Sodium Cation Migration Above the Diimine π‐System of Solvent Coordinated dpp‐BIAN Sodium Aluminum Complexes (dpp‐BIAN=1,2‐Bis[(2,6‐diisopropylphenyl)imino]acenaphthene)

The reactions of dialumane [L(thf)Al-Al(thf)L] (1, L=[{(2,6-iPr2C6H3)NC(Me)}2](2-)) with stilbene and styrene afforded the oxidation/insertion products [L(thf)Al(CH(Ph)-CH(Ph))AlL] (2) and [L(thf)Al(CH(Ph)-CH2)Al(thf)L] (3), respectively. In the presence of Na metal, precursor 1 reacted with butadienes, possibly through the reduced "dialumene" or the "carbene-like" :AlL species, to yield aluminacyclopentenes [LAl(CH2C(Me)=C(Me)CH2)Na]n (4 a) and [Na(dme)3][LAl(CH2C(Me)=CHCH2)] (4 b, dme=dimethoxyethane) as [1+4] cycloaddition products, as well as the [2+4] cycloaddition product 1,6-dialumina-3,8-cyclodecadiene, [{Na(dme)}2][LAl(CH2C(Me)=C(Me)CH2)2AlL] (5). The possible mechanisms of the cycloaddition reactions were studied by using DFT computations.

Section: Resultssupporting

confidence: 89%

Reactivity of Dialumane and “Dialumene” Compounds toward Alkenes

Zhao

Lei

Dong

et al. 2013

“…Keywords: EPR spectroscopy · gallium · metal-metal interactions · N ligands · structure elucidation · zinc ([dpp-bian] nÀ , n = 1, 2). [7] Animated by the successful synthesis of the dizinc compound 1, we suggested that the dppbian ligand may also be able to stabilize homonuclear bonds of Group 13 metals and possibly even heteronuclear bonds between Group 12 and Group 13 metals. The isolation of both, dpp-bian-supported digallium and dpp-bian-supported zinc-gallium compounds confirmed this suggestion.…”

Section: With K 3 a C H T U N G T R E N N U N G [Dpp-bian] And The Hementioning

confidence: 96%

[(dpp‐bian)GaGa(dpp‐bian)] and [(dpp‐bian)ZnGa(dpp‐bian)]: Synthesis, Molecular Structures, and DFT Studies of These Novel Bimetallic Molecular Compounds

Fedushkin

Lukoyanov

Ketkov

et al. 2007

Self Cite

1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene) (dpp-bian) stabilizes gallium-gallium and zinc-gallium bonds (compounds 1-3). The compound [(dpp-bian)Ga-Ga(dpp-bian)] (2) was prepared by the reaction of GaCl3 with K3[dpp-bian] and the heterometallic [(dpp-bian)Zn-Ga(dpp-bian)] (3) was prepared by a simple one-pot reaction of [{(dpp-bian)ZnI}(2)] with GaCl3 and K4[dpp-bian]. In contrast to [(dpp-bian)Zn-Zn(dpp-bian)] (1) and 3, compound 2 is ESR silent, thus proving the dianionic character of both dpp-bian ligands. The solution ESR spectrum of 3 reveals the coupling of an unpaired electron with the gallium nuclei (69)Ga and (71)Ga (A((69)Ga)=0.97, A((71)Ga)=1.23 mT), thus confirming the presence of Zn-Ga bonds in solution. According to the results of the X-ray crystal structure analyses the metal-metal bond lengths in 2 (2.3598(3) A) and 3 (2.3531(8) A) are close to that found in 1 (2.3321(2) A). The electronic structures of compounds 2 and 3 were studied by DFT (B3 LYP/6-31G* level). The metal-metal pi bond in 2 is mainly formed by overlap of the p orbitals of Ga in the HOMO and HOMO-1, the latter showing a stronger interaction. The s and p orbitals of Ga overlap in the deeper located HOMO-17 producing a Ga-Ga sigma bond. In contrast to the Zn-Zn bond in 1, which has 95 % s character, the NBO (natural bond order) analysis of 2 reveals 67.8 % s, 32.0 % p, and 0.2 % d character for the Ga-Ga bond. Compound 3 has a doublet electronic ground state. The unpaired electron occupies the alpha HOMO-1 localized at the Zn-containing fragment. The Ga-Zn bond is mainly formed by overlap of the metal orbitals in the alpha HOMO-6 and beta HOMO-5. According to the results of the NBO analysis, the Zn wave functions are responsible for 28.7 % of the Zn-Ga bond, with 96.7 % s, 1.0 % p, and 2.3 % d character.

“…The redox non‐innocent behavior of Ar‐BIAN compounds has been evident since the beginning and in the last decade a number of complexes has been reported, mainly by the groups of Fedushkin and Schumann, in which the BIAN ligand has been reduced by up to four electrons 63. 77–80 However, this chemistry has been mostly limited to sterically encumbered ligands (e.g., 2,6‐ i Pr 2 C 6 H 3 ‐BIAN) and little quantitative information on the electronic effect of different substituents is available 81–83…”

Section: Introductionmentioning

confidence: 99%

Easy Entry into Reduced Ar‐BIANH₂ Compounds: A New Class of Quinone/Hydroquinone‐Type Redox‐Active Couples with an Easily Tunable Potential

Viganò

Ferretti

Caselli

et al. 2014

Ar-BIANH2 bearing different substituents on the aryl rings have been synthesized in high yield by reduction of the corresponding bis(aryl)acenaphthenequinonediimine (Ar-BIAN) compounds. The structure of p-CH3 C6 H4 -BIANH2 in the solid state was determined by X-ray diffraction. An exhaustive voltammetric investigation of the two parallel BIAN and BIANH2 series afforded a first rationalization of the redox properties of these molecules, highlighting their analogies with quinone/hydroquinone systems. Such analogies, in combination with the much more negative reduction potential range of Ar-BIAN compounds with respect to quinones, can afford to extend the range of reduction potentials so far obtainable by the use of quinones.