Oligoorganogermanes: interplay between aryl and trimethylsilyl substituents

Derivatives of main group elements containing element–element bonds are characterized by unique properties due to -conjugation, which is an attractive subject for investigation. A novel series of digermanes, Ar3Ge-Ge(SiMe3)3, containing aryl (Ar = p-C6H4Me (1), p-C6H4F (2), C6F5 (3)) and trimethylsilyl substituents, was synthesized by the reaction of germyl potassium salt, [(Me3Si)3GeK*THF], with triarylchlorogermanes, Ar3GeCl. The optical and electronic properties of such substituted oligoorganogermanes were investigated spectroscopically by UV/vis absorption spectroscopy and theoretically by DFT calculations. The molecular structures of compounds 1 and 2 were studied by XRD analysis. Conjugation between all structural fragments (Ge-Ge, Ge-Si, Ge-Ar, where Ar is an electron-donating or withdrawing group) was found to affect the properties

Bis[5-(4-bromo­phen­yl)-4-(tert-but­oxy­carbon­yl)pyrrolidine-2-carboxyl­ato]copper(II) dihydrate

In the title compound, [Cu(C16H19BrNO4)2]·2H2O, the CuII ion resides on an inversion centre and is coordinated by two O and two N atoms from two enanti­omeric 5-(4-bromo­phen­yl)-4-(tert-but­oxy­carbon­yl)pyrrolidine-2-carboxyl­ate ligands in a distorted square-planar geometry. The relative stereochemistry of the three stereogenic C atoms in each ligand has been determined. In the crystal, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules into layers parallel to the bc plane. The crystal studied was twinned by pseudo­merohedry with twin fractions of 0.719 (3) and 0.281 (3)

2-[(1RS,3RS,3aRS,6aSR)-5-Benzyl-4,6-dioxo-3-phenyl­octa­hydro­pyrrolo­[3,4-c]pyrrol-1-yl]acetamide

In the title compound, C21H21N3O3, the relative stereochemistry of the four stereogenic C atoms has been determined. The dihedral angle between the phenyl rings is 77.63 (7)°. In the crystal, ribbons spread along the a axis are formed by N—H⋯O hydrogen bonds. C—H⋯π inter­actions also occur

Trichlorido{2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1-trimethyl­silyl-1H-imidazole-κN 3}titanium(IV) tetra­hydro­furan hemisolvate

The title compound, [Ti(C15H23N2Si)Cl3]·0.5C4H8O, has been prepared from {2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1H-imidazolyl-κN 1}bis­(N,N-diethyl­amido-κN)titanium(IV), (C12H14N2)Ti(NEt2)2, by reaction with excess of Me3SiCl in tetra­hydro­furan (THF) at 353 K. The crystal structure contains THF as adduct solvent, disordered around a center of inversion. The presence of THF and the adduct ratio has been independently supported by 1H NMR spectroscopy. The coordination polyhedron of the Ti atom is distorted square-pyramidal, assuming the cyclo­penta­dienyl (Cp) ring occupies one coordination site. The Ti, Si and CH2 group C atoms only deviate slightly from the imidazole ring plane [by 0.021 (4), 0.133 (4) and 0.094 (4) Å, respectively]. Comparison of the principal geometric parameters with those of the few known structurally characterized analogues reveal small differences in bond lengths and angles at the Ti atom. The title complex is only stable in THF-d 8 in the presence of excess Me3SiCl, otherwise it exists in an equilibrium with equimolar amounts of dichlorido{2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1H-imidazolyl-κN 3}titanium(IV) and chloro­trimethyl­silane

Donor-acceptor molecular oligogermanes: Novel properties and structural aspects

The linear oligogermyl amide 2, Ph3GeGeMe2NMe2, was obtained by reacting Ph3GeLi with 1, Me2Ge(Cl)NMe2. The amide 2 was used for the synthesis of molecular oligogermanes 3, Ph3GeGeMe2Ge(C6F5)3, and 4, [Ph3GeGeMe2]2Ge(C6F5)2, containing electron donor (Me, Ph) and acceptor (C6F5) groups, by using a hydrogermolysis reaction in n-hexane. The molecular structures of 3 and 4 were studied by XRD. It was shown that in a crystal 3 forms wide channels, in which the solvated nonpolar n-hexane molecule is present. The NMR (1H, 13C and 19F), optical (UV/vis absorption, luminescence) and electrochemical (cyclic voltammetry) properties of both compounds were also studied. The impact of the substitution type by the electron withdrawing groups (at the terminal position, such as in 3, or within the compound, such as in 5), on the physical properties was also studied

4-[(1RS,5RS,7SR)-5-Methyl-2,4-dioxo-3,6-diazabicyclo[3.2.1]octan-7-yl]benzonitrile

In the title compound, C14H13N3O2, the relative stereochemistry of the three stereogenic C atoms has been determined. In the crystal, N—H...O hydrogen bonds link the molecules into chains of inversion dimers running along the b axis

Oligoorganogermanes: Interplay between Aryl and Trimethylsilyl Substituents

Derivatives of main group elements containing element–element bonds are characterized by unique properties due to σ-conjugation, which is an attractive subject for investigation. A novel series of digermanes, Ar3Ge-Ge(SiMe3)3, containing aryl (Ar = p-C6H4Me (1), p-C6H4F (2), C6F5 (3)) and trimethylsilyl substituents, was synthesized by the reaction of germyl potassium salt, [(Me3Si)3GeK*THF], with triarylchlorogermanes, Ar3GeCl. The optical and electronic properties of such substituted oligoorganogermanes were investigated spectroscopically by UV/vis absorption spectroscopy and theoretically by DFT calculations. The molecular structures of compounds 1 and 2 were studied by XRD analysis. Conjugation between all structural fragments (Ge-Ge, Ge-Si, Ge-Ar, where Ar is an electron-donating or withdrawing group) was found to affect the properties

(1SR,3RS,3aSR,6aRS)-Methyl 5-methyl-4,6-dioxo-3-[2-(trifluoromethyl)phenyl]octahydropyrrolo[3,4-c]pyrrole-1-carboxylate

In the title compound, C16H15F3N2O4, the relative stereochemistry of the four stereogenic C atoms has been determined. The carboxymethyl and 2-(trifluoromethyl)phenyl substituents of the pyrrolidine cycle have a cis mutual arrangement. The five-membered saturated azacycle adopts an envelope conformation with the N atom occupying the flap position. In the crystal, adjacent molecules are combined in centrosymmetric dimers by two weak N—H...O hydrogen bonds

Crystal structure of (Z)-N-benzylidene-1-phenylmethanamine oxide hydrogen peroxide monosolvate

The title adduct, C14H13NO·H2O2, consists of (Z)-N-benzylidene-1-phenylmethanamine oxide and hydrogen peroxide molecules in a 1:1 ratio. The organic coformer adopts a skew geometry with an inter-aryl-ring dihedral angle of 81.9 (2)°. In the crystal, the organic and peroxide molecules are linked through both peroxide O—H donor groups to oxide O-atom acceptors, giving one-dimensional chains extending along the b axis. Present also are weak intermolecular C—H...O hydrogen-bonding interactions