Isolobal analogy between trivalent boron and divalent silicon

1990 ◽  
Vol 102 (2) ◽  
pp. 107-115
Author(s):  
Eluvathingal D Jemmis ◽  
Bharatam V Prasad ◽  
PV A Prasad ◽  
Seiji Tsuzuki ◽  
Kazutoshi Tanabe
Keyword(s):  
Isolobal Analogy

scholarly journals Half- and mixed-sandwich metallacarboranes for potential applications in medicine

2019 ◽  
Vol 91 (4) ◽  
pp. 563-573 ◽  
Author(s):  
Marta Gozzi ◽  
Benedikt Schwarze ◽  
Evamarie Hey-Hawkins
Keyword(s):  
Organic Chemistry ◽  
Transition Metal ◽  
Transition Metals ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Structural Features ◽  
Biological Stability ◽  
Potential Applications ◽  
Sandwich Type ◽  
Isolobal Analogy

Abstract Today, medicinal chemistry is still clearly dominated by organic chemistry, and commercially available boron-based drugs are rare. In contrast to hydrocarbons, boranes prefer the formation of polyhedral clusters via delocalized 3c2e bonds, such as polyhedral dicarba-closo-dodecaborane(12) (closo-C2B10H12). These clusters have remarkable biological stability, and the three isomers, 1,2- (ortho), 1,7- (meta), and 1,12-dicarba-closo-dodecaborane(12) (para), have attracted much interest due to their unique structural features. Furthermore, anionic nido clusters ([7,8-C2B9H11]2−), derived from the neutral icosahedral closo cluster 1,2-dicarba-closo-dodecaborane(12) by deboronation followed by deprotonation are suitable ligands for transition metals and offer the possibility to form metallacarboranes, for example via coordination through the upper pentagonal face of the cluster. The isolobal analogy between the cyclopentadienyl(–1) ligand (Cp−) and [C2B9H11]2− clusters (dicarbollide anion, Cb2−) is the motivation in using Cb2− as ligand for coordination to a metal center to design compounds for various applications. This review focuses on potential applications of half- and mixed-sandwich-type transition metal complexes in medicine.

Pd/X group interchange in the [Pd(Br)(PH3)(C6H5)(C6H5X)] system — Theoretical insights from the isolobal analogy perspective

2009 ◽  
Vol 87 (7) ◽  
pp. 838-849 ◽  
Author(s):  
Alain Dedieu ◽  
Antonio J. Mota
Keyword(s):  
Gas Phase ◽  
Geometry Optimization ◽  
Reductive Elimination ◽  
Diffraction Structure ◽  
Elimination Mechanism ◽  
B3lyp Calculations ◽  
Isolobal Analogy ◽  
Electronegative Atom ◽  
Gas Phase Electron Diffraction ◽  
Stable Structures

DFT-B3LYP calculations have been carried out to assess the fate of the Pd/X group intermolecular exchange in the [PdBr(PH3)(C6H5)(C6H5X)] system, where X is either H, an electropositive atom, or a group such as Li, Na, BH2, AlH2, BeH or BeCH3, and an electronegative atom, or a group such as F, Cl, Br, CH3, OH, and SH. The transfer of H is best viewed as involving the migration of a proton between the two phenyls. At variance with this result, the transfer of the more electropositive entities such as X = Li, Na, BH2, AlH2, BeH, or BeCH3 is not complete. It stops halfway to yield a stable structure in which X can experience interactions with the two phenyl groups that are quite ionic. These stable structures are rationalized through isolobal analogy arguments. In the case of beryllium, the correspondence has been made also with the experimentally known cyclopentadienylberyllium borohydride system, CpBeH4. The results of the DFT geometry optimization call for a re-examination of the gas-phase electron-diffraction structure determination, especially for the bond distances and angles that pertain to the two bridging hydrogens. For the halogen series X = F, Cl, or Br and for the electronegative groups CH3, OH, or SH, the transfer between the two phenyls takes place via a two-step Pd(II)/Pd(IV) oxidative addition/reductive elimination mechanism. The associated energy barriers are nevertheless quite high, except for Br and SH for which the process might be feasible. The dimerization of the PdBr(PH3)(C6H5) system is also analyzed within the isolobal analogy framework.

scholarly journals Ab InitioTheoretical Investigation on the Geometrical and Electronic Structures of Gallium Aurides:GaAun0/-andGa2Aun0/-  (n=1–4)

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Wen-Zhi Yao ◽  
Jian-Bin Yao ◽  
Si-Dian Li
Keyword(s):  
Density Functional ◽  
Systematic Investigation ◽  
Strong Interactions ◽  
Hydrogen Atoms ◽  
Covalent Bonds ◽  
Functional Theory ◽  
The Face ◽  
Natural Density ◽  
Isolobal Analogy ◽  
Geometric And Electronic Properties

This study presents a systematic investigation of the geometric and electronic properties of GaAun0/-and Ga2Aun0/-(n= 1–4) clusters based on density functional theory and wave function theory. Detailed orbital analyses, adaptive natural density partitioning, and electron localization function analyses are performed and relevant results are discussed. GaAun0/-(n= 1–4) clusters withn-Au terminals and Ga2Aun0/-(n= 1–4) clusters with bridged Au atoms possess geometric structures and bonding patterns similar to those of the corresponding gallium hydrides GaHn0/-and Ga2Hn0/-. Ga–Au interaction is predicted to occur through highly polar covalent bonds in monogallium aurides. In contrast to the highly symmetric ground states ofC2vGa2Au,C2vGa2Au2, andD3hGa2Au3,C3vGa2Au4is composed of strong interactions between a Ga+cation and the face of a tetrahedral GaAu4−anion. The adiabatic and vertical detachment energies of the anions under study are calculated to facilitate their experimental characterization. Geometric and electronic structural comparisons with the corresponding gallium hydrides are conducted to establish an isolobal analogy between gold and hydrogen atoms.

The Isolobal Analogy“”

1986 ◽  
Vol 25 (9) ◽  
pp. 837-839 ◽  
Author(s):  
Peter Hofmann ◽  
Helmut R. Schmidt
Keyword(s):  
Isolobal Analogy
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