The first crystal structures of the highly energetic tetraazidoborate anion and boron triazide adducts with quinoline and pyrazine as well as of tetramethylpiperidinium azide have been determined. Synthesis procedures and thorough characterization by spectroscopic methods of these hazardous materials are given. Quantum chemical calculations were carried out for B(N(3))(4)(-), B(N(3))(3), C(5)H(5)N.B(N(3))(3), (N(3))(3)B.NC(4)H(4)N.B(N(3))(3), and the hypothetical C(3)H(3)N(3).[B(N(3))(3)](3) at HF, MP2, and B3-LYP levels of theory. The structure of tetraazidoborate was optimized to S(4) symmetry and confirmed the results obtained from the X-ray diffraction analysis. The dissociation enthalpies for the pyridine (model for quinoline) as well as for the pyrazine adduct were calculated. For pyridine-boron triazide a value of 10.0 kcal mol(-1) (for pyrazine-bis(boron triazide) an average of 2.35 kcal mol(-1) per BN unit) was obtained.

The reduction of black‐blue tris(supersilyl)digallanyl [R*2Ga−GaR*]· (R* = SitBu3 = supersilyl) in organic solvents with Na, NaC10H8, or NaR* leads to deep‐red sodium tris(supersilyl)digallanide−THF(1/3) NaGa2R*3×3THF = [R*2Ga−GaR*Na(THF)3], which transforms in the presence of 18‐crown‐6 into deep‐blue sodium tetrakis(supersilyl)trigallanide−18‐crown‐6(1/1)−THF(1/2) [Na(18‐C‐6)(THF)2]+[R*2Ga−GaR*−GaR*]−.The oxidation of the latter anion with R*Br or TCNE as well as the reaction of the digallanyl R*3Ga2· with R*Br leads to deep‐green tetra(supersilyl)cyclotrigallanyl [···R*Ga−GaR*2−GaR*···]·. The latter radical thermolizes at 100 °C to dark‐violet tetrakis(supersilyl)‐tetrahedro‐tetragallane R*4Ga4 besides the digallanyl R*3Ga2·. This is also prepared from NaR* and GaCl3 or R*2GaCl, as well as by oxidation of R*3Ga2−, and itself thermolizes with formation of the tetrahedrane R*4Ga4. According to X‐ray structure analyses of the mentioned compounds, the Ga−Ga bond of the digallanide NaGa2R*3×3THF (NMR spectroscopically observed) is comparably short (2.380 Å), approaching a bond order of 2. In fact, it is distinctly shorter than the Ga−Ga bond (2.420 Å) in the digallanyl R*3Ga2· (EPR spectroscopically observed). The Ga atoms of the trigallanyl R*4Ga3· (EPR spectroscopically observed) are located at the corners of a triangle with two shorter R*2Ga−GaR* sides (2.527 Å) and a comparably longer R*Ga−GaR* basis (2.879 Å). The mean value of the two Ga−Ga bonds in the trigallanide R*4Ga3− (NMR spectroscopically observed) is as long (2.53 Å) as the short Ga−Ga bonds in R*4Ga3·. The anion shows an intramolecular CH3···Ga contact (C−Ga 2.10 Å) between one peripheral methyl group of the R*2Ga entity and the anionic Ga atom in [R*2Ga−GaR*−GaR*]−.

Rarity value is something that main group complexes of N‐heterocyclic carbenes still have. With a triscarbene chelating carbon analogue of Trofimenko's tris(pyrazolyl)borate the solvent free, dinuclear lithium complex 1 was successfully synthesized, in which the lithium atoms are only bound to carbene carbon atoms.

The lithiation of 2‐(aminomethyl)pyridine and the subsequent reaction with ClSiMe2tBu yields (tert‐butyldimethylsilyl)(2‐pyridylmethyl)amine (1). The metalation of 1 with dimethylzinc gives colorless dimeric methylzinc 2‐pyridylmethyl(tert‐butyldimethylsilyl)amide (2), which crystallizes in the triclinic space group P1¯. The solvent‐free thermal decomposition of 2 at 150 °C leads to the evolution of methane, the precipitation of zinc metal and the formation of amine 1, bis(methylzinc)—1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethane (3), and bis[(tert‐butyldimethylsilyl)(2‐pyridylmethyl)amido]zinc (4). Compound 3 can be obtained in good yield by reacting 2 with dimethylzinc at elevated temperatures in toluene. During this reaction, zinc metal precipitates and methane is evolved. The C−C coupling product 3 crystallizes in the tetragonal space group I41cd. The lithiation of 1 and the subsequent metathesis reaction with anhydrous ZnCl2 yields complex 4 almost quantitatively.

A series of amine solvates of LiBH4 and NaBH4 have been prepared and characterized by IR and NMR spectroscopy as well as by X-ray single-crystal structure determinations. LiBH4 crystallizes from pyridine as LiBH4·3(py), 1, in which the BH4 anion acts as a bidentate ligand. However, in the structure of LiBH4·3py*, 2 (py* = p-benzylpyridine), a tridentate BH4 group is observed. In contrast, LiBH4·2(coll), 3 (coll = 2,4,6-trimethylpyridine, collidine), possesses only a bidentate tetrahydridoborate group, while a tridentate BH4 group is present in monomeric LiBH4·PMDTA, 4 (PMDTA = pentamethyldiethylenetriamine). In contrast, NaBH4·PMDTA, 6, is dimeric in the solid state:  three of the four H atoms of each BH4 group coordinate to the Na atoms; two form a double bridge to two Na atoms while the third one is bonded only to one Na center. LiBH4·TMTA, 5 (TMTA = trimethylhexahydrotriazine), is also dimeric; however, only two of the nitrogen atoms of the TMTA ligand coordinate to Li. The BH4 groups bridge the two Li centers each with one H atom coordinating to two Li atoms, and two bind to a single Li atom. A totally different situation exists for NaBH4·TMTCN, 7 (TMTCN = trimethyltriazacyclononane), which is tetrameric in the crystal. Only one hydrogen atom of the BH4 group functions as a hydride bridge and binds to three Na centers. The molecule contains a Na4B4 heterocubane core. Thus, the different modes of the interaction of the BH4 groups with the alkali metal atoms are determined by the number of donor atoms from the neutral amine ligand and the size of the cation. No definitive conclusion as to the structure of the amine solvates can be derived from IR and/or 11B NMR spectra for the solution state. The crystallographic data are as follows. 1:  a = 10.9939(5) Å, b = 9.9171(4) Å, c = 14.8260(8) Å, β = 94.721(3)°, V = 1611.0(1) Å3, monoclinic, space group P2(1)/n, Z = 4, R 1 = 0.0823. 2:  a = 10.121(1) Å, b = 12.417(2) Å, c = 13.462(3) Å, α = 83.189(2)°, β = 86.068(3)°, γ = 69.166(4)°, V = 1369.3(5) Å3, triclinic, space group P1̄, Z = 2, R 1 = 0.0689. 3:  a = 28.527(3) Å, b = 10.858(1) Å, c = 11.319(1) Å, V = 3505.7(6) Å3, orthorhombic, space group Fdd2, Z = 8, R 1 = 0.0502. 4:  a = 7.591(3) Å, b = 15.325(6) Å, c = 8.719(4) Å, β = 99.80(2)°, V = 999.5(7) Å3, monoclinic, space group P2(1)/c, Z = 4, R 1 = 0.0416. 5:  a = 14.68(1) Å, b = 11.830(7) Å, c = 16.960(8) Å, V = 2946(3) Å, orthorhombic, space group P2(1)2(1)2(1), Z = 8, R 1 = 0.0855. 6:  a = 9.993(2) Å, b = 10.008(3) Å, c = 14.472(4) Å, β = 93.55(2)°, V = 1444.6(7) Å3, monoclinic, space group P2(1)/n, Z = 4, R 1 = 0.0455. 7:  cubic, a = b = c = 13.859(5) Å, V = 2662(2) Å3, cubic, space group I4̄3m, Z = 8, R 1 = 0.0871.