The Sodium Siloxides (<i>t</i>Bu₃SiONa)₄ and (<i>t</i>Bu₂PhSiONa)₄: Synthesis and X-ray Crystal Structure Analysis

The sodium siloxides (tBu3SiONa)4 and (tBu2PhSiONa)4 can be synthesized almost quantitatively from the reaction of the sodium silanides tBu3SiNa and tBu2PhSiNa with N2O in tetrahydrofuran at −78 °C. (tBu3SiONa)4 and (tBu2PhSiONa)4 are the first structurally characterized sodium siloxides featuring a heterocubane framework in the solid state. X-ray quality crystals of the supersilanol, tBu3SiOH (monoclinic, C2/c), were obtained from the thermolysis of tBu3SiNaN−NNSitBu3 in the presence of water

The Sodium Siloxides (<i>t</i>Bu₃SiONa)₄ and (<i>t</i>Bu₂PhSiONa)₄: Synthesis and X-ray Crystal Structure Analysis

The sodium siloxides (tBu3SiONa)4 and (tBu2PhSiONa)4 can be synthesized almost quantitatively from the reaction of the sodium silanides tBu3SiNa and tBu2PhSiNa with N2O in tetrahydrofuran at −78 °C. (tBu3SiONa)4 and (tBu2PhSiONa)4 are the first structurally characterized sodium siloxides featuring a heterocubane framework in the solid state. X-ray quality crystals of the supersilanol, tBu3SiOH (monoclinic, C2/c), were obtained from the thermolysis of tBu3SiNaN−NNSitBu3 in the presence of water

The Sodium Cuprate (<i>t</i>Bu₃Si)₂CuNa: Formation and X-ray Crystal Structure Analysis

(tBu3Si)2CuNa(THF)n (1; n = 2, 4) is the first structurally characterized sodium cuprate and represents a heavier homologue of the well-known lithium cuprates. Yellow crystals of (tBu3Si)2CuNa(THF)2 (1a) were obtained from heptane (space group P21/n); the ion-separated form (tBu3Si)2CuNa(THF)4 (1b) crystallized from toluene (space group R3̄)

The Sodium Siloxides (<i>t</i>Bu₃SiONa)₄ and (<i>t</i>Bu₂PhSiONa)₄: Synthesis and X-ray Crystal Structure Analysis

The sodium siloxides (tBu3SiONa)4 and (tBu2PhSiONa)4 can be synthesized almost quantitatively from the reaction of the sodium silanides tBu3SiNa and tBu2PhSiNa with N2O in tetrahydrofuran at −78 °C. (tBu3SiONa)4 and (tBu2PhSiONa)4 are the first structurally characterized sodium siloxides featuring a heterocubane framework in the solid state. X-ray quality crystals of the supersilanol, tBu3SiOH (monoclinic, C2/c), were obtained from the thermolysis of tBu3SiNaN−NNSitBu3 in the presence of water

The Sodium Siloxides (<i>t</i>Bu₃SiONa)₄ and (<i>t</i>Bu₂PhSiONa)₄: Synthesis and X-ray Crystal Structure Analysis

The sodium siloxides (tBu3SiONa)4 and (tBu2PhSiONa)4 can be synthesized almost quantitatively from the reaction of the sodium silanides tBu3SiNa and tBu2PhSiNa with N2O in tetrahydrofuran at −78 °C. (tBu3SiONa)4 and (tBu2PhSiONa)4 are the first structurally characterized sodium siloxides featuring a heterocubane framework in the solid state. X-ray quality crystals of the supersilanol, tBu3SiOH (monoclinic, C2/c), were obtained from the thermolysis of tBu3SiNaN−NNSitBu3 in the presence of water

Ru-Catalyzed Benzannulation Leads to Luminescent Boron-Containing Polycyclic Aromatic Hydrocarbons

A series of boron-containing polycyclic aromatic hydrocarbons (PAHs) have been synthesized through the Ru-catalyzed cyclization of aryl ene-ynes. The benchtop-stable products show deep blue photoluminescence. Reversible electrochemical reduction is possible at moderate electrode potentials (about −2.0 V vs FcH/FcH⁺); some of the compounds also underwent reversible oxidation. The systematic expansion of the PAH scaffolds permitted the analysis of even subtle structure–property relationships

A Chloro-Bridged Dimanganese Complex and an Oxo-Bridged Dititanium Complex of a Ditopic Bis(pyrazol-1-yl)borate Ligand

The synthesis and crystal structure analysis of the ditopic p-phenylene-bridged bis(pyrazol-1-yl)borate [[p-C6H4(Bpz2tBu)2]Li2] (LLi2; pz = pyrazol-1-yl) is described. A salt metathesis reaction between LLi2 and MnCl2 in THF leads to the dinuclear complex [L[Mn(THF)]2(μ-Cl)2] featuring a central diamond MnII−(μ-Cl)2−MnII core (X-ray crystal structure analysis). Treatment of LLi2 with 2 equiv of [Ti(NMe2)3Cl] gives the dinuclear titanium compound [L[Ti(NMe2)3]2]. Upon reaction of LLi2 with [Ti(NMe2)2Cl2] and water, the μ-oxo-bridged dititanium species [L[Ti(NMe2)Cl]2(μ-O)] is obtained in excellent yield (X-ray crystal structure analysis)

Facile Synthesis of (3,5-(CF₃)₂C₆H₃)₂BX (X = H, OMe, F, Cl, Br): Reagents for the Introduction of a Strong Boryl Acceptor Unit

The reaction of (3,5-(CF3)2C6H3)Li ((Fxyl)­Li) with BH3·SMe2 in Et2O furnishes Li­[(Fxyl)­BH3] in an essentially quantitative yield. Hydride abstraction with Me3SiCl followed by the addition of a second equivalent of (Fxyl)Li gives Li­[(Fxyl)2BH2] in 71% yield. Treatment of Li­[(Fxyl)2BH2] with 1 equiv of Me3SiCl and a subsequent targeted methanolysis provide access to the methoxyborane (Fxyl)2BOMe. The latter compound serves as starting material for the synthesis of the haloboranes (Fxyl)2BX (X = F, Cl, Br) through the reaction with KHF2/Me3SiCl, BCl3, and BBr3, respectively. All three haloboranes, as well as key synthesis intermediates, have been structurally characterized by X-ray crystallo­graphy

B₂,N₄‑Doped Heptacenes: Ambipolar Charge-Transfer Compounds with Deep LUMO Levels

The B2,N4-doped heptacene H4 in which two N,N′-dihydrophenazine units are linked by two BMes bridges (Mes = mesityl) was synthesized via fourfold Buchwald−Hartwig coupling between 2,3,6,7-tetrachloro-9,10-dimesityl-9,10-dihydro-9,10-diboraanthracene and o-phenylenediamine (tBuXPhos-Pd-G3, DBU/NaOTf, 2-MeTHF, 50 °C, 16 h). Upon exposure to ambient air, H4 is oxidized to its N,N′-dihydro form H2; further oxidation with MnO2 furnishes the di(phenazine) derivative H0. Stirring under a blanket of H2 in the presence of Pd/C hydrogenates H0 back to H2 and ultimately H4. Yellow-colored H0 is a remarkably good electron acceptor with a LUMO-energy level of −3.9 eV; upon irradiation with a 405 nm LED in the presence of THF or 1,4-cyclohexadiene, H0 accepts two H atoms to furnish H2. One-electron reduction of H0 yields the isolable radical-anion salt Li[H0] (lithium naphthalenide, THF, −30 °C to rt). The ambipolar compounds H2 and H4 possess a navy blue and deep purple color, respectively, due to charge-transfer interactions from the electron-rich N,N′-dihydrophenazine donor(s) to the electron-accepting B2C4 core

Mononuclear (<i>O</i>,<i>O</i>′ or <i>N</i>,<i>N</i>′) and Heterodinuclear (<i>O</i>,<i>O</i>′ and <i>N</i>,<i>N</i>′) Transition-Metal Complexes of <i>ortho</i>-Quinoid Bis(pyrazol-1-yl)methane Ligands

The ortho-hydroquinone-substituted bis­(3,5-dimethylpyrazol-1-yl)­methane ligand (HO)2C6H3–C­(H)­(pzMe,Me)2 (7) has been synthesized and fully characterized. Together with its bis­(3-tert-butylpyrazol-1-yl)­methane congener (HO)2C6H3–C­(H)­(pztBu)2 (6), 7 was employed in oxidation and complexation studies. 6 has been oxidized with 2,3-dichloro-5,6-dicyano-para-benzoquinone to the corresponding ortho-benzoquinone form 9 on a preparative scale. Pure samples of 9 are stable for several hours in solution and for approximately one day in the solid state. Attempts at a N,N′ coordination of [PdCl2] to 6 led to decomposition of the −C­(H)­(pztBu)2 moiety, whereas an introduction of [PdCl2] exclusively at the N,N′ site was possible in high yield for ligand 7. A selectively O,O′-chelated [(p-cym)­Ru]2+ complex was accessible for ligand 6, but not for 7. In contrast, [(ppy)2Ir]+ and [(Cp*)­Ir]2+ gave O,O′ complexes with both donors 6 and 7 (Hppy = 2-phenylpyridine; HCp* = pentamethylcyclopentadiene). The heterodinuclear complex [(Cp*)­Ir­(O)2C6H3–C­(H)­(pzMe,Me)2PdCl2] (16) was obtained from 14 and [(MeCN)2PdCl2]