Gallium Ligand Coordinated Group 15 Compounds (LGa−ECp', L=(CHNMe)₂CH, E=N − Bi, Cp'=η¹‐C₅H₅): Changeover from Electron‐Sharing to Donor‐Acceptor σ‐Interaction

Abstract

We have analyzed the electronic structure and bonding situation in monomeric compounds of gallium with group 15 elements (LGaÀ ECp', L = (CHNMe) 2 CH, E=N (1), P (2), As (3), Sb (4) and Bi ( 5)) at the M06/def2-TZVPP//BP86/def2-SVP level of theory. The compounds 1-5 have a singlet ground state with a polarized GaÀ E double bond. The molecular orbital analysis indicates that the GaÀ E π-MO and the lone pair on E are susceptible to nucleophilic reactivity. The nucleophilic reactivity of GaÀ E π-MO increases, and that of lone pair on E reduces when the compound changes from 1 to 5. The EDA-NOCV analysis indicates that the nitrogen and phosphorous form charge-separated electron-sharing σ-bond with Ga. The appa-rent switchover between the electron-sharing σ-interaction and donor-acceptor σ-interaction occurs when the group 15 element is arsenic. On the other hand, antimony and bismuth exhibit donor-acceptor interaction with the LGa fragment in compounds 4 and 5. The π-bond in 1-5 is similar and is formed by the donation of the p-type lone pair on E-atom (p z ) to the empty p z -orbital of Ga. The bonding analysis also shows that the strength of π-bonding is reduced on moving towards the heavier elements. A very high first and second proton affinity indicates that group 15 elements in compounds 1-5 act as double Lewis bases.

Ligand‐stabilized heteronuclear diatomics of group 13 and 15

“…The GaN distance (1.910 Å) falls in the range of GaN single bonds (1.829–2.026 Å) found in gallium monoamides 83 . For the heavier homologues, calculated distances are similar to both empirical single‐bond covalent radii and experimentally reported single bonds 84 . The InN bond distance of 2.123 Å is similar to that in indium monoamides (2.054 Å, 2.104 Å), 83 while both InN and InBi (2.944 Å) distances are also similar to single bond covalent radii (2.13 and 2.93 Å) 67 .…”

“… 83 For the heavier homologues, calculated distances are similar to both empirical single‐bond covalent radii and experimentally reported single bonds. 84 The In—N bond distance of 2.123 Å is similar to that in indium monoamides (2.054 Å, 2.104 Å), 83 while both In—N and In—Bi (2.944 Å) distances are also similar to single bond covalent radii (2.13 and 2.93 Å). 67 The In—P, In—As, and In—Sb distances are marginally longer than their respective single bond covalent radii: In—P 2.53 Å, In—As 2.63 Å, and In—Sb 2.82 Å.…”

“…83 For the heavier homologues, calculated distances are similar to both empirical singlebond covalent radii and experimentally reported single bonds. 84 The…”

Organic Allene vs Organometallic Allene─Preference Toward Allylic Anionic Delocalization, Dative Bonding, and Tunable Reactivity

“…The Δ E Pauli and Δ E elect are higher and lower, respectively, for the bonding possibility B in comparison to bonding possibility A, tantamount to the observation in 1 . It can be inferred that for systems with comparable electronic scenarios, destablization due to Pauli’s repulsion will be higher for systems with closed shell interactions, while stabilization due to the electrostatic interaction will be higher for the same . The Δ E orb is further decomposed into contributions from orbitals having different symmetries and the corresponding deformation densities are given in Figure .…”