Reactions of main group compounds with azides forming organic nitrogen-containing species

Since the seminal discovery of phenyl azide by Grieß in 1864, a variety of organic azides (R-N3) have been developed and extensively studied. The amenability of azides to a number of reactions has expanded their utility as building blocks not only in organic synthesis but also in bioorthogonal chemistry and materials science. Over the decades, it has been demonstrated that the reactions of main group compounds with azides lead to diverse N-containing main group molecules. In view of the pronounced progress in this area, this review summarizes the reactions of main group compounds with azides, emphatically introducing their reaction patterns and mechanisms. The reactions of forming inorganic nitrogen species are not included in this review.

Cutting edge of diphenyl phosphorazidate (DPPA) as a synthetic reagent – A fifty-year odyssey

Recent developments of diphenyl phosphorazidate (DPPA, (C6H5O)2P(O)N3) has been reviewed.

An α-diiminato germylene family: syntheses, structures, and reactivity towards C-C coupled digermylene and digermylene oxide

The synthesis and reactivity of a rigid α-diiminate ligand supported chlorogermylene 2 was demonstrated. The reaction of 2 with hydride donor K[BH(sBu)3] yielded a hydride addition product, a five-membered 6π-aromatic...

Lewis acidic alkaline earth metal complexes with a perfluorinated diphenylamide ligand

Alkaline earth metal chemistry with the anion [N(C₆F₅)₂]⁻ has been explored. Complexes are stabilized by metal⋯F interactions. Mg[N(C₆F₅)₂]₂ is a stronger Lewis acid than B(C₆F₅)₃.

Chlorogermylenes and -stannylenes stabilized by diimidosulfinate ligands: synthesis, structures, and reactivity

The reaction of the lithium salt of N,N'-di-tert-butyldiimidosulfinate ([PhS(N^tBu)₂]Li) having a phenyl group on the sulphur atom with ECl₂·(dioxane) (E = Ge, Sn) afforded the corresponding chlorogermylene [PhS(N^tBu)₂]GeCl 1 and -stannylene [PhS(N^tBu)₂]SnCl 2, respectively. In contrast, treatment of the N,N'-bis(trimethylsilyl)diimidosulfinate ion ([PhS(NSiMe₃)₂]^-) with ECl₂·(dioxane) resulted in the unexpected formations of six-membered 1,3-bis(chlorogermylene) [PhS(NSiMe₃)₂(η¹-η¹-GeCl)₂[μ-NSPh(NHSiMe₃)] 7 and -stannylene [PhS(NSiMe₃)₂(η¹-η¹-SnCl)₂[μ-NSPh(NHSiMe₃)] 8. The structures of these chlorometallylene derivatives were fully characterized on the basis of their NMR spectroscopic data and X-ray diffraction. In the crystalline states of 1 and 2, the diimidosulfinate ligands chelate to the metal centre to form slightly hinged four-membered EN₂S rings. On the other hand, X-ray analyses of 7 and 8 revealed that the central six-membered E₂N₃S rings adopt a distorted boat-conformation, and one diimidosulfinate ligand coordinates to the metal centre in a bridging monodentate μ-η¹-η¹-fashion. As the reactivity of 1 and 2, the oxidation of 1 with elemental chalcogen (S₈ or Se) afforded the corresponding tetra-coordinated germanium compounds [PhS(N^tBu)₂]Ge([double bond, length as m-dash]Ch)Cl 3 (Ch[double bond, length as m-dash]S) and 4 (Ch[double bond, length as m-dash]Se). In sharp contrast, the reactions of 2 with elemental chalcogen resulted in the formation of four-membered Sn₂Ch₂ ring compounds, 1,3,2,4-dichalcogenadistannetanes {(PhS(N^tBu)₂)SnCl(μ-Ch)}₂5 (Ch[double bond, length as m-dash]S) and 6 (Ch[double bond, length as m-dash]Se).

Basic Reactivity Pattern of a Cyclic Disilylated Germylene

In order to estimate the reactivity of disilylated germylene phosphine adducts, a cyclic version of this compound class was reacted with a number of different reagents. Reactions with the chalcogens sulfur, selenium, and tellurium led to dimers of the heavy ketone analogues. Reactions with water and ethyl bromide proceeded to give the respective oxidized germanol and germyl bromide. Two different reactions with alkynes were observed which led either to a germacyclopropene, by addition of tolane to the germylene, or to a silagermacyclobutene, likely formed by addition of the alkyne across a silagermene. Reaction via the silagermene was also observed in the reaction with benzophenone. Reaction of a germylene phosphine adduct with GeCl2·(dioxane) provided insertion of the silylated germylene into a Ge-Cl bond, leading to a germylated chlorogermylene phosphine adduct.

Isolation of a Cyclic (Alkyl)(amino)germylene

A 1,4-addition of a dichlorogermylene dioxane complex with α,β-unsaturated imine 1 gave a dichlorogermane derivative 2 bearing a GeC₃N five-membered ring skeleton. By reducing 2 with KC₈, cyclic (alkyl)(amino)germylene 3 was synthesized and fully characterized. Germylene 3 readily reacted with TEMPO, N₂O and S₈, producing the 1:2 adduct 4, the oxo-bridged dimer 5 and the sulfido-bridged dimer 6, respectively.

The Bis(pentafluoroethyl)germylene Trimethylphosphane Adduct (C2 F5 )2 Ge⋅PMe3 : Characterization, Ligand Properties, and Reactivity

The synthesis of the germylene phosphane adduct (C2 F5 )2 Ge⋅PMe3 is described. Starting from (C2 F5 )3 GeH in an excess of PMe3 , heating was applied, whereupon reductive elimination of C2 F5 H occurred. The molecular structure was ascertained by X-ray diffraction and compared with information obtained by quantum chemical methods. The ligand properties were derived by studying the IR spectrum of the nickel(0) complex [Ni(CO)3 {Ge(C2 F5 )2 (PMe3 )}] in the CO region. (C2 F5 )2 Ge⋅PMe3 turned out to be a π-accepting ligand comparable to PMe3 , in terms of Tolman's electronic parameter. Furthermore a [2+4] cycloaddition reaction with 2,3-dimethyl-1,3-butadiene, and σ-bond insertion reactions were recorded. Activation of the C-Cl bond in dichloromethane gives rise to the formation of the phosphonium ylide complex [(C2 F5 )2 Cl2 Ge-CH2 PMe3 ], which was fully characterized by X-ray diffraction.

Cationic Five-Coordinate Bis(guanidinato)silicon(IV) Complexes with SiN4 El Skeletons (El=S, Se): "Heterolytic Activation" of S-S and Se-Se Bonds

The donor-stabilized silylene [iPrNC(NiPr2 )NiPr]2 Si (2) reacts with PhEl-ElPh (El=S, Se) to form the respective cationic five-coordinate bis(guanidinato)silicon(IV) complexes {[iPrNC(NiPr2 )NiPr]2 SiSPh}(+) PhS(-) (4) and {[iPrNC (NiPr2 )NiPr]2 SiSePh}(+) PhSe(-) (5). Compounds 4 and 5 were characterized by crystal structure analyses and NMR spectroscopic studies in the solid state.

Synthesis and reactivity of a germylene stabilized by a boraguanidinate ligand

The reactivity of a germylene stabilized by a boraguanidinate ligand with various reagents is reported.

Crystal structure of 2,6-bis(2-hydroxy-5-methylphenyl)-4-phenylpyridinium bromide dichloromethane hemisolvate hemihydrate

The asymmetric unit in the structure of the title compound, C₂₅H₂₂NO₂⁺·Br ⁻·0.5CH₂Cl₂·0.5H₂O, comprises two pseudosymmetry-related cations, two bromide anions, a di­chloro­methane molecule and a water mol­ecule of solvation. The two independent cations are conformationally similar with the comparative dihedral angles between the central pyridine ring and the three benzene substituent rings being 3.0 (2), 36.4 (1) and 24.2 (1)°, and 3.7 (2), 36.5 (1) and 24.8 (1)°, respectively. In the crystal, the cations, anions and water mol­ecules are linked through O—H⋯O and O—H⋯Br hydrogen bonds, forming an insular unit. Within the cations there are also intra­molecular N—H⋯O hydrogen bonds. Adjacent centrosymmetrically related aggregates are linked by π–π stacking inter­actions between the pyridine ring and a benzene ring in both cations [ring-centroid separations = 3.525 (3) and 3.668 (3) Å], forming chains extending across the ac diagonal. Voids between these chains are filled by dichloromethane molecules.

Crystal structure of 4,8-di-tert-butyl-6,6-dichloro-13-ethyl-2,10-dimethyl-13,14-dihydro-12H-dibenzo[d,i][1,3,7,2]dioxazasilecine toluene 0.25-solvate

The coordination polyhedron at the silicon atom in the title compound, C26H37Cl2NO2Si·0.25C7H8, is typical for pentacoordinated silicon derivatives and represents a slightly distorted trigonal bipyramid with an N atom and a Cl atom in the apical positions and the two O atoms and the other Cl atom occupying the equatorial sites. There are two independent molecules in the asymmetric unit. The N–Si–Cl fragment in each is close to linear [178.24 (5) and 178.71 (5)°], in good agreement with 4e–3ctheory, as is the elongation of the apical bond lengths [Si—Cl = 2.1663 (7) and 2.1797 (7) Å] in comparison with the equatorial bonds [Si—Cl = 2.0784 (7) and 2.0748 (7) Å]. Orthogonal least-squares fitting of the two independent molecules resulted in r.m.s. deviation of 0.017 Å. The conformations of the two molecules are almost the same, with corresponding torsion angles differing by less than 5.5°. The toluene solvent molecule is disordered about an inversion centre.

Effective, transition metal free and selective C–F activation under mild conditions

A simple and effective aromatic nucleophilic monosubstitution reaction for the synthesis of aromatic amines via selective C–F bond cleavage of various fluoroarenes with primary and secondary aromatic amines is demonstrated.

Crystal structure of a mixed-valence μ-oxide Sn12 cluster

The mixed-valence μ-oxide Sn12 cluster, deca-carbonyl-tetra-μ4-oxido-hexa-μ3-oxido-tetra-kis-[μ-2,2'-(pyridine-2,6-di-yl)bis(1,1-di-phenyl-ethano-lato)]deca-tin(II)ditin(IV)dimolyb-denum(O)(2 Mo-Sn) toluene hepta-solvate, [Mo2Sn12(C33H27NO2)4O10(CO)10]·7C7H8, has a crystallographically imposed inversion centre. The asymmetric unit also contains three and a half toluene solvent mol-ecules, one of which is disordered about a centre of symmetry. The complex mol-ecule comprises six distinct Sn atom species with four different coordination numbers, namely 3, 4, 5, and 6. The Sn(II) atoms forming the central Sn10O10 core adopt distorted trigonal-pyramidal, square-pyramidal and octa-hedral coordination geometries provided by the μ-oxide atoms and by the O- and N-donor atoms of two pyridinedi-ethano-late ligands. The terminal Sn(IV) atoms have distorted trigonal-bipyramidal coordination geometries, with a μ4-oxide atom and the N atom of a pyridinedi-ethano-late ligand occupying the axial positions, and the Mo atom of a Mo(CO)5 group and the alk-oxy O atoms of a ligand forming the equatorial plane. In the crystal, weak intra- and inter-molecular C-H⋯O hydrogen bonds are observed.