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Chemical Bond I: Lewis Scheme
Published in Franco Battaglia, Thomas F. George, Understanding Molecules, 2018
Franco Battaglia, Thomas F. George
The scheme applies to heteronuclear diatomic and polyatomic molecules. Among such diatomic molecules, the hydrogen halides, HX with X a halogen, fulfill the scheme: An instance where the scheme does not apply is the carbon monoxide molecule, CO. Lewis scheme is then extended by introducing the concept of dative bond, where both electrons of the bond pair are provided by one atom only. In this case, the bond is denoted by an arrow from the donor to the acceptor atom (alternatively, a dative bond is denoted by a positive charge on the donor atom and a negative charge on the acceptor atom). The carbon monoxide molecule is then represented as in Figure 6.2.
Acids and Bases
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
A dative bond is a two-center, two-electron covalent bond in which both electrons come from the same atom. A dative bond is also called a coordinate covalent bond or simply a coordinate bond. Is it possible to view a Brønsted–Lowry acid in terms of the Lewis acid definition?
General Chemistry
Published in Steven L. Hoenig, Basic Chemical Concepts and Tables, 2019
A coordinate covalent bond, also referred to as a dative bond, is a bond in which both pairs of electrons are donated by one atom and are shared between the two, for example:
The study on gas phase dehydrogenation reactions of transition metal cation and ethylene
Published in Molecular Physics, 2023
Wei Li, Ning Ding, Xunlei Ding, Xiaonan Wu
The results of ETS-NOCV analysis of the intermediate MC2H4+ are shown in Table 2. For M = Os, Ir and Pt, the σ donation interaction are −3.36, −2.98 and −2.51 eV. The π back-donation interaction are −1.05, −0.72 and −0.59 eV. The calculated data of ETS-NOCV of MC2H4+ indicate that the dative bond of M+ and ligand C2H4 is formed between the σ donation from M+ to C2H4 and π back-donation from C2H4 to M+. The σ donation interaction are greater than π back-donation for all complexes and the σ donation and π back-donation interactions are decreased in the sequence of Os > Ir > Pt. Therefore, the interaction of metal M+ and C2H4 is stronger and the C–C bond of C2H4 is weaker in the order of Os, Ir, Pt.
Photo-induced primary processes of trans-[Co(acac)2(N3)(py)] in liquid solution studied by femtosecond vibrational and electronic spectroscopies
Published in Molecular Physics, 2021
Tobias Unruh, Luis I. Domenianni, Peter Vöhringer
Finally, we emphasize the remarkable photochemical stability of trans-[1]. From the UV-mIR-spectra and kinetic traces, it can be deduced that the GSB recovers quantitatively within less than 100 ps. The photochemical inertness seen here is quite in contrast to what was observed previously for other azido-cobalt(III) complexes [29–32]. We believe that the sequential electron-transfer pathway effectively protects trans-[1] from any light-driven transformation. The optically prepared 1LMCTacac-state may actually be inclined to partial acac-detachment from the metal because of occupancy in the anti-bonding Co-dx2−y2 orbital. However, the Co−O bond breakage is fully suppressed by the highly efficient primary electron transfer from the azido-ligand to the acac-radical occurring within only ∼200 fs. The resultant 1LMCTazide-state, on the other hand, has occupancy in the anti-bonding Co-dz2 orbital and would therefore be expected to have a propensity for losing either of the two axial ligands, i.e. the azidyl radical or the pyridine. Both pathways would be energetically allowed with the pyridine loss being slightly favoured (cf. Table 3, supplemental material). But yet again, the secondary electron transfer takes place in less than 2 ps and can thus again efficiently quench any dative bond breakage. Just like 1LMCTacac, the intermediate excited metal-centered state, 1MC, is prone to acac-detachment.
Dative versus electron-sharing bonding in N-imides and phosphane imides R3ENX and relative energies of the R2EN(X)R isomers (E = N, P; R = H, Cl, Me, Ph; X = H, F, Cl)*
Published in Molecular Physics, 2019
Tao Yang, Diego M. Andrada, Gernot Frenking
The dative bond in main group compounds has attracted wide interest in recent years [1]. Recently, we reported a comprehensive theoretical study on the relative stabilities and bonding nature in N-oxides and phosphane oxides R3E-O (E = N, P; R = H, F, Cl, Me, Ph) [2]. It was shown that the best description of the N–O bond in R3NO depends on the nature of the substituent R. The halogen systems F3NO and Cl3NO and the triphenyl species Ph3NO possess dative bonds R3N→O, whereas the N–O bonds in H3NO and Me3NO are better described in terms of electron-sharing single bonds between charged fragments R3N+-O−. In contrast, all phosphane oxides R3PO are best depicted with electron-sharing single bonds between charged fragments R3P+-O−. In the present study, we extend this work to the isoelectronic N-imides and phosphane imides R3ENX (E = N, P; R = H, Cl, Me, Ph; X = H, F, Cl). The main purpose of this paper is to disclose the relative stabilities of R3ENX with respect to the R2EN(X)R isomers and to elucidate the nature of the chemical bond. Should they be described as the dative bond between neutral fragments or as the electron-sharing bond between neutral or charged fragments? Do the substituents R and X also significantly influence the bond nature? These are the questions that shall be answered in this work.