1,3‐Bis[2‐(dimethylaminomethyl)phenyl]triselenide

The title compound, C₁₈H₂₄N₂Se₃, consists of discrete molecules; owing to the presence of strong intramolecular N...Se interactions [N...Se = 2.671 (4) and 2.873 (4) Å], the chalcogen Se atoms of the angular Se₃ chain exhibit different coordination geometries, i.e. the terminal Se atoms are tricoordinated and exhibit a T‐shaped environment of the CNSe₂ core [N...Se—Se = 173.73 (9) and 172.29 (9)°], while the central Se atom is dicoordinated to the other two Se atoms, with an Se—Se—Se angle of 108.32 (2)°.     

1,3‐Bis[2‐(2‐hydroxybenzylideneamino)phenoxy]propane

The title compound {systematic name: 2,2′‐[1,3‐propanediyldioxydi‐o‐phenylenebis(nitrilomethylidyne)]diphenol}, C₂₉H₂₆N₂O₄, exists as the phenol–imine form in the crystal, and there are strong intramolecular O—H⋯N hydrogen bonds, with O⋯N distances of 2.545 (2) and 2.579 (2) Å. The C=N imine bond distances are in the range 1.276 (2)–1.279 (2) Å and the C=N—C bond angles are in the range 123.05 (16)–124.64 (17)°. The configurations about the C=N bonds are anti (1E).     

[1,3‐Bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]chloridogold(I)

The molecule of the title compound, [AuCl(C₂₇H₃₆N₂)], which belongs to a class of potentially catalytically active N‐heterocyclic carbene complexes, has crystallographic C₂ symmetry and approximate C_2v symmetry. The structure is isostructural with the Cu^I and Ag^I analogues. A previous report of the structure of the title compound as its toluene solvate [Fructos et al. (2005). Angew. Chem. Int. Ed. 44 , 5284–5288] has inaccurate geometry for the complex molecule as a consequence of probable incorrect refinement in the space group Cc, instead of C2/c [Marsh (2009). Acta Cryst. B 65 , 782–783]. The Au—C bond length of 1.998 (4) Å in the title compound is more consistent with the mean distance of 1.979 (14) Å found in 52 other reported [AuCl(carbene)] complexes than with the shorter distance of 1.942 (3) Å given for the refinement in the space group Cc for the toluene solvate and the value of 1.939 Å obtained from the recalculation of that structure in C2/c.     

Synthesis of 1,3‐Bis(tetracyano‐2‐azulenyl‐3‐butadienyl)azulenes by the [2+2] Cycloaddition–Retroelectrocyclization of 1,3‐Bis(azulenylethynyl)azulenes with Tetracyanoethylene

1,3‐Bis(azulenylethynyl)azulene derivatives 9–14 have been prepared by palladium‐catalyzed alkynylation of 1‐ethynylazulene 8 with 1,3‐diiodoazulene 1 or 1,3‐diethynylazulene 2 with the corresponding haloazulenes 3–7 under Sonogashira–Hagihara conditions. Bis(alkynes) 9–14 reacted with tetracyanoethylene (TCNE) in a formal [2+2] cycloaddition–retroelectrocyclization reaction to afford the corresponding new bis(tetracyanobutadiene)s (bis(TCBDs)) 15–20 in excellent yields. The redox behavior of bis(TCBD)s 15–20 was examined by using CV and differential pulse voltammetry (DPV), which revealed their reversible multistage reduction properties under the electrochemical conditions. Moreover, a significant color change of alkynes 9–14 and TCBDs 15–20 was observed by visible spectroscopy under the electrochemical reduction conditions.     

8,19-Dimethyl-tetraepoxy[22]annulen(2.1.2.1): ein erstes Tetraepoxy-Verbrücktes aromatisches [22]Annulen

8,19-Dimethyl-tetraepoxy[22]annulen(2.1.2.1): The First Tetraepoxy-Bridged Aromatic[22]Annulene By McMurry reaction of 5,5′-ethylidenebis[furan-2-carbaldehyde] ( 15 ), a syn/anti mixture 16 of (E,E)- and (Z,Z)-8,19-dihydro-8,19-dimethyl-tetraepoxy[22]annulene is obtained. The (E/E)-isomers 16 are the first rotation- ally active noncyclic conjugated macrocycles, where the (E)-ethenediyl moieties rotate around the connecting single bonds. The dihydro-tetraepoxy[22]annulenes 16 are dehydrogenated by (Ph₃C)BF₄ as well as by O₂ to give the tetraepoxy[22]annulene 11 . The spectroscopic data support the character of 11 as an aromatic, diatropic ring system, which is rather sensitive towards O₂. In the oxidation mixture obtained from 11 , beside polymeric products, two compounds 19 and 20 can be isolated, carrying one and two CHO groups, respectively, resulting by oxidation of one or both Me-groups but having retained the aromatic 22π system of 11 .     

Synthese und Eigenschaften von [Ph2(Carb)P]AlCl4 (Carb = 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐yliden) – ein stabiler Carben‐Komplex des dreiwertigen Phosphors [1]

Synthesis and Properties of [Ph₂(Carb)P]AlCl₄ (Carb = 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) – a Stable Carbene Complex of Trivalent Phosphorus [1] 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene ( 7 , Carb) reacts with chlorodiphenylphosphane to give the cationic phosphane [Ph₂(Carb)P]Cl ( 10 ) which is transferred to the more stable salt [Ph₂(Carb)]AlCl₄ ( 13 ) on treatment with AlCl₃. The cationic phosphane selenide [Ph₂(Carb)PSe]AlCl₄ ( 14 ) is obtained from 13 and selenium. Spectroscopic and structural data indicate [Ph₂(Carb)P]⁺ to be a cationic analogue of Ph₃P. The X‐ray structure of 13 is reported.     

Bis(enaminones) as Versatile Precursors for Novel Bis([1,2,4]triazolo[1,5‐a]pyrimidines) and Bis(2‐thioxo‐2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐ones)

Novel bis([1,2,4]triazolo[1,5‐a]pyrimidines) and bis(2‐thioxo‐2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐ones) were prepared utilizing bis(enaminones) as precursors. The structures of the prepared compounds were elucidated by several spectral tools as well as elemental analyses.     

Crystallographic report: Bis[tris(2‐methyl‐2‐phenylpropyl)tin] piperazinyldithiocarbamate

The centrosymmetric structure of bis[tris(2‐methyl‐2‐phenylpropyl)tin]piperazinyldithiocarbamate contains four‐coordinated tin and monodentate dithiocarbamate ligands. Copyright © 2004 John Wiley & Sons, Ltd.     

A Convenient,Selective Synthesis of Bis[2,4‐bis(trifluoromethyl)phenyl]phosphane Derivatives Starting from 1,3‐Bis(trifluoromethyl)benzene

The reaction of the sterically shielded phosphane derivative, dichlorodiethylaminophosphane, Cl₂PNEt₂, with an excess of a mixture of 2,6‐bis(trifluoromethyl) and 2,4‐bis(trifluoromethyl)phenyl lithium gives bis[2,4‐bis(trifluoromethyl)phenyl]diethylaminophosphane, [2,4‐(CF₃)₂C₆H₃]₂PNEt₂, in 72 % yield as a colourless solid, while 2,6‐bis(trifluoromethyl)phenyl lithium remains unchanged in solution. The amino derivative crystallizes in the monoclinic space group P2₁/c (a 869.2(1), b 1857.4(1), c 1357.6(1) pm, β 100.57(4)°, Z = 4). Treatment of [2,4‐(CF₃)₂C₆H₃]₂PNEt₂ in CHCl₃ solution with conc. HCl allows the synthesis of [2,4‐(CF₃)₂C₆H₃)]₂PCl. [2,4‐(CF₃)₂C₆H₃]₂PCl reacts with H₂O in THF solution with quantitative formation of the corresponding secondary phosphane oxide. To obtain bis[2,4‐bis(trifluoromethyl)phenyl]phosphinic acid, [2,4‐(CF₃)₂C₆H₃]₂P(O)OH, quantitatively, a CHCl₃ solution of [2,4‐(CF₃)₂C₆H₃]₂P(O)H, has to be stirred in an NO₂ atmosphere. The phosphinic acid crystallizes is the triclinic space group (a 754.2(1), b 927.6(2), c 1305.5(2) pm, α 85.11(2)°, β 75.45(1)°, γ 79.99(2)°, Z = 2). From the reaction of the phosphinic acid with either elemental sodium or with cyanide salts, the corresponding phosphinate salts are obtained in an almost quantitatively yield.     

[1,3‐Bis(4‐nitrophenyl)triazenido](triphenylphosphine)gold(I)

In the title complex, [Au(C₁₂H₈N₅O₄)(C₁₈H₁₅P)], the coordination geometry about the Au^I ion is linear, with one deprotonated 1,3‐bis(4‐nitro­phenyl)­triazenide ion, [O₂NC₆H₄N=N–NC₆H₄NO₂]⁻, acting as a monodentate ligand (two‐electron donor), and one neutral tri­phenyl­phosphine mol­ecule completing the metal coordination. The triazenide ligand is almost planar (r.m.s. deviation = 0.0767 Å), with the largest interplanar angle being 11.6 (7)° between the phenyl ring of one of the terminal 4‐nitro­phenyl substituents and the plane defined by the N=N—N triad. The Au—N and Au—P distances are 2.108 (5) and 2.2524 (13) Å, respectively. Pairs of mol­ecules generated by centrosymmetry are associated into a supramolecular array via intermolecular C—H⋯O inter­actions, and N⋯C and N⋯O π–π interactions.     

Systematische Studie zu den Koordinationseigenschaften des Guanidin‐Liganden N1,N2‐Bis(1,3‐dimethylimidazolidin‐2‐yliden)‐ethan‐1,2‐diamin mit den Metallen Mn,Co, Ni,Ag und Cu

A Systematic Study on the Coordination Properties of the Guanidine Ligand N¹,N²‐Bis(1,3‐dimethylimidazolidin‐2‐ylidene)‐ethane‐1,2‐diamine with the Metals Mn, Co, Ni, Ag and Cu The syntheses and characterization of the compounds [Mn(DMEG₂e)Cl₂] ( 1 ), [Co(DMEG₂e)Cl₂] ( 2 ), [Ni(DMEG₂e)₂]I₂ ( 3 ), [Cu(DMEG₂e)I] ( 4 ) and {[Ag(DMEG₂e)]BF₄}_n ( 5 ) with the bisguanidine ligand N¹,N²‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)ethane‐1,2‐diamine (DMEG₂e) are described. All complexes are synthesized by the reaction of the corresponding metal salt with the DMEG₂e ligand in MeCN or THF. The coordination of the metal atoms vary from a distorted tetrahedron in 1 and 2 , a distorted trigonal planar coordination in 4 to linear coordination in 5 . Contrasting to the compounds 1 , 2 , 4 and 5 which exhibit a 1:1 ratio of metal to ligand, two DMEG₂e ligands are bound to the Ni atom in the case of 3 resulting in a coordination polyhedron which represents the stage exactly in the middle between the square‐planar and the tetrahedral geometry. Whereas crystals of 1 , 2 , 3 and 4 contain discrete molecules, in 5 the Ag atoms are alternately linked by two different DMEG₂e ligands to form a chain structure. The comparative discussion of several DMEG₂e containing complexes with the compounds reported herein supplements this systematic study.     

Neutrale aromatische Tetraepoxyannulene: Tetraepoxy[26]annulene(4.2.2.2) und Tetraepoxy[30]annulene(4.4.4.2) – Systeme mit hoher molekularer Dynamik

Neutral Aromatic Tetraepoxyannulenes: Tetraepoxy[26]annulenes(4.2.2.2) and Tetraepoxy[30]annulenes(4.4.4.2) – Systems with High Molecular Dynamics The twofold cyclizing Wittig reaction of the bis‐aldehyde 6 with the ylide of the bis‐phosphonium salt 7 yields tetraepoxy[26]annulene(4.2.2.2) 4 , which exists in the two isomeric forms 4a (EE,Z,E,Z) and 4b (EE,Z,E,E). Annulene 4a is a highly dynamic system down to −80°. Temperature‐dependent ¹H‐NMR spectra of 4a establish that the (E,E)‐buta‐1,3‐dien‐1,4‐diyl as well as the (E)‐ethen‐1,2‐diyl bridges rotate around the adjacent σ‐bonds in a synchronous manner. Isomer 4b , for steric reasons, is rigid. By Wittig reaction of the bis‐aldehyde 8 with the ylide of the bis‐phosphonium salt 9 , the tetraepoxy[30]annulene(4.4.4.2) 5 is obtained, which exists also in two isomeric forms, 5a and 5b . Only 5a (EE,ZE,EE,Z) can be isolated in pure form. Like 4a , 5a is highly dynamic, the (E,E)‐buta‐1,3‐dien‐1,4‐diyl as well as the opposite (E)‐ethen‐1,2‐diyl bridge being able to rotate down to −80°. The ¹H‐NMR spectrum at −80° indicates that 5a exists in the stable conformation 5a′ . The 26‐ and 30‐membered annulenes belong to the most expanded neutral annulenes known hitherto; their ¹H‐NMR spectra confirm that they still have diatropic, aromatic character.     

1,3‐Bis(2,4‐dibromophenyl)triazene

The crystal structure of the title compound, C₁₂H₇Br₄N₃, shows that the stereochemistry about the N=N double bond of the N=N—N(H) moiety is trans. The whole mol­ecule deviates slightly from planarity (r.m.s. deviation 0.164 Å). While one of the aryl substituents is almost coplanar with the triazene chain, weak intermolecular Br?C contacts cause the second aryl substituent to deviate by an angle of 9.1 (8)° from the plane defined by the N=N—N group. Weak intermolecular N—H?Br interactions between mol­ecules related by the diagonal glide plane give rise to chains, which are stacked along the [100] crystallographic direction. An unequal distribution of double‐bond character between the N atoms suggests a delocalization of π electrons over the diazo­amino group and the adjacent aryl groups.     

Synthesis,Crystal Structure and Spectroscopic Properties of [2,13‐Bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,01.18,07.12)docosane]copper(II) Diperchlorate Acetonitrile Disolvate

The N‐functionalized macrocyclic ligand 2,13‐bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,0^1.18,0^7.12)docosane (L³) and its copper(II) complex were prepared. The crystal structure of [Cu(L³)](ClO₄)₂·2CH₃CN was determined by single‐crystal X‐ray diffraction at 150 K. The copper atom, which lies on an inversion centre, has a square planar arrangement and the complex adopts a stable trans‐III configuration. The longer distance [2.081(2) Å] for Cu–N(tertiary) compared to 2.030(3) Å for Cu–N(secondary) may be due to the steric effect of the attached naphthalenylmethyl group on the tertiary nitrogen atom. Two perchlorate ions are weakly attached to copper in axial sites and are further connected to the ligand of the cation through NH ··· O hydrogen bonds [N ··· O 3.098 Å]. IR and UV/Vis spectroscopic properties are also described.     

1,3‐Bis(trimethylsilyl)‐1,3,2‐diazaphospha‐[3]ferrocenophanes

The 2‐tert‐butyl, 2‐phenoxy, and 2‐diethylamino derivatives of 1,3‐bis(trimethylsilyl)‐1,3,2‐diazaphospha‐[3]ferrocenophane were prepared, and the molecular structure of the latter was determined by X‐ray diffraction. The phosphines could be oxidized by their slow reactions with sulfur or selenium, and the molecular structures of three sulfides and one selenide were determined. In contrast, the synthesis of oxides was less straightforward. All new compounds were characterized in solution by multinuclear magnetic resonance methods (1D and 2D ¹H, ¹³C, ¹⁵N, ²⁹Si, ³¹P, and ⁷⁷Se NMR spectroscopy).