Synthesis and Structural Characterization of an Exclusively N-Based Tetrameric Aluminum(I) Compound

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 = CH3+ (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 peri-interaction, sterical interactions are characterized essentially by geometrical and energetical changes.

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Peri‐Interactions in 8‐Diphenylphosphino‐1‐bromonaphthalene, 6‐Diphenylphosphino‐5‐bromoacenaphthene, and Derivatives

Synthesis of a Functional Aluminium Alkynide, Me3C-C≡C-AlBr2, and its Reactions with the Bulky Lithium Compound LiCH(SiMe3)2



Treatment of aluminium tribromide with the lithium alkynide (Li)C≡C-CMe3 afforded the aluminium alkynide Me3C-C≡C-AlBr2 (1) in an almost quantitative yield. 1 crystallizes with trimeric formula units possessing Al3C3 heterocycles and the anionic carbon atoms of the alkynido groups in the bridging positions. A dynamic equilibrium was determined in solution which probably comprises trimeric and dimeric formula units. Reaction of 1 with one equivalent of LiCH(SiMe3)2 yielded the compound [Me3C-C≡C-Al(Br)-CH(SiMe3)2]2 (2), which is a dimer via Al-C-Al bridges. Two equivalents of the lithium compound gave a mixture of four main-products, which could be identified as 2, Li[Me3C-C≡C-Al{CH(SiMe3)2}3] (3), Me3C-C≡C-Al[CH(SiMe3)2]2 (4), and Al[CH(SiMe3)2]3. The lithium atom of 3 is coordinated by the C≡C triple bond and an inner carbon atom of one bis(trimethylsilyl)methyl group. Further interactions were observed to C-H bonds of methyl groups.

Synthese eines funktionalen Aluminiumalkinids, Me3C‐C≡C‐AlBr2, und dessen Reaktionen mit der sperrigen Lithiumverbindung LiCH(SiMe3)2

Re-investigation of ortho-metalated N,N-dialkylbenzylamine complexes of rare-earth metals. First structurally characterized arylates of neodymium and gadolinium Li[LnAr4]

Synthesis and crystal structures of organometallic compounds containing the ligands C(SiMe3)2(SiMe2H) and C(SiMe2Ph)2(SiMe2H)

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Halides of ortho-substituted arylaluminum compounds with coordination numbers four and five

Twofold Borylation of Benzene Derivatives with (Diisoalkylamino)boradiyl Units



The reaction of subvalent boron species generated by the defluorination of difluoro(diorganylamino)borane with Na/K alloy in the presence of 1,4-disubstituted benzene derivatives leads to products which contain two (diorganylamino)boradiyl units and two remaining double bonds which are located on the substituted C atoms. Compounds 5 to 8 exhibit structures based on a 2,8-diborabicyclo[3,2,1]octa-3,6-diene skeleton while 9 shows a skeleton with a 1,3a,4,6a-tetrahydroborolo[3,2-b]borole structure. The latter structure corresponds to that of 1 obtained in the same reaction with benzene. The compounds are characterized by elemental analyses and spectroscopically [MS, NMR (1H, 11B, 13C, 15N, 19F, 29Si)]. X-ray structure analyses are presented for 1, 6, 7, 8, and 9.

Christian Böker

Papers

Halides of ortho-substituted arylaluminum compounds with coordination numbers four and five

Zweifache Borylierung von Benzolderivaten mit (Diisoalkylamino)boradiyl‐Einheiten