937), Freud's contemporary and rival, everyone seeks superiority. But only those who can adapt their aspirations to meet the needs of others find fulfilment. Children who are rejected or pampered are so desperate for superiority that they fail to develop social feeling, and endanger themselves and society. This article argues that Mahy's realistic novels invite Adlerian interpretation. It examines the character of Hero, the elective mute who is the narrator-protagonist of The Other Side of Silence (1995) , in terms of her experience of rejection. The novel as a whole, it is suggested, stresses the destructiveness of the neurotically driven quest for superiority. Turning to Mahy's supernatural romances, the article considers novels that might seem to resist the Adlerian template. Focusing, in particular, on the young female protagonists of The Haunting (1982) and The Changeover (1984), it points to the ways in which their magical power is utilised for the sake of others. It concludes with the suggestion that the triumph of Mahy's protagonists lies not so much in their generally celebrated ‘empowerment’, as in their transcendence of the goal of superiority for its own sake.

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