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Triply Bonded GalliumPhosphorus Molecules: Theoretical Designs and Characterization

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journal contribution
posted on 2017-08-16, 00:00 authored by Jia-Syun Lu, Ming-Chung Yang, Ming-Der Su
The effect of substitution on the potential energy surfaces of triple-bonded RGaPR (R = F, OH, H, CH3, SiH3, SiMe­(SitBu3)2, SiiPrDis2, Tbt (C6H2-2,4,6-{CH­(SiMe3)2}3), and Ar* (C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)) compounds was theoretically examined by using density functional theory (i.e., M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The theoretical evidence strongly suggests that all of the triple-bonded RGaPR species prefer to select a bent form with an angle (∠Ga–P–R) of about 90°. Moreover, the theoretical observations indicate that only the bulkier substituents, in particular, for the strong donating groups (e.g., SiMe­(SitBu3)2 and SiiPrDis2) can efficiently stabilize the GaP triple bond. In addition, the bonding analyses (based on the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) reveal that the bonding characters of such triple-bonded RGaPR molecules should be regarded as R′Ga←PR′. In other words, the GaP triple bond involves one traditional σ bond, one traditional π bond, and one donor–acceptor π bond. Accordingly, the theoretical conclusions strongly suggest that the GaP triple bond in such acetylene analogues (RGaPR) should be very weak.