The syntheses and full characterizations of the peri-substituted naphthalenes (Nap) and acenaphthenes (Ace) 1-Br-8-(Ph2P)-Nap (1a) and 5-Br-6-(Ph2P)-Ace (1b), as well as their derivatives 1-Br-8- [Ph2P(E)]-Nap [E = CH3 + (counterion I-) (2a); E = O (3a); E = S (4a); E = Se (5a)] and 5-Br-6-[Ph2P(E)]-Ace [E = CH 3 + (counterion I-) (2b); E = O (3b); E = S (4b); E = Se (5b)] are reported. In order to quantify the energetic and electronic effects of the peri-interactions, an additional set of molecules, 1c-5c, with the bromine atom and the Ph2P(E) fragment on opposite sides of the naphthalene group was generated, which serves as reference because 1c-5c exhibit negligible peri-interactions. The molecular arrangements of all 15 compounds were optimized at the B3PW91/6-311+G(2df,p) level of theory. The analysis of the peri-interactions was not only based on the inspection of the molecular arrangement and energies alone, but extended to a set of real-space bonding indicators (RSBI). These indicators were derived from theoretically calculated electron densities and pair densities, respectively. Particularly, the stockholder, Atoms-In-Molecules (AIM) and Electron-Localizability-Indicator (ELI-D) space partitioning schemes were used to produce Hirshfeld surfaces (HS), bond topological properties and basins of localized bonding and nonbonding electron pairs. Since 1c-5c are 35-58 kJ·mol-1 lower in energy than their counterparts 1a-5a, the hypothesis of a mainly repulsive peri-interaction in 1a/b-5a/b was confirmed. The shapes and contact patterns of the HSs of atoms and fragments involved in the peri-interactions (Br, P, E = CH3 +, O, S, Se) reveal that only in 1a and 1b are peri-interactions exhibited between the bromine and the phosphorus atoms. In all other cases (2a/b-5a/b), the interaction mainly occurs between the bromine atom and the E atom/fragment. According to the bond topological properties and the electron populations within the (non)bonding ELI-D basins, which both are almost unaffected by the Br-P/E periinteraction, sterical interactions are characterized essentially by geometrical and energetical changes.© 2013 WILEY-VCH Verlag GmbH and Co.
|Journal||Zeitschrift fur Anorganische und Allgemeine Chemie|
|Early online date||4 Jun 2013|
|Publication status||Published - 14 Oct 2013|