Variation of calculated single bond lengths in saturated hydrocarbon and silicon hydride molecules

1980 ◽  
Vol 18 (6) ◽  
pp. 1449-1463 ◽  
Author(s):  
W. S. Verwoerd
Keyword(s):  
Saturated Hydrocarbon ◽  
Single Bond ◽  
Silicon Hydride ◽  
Bond Lengths

scholarly journals Crystal structure ofN′′-benzyl-N′′-[3-(benzyldimethylazaniumyl)propyl]-N,N,N′,N′-tetramethylguanidinium bis(tetraphenylborate)

2015 ◽  
Vol 71 (12) ◽  
pp. o1086-o1087
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Methyl Groups ◽  
Two Dimensional ◽  
Single Bond ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Bond Character

In the crystal structure of the title salt, C24H38N42+·2C24H20B−, the C—N bond lengths in the central CN3unit of the guanidinium ion are 1.3364 (13), 1.3407 (13) and 1.3539 (13) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The bonds between the N atoms and the terminal methyl groups of the guanidinium moiety and the four C—N bonds to the central N atom of the (benzyldimethylazaniumyl)propyl group have single-bond character. In the crystal, C—H...π interactions between the guanidinium H atoms and the phenyl C atoms of the tetraphenylborate ions are present, leading to the formation of a two-dimensional supramolecular pattern parallel to theacplane.

scholarly journals Chemie und Strukturchemie der Phosphide und Polyphosphide, 41 Synthese, Struktur und Eigenschaften neuer silyl-, germyl- und stannylsubstituierter Heptaphosphane(3) P7(MPh3)3 mit M = Si, Ge, Sn / Chemistry and Structural Chemistry of Phosphides and Polyphosphides, 41 Synthesis, Structure and Properties of New Silyl, Germyl and Stannyl Substituted Heptaphosphanes(3) P7(MPh3)3 with M = Si, Ge, Sn

1986 ◽  
Vol 41 (8) ◽  
pp. 991-999 ◽  
Author(s):  
Carlos Mujica ◽  
Dieter Weber ◽  
Hans-Georg von Schnering
Keyword(s):  
Raman Spectra ◽  
Driving Force ◽  
Structural Chemistry ◽  
Fold Axis ◽  
Structure And Properties ◽  
Single Bond ◽  
Bond Lengths ◽  
Lower Solubility

Abstract , 41 [1] Synthese, Struktur und Eigenschaften neuer silyl-, germyl-und stannylsubstituierter Heptaphosphane(3) P7(MPh3)3 mit M = Si, Ge, Sn Chemistry and Structural Chemistry of Phosphides and Polyphosphides, 41 [1] Synthesis, Structure and Properties of New Silyl, Germyl and Stannyl Substituted Heptaphosphanes(3) P7(MPh3)3 with M = Si, Ge, Sn Silyl-, Germyl-and Stannyl-substituted H eptaphosphanes(3), 3,5,7-T riphenylm etalla[2.2.1.02'6]hepta-phosphanes, Structures, Raman Spectra, 31P NM R Spectra New derivatives P7(M Ph3) 3 (M = Si, G e, Sn) o f the heptaphosphanortricyclen cage were synthesized by reactions o f P7(SiM e,) 3 with com pounds CIMPh,. The driving force o f the reaction is the lower solubility o f the P7(M P h,) 3 com pounds. W hereas crystals of P7(SiM e3) 3 are enan-tiom orphs, the new com pounds P7(M Ph3) 3 crystallize as racemates. With decreasing M size, the nortricyclen cage P7 is slightly twisted about the 3-fold axis. The main P -P bond lengths in the cage follow the relation A (basal) — 221.8 pm > B (basal-equatorial) = 219.0 pm > C (equato-rial-apical) = 218.5 pm. The m ean bond lengths P —Si = 228.6 and P —Ge = 234.9 and P —Sn = 253.5 pm are slightly larger than the standard single bond distances. The IR absorptions show only very small M -dependent variations in the characteristic internal cage vibrations. Similar effects are recognized in the 3,P NM R chem ical shifts.

scholarly journals Crystal structure of the cage derivative pentacyclo[5.4.0.02,6.03,10.05,9]undeca-8,11-dione ethylene dithioketal

2014 ◽  
Vol 70 (10) ◽  
pp. 246-248
Author(s):  
Sambasivarao Kotha ◽  
Nampalli Sreenivasachary ◽  
Deepak Deodhar ◽  
Mobin Shaikh
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Single Bond ◽  
Bond Angles ◽  
Bond Lengths

The title pentacycloundecane cage derivative, C13H14OS2, was identified during a thioketalization reaction. The reaction selectively gave the title compound and the product corresponding to bis-ketal was not formed. The title compound exhibits unusual Csp3—Csp3single bond lengths ranging from 1.495 (3) to 1.581 (2) and strained bond angles as small as 89.29 (12) and as large as 115.11 (11)°.

Structure and bonding in square-planar chalcogen rings

1992 ◽  
Vol 70 (2) ◽  
pp. 348-352 ◽  
Author(s):  
Leif J. Saethre ◽  
Odd Gropen
Keyword(s):  
Potential Model ◽  
Population Analysis ◽  
Atomic Charge ◽  
Molecular Structures ◽  
Basis Set ◽  
Single Bond ◽  
Bond Lengths ◽  
Square Planar ◽  
Structure And Bonding ◽  
D Orbitals

The molecular structures of square-planar X42+, X4+, and X4 (X = S, Se, Te) have been calculated using the effective core potential model. For X42+ the agreement between experimental and calculated values is excellent provided that d orbitals are included in the basis set. For the hypothetical molecules X4+ and X4 the bond lengths are found to increase dramatically as one and, subsequently, two electrons are added to the systems. Extensive population analysis shows that this increase is almost exclusively due to loss of bonding in the π system, whereas the bonding in the σ system remains relatively unaltered. These results make it possible to predict covalent single bond radii for S, Se, and Te for which the influence of π repulsion is removed. From the calculated variation of bond lengths with atomic charge, bond lengths are predicted for a series of planar disulphide rings. Keywords: structure, bonding, chalcogen, theoretical, ECP.

The crystal and molecular structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, a phosphorus–silicon heterocycle

1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Single Bond ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Bond Lengths

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.

scholarly journals N′′-(4-Methoxyphenyl)-N,N,N′-trimethyl-N′-phenylguanidine

2014 ◽  
Vol 70 (4) ◽  
pp. o460-o460 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Wolfgang Frey ◽  
Willi Kantlehner
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Planar Geometry ◽  
Single Bond ◽  
Bond Lengths ◽  
Compound C ◽  
Centrosymmetric Dimers ◽  
Bond Character

In the title compound, C17H21N3O, the C—N bond lengths in the guanidine unit are 1.2889 (19), 1.3682 (19) and 1.408 (2) Å, indicating double- and single-bond character. The N—C—N angles are 115.10 (13), 119.29 (15) and 125.61 (14)°, showing a deviation of the CN3plane from an ideal trigonal–planar geometry. In the crystal, non-classical C—H...O hydrogen bonds between methyl H atoms and methoxy O atoms are present, generating centrosymmetric dimers running in the [101] direction.

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.

Empirical Interatomic Potential for Si-H Interactions

1993 ◽  
Vol 317 ◽  
Author(s):  
M.V. Ramana Murty ◽  
Harry A. Atwater ◽  
Thomas J. Watson
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Interatomic Potential ◽  
Silicon Surfaces ◽  
Vibrational Modes ◽  
Silicon Hydride ◽  
Computationally Efficient ◽  
Bond Lengths

An empirical TersofF-type interatomic potential has been developed for describing Si-H interactions. The potential gives a reasonable fit to bond lengths, angles and energetics of silicon hydride molecules and hydrogen-terminated silicon surfaces. The frequencies of most vibrational modes are within 15% of the experimental and ab initio theory values. The potential is computationally efficient and suitable for molecular dynamics investigations of various processing treatments of hydrogen-terminated silicon surfaces.

scholarly journals Expected Values of Some Molecular Descriptors in Random Cyclooctane Chains

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2197
Author(s):  
Zahid Raza ◽  
Muhammad Imran
Keyword(s):  
Molecular Descriptors ◽  
Saturated Hydrocarbon ◽  
Molecular Graph ◽  
Chemical Compounds ◽  
Total Surface Area ◽  
Single Bond ◽  
Zagreb Index ◽  
Augmented Zagreb Index ◽  
Explicit Formulae ◽  
Expected Values

The modified second Zagreb index, symmetric difference index, inverse symmetric index, and augmented Zagreb index are among the molecular descriptors which have good correlations with some physicochemical properties (such as formation heat, total surface area, etc.) of chemical compounds. By a random cyclooctane chain, we mean a molecular graph of a saturated hydrocarbon containing at least two rings such that all rings are cyclooctane, every ring is joint with at most two other rings through a single bond, and exactly two rings are joint with one other ring. In this article, our main purpose is to determine the expected values of the aforementioned molecular descriptors of random cyclooctane chains explicitly. We also make comparisons in the form of explicit formulae and numerical tables consisting of the expected values of the considered descriptors of random cyclooctane chains. Moreover, we outline the graphical profiles of these comparisons among the mentioned descriptors.

scholarly journals N,N,N′,N′-Tetramethyl-N′′-[2-(trimethylazaniumyl)ethyl]guanidinium bis(tetraphenylborate) acetone disolvate

IUCrData ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Two Dimensional ◽  
Single Bond ◽  
Asymmetric Unit ◽  
Bond Lengths ◽  
Phenyl Rings ◽  
Solvent Molecules ◽  
Bond Character

The asymmetric unit of the title solvated salt, C10H26N42+·2C24H20B−·2C3H6O, comprises one cation, two tetraphenylborate ions and two acetone solvent molecules. The N and methyl C atoms of the terminal trimethylammonium group are disordered over two sets of sites, with a refined occupancy ratio of 0.846 (3):0.154 (3). The C—N bond lengths in the central C3N unit of the guanidinium ion range between 1.3308 (16) and 1.3508 (16) Å, indicating a degree of double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The C—N bond lengths in the terminal trimethylammonium group have values close to that of a typical single bond, and the second positive charge is localized there. In the crystal, the guanidinium ion is connected by N—H...O and C—H...O hydrogen bonds with the acetone molecules. C—H...π interactions are present between the guanidinium H atoms and the phenyl rings of the tetraphenylborate ions, leading to the formation of a two-dimensional supramolecular pattern along thebcplane.

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