Crystal structures of 2,3,8,9,14,15-hexa-methyl-5,6,11,12,17,18-hexa-aza-tri-naphthyl-ene and 2,3,8,9,14,15-hexa-phenyl-5,6,11,12,17,18-hexa-za-tri-naphthyl-ene di-chloro-methane disolvate

The crystal structures of two substituted HATN (hexa-aza-tri-naphthyl-ene) derivatives, namely 2,3,8,9,14,15-hexa-methyl- and 2,3,8,9,14,15-hexa-phenyl-5,6,11,12,17,18- hexa-zatri-naphthyl-ene (HATNMe6 and HATNPh6), are reported. Whereas the structure of the methyl-substituted derivative (HATNMe6) contains no solvent mol-ecules (C30H24N6), the hexa-phenyl-substituted structure (HATNPh6) contains two mol-ecules of di-chloro-methane (C60H36N6·2CH2Cl2). This class of planar bridging ligands is known for its electron-deficient systems and its ability to form π-π stacking inter-actions. Indeed, in both crystal structures strong π-π stacking inter-actions are observed, but with different packing features. The di-chloro-methane mol-ecules in the crystal structure of HATNPh6 are situated in the voids and are involved in C-H⋯N contacts to the nitro-gen atoms of the pyrazine units.

Consecutive Multicomponent Reactions: Synthesis of 3-Acyl-4-alkynyl-Substituted 1,3-Thiazolidines

This work describes the synthesis of compounds containing thiazolidine and propargylamidic motifs. Their preparation follows a synthetic route containing two multicomponent reactions. First, the Asinger four-component reaction is used to prepare 3-thiazolines and 3-oxazolines. Secondly, these heterocyclic imines are converted into propargylamides by a copper-catalyzed three-component reaction using acyl chlorides and terminal alkynes. The synthetic route is characterized by mild conditions and many functional groups are tolerated. The formation of an unexpected α-alkynoxyamide is also presented.

Crystal structure of the η4-ketimine titanium complex (di-phenyl-amido-κN){3-methyl-6-[(4-methyl-phen-yl)(phenyl-aza-nid-yl)methyl-idene]cyclo-hexa-2,4-dien-1-yl-κ2N,C1}(η5-penta-methyl-cyclo-penta-dien-yl)titanium(IV)

The mol­ecular structure of the titanium(IV) half-sandwich title complex comprises one penta­methyl­cyclo­penta­dienyl ligand, one di­phenyl­amido ligand and one η⁴-bound ketimine ligand, leading to a three-legged piano-stool geometry.

The mol­ecular structure of the title titanium(IV) half-sandwich complex, [Ti(η⁵-C₁₀H₁₅)(η⁴-C₂₁H₁₉N)(C₁₂H₁₀N)], shows a three-legged piano-stool geometry at the central Ti^IV atom, comprising of one penta­methyl­cyclo­penta­dienyl ligand, one bidentate ketimine ligand in an η⁴-coordination mode and one monodentate di­phenyl­amide ligand. Except for van der Waals forces, there are no significant inter­molecular inter­actions in the crystal.

Crystal structure of the formal 20 electron zirconocene penta-fulvene complex Cp2Zr(η5,η1-adamantyl-idene-penta-fulvene):toluene:n-hexane = 1:0.125:0.125

The crystal structure of a solvated zirconocene penta-fulvene complex with a bulky adamantyl-idene substitution pattern, namely (η5,η1-adamantyl-idene-penta-fulvene)bis-(η5-cyclo-penta-dien-yl)zirconium(IV)-toluene-n-hexane (8/1/1), [Zr(C15H18)(C5H5)2]·0.125C7H8·0.125C6H14, is reported. Reducing zirconocene dichloride with magnesium results in the formation of a low-valent zirconocene reagent that reacts readily with adamantyl-idene-penta-fulvene to give the aforementioned complex. Single crystal X-ray diffraction proves the dianion-like η5:η1 binding mode of the fulvene ligand to the central ZrIV atom. The asymmetric unit contains four independent mol-ecules of [η5:η1-adamantyl-idene-penta-fulvene]bis-[(η5)-cyclo-penta-dien-yl]zirconium(IV), together with half a mol-ecule of toluene disordered with half a mol-ecule of n-hexane (the solvent mol-ecules have no direct influence on the complex). In each of the four complex mol-ecules, the central ZrIV atom has a distorted tetra-hedral coordination environment. The measured crystal consisted of two domains with a refined ratio of 0.77:0.23.

Crystal structure of n-butyl-tris(dicyclo-hexylamido)hafnium(IV), C40H75HfN3

C40H75HfN3, monoclinic, P21/n (no. 14), a = 10.7446(3) Å, b = 13.6547(4) Å, c = 26.5464(9) Å, β = 92.2375(15)°, V = 3891.8(2) Å3, Z = 4, Rgt(F) = 0.0195, wRref(F2) = 0.0461, T = 100(2) K.

Facile Access to Amido (Thio)xanthates under Eco-Friendly Conditions by One-Pot Three-Component Reaction (3-CR)

A straightforward three-component reaction (3-CR) for the preparation of a variety of biologically interesting amido (thio)xanthates has been developed. By the proper choice of a potassium (thio)xanthate salt, a cyclic or acyclic imine, and an acyl chloride as substrates a broad scope with respect to the substituents can be realized. This operationally simple one-pot method proceeds under mild and environmentally friendly conditions while potassium chloride is produced as the single waste-product.

Chirality as a tool for function in porous organic cages

The control of solid state assembly for porous organic cages is more challenging than for extended frameworks, such as metal-organic frameworks. Chiral recognition is one approach to achieving this control. Here we investigate chiral analogues of cages that were previously studied as racemates. We show that chiral cages can be produced directly from chiral precursors or by separating racemic cages by co-crystallisation with a second chiral cage, opening up a route to producing chiral cages from achiral precursors. These chiral cages can be cocrystallized in a modular, 'isoreticular' fashion, thus modifying porosity, although some chiral pairings require a specific solvent to direct the crystal into the desired packing mode. Certain cages are shown to interconvert chirality in solution, and the steric factors governing this behavior are explored both by experiment and by computational modelling.

Crystal structures of titanium-aluminium and -gallium complexes bearing two μ2 -CH3 units

The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = meth-yl) with two μ2-coordinating methyl groups, namely [μ-1(η5)-(adamantan-1-yl-2κC1)cycylo-penta-dien-yl]di-μ2-methyl-methyl-2κC-[1(η5)-penta-methyl-cyclo-penta-dien-yl]aluminiumtitanium(III), [AlTi(CH3)3(C10H15)(C15H18)], and [μ-1(η5)-(adamantan-1-yl-2κC1)cycylo-penta-dien-yl]di-μ2-methyl-methyl-2κC-[1(η5)-penta-methyl-cyclo-penta-dien-yl]galliumtitanium(III), [GaTi(CH3)3(C10H15)(C15H18)], are reported. Reacting a dinuclear nitro-gen-bridged low-valent titanium(III) complex with the Lewis acids AlMe3 or GaMe3 results in the loss of mol-ecular di-nitro-gen and the formation of two monomeric titanocene(III) fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E-C bond involving the penta-fulvene ligand while the bridging and terminal methyl groups remain intact.

Hydroaminoalkylation of Allylsilanes and a One-Pot Procedure for the Synthesis of 1,5-Benzoazasilepines

Allylsilanes undergo highly regioselective intermolecular alkene hydroaminoalkylation with secondary amines in the presence of a titanium mono(formamidinate) catalyst. Corresponding reactions of a suitable allyl(2-bromophenyl)silane which exclusively deliver the branched hydroaminoalkylation products combined with a subsequent Buchwald-Hartwig amination result in the development of an elegant one-pot procedure for the synthesis of literature-unknown silicon analogues of 1,5-benzodiazepines, the so-called 1,5-benzoazasilepines.

Cerium-catalyzed, oxidative synthesis of annulated, tetrasubstituted dihydrofuran-derivatives

Densely functionalized, annulated dihydrofuran derivatives are prepared from β-oxoesters and silylenolethers by a cerium-catalyzed aerobic oxidation.

Crystal structure of an isomeric bis[(η5:η1-6,6-di-p-tolylpentafulvene)(η5-pentamethylcyclopentadienyl)titanium(III)]-μ2,η1:η1-dinitrogen complex, C60H66N2Ti2

C60H66N2Ti2, triclinic, P1̅ (no. 2), a = 8.8070(3) Å, b = 11.9544(5) Å, c = 12.3447(5) Å, α = 66.7623(13)°, β = 89.0505(13)°, γ = 80.9952(13)°, V = 1178.06(8) Å3, Z = 1, Rgt(F) = 0.0426, wRref(F2) = 0.1046, T = 100(2) K.

Formation of δ-Lactones by Cerium-Catalyzed, Baeyer-Villiger-Type Coupling of β-Oxoesters, Enol Acetates, and Dioxygen

Formation of δ-lactones is observed when cyclopentanone-2-carboxylates are converted in a cerium-catalyzed reaction with α-aryl vinyl acetates under oxidative conditions. The products of this transformation possess a 1,4-dicarbonyl constitution together with a quaternary carbon center. Atmospheric oxygen is the oxidant in this process, which can be regarded as ideal from economic and ecological points of view. Further advantages of this new C-C coupling and oxidation reaction are its operational simplicity and the application of nontoxic and inexpensive CeCl3·7 H2O as precatalyst. This so far unprecedented reaction is proposed to proceed via 1,2-dioxane derivatives, which decompose under formation of an oxycarbenium cation in a Baeyer-Villiger-type pathway. This mechanistic picture is supported by the observation that electron-rich (donor substituted or heteroaromatic) enol esters give higher yields than electron deficient congeners. Apart from 1,4-diketones and α-hydroxylated β-oxoesters formed as byproducts, the yields of δ-lactones range from moderate to good (up to 74%).

Four-Component Reaction for the Synthesis of Dithiocarbamates Starting from Cyclic Imines

An efficient one-pot, four-component reaction for the synthesis of dithiocarbamates using carbon disulfide, cyclic imines, acid chlorides, and commercially available primary or secondary amines has been developed by performing an acid chloride addition to a heterocyclic imine followed by subsequent nucleophilic substitution of in situ generated dithiocarbamic acid. With the aid of the newly developed and powerful multicomponent reaction, a direct route for the synthesis of 24 unknown dithiocarbamates in moderate to good yield under mild conditions is enabled.

Remarkable stability of tetrabenzo[a,c,g,i]fluorenyl ammonium salts in water: syntheses, reactions, and crystal structures

Deprotonation of 8bH-tetrabenzo[a,c,g,i]fluorene (8bH-Tbf), an extremely large benzannulated cyclopentadienyl derivative, by [NR3R'][OH] (R = (n)Bu, Et; R' = (n)Bu, Et, Bn) leads to a series of Tbf ammonium salts of the type [NR3R'][Tbf]. These cyclopentadienide analogs were smoothly isolated from a hydrous medium and structurally characterized by single X-ray diffraction. Subsequent reactions demonstrate the high potential of derivatization by converting the presented [Tbf] anions into functionalized Tbf compounds.

Guest control of structure in porous organic cages

Two porous organic cages with different thermodynamic polymorphs were induced by co-solvents to interchange their crystal packing modes, thus achieving guest-mediated control over solid-state porosity. In situ crystallography allows the effect of the co-solvent guests on these structural interconversions to be understood.