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.

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The reactions of (dpp-BIAN)Zn−Zn(dpp-BIAN) (1) with PhCCH and of [(dpp-BIAN)Zn(μ-I)]2 (2) with potassium hydride yield the binuclear complexes [(dpp-BIAN)Zn(μ-CCPh)]2 (3) and [(dpp-BIAN)Zn(μ-H)]2 (4), respectively (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene). Complex 3 is also obtained by thermal dehydrogenation of [dpp-BIAN(H)]Zn(CCPh) (5), which in turn can be prepared by reacting ZnI2 with equimolar amounts of [dpp-BIAN(H)]Na and PhCCNa. The paramagnetic compounds 3 and 4 have been characterized by ESR spectroscopy; the diamagnetic complex 5, by 1H NMR spectroscopy. The molecular structures of 3 and 4 have been determined by single-crystal X-ray diffraction. The electronic structure of complex 4 has been examined by DFT.

Closely following the procedure for the preparation of the base-stabilized dichlorosilylene complex NHC ⋅SiCl reported by Roesky, Stalke, and co-workers (Angew. Chem. Int. Ed. 2009, 48, 5683-5686), a few crystals of the salt [NHC -H⋅⋅⋅Cl⋅⋅⋅H-NHC ]Si(SiCl ) were isolated, aside from the reported byproduct [NHC -H ⋅⋅⋅Cl ], and characterized by X-ray crystallography (NHC =N,N-di(2,6-diisopropylphenyl)imidazo-2-ylidene). They contain the weakly coordinating anion Si(SiCl ) , which was also obtained in high yields upon deprotonation of the conjugate Brønsted acid HSi(SiCl ) with NHC or PMP (PMP=1,2,2,6,6-pentamethylpiperidine). The acidity of HSi(SiCl ) was estimated by DFT calculations to be substantially higher than those of other H-silanes. Further DFT studies on the electronic structure of Si(SiCl ) , including the electrostatic potential and the electron localizability, confirmed its low basicity and nucleophilicity compared with other silyl anions.

The high-resolution X-ray diffraction analysis of the electron density distribution and plane-wave density functional theory has been applied to estimate the lattice energy and barrier to rotation of a benzene ring in the crystal of (eta(6)-C(6)H(6))(2)Cr. Experimental data made it possible to perform analysis of the metal-(pi-ligand) bond and estimate the nature and energy of weak H...H and H...C intermolecular interactions in the crystal. Summation of the intermolecular H...H and H...C interaction energies makes it possible to reproduce the experimental sublimation enthalpy value with high accuracy.

A new redox‐amphoteric ligand comprising a p‐phenylene‐extended tetrathiafulvalene (TTF) core and two o‐quinone termini has been synthesized. This work was performed in an attempt to synthesize a bridging ligand by combining one of the most powerful organic donors with strong acceptor units in a single molecule. The product was isolated in the doubly reduced diprotonated form. An X‐ray diffraction study revealed a rigid and planar structure for this molecule. This is the first example of an air‐stable p‐phenylene‐extended TTF with an unprotected central ring. The diquinone form itself has been prepared by oxidation of the doubly reduced diprotonated species and then characterized in solution. The electronic spectrum of this compound contains an intense peak that corresponds to intramolecular charge transfer. The spectroscopic and structural studies of both compounds were accompanied by DFT calculations. A singlet biradical ground state was predicted for the doubly reduced diprotonated form.

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