Ligand effects due to resonance character in LAuCCH− (L = F, Cl, Br, I, CCH) complexes: an NBO/NRT analysis

Abstract

The organogold complexes of LAuCCH(-) (L = F, Cl, Br, I, CCH) were investigated using natural bond orbital/natural resonance theory (NBO/NRT) methods. The NBO/NRT results strongly support the general resonance-type three-center-four-electron (3c/4e) picture of LAuCCH: L(-): Au-CCH ↔ L-Au :CCH(-), arising from hyperconjugation interactions. The sums of ionic and covalent contributions to both L-Au and Au-CCH bonds are all slightly larger than that due to the additional π-back bonding within the 3c/4e hyperbonded triad. This complementary relationship between L-Au and Au-CCH bond orders implies a competing relationship between the ancillary ligand and CCH around the gold atom. We discuss the ligand effects in the LAuCCH(-) series on the basis of this competing relationship.

Equivalent and Complement of the ω-Bonding Model and Charge-Shift Bonding Model: A Natural Bond Orbital/Natural Resonance Theory/Atoms in Molecules Investigation via Cu/Ag/Au Bonding in BMX (B = H2O, H2S, NH3, and PH3; M = Cu, Ag, and Au; and X = F, Cl, Br, and I)

“…Then, what is the Cu/Ag/Au bonding like? Actually, the importance of ω-bonding for Cu/Ag/Au bonding was recognized in our studies from 2015 to 2017. − We demonstrated that Cu/Ag/Au bonding is like ω-bonding based on the preliminary analysis of two-resonance structures and their weights. Soon after, Lu et al performed a similar investigation on some XH 2 P–MY complexes, providing additional examples to support our results.…”

“…Nevertheless, on the basis of the natural bond orbital (NBO) and natural resonance theory (NRT) methods, our earlier studies established that the studied Cu/Ag/Au-bonded complex should be better represented as a resonance hybrid of two natural Lewis structures. 16,17 This resonance description exhibits a formal resemblance to H bonding. However, with 21−28 The CS bond belongs to a new class of chemical bonds, emerging from the valent bond (VB) theory, and it is supported by the atoms in molecules (AIM) theory.…”

“…The Au bond should be considered as a coordinate bond. Nevertheless, on the basis of the natural bond orbital (NBO) and natural resonance theory (NRT) methods, our earlier studies established that the studied Cu/Ag/Au-bonded complex should be better represented as a resonance hybrid of two natural Lewis structures. , This resonance description exhibits a formal resemblance to H bonding. However, with further investigation, we found that the covalency of Cu/Ag/Au bonding is dual (dative and electron-shared bonding) from the localized NBO/NRT viewpoint .…”

Insight into the Bonding Mechanism and the Bonding Covalency in Noble Gas–Noble Metal Halides: An NBO/NRT Investigation

“…53 On the basis of this result, they proposed that this finding can be extended into any atom (X) in the periodic table that involves intermolecular bonding of D−X•••A complexes. Recent studies in our group extend this conservation concept into Cu/Ag/Aubonding complexes 23,54 and noble-gas hydrides. 22 Here, we discuss the conservation of the bond order in the noble gas− noble metal halides.…”