Boron/Nitrogen Substitution of the Central Carbon Atoms of the Biphenalenyl Diradical π Dimer: A Novel 2e–12c Bond and Large NLO Responses

Abstract

On the basis of the famous staggered biphenalenyl diradical π dimer 1, the eclipsed biphenalenyl (1 a), with no centrosymmetry, was obtained by rotating a layer of 1 by 60° around its central axis. Furthermore, the central carbon atoms of 1 and 1 a were substituted by boron and nitrogen atoms to form 2 and 2 a with a novel 2e–12c bond. We found that the novel 2e–12c bond is formed by the electron pair of the occupied orbital of the phenalenyl monomer substituted by the nitrogen atom and the unoccupied orbital of the phenalenyl monomer substituted by the boron atom. As a result of the novel 2e–12c bond, 2 and 2 a exhibit a fascinating interlayer charge‐transfer transition character, which results in a significant difference in the dipole moments (Δμ) between the ground state and the crucial excited state. The values of Δμ for 2 and 2 a are 6.4315 and 6.9253 Debye, clearly larger than the values of 0 and 0.0015 Debye for 1 and 1 a. Significantly, the boron/nitrogen substitution effect can greatly enhance the first hyperpolarizabilities (β0) of 2 and 2 a with a novel 2e–12c bond compared with 1 and 1 a with a traditional 2e–12c bond: 0 and 19 a.u. for 1 and 1 a are much lower than 3516 and 12272 a.u. for 2 and 2 a. Furthermore, the interaction energies (Eint)of 2 and 2 a are larger than those of 1 and 1 a, which could be considered as a signature of reliability for the newly designed dimers. Our present work will be beneficial for further theoretical and experimental studies on the properties of molecules with the novel 2e–12c bond.

Large Nonlinear Optical Responses of Dimers Bearing a Donor and Acceptor: Long, Intradimer Multicenter Bonding

“…The sign of β y total component is positive, suggests that during a polarization process electronic charge from TTF is expected to migrate to the TCNE, TCNQ, TCNP and TCNB monomers. 78 Table 3 are found comparable to those of long, multicenter bonding molecules previously studied by Zhong et al 80 and ferrocene-based complexes studied by us. 26,81 Moreover, β vec match well with β tot , since the dipole moment has no vanished.…”

Evaluation of protein engineering and process optimization approaches to enhance antibody drug manufacturability

“…In our previous articles, the MP2 method has been chosen for calculating the first hyperpolarizability. [29–33] This is because, with reasonable computation costs, the MP2 results are also very close to those obtained from the more sophisticated correlation methods (for example, the QCISD[34]). The magnitude of the applied electric field was chosen as 0.001 au for the calculation of the hyperpolarizability, which is proven to be the most adequate value for the numerical differentiation.…”

Helical Carbon Segment in Carbon–Boron–Nitride Heteronanotubes: Structure and Nonlinear Optical Properties

“…First, as shown in Figure 3, the calculated b 0 value of [8] 109.92 107.69 angle CBN [8] 114.88 115.59 angle NBN [8] 107.37 109.43 angle BNB [8] 111.77 111.33 Table 2. [52][53][54][55] For general molecules, the charge-transfer distance is related to the difference in dipole moment between the crucial transition states (Dm). in PA-9 (hydrogen is used as a passivated atom to ensure that all C atoms display sp 2 hybridization).…”