Non‐Bonding Electron Pair versus π‐Electrons in Solution Phase Halogen Bond Catalysis: Povarov Reaction of 2‐Vinylindoles and Imines

2020 ◽  
Vol 362 (15) ◽  
pp. 3208-3212 ◽  
Author(s):  
Takumi Suzuki ◽  
Satoru Kuwano ◽  
Takayoshi Arai
Keyword(s):  
Electron Pair ◽  
Halogen Bond ◽  
Solution Phase ◽  
Povarov Reaction ◽  
Bonding Electron

scholarly journals Halogen bonding, chalcogen bonding, pnictogen bonding, tetrel bonding: origins, current status and discussion

2017 ◽  
Vol 203 ◽  
pp. 485-507 ◽  
Author(s):  
Lee Brammer
Keyword(s):  
Solid State ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Main Group ◽  
Solution Phase ◽  
Current Status ◽  
Solid State Chemistry ◽  
Main Group Elements ◽  
Past Work

The role of the closing lecture in a Faraday Discussion is to summarise the contributions made to the Discussion over the course of the meeting and in so doing capture the main themes that have arisen. This article is based upon my Closing Remarks Lecture at the 203rdFaraday Discussion meeting on Halogen Bonding in Supramolecular and Solid State Chemistry, held in Ottawa, Canada, on 10–12thJuly, 2017. The Discussion included papers on fundamentals and applications of halogen bonding in the solid state and solution phase. Analogous interactions involving main group elements outside group 17 were also examined. In the closing lecture and in this article these contributions have been grouped into the four themes: (a) fundamentals, (b) beyond the halogen bond, (c) characterisation, and (d) applications. The lecture and paper also include a short reflection on past work that has a bearing on the Discussion.

The role of non-bonding electron pairs in the asymmetric coordination environments of 1,1-dithiolate complexes

1976 ◽  
Vol 29 (11) ◽  
pp. 2541 ◽  
Author(s):  
BF Hoskins ◽  
CD Pannan
Keyword(s):  
Electron Pair ◽  
Central Atom ◽  
Main Group ◽  
Valence Shell ◽  
Electron Pairs ◽  
Shell Electron ◽  
Dithiolate Complexes ◽  
Asymmetric Coordination ◽  
Bonding Electron

Various forms of asymmetry in the lengths of the bond between the central atom and sulphur, found in differing coordination environments of 1,1-dithiolate compounds involving main group atoms, have been successfully rationalized by considering both the valence shell electron pair repulsion theory and the effect of the restricted ligand bite distance.

scholarly journals Orbital Exchange Calculations: An Alternative View of the Chemical Bond

2020 ◽  
Author(s):  
Paul Merrithew
Keyword(s):  
Chemical Bond ◽  
Electron Pair ◽  
Pauli Principle ◽  
Alternative View ◽  
Atomic Orbitals ◽  
Left Hand ◽  
Bond Lengths ◽  
Usual Manner ◽  
Selection Of ◽  
Bonding Electron

The purpose of this paper is to explore a model of the chemical bond which does not assume that the electrons of the chemical bonding electron pair can be unambiguously identified with either the left hand or right hand of the bonding atoms when their orbitals overlap to bond. In order to provide maximum flexibility in the selection of the electron’s orbitals, the orbitals have been represented as spatial arrays and the calculations performed numerically. This model of the chemical bond assumes that the identifiability of the bonding electrons is a function of 1-(overlap/(1+overlap)) where the overlap of the two bonding electron’s orbitals is calculated in the usual manner. The kinetic energy of the bonding electron pair and the energy required to meet the orthogonality requirements, mandated by the Pauli principle, are a function of overlap/(1+overlap). The model assumes that the bonding orbitals are straight-forward atomic orbitals or hybrids of these atomic orbitals. The results obtained by applying this simple approach to eleven di-atomics and seven common poly-atomics are quite good. The calculated bond lengths are generally within 0.005Å of the measured values and bond energies to within a few percent. Bond lengths for bonds to H are about 0.02 Å high. Except for H2, bond lengths are determined, independent of bond energy, at that point where overlap/(1+overlap) equals 0.5.

Recent Advances in Halogen Bond-assisted Organic Synthesis

2020 ◽  
Vol 24 (18) ◽  
pp. 2118-2152
Author(s):  
Shigeyuki Yamada ◽  
Tsutomu Konno
Keyword(s):  
Organic Synthesis ◽  
Crystal Engineering ◽  
Electron Pair ◽  
Molecular Design ◽  
Halogen Bond ◽  
Covalent Bond ◽  
Lewis Base ◽  
Organic Transformations ◽  
Hydrogen Bond Interaction ◽  
Significant Attention

Halogen bond interactions, which take place between an electrophilic halogen and the electron-pair of a Lewis base and exhibit high directionality (approximately 180°), are non-covalent bond interactions similar to the hydrogen bond interaction. Many reports on halogen bond interactions have been published thus far, but many of them discuss halogen bond in the context of crystal engineering of supramolecular architecture. Since a seminal report by Bolm in 2008, halogen bond-assisted or -promoted organic synthesis has received significant attention. This review aims to introduce the molecular design of suitable halogen bond donors and organic transformations involving halogen bond interactions to afford a variety of organic compounds.

Applications of halogen bonding in solution

2015 ◽  
Vol 87 (1) ◽  
pp. 15-41 ◽  
Author(s):  
Andreas Vargas Jentzsch
Keyword(s):  
Halogen Atom ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Solvent System ◽  
Noncovalent Interaction ◽  
Solution Phase ◽  
Anion Binding ◽  
Lewis Bases ◽  
The Past ◽  
Catalytic Applications

AbstractHalogen bonding is the noncovalent interaction where the halogen atom acts as an electrophile towards Lewis bases. Known for more than 200 years, only recently it has attracted interest in the context of solution-phase applications, especially during the last decade which was marked by the introduction of multitopic systems. In addition, the small yet rich collection of halogen-bond donor moieties that appeared in this period is shown to be versatile enough as to be applied in virtually any solvent system. This review covers the applications of halogen bonding in solution during the past ten years in a semi-comprehensive way. Emphasis is made on molecular recognition, catalytic applications and anion binding and transport. Medicinal applications are addressed as well with key examples. Focussing on the major differences observed for halogen bonding, as compared to the ubiquitous hydrogen bonding, it aims to contribute to the design of future solution-phase applications.

Oxotellurate(IV) der Lanthanide: II. Die isotype Reihe M2Te5O13 (M = Dy – Lu) / Oxotellurates(IV) of Lanthanides: II. The Isotypic Series M2Te5O13 (M = Dy – Lu)

2005 ◽  
Vol 60 (7) ◽  
pp. 720-726 ◽  
Author(s):  
Steffen F. Meier ◽  
Thomas Schleid
Keyword(s):  
Electron Pair ◽  
Three Dimensional ◽  
Lone Pair ◽  
Formula Unit ◽  
Partial Structure ◽  
Tellurium Oxide ◽  
Stereochemical Activity ◽  
Formula Type ◽  
Trigonal Prismatic ◽  
Bonding Electron

For the shortly discovered formula type M2Te5O13 (triclinic, P1̄), the establishment of an isostructural series in the last third of the lanthanide family (M = Dy - Lu) was possible. The excessive formula unit TeO2 additional to the well-known composition M2Te4O11 (monoclinic, C2/c) leads to the slicing of the [M2O10]14− layers which are typical for the tellurium-oxide poorer compounds. By coupling together the bicapped trigonal prismatic (M1, CN = 8) and the pentagonal bipyramidal (M2, CN = 7) lanthanide-oxygen polyhedra via edges, [M4O20]28− bands are formed stretching along the a axis and piling up to a primitive rod-packing. The linkage of these bands occurs parallel to the (010) plane via Te3 as well as via Te4 parallel to (100). Besides the usual 3+1 coordination, two of the five crystallographically independent tellurium sites are coordinated regularly fourfold (d(Te−O) ≈ 186−213 pm) and even 3+2-fold by oxygen atoms. The tellurium-oxygen polyhedra form corrugated layers running parallel to (101) which follow so close to each other that the tellurium-oxygen partial structure appears to be almost three-dimensional at a passing glance. As in M2Te4O11-type representatives, the non-bonding electron pair (lone pair) of each Te4+ cation shows stereochemical activity which always appears to flock together in large tellurium neighboured positions.

Al2Sb2I12: Vierkern-Einheiten in einem 1:1-Addukt aus AlI3 und SbI3 / Al2Sb2I12: Tetrameric Units in a 1:1 Adduct of AlI3 and SbI3

1983 ◽  
Vol 38 (12) ◽  
pp. 1539-1542 ◽  
Author(s):  
Siegfried Pohl
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Electron Pair ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Layer Structures ◽  
R Value ◽  
Stereochemical Activity ◽  
Bonding Electron

Al2Sb2I12 (1) was prepared by heating stoichiometric amounts of AlI3 and SbI3 in CS2. The crystal structure of 1 was determined from single crystal X-ray data. The compound crystallizes in the monoclinic space group C2/m with a = 1644.0(3), b = 1318.3(2), c = 728.9(1) pm, β = 119.33(1)°, and Z = 2. The structure was refined by least squares methods to a final unweighted R value of 0.064 for 676 nonequivalent reflections.The structure is built up of Al2Sb2I12 units in which two Sb-I octahedra share four common edges with two Al-I tetrahedra. As a consequence of the stereochemical activity of the non-bonding electron pair of antimony these cations are displaced from the centers of the iodine octahedra so that three different Sb-I bonds with distances of 270.8, 312.3, and 358.9 pm are observed in 1. The structure of Al2Sb2I12 can also be derived from the layer structures of the BiI3 type

Metal-Complexes of Thiocholinate, -SCH2CH2Nme3+. I. Preparation and Crystal-Structure of Pentakis(Thiocholinato)Dilead(II) Hexafluorophosphate

1986 ◽  
Vol 39 (3) ◽  
pp. 383 ◽  
Author(s):  
IG Dance ◽  
PJ Guerney ◽  
AD Rae ◽  
ML Scudder ◽  
AT Baker
Keyword(s):  
Crystal Structure ◽  
Fourier Transform ◽  
Aqueous Solutions ◽  
Electron Pair ◽  
Stacking Faults ◽  
Water Soluble ◽  
Lead Atom ◽  
Crystal Data ◽  
Linear Chains ◽  
Bonding Electron

Aqueous solutions containing lead(II) and deprotonated thiocholine contain water-soluble homoleptic lead thiolates , which crystallize as yellow needles of [Pb2(SCH2CH2NMe3)5] (PF6)4 in the presence of PF6-, but crystallize [ Pb (SCH2CH2NMe3)2](ClO4)2 with 1 : 2 stoichiometry in the presence of ClO4-. Crystalline [Pb2(SCH2CH2NMe3)5](PF6)4 contains almost linear chains composed of end-linked {(SR)2Pb(μ-SR) Pb (SR)2} coordination units, within which the primary Pb -S coordination (mean 2.73 Ǻ, sample e.s.d . 0.10 Ǻ) is orthogonal trigonal (S- Pb -S, mean 88.9°, sample e.s.d .3.7°) at each lead atom. Within the {Pb2(SR)5} unit there is one double bridge with two rimary bonds, and one double bridge involving one secondary Pb --S connection (mean 3.23 Ǻ, sample e.s.d . 0.12 Ǻ). Three double-bridges involving secondary Pb --S coordination link the ends of the dimetallic units, and consequently bis - and tris -double thiolate bridges alternate along the chain. Overall coordination at each lead atom is pseudo-octahedral, with one non-bonding electron pair and two cis secondary Pb --S bonds. The cationic tails of the ligands radiate from the chains into a matrix of PF6- ions, and the chains are approximately hexagonally close-packed with a separation of 14.4 Ǻ. Along the b axis there are homogeneous stacks of the ammonium functions, the anions, and the Pb, S chains, with a pseudo-symmetric repeat of b/3 in each stack, allowing disorder due to stacking faults. This disorder has been adequately modelled in the refinement, which also incorporated back-Fourier-transform techniques to avoid inaccuracies due to spherically disordered PF6- ions. Crystal data: Cc, 25.535(8), b 43.13(1), c 15.123(5)Ǻ, β 100.36(9)°, Z 12 (× Pb2S5C25H65N5P4F24), 3585 observed data, R 0.066.

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