Search

The aim of this work was to describe the vibrations connected with the short hydrogen bonds of differing geometries in 2,4-dinitrobenzoic acid and in 2,4-dinitrobenzoic acid complexed in two ratios with pyridine. All three compounds contain short hydrogen bonds either between two acid molecules (OH ⋯ O bond) or between acid and pyridine (NH ⋯ O bonds) or both. We selectively deuterated the proton of the 2,4-dinitrobenzoic acid molecule involved in the proton transfer to aid in the assignment of the H-bond protonic modes. The compounds have been characterized with single crystal X-ray diffraction, CHN elemental analysis, FT-IR and IINS spectroscopy. We show that our combination of analytical methods with DFT calculations represents a fruitful approach to observe the relationship between the geometries of hydrogen bonds and their dynamics.

A solution of potassium nonaflate (n-C4F9SO3K = NfOK) in boiling acetonitrile forms, on subsequent cooling, a stable crystalline 1 : 1 supramolecular complex. The structures of NfOK and NfOK·CH3CN were elucidated by single-crystal X-ray structure determination. Lithium and sodium nonaflate were crystallized as a dioxane solvate and hydrate, respectively, whereas the rubidium and caesium salts crystallize without intercalated solvent molecules. All of the compounds crystallize as layer structures with a perfect segregation of the ionic parts from the fluorous tails.

Addition of lithiated methoxyallene to aziridine derivatives provided the expected primary addition products. The less substituted carbon of the aziridine ring was attacked selectively. The primary adducts could be converted to enantiopure piperidine derivatives or β-amino acid derivatives. The unexpected reactions lead to a tricyclic sulfonamide and to alkynyl-substituted aminoethers. The efficient two-step conversion of a piperidone derivative to a benzomorphan demonstrates the potential of this approach to biologically active compounds.

Lewis acid promoted rearrangements of different 4-alkoxy-substituted 1,2-oxazines syn-1 are reported. Depending on the nature of this alkoxy group different reaction pathways are possible either providing bicyclic 1,2-oxazinones 2 or the novel tricyclic products 3–5. A mechanistic rational describing the role of the 4-alkoxy group is presented. The key step for formation of tricyclic skeletons 3–5 is a 1,2-alkyl shift. Hydrogenation reactions of these tricyclic compounds gave unsaturated 1,2-oxazines 12 and 13 or tetrahydrofurans 15a–c/16a–c depending on the time of hydrogenolysis. Tetrahydrofuryl-annulated 1,2-oxazine 12 was used for further transformations into complex substituted tetrahydrofurans. Reduction with sodium cyanoborohydride and subsequent cleavage of the N,O-bond by hydrogenation furnished aminofuran derivative 19. Alternatively treatment with a strong base such as n-butyllithium afforded imidoester 21 via a Beckmann-type fragmentation.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

A series of 4-pyridyl nonaflates was coupled with several terminal alkynes to efficiently provide new 4-alkynyl-substituted 3-alkoxypyridine derivatives. Apt conditions were developed for their conversion into furo[2,3-c]pyridines. Sonogashira reactions of 4-alkoxy-substituted 3-pyridyl nonaflates allowed an access to regioisomeric furo[3,2-c]pyridines. For both types of alkynyl-substituted alkoxypyridinesan alternative method for cyclization employing iodine monochloride furnished iodinated furo[2,3-c]- or furo[3,2-c]pyridines, which can undergo a second palladium-catalyzed step. Iodination of 4-hydroxypyridine derivative 24 with iodine afforded a pentasubstituted pyridine which after Sonogashira reaction immediately undergoes a cyclization to furo-pyridine 25. Thus, three different types of furo-pyridines can be prepared starting from one precursor. Several compounds prepared are fluorescent and show strong Stokes shifts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

In this report, we describe our experiments dealing withsamarium diiodide promoted cyclizations of quinolyl-substituted ketones 6–12 and also the attempted reductive cyclization of carbazole-containing ketone 13. These precursors were prepared by Heck-type coupling reactions of the corresponding hetaryl nonaflates with adequately substituted olefins as a key step. The cyclization of compounds 7–12 led to nitrogen-containing tri- and tetracyclic compounds 23–28 in moderate to good yields and generally proceeded in a highly diastereoselective fashion. The azatetracycles present steroid-like skeletons but with unnatural cis–cis annulation of rings B, C and D. We also describe the chemical modification of the styrene-type double bond of these products, which provided highly functionalized steroid-type compounds such as 29, 30 and 32.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Proline-promoted Mannich reactions of a series of cycloalkanones with formalin and aniline followed by N-acetylation provided precursors 9- 12 for samarium diiodide mediated cyclizations. The ketyl-aryl coupling of these compounds furnished angularly fused piperidine derivatives such as 13 in good yields. Highly stereoselective dihydroxylation gave compounds of type 14 with five contiguous stereogenic centers. Our modular approach to this type of compounds involves just four simple steps and is fairly general. For the conversion of 10 into 15 we could demonstrate that the toxic and carcinogenic additive HMPA can be successfully replaced by lithium bromide and 1,3-dimethyl-2-imidazolidinone (DMI).

Acid-catalyzed transformations of carbohydrate-derived 3,6-dihydro-2H-1,2-oxazines such as 1, 5 and 13 provided a set of enantiopure furano-1,2-oxazines or pyrano-1,2-oxazines. The reaction conditions determined the degree of solvolysis of the compounds. An X-ray analysis of product 6 revealed an interesting network of hydrogen bonds. Reductive cleavage of the N–O bond of the 1,2-oxazines either by hydrogen/palladium or by samarium diiodide furnished enantiopure aminofuran and -pyran derivatives, e.g. 9 and 11 or compound 16, which can be regarded as protected 4-amino-1,4-dideoxyhex-3-ulose or 4-amino-1,4-dideoxyoct-3-ulose derivatives. We thus have established a short and stereocontrolled route to amino carbohydrate derivatives with 1,2-oxazines as crucial relay compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The synthesis, crystal structure, and magnetic properties of two trinuclear oxo-centered carboxylate complexes are reported and discussed: [Cr3(μ3-O)(μ2-PhCOO)6(H2O)3]NO3·4H2O·2CH3OH (1) and [Cr3(μ3-O)(μ2-PhCOO)2(μ2-OCH2CH3)2(bpy)2(NCS)3] (2). For both complexes the crystal system is monoclinic, with space group C2/c for 1 and P1/n for 2. The structure of complex 1 consists of discrete trinuclear cations, associated NO3- anions, and lattice methanol and water molecules. The structure of complex 2 is built only by neutral discrete trinuclear entities. The most important feature of 2 is the unusual skeleton of the [Cr3O] core due to the lack of peripheral bridging ligands along one side of the triangular core, which is unique among the structurally characterized (μ3-oxo)trichromium(III) complexes. Magnetic measurements were performed in the 2−300 K temperature range. For complex 1, in the high-temperature region (T > 8 K), experimental data could be satisfactorily reproduced by using an isotropic exchange ...

Methyl 2-trimethylsiloxycyclopropanecarboxylates 1, 2-aminopyridine (2), and isonitriles 3 combine in a one-pot reaction to provide a series of novel δ-amino acids 4 incorporating an imidazo[1,2-a]pyridine backbone. Scope and limitations of this new three-component synthesis were investigated. Several reactions of compounds 4 affording suitably protected derivatives such as 5, 6 and 9 were performed to allow couplings with L-alanine derivatives. The expected peptides 11 and 12 were obtained by standard coupling reactions with excellent or moderate yield. Cyanide-catalyzed reactions converted compounds 4e and 4h into tricyclic δ-lactams 10e and 10h in very good yields.

The two rhenium(IV)-copper(II) heterometallic complexes [CuL β ][ReCl 4 (ox)].DMF (1) and [(CuL α ) 2 Cl][ReCl 4 (ox)]Cl (2) (Lp = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene and L α = N-dl-5,7,7,12,12,14-hexamethyl-1,4,8,11 -tetraazacyclotetradeca-4,14-diene) were synthesized, and the crystal structures of both compounds were determined at 173(2) K. Complex 1 crystallizes in a monoclinic space group P2 1 , with a = 9.365(2) A, b = 15.150(2) A, c = 10.776(1) A, β = 110.01(1)°, Z = 2, whereas 2 crystallizes in an orthorhombic space group Pca2 1 with a = 16.660(5) A, b = 16.017(5) A, c = 17.066(5) A, and Z = 4. The CuLp macrocycle cation is approximately planar and coordinated from above and below by [ReCl 4 (ox)] 2 - units through the bis(bidentate) oxalato ligands. It features an oxalato-bridged heterometallic Re I V -Cu I I zigzag chain, the shortest intrachain metal-metal distances are Re...Cu = 5.568(2) and 5.870(2) A in the direction of the b axis. The crystal structure of 2 consists of dinuclear complex cations [(CuL α ) 2 Cl] 3 + with [Re-Cl 4 ox] 2 - and isolated Cl - as counter anions. Cu atoms in CuL α are only fivefold coordinated in a square pyramidal surrounding, and the cations (CuL α ) 2 + are connected in pairs by chloride. The intramolecular Cu...Cu separation is 4.885(3) A, the shortest Re...Cu distance is 7.612(3) A. The magnetic behavior of 1 and 2 has been investigated over the temperature range 1.7-300 K. Compound 1 behaves like a ferrimagnetic Cu I I -Re I V dimetallic, one-dimensional chain with intrachain antiferromagnetic coupling. Compound 2 shows weak antiferromgunetic interactions within the Cu I I -Cu I I units.

Reaction of the rhenium(IV) compound, [Bu4N]2ReCl4ox, with the highly unsaturated tetraazabismacrocyclic copper(II) complex cation [CuCuL]4+ (L = 6,13-Bis(dodecylaminomethylidene)-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene) produced a new kind of heterobimetallic compound: [CuCuL][ReCl4ox]2 · 2DMF in which [ReCl4ox]2− anions and [CuCuL]4+ cations are linked by electrostatic forces. The crystal structure of this compound was determined at 173(2) K. It crystallizes triclinic, space group P 1 ¯ , with a = 9.441(4), b = 11.032(5), c = 15.261(7) A, α = 89.05(1)°, β = 88.93(1)°, γ = 77.09(1)°, Z = 1, R1 = 0.0557, wR2 = 0.1332. The magnetic behavior of this compound has been investigated over the temperature range 1.72–300 K. The compound behaves as a ferrimagnetic CuIIReIV bimetallic, chain with intrachain antiferromagnetic coupling.

A series of bicyclic alkenyl nonaflates was prepared in good yields by deprotonation of the corresponding 8-oxabicyclo[3.2.1]oct-6-en-3-ones and a sulfur relative with LDA followed by trapping with nonafluorobutanesulfonyl fluoride (NfF). The resulting compounds undergo Heck couplings to methyl acrylate under standard conditions, generally providing bicyclic dienes in satisfactory yields. For nonaflates 2 and 12 a novel base-promoted fragmentation reaction to substituted furan derivatives was observed. Several Diels–Alder reactions of the bicyclic dienes were conducted leading to polycyclic compounds. Whereas the diastereofacial selectivity with respect to the oxygen or sulfur bridge of the dienes is excellent, the exo/endo selectivity strongly depends on the substitution patterns of the bicyclic diene and the dienophile. The results presented demonstrate the potential of bicyclic nonaflates to serve as versatile building blocks in diversity-orientated synthesis.

Addition of lithiated methoxyallene to pivalonitrile afforded after aqueous workup the expected iminoallene 1 in excellent yield. Treatment of this intermediate with silver nitrate accomplished the desired cyclization to the electron-rich pyrrole derivative 2 in moderate yield. Surprisingly, trifluoroacetic acid converted iminoallene 1 to a mixture of enamide 3 and trifluoromethyl-substituted pyridinol 4 (together with its tautomer 5). A plausible mechanism proposed for this intriguing transformation involves addition of trifluoroacetate to the central allene carbon atom of an allenyl iminium intermediate as crucial step. Enamide 3 is converted to pyridinol 4 by an intramolecular aldol-type process. A practical direct synthesis of trifluoromethyl-substituted pyridinols 4, 10, 11, and 12 starting from typical nitriles and methoxyallene was established. Pyridinol 10 shows an interesting crystal packing with three molecules in the elementary cell and a remarkable helical supramolecular arrangement. Trifluoromethyl-substituted pyridinol 4 was converted to the corresponding pyridyl nonaflate 13, which is an excellent precursor for palladium-catalyzed reactions leading to pyridine derivatives 14-16 in good to excellent yields. The new synthesis of trifluoromethyl-substituted pyridines disclosed here demonstrates a novel reactivity pattern of lithiated methoxyallene which is incorporated into the products as the unusual tripolar synthon B.

Durch Reaktion von Eisen(III)-chlorid in Diethylether mit Natrium-tert-butylat konnte das homoleptische dimere tert-Butoxid [Fe2(OtBu)6] (1) hergestellt werden. Die Chloro-Derivate [Fe2Cl2(OtBu)4] (2) und [Fe2Cl4(OtBu)2] (3) wurden durch Liganden-Austausch zwischen 1 und Eisen(III)-chlorid synthetisiert. In 1, 2 und 3 liegen jeweils zwei kantenverknupfte Tetraeder mit zwei tert-Butoxo-Gruppen als Bruckenliganden vor. Eine entscheidende Rolle fur die Synthese von 1, 2 und 3 spielt das verwendete Losungsmittel Diethylether, wobei sich primar das Dietherat des Eisen(III)-chlorids FeCl3(OEt2)2 (4) bildet. Durch Reaktion von Eisen(III)-chlorid mit Tetrabutylammoniummethoxid in Methanol konnte daruberhinaus ein Chloro-Methoxo-Oxo-Hexaeisen-Cluster [N(nBu)4]2[Fe6OCl6(OMe)12] (5) mit Tetrabutylammonium als Kation synthetisiert und strukturell charakterisiert werden. Alkoxo Compounds of Iron(III): Syntheses and Characterization of [Fe2(OtBu)6], [Fe2Cl2(OtBu)4], [Fe2Cl4(OtBu)2] and [N(nBu)4]2[Fe6OCl6(OMe)12] The reaction of iron(III)chloride in diethylether with sodium tert-butylat yielded the homoleptic dimeric tert--butoxide Fe2(OtBu)6 (1). The chloro-derivatives [Fe2Cl2(OtBu)4] (2), and [Fe2Cl4(OtBu)2] (3) could be synthesized by ligand exchange between 1 and iron(III)chloride. Each of the molecules 1, 2, and 3 consists of two edge-sharing tetrahedrons, with two tert-butoxo-groups as μ2-bridging ligands. For the synthesis of the alkoxides 1, 2, and 3 diethylether plays an important role. In the first step the dietherate of iron(III)chloride FeCl3(OEt2)2 (4) is formed. The reaction of iron(III)chloride with tetrabutylammonium methoxide in methanol results in the formation of a tetrabutylammonium methoxo-chloro-oxo-hexairon cluster [N(nBu)4]2[Fe6OCl6(OMe)12] (5). Crystal structure data:1, triclinic, P1¯, a = 9.882(2) A, b = 10.523(2) A, c = 15.972(3) A, α = 73.986(4)°, β = 88.713(4)°, γ = 87.145(4)°, V = 1594.4(5) A3, Z = 2, dc = 1.146 gcm—1, R1 = 0.044; 2, monoclinic, P21/n, a = 11.134(2) A, b = 10.141(2) A, c = 12.152(2) A und β = 114.157(3)°, V = 1251.8(4) A3, Z = 2, dc = 1.377 gcm—1, R1 = 0.0581; 3, monoclinic, P21/n, a = 6.527(2) A, b = 11.744(2) A, c = 10.623(2), β = 96.644(3)°, V = 808.8(2) A3, Z = 2, dc = 1.641 gcm—1, R1 = 0.0174; 4, orthorhombic, Iba2, a = 23.266(5) A, b = 9.541(2) A, c = 12.867(3) A, V = 2856(2) A3, Z = 8, dc = 1.444 gcm—1, R1 = 0.0208; 5, trigonal, P31, a = 13.945(2) A, c = 30.011(6) A, V = 5054(2) A3, Z = 6, dc = 1.401 gcm—1; Rc = 0.0494.

Based on our earlier results employing lithiated methoxyallene 2 as C(3) building block and imines 3 for the synthesis of dihydropyrrole derivatives 5, we have investigated chiral imines 6, 10, and 15 as electrophilic components. Combined with lithiated alkoxyallenes, these imines provide the corresponding primary adducts and finally the dihydropyrrole derivatives 8, 12, 17, 20, and 22 in good yields and with high to excellent syn selectivities. This stereochemical outcome is interpreted as a result of alpha-chelate control. Treatment with hydrochloric acid converted syn-8 and syn-12 into bicyclic compounds 9 and 13, whereas under more mildly acidic conditions adduct syn-17 was transformed into diol syn-18. The total synthesis of the uncommon gamma-amino acid (-)-detoxinine could be achieved by starting from (S)-malic acid, which was converted into imine 15 in four steps. Lithiated benzyloxyallene added to imine 15 and efficiently furnished the crucial dihydropyrrole derivative syn-22. The hydrogenolysis of this compound did not directly provide the protected triol 29 as anticipated, but a stepwise protocol made the triol available in a fairly satisfactory manner. A second crucial step of the synthesis was the selective oxidation of 29, which could be achieved by employing platinum dioxide and oxygen. The resulting bicyclic lactone 30 was smoothly transformed into enantiopure (-)-detoxinine. Thus, a fairly short synthesis of this natural product based on a lithiated alkoxyallene could be performed, demonstrating the potential of these intermediates for syntheses of interesting functionalized heterocyclic compounds.

Durch Umsetzung von ortho-Vanadinsauremethylester [VO(OMe)3] mit Quadratsaure und Kalium- bzw. Caesiumhydroxid konnten unter Solvothermalbedingungen die Verbindungen K4[VIV12O12(OCH3)16(C4O4)6] (2) und Cs10[VIV24O24(OCH3)32(C4O4)12][VIV8O8(OCH3)16(C2O4)] (3) synthetisiert werden. Mit Tetra-n-butyl- bzw. Tetra-n-ethylammoniumfluorid erhalt man [N(nBu)4]2[VIV8O8(OCH3)16(VIVOF4)] (4) und [N(Et)4]2[VIV8O8(OCH3)16(VIVOF4)] (5). In den Verbindungen 2 und 3 sind an den Ecken eines Tetraeders bzw. Wurfels sitzende {(VO)3(OMe)4}-Gruppen entlang der Tetraeder- bzw. Wurfelkanten uber sechs bzw. zwolf Quadratatogruppen miteinander verknupft. Die achtkernigen Anionen in den Verbindungen 3, 4 und 5 kann man sich aus oligomeren, kettenformigen Fragmenten des Vanadinsauremethylesters, die sich um die Anionen C2O42— oder VOF4— zum Ring schliessen, aufgebaut denken. Kristalldaten: 2, tetragonal, P43, a = 18, 166(3)A, c = 29, 165(7)A, V = 9625(3)A3, Z = 4, dc = 1, 469 gcm—3; 3, orthorhombisch, Pbca, a = 29, 493(5)A, b = 25, 564(4)A, c = 31, 076A, V = 23430(6)A3, Z = 4, dc = 1, 892 gcm—3; 4, monoklin, P21/n, a = 9, 528(1)A, b = 23, 021(2)A, c = 19, 303(2)A, β = 92, 570(2)°, V = 4229, 8(5)A3, Z = 2, dc = 1, 391 gcm—3; 5, monoklin, P21/n, a = 16, 451(2)A, b = 8, 806(1)A, c = 23, 812(1)A, β = 102, 423(2)°, V = 3368, 7(6)A3, Z = 2, dc = 1, 534 gcm—3. >From Small Fragments to New Poly-alkoxo-oxo-metalate Derivatives: Syntheses and Crystal Structures of K4[VIV12O12(OCH3)16(C4O4)6], Cs10[VIV24O24(OCH3)32(C4O4)12][VIV8O8(OCH3)16(C2O4)], and M2[VIV8O8(OCH3)16(VIVOF4)] (M = [N(nBu)4] or [NEt4]) By solvothermal reaction of ortho-vanadicacid ester [VO(OMe)3] with squaric acid and potassium or caesium hydroxide the compounds K4[VIV12O12(OCH3)16(C4O4)6] (2) and Cs10[VIV24O24(OCH3)32(C4O4)12][VIV8O8(OCH3)16(C2O4)] (3) could be syntesized. With tetra-n-butyl- or tetra-n-ethylammonium fluoride [N(nBu)4]2[VIV8O8(OCH3)16(VIVOF4)] (4) and [N(Et)4]2[VIV8O8(OCH3)16(VIVOF4)] (5) could be isolated. In 2 and 3 the corners of a tetrahedron or cube resp. are occupied by {(VO)3(OMe)4} groups and connected along the edges of the tetrahedron resp. cube by six or twelve resp. squarato-groups. The octanuclear anions in the compounds 3, 4, and 5 are assumedly built up by fragments of the ortho-vanadicacid ester [VO(OMe)3]. Around the anions C2O42— or VOF4— these oligormeric chains are closed to a ring . Crystal data: 2, tetragonal, P43, a = 18.166(3)A, c = 29.165(7)A, V = 9625(3)A3, Z = 4, dc = 1.469 gcm—3; 3, orthorhombic, Pbca, a = 29.493(5)A, b = 25.564(4)A, c = 31.076A, V = 23430(6)A3, Z = 4, dc = 1.892 gcm—3; 4, monoclinic, P21/n, a = 9.528(1)A, b = 23.021(2)A, c = 19.303(2)A, β = 92.570(2)°, V = 4229.8(5)A3, Z = 2, dc = 1.391 gcm—3; 5, monoclinic, P21/n, a = 16.451(2)A, b = 8.806(1)A, c = 23.812(1)A, β = 102.423(2)°, V = 3368.7(6)A3, Z = 2, dc = 1.534 gcm—3.

In this paper, the syntheses of a variety of substituted phenyl pyrenes 5a−n by Suzuki cross-coupling and of two decoupled analogues 10 and 17 are reported. These compounds have been investigated by fluorescence spectroscopy. The solvatochromism of their emission bands (Stokes shift) and the quantum yields in methylcyclohexane and acetonitrile have been determined. Furthermore, the crystal structure of a pyrenyl-tris(2,2′-bipyridine)ruthenium(II) complex 19 is presented.

(μ-Phthalimidocarbyne)tricarbonyldicyclopentadienyldiiron(1+) (2) which, due to the facile cleavage with cis-[Fe2Cp2(CN)(μ-CO)2CO]− (1) of its μ-CN bond to give ‘tetraferrio-azaallenium’ [(OC)3Cp2Fe2(μ4-CNC)Fe2Cp2(CO)3]+ (3), has been termed ‘activated cyanide’ reacts with pyrrolidine with ring opening to give the μ-acylisocyanide complex 5 carrying a further amido function in the o-position. Butyllithium gives rise to only traces of the corresponding mono deacylation product 6 while the main product is 3. Formation of complex 3 which is presumed to occur via partial bis-deacylation of 2 to give 1 and subsequent recombination with loss of phthalimide also dominates the reactions of 2 with CN− and [W(CN)(CO)5]−. Here, however, the nucleophile also attacks the μ-carbyne carbon atom to give moderate yields of the desired μ-cyanoalkyliden complexes 7 and 10, the latter with [W]CN↔[W]NC isomerization and C–C bond formation. With [Cr(CN)(CO)5]−, in contrast, substitution of a terminal CO ligand occurs with formation of the cyano-bridged trinuclear complex 9. The structures of complexes 7, 9 and 10 have been elucidated by X-ray analysis. Action upon ‘tetraferrio-azaallenium’ 3 of the primary amines H2NCH2CH2R (R=Me, OMe, Ph) gives rise in low yields to the respective terminal isocyanides in compounds 11–13. Here as in the reaction with NaNH2 to give 14, a terminal carbonyl ligand is converted into an isocyanide or, respectively, cyano ligand by an exchange of oxygen for NR (N−). A second though less efficient approach to 14 is CO substitution in 3 by NaCN. Disubstitution of 3 to give 15 is observed with trimethylphosphite. In the reactions of 3 with diamines (H2NCH2CH2NH2, H2NCH2CH2CH2CH2NH2), on the other hand, cluster fragmentation occurs with formation of the mononuclear complexes 16 and 17 containing cyclic diaminocarbene ligands. A cyclic μ-aminocarbyne diiron complex 18 is obtained in traces from 3 and pyrrolidine.

We have studied the preparation and isolation of the halogenated alkylidene oxonium salts CH(3)OCHX(+)MF(6)(-) (X = Cl, F; M = As, Sb). Addition of dichloromethylmethylether at -78 degrees C to the superacidic media HF/MF(5) resulted in the formation of the chlorine compounds CH(3)OCHCl(+)MF(6)(-), whereas at -65 degrees C the fluorinated salts CH(3)OCHF(+)MF(6)(-) are formed by a chlorine/fluorine exchange. The salts are characterized by their low-temperature IR and Raman spectra. Additionally, the crystal structures of the hexafluoroantimonates are presented. The structures of the cations turned out to be different in some points. The salt CH(3)OCHF(+)SbF(6)(-) crystallizes in the monoclinic space group P2(1)/c with 4 molecules in the unit cell and a = 9.942(2), b = 7.454(2), and c = 10.297(3) Å; beta = 111.27(2) degrees. The salt CH(3)OCHCl(+)SbF(6)(-) crystallizes in the monoclinic space group P2(1)/c with 4 formula in the unit cell and a = 5.970(3), b = 12.019(5), and c = 10.994(5) Å; beta = 92.59(3) degrees.

The largest isopolyoxotunstate ion known to date, W24 O8424- (structure shown in the picture), isolated as the cesium salt, and a chainlike polyoxotungstate ion made up of planar W4 O16 units, isolated as the sodium salt, hide behind the simple empirical formulas of the title compounds.

The heterobimetallic iron(II)–chromium(>0>) complexes [(OC)2CpFe(µ-η1∶η7-C7H6)Cr(CO)3]+ and [(OC)2CpFe(µ-η1∶η7-C2C7H6)Cr(CO)3]+ containing the bridging carbene ligand cycloheptatrienylidene C7H6 and the cumulogous allenylidene ligand (cycloheptatrienylidene)ethenylidene C2C7H6 have been prepared and their properties studied. The former has been prepared by hydride abstraction from the heterobimetallic µ-η1∶η6-cyclohepta-1,3,5-trien-2-yl complex obtained by lithiation of 2-trimethylstannyl-cyclohepta-1,3,5-triene followed by reaction with [FeCp(CO)2Br] and [Cr(CO)3(NCEt)3]. Treatment of 7-ethynyl-cyclohepta-1,3,5-triene with LiBun and consecutive reaction with [FeCp(CO)2Br] and [Cr(CO)3(NCEt)3] led to the formation of endo-[(OC)2CpFe(µ-η1∶η6-CC–C7H7)Cr(CO)3] which was treated with [Ph3C][BF4] to give [(OC)2CpFe(µ-η1∶η7-C2C7H6)Cr(CO)3][BF4]. The crystal structures of [(OC)2CpFe(µ-η1∶η6-C7H7)Cr(CO)3], [(OC)2CpFe(µ-η1∶η7-C7H6)Cr(CO)3][PF6]·0.25CH2Cl2 and [(OC)2CpFe(µ-η1∶η7-C2C7H6)Cr(CO)3]+[BF4]·CH2Cl2 have been determined.

C15H17BrO5, monoclinic, P121/n1 (no. 14), a = 11.295(2) Å, b = 23.628(5) Å, c = 16.610(3) Å, β = 92.145(5)°, V = 4429.7 Å3, Z = 12, Rgt(F) = 0.038, wRref(F2) = 0.105, T = 173 K.

Der dreizahnige Ligand 2-(2-Hydroxy-5-methylphenyl)-6-(2-hydroxyphenyl)pyridin 4a wurde synthetisiert und rontgenographisch charakterisiert. Die Verbindung bildet mit Kupfer(II) einen Komplex der Zusammensetzung Cu2L2. Aus Pyridin kristallisiert 2-(2-Hydroxy-5-methylphenyl)-6-(2-hydroxyphenyl)pyridinato(2−)-dipyridin-kupfer(II) 4c mit der Koordinationszahl 5 aus. Kristallstrukturanalyse von 4a: Raumgruppe An, Z = 8, 1994 beobachtete unabhangige Reflexe, R = 0,069, Gitterabmessungen bei 295 K: a = 960,6(2) pm, b = 1678,5(3) pm, c = 1824,5(3) pm, β = 100,89(3)° Kristallstrukturanalyse von 4c: Raumgruppe P21/c, Z = 4, 847 beobachtete unabhangige Reflexe, R = 0,064, Gitterabmessungen bei 295 K: a = 901,8(1) pm, b = 1781,2(3) pm, c = 1494,2(3) pm, β = 104,83(2)° Synthesis and Structure of the Copper Complex 2-(2-Hydroxy-5-methylphenyl)-6-(2-hydroxyphenyl)pyridinato(2−)dipyridin-copper(II) and of the free Ligand The tridentate diacidic ligand 2-(2-hydroxy-5-methyl)-6-phenyl-6-(2-hydroxyphenyl)pyridine 4a was synthesized and characterized by X-ray structural analysis. The compound forms a copper complex, 2-(2-Hydroxy-5-methyl-phenyl)-6-(2-hydroxyphenyl)pyridinato(2−)-dipyridine copper(II), which was crystallized from pyridine solution. The coordination number of the central atom copper ist five.

1,1′-Methylene-3,3′-dialkyldiimidazolium salts have been deprotonated with n -butylithium in the presence of palladium(II) iodide to give the percarbene complexes 1 (alkyl=Me) and 2 (alkyl=Et), each containing two bidentate 1,1′-methylene-3,3′-dialkyldiimidazolin-2,2′-diylidene chelate ligands. The X-ray structure analysis of 1 reveals a stereochemistry in which the two spiro-linked six-membered metallacycles adopt boat-like conformations strongly bending out of the PdC 4 coordination plane in opposite directions. The carbenoid imidazole rings, which are rotated by +42 and −43°, respectively, relative to this plane, break down into two tightly bound π-systems (N4C4N, CC) connected by long CN bonds.

Synthesis and Crystal Structure of [N(Hex)4][Cu2(CN)3] [N(Hex)4][Cu2(CN)3] has been prepared by solvothermal reaction of CuCN with Tetra-n-hexylammoniumiodide in acetone. The crystal structure is built up by condensed (CuCN)6 and (CuCN)7 rings, forming a zeolith type cyanocuprate(I) framework [Cu2(CN)3—]. Space group R3; α = 44.482(6), c = 21.283(4) A, V = 36471(9) A3; Z = 9.

Solid 1,2-Se2S5 polymerizes endothermically at 47°C to give a linear polymer which after stretching and extraction consists of helical molecules similar to those of polymeric sulfur. Heating of the polymer results in slow exothermic depolymerization at 84°C to give a mixture of seven cyclic SenS8–n molecules which melts at 111°C. When the polymeric Se2S5 is refluxed with CS2 the initial depolymerization Products are 1,2-Se2S5, SeS5 and 1,2,3-Se3S5 but in addition SeS7 and 1,2-Se2S6 are formed. These results indicate the atomic sequence –SeS5Se– in the polymer. The powder x-ray diffraction pattern and Raman spectrum of the polymer as well as its lattice parameters are reported and the Probable mechanism of its depolymerization is discussed. Schwefelverbindungen. 164. Thermische Polymerisation des cyclischen Selensulfids 1,2-Se2S5 – eine Untersuchung mittels DSC, HPLC, Ramanspektroskopie und Rontgenbeugung Kristallines 1,2-Se2S5 polymerisiert bei 47°C endotherm zu einem kettenformigen Polymer, das nach Streckung und Extraktion aus helicalen Molekulen ahnlich denen im polymeren Schwefel besteht. Beim Erhitzen zersetzt sich das Polymer bei 84°C exotherm zu einer Mischung aus sieben cyclischen SenS8–n-Molekulen; diese Mischung schmilzt bei 111°C. Wenn das polymere Se2S5 mit CS2 gekocht wird, enstehen primar 1,2-Se2S5, SeS5 und 1,2,3-Se3S5, aber zusatzlich werden SeS7 und 1,2-Se2S6 beobachtet. Diese Ergebnisse sprechen fur die Atomfolge –SeS5Se– in dem Polymer, dessen Pulverdiagramm, Gitterkonstanten und Ramanspektrum mitgeteilt werden.

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds were used as substrates for palladium-catalyzed coupling reactions. Fluorescence measurements of the biscoupled products showed a maximum of emission in the violet region of the spectrum.

N,N-Dimethylformamidinium-halometallates(I), [(DM F)2H][Me3X4] with Me3X4 = Cu3I4 -, Cu3I2Br2 -, Cu3I3Cl-, Ag2CuI4 -, Ag3I4 -, Ag3I3Br- and Ag3I3Cl- were obtained by reacting Cul or Agl with HI, HBr or HC1 in DMF. The crystal structures of the isostructural compounds (space group Pccn) are built by hydrogen-bridged DMF molecules, (DMF)2H+, as cations and a new type of polymeric anion formed by edge sharing tetrahedra triple chains. The chains consist of a double layer of halogen atoms where Cu(I) and Ag(I) cations are located in tetrahedral holes. There are two kinds of halogen positions in the chains. One of them bridges two metal ions, the other is coordinated by four metal ions. In the anion chains ∞ 1,[Cu3I2Br2 -], ∞ 1[Cu3I3Cl-], ∞ 1[Ag3I3Br-] and ∞ 1[Ag3I3Cl-] the lighter halogen atoms occupy the positions bridging two metal ions. The O—H—O distances range from 235-243 pm. They indicate strong hydrogen-bonding between the two DMF molecules in the (DMF)2H+ cations.

The synthesis, crystal structure, and magnetic properties of two trinuclear oxo-centered carboxylate complexes are reported and discussed: [Cr3(mu3-O)(mu2-PhCOO)6(H2O)3]NO3.4H2O.2CH3OH (1) and [Cr3(mu3-O)(mu2-PhCOO)2(mu2-OCH2CH3)2(bpy)2(NCS)3] (2). For both complexes the crystal system is monoclinic, with space group C2/c for 1 and P1/n for 2. The structure of complex 1 consists of discrete trinuclear cations, associated NO3- anions, and lattice methanol and water molecules. The structure of complex 2 is built only by neutral discrete trinuclear entities. The most important feature of 2 is the unusual skeleton of the [Cr3O] core due to the lack of peripheral bridging ligands along one side of the triangular core, which is unique among the structurally characterized (mu3-oxo)trichromium(III) complexes. Magnetic measurements were performed in the 2-300 K temperature range. For complex 1, in the high-temperature region (T8 K), experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -2J12S1S2 - 2J13S1S3 - 2J23S2S3 (J12 = J13 = J23) with Jij = -10.1 cm(-1), g = 1.97, and TIP = 550 x 10(-6) emu mol(-1). The antisymmetric exchange interaction plays an important role in the magnetic behavior of the system, so in order to fit the experimental magnetic data at low temperature, a new magnetic model was used where this kind of interaction was also considered. The resulting fitting parameters are the following: Gzz = 0.25 cm(-1), delta = 2.5 cm(-1), and TIP = 550 x 10(-6) emu mol(-1). For complex 2, the experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -2J1(S1S2 + S1S3) - 2J2(S2S3) with J1 = -7.44 cm(-1), J2 = -51.98 cm(-1), and g = 1.99. The magnetization data allows us to deduce the ground term of S = 1/2, characteristic of equilateral triangular chromium(III) for complex 1 and S = 3/2 for complex 2, which is confirmed by EPR measurements.

The complexes of general formula [ML]2[Mn(NCS)4](ClO4)2 (where M = Cu(II), Ni(II); L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) were obtained and the crystal structures of both heteronuclear compounds were determined at 173 K. Complex [CuL]2[Mn(NCS)4](ClO4)2 (1) crystallizes in a monoclinic space group, C2/c, with a = 41.297(9) A, b = 7.571(2) A, c = 16.417(4) A, beta = 96.97(15) degrees, Z = 8, whereas complex [NiL]2[Mn(NCS)4](ClO4)2.H2O (2) crystallizes in a monoclinic space group, P2/c, with a = 21.018(5) A, b = 7.627(2) A, c = 16.295(4) A, beta = 104.47(1) degrees, Z = 4. The magnetic behaviour of (1) and (2) has been investigated over the temperature range 1.8-300 K. Complex (1) displays ferromagnetic coupling inside the trinuclear core of CuMnCu and compound (2) behaves like a mononuclear Mn(II) system. The magnetic properties of the second compound (2) with a similar trinuclear structure shows that Ni(II) ions have a diamagnetic character and a rather weak zero-field splitting at the central Mn(II) ion occurs. Finally, the magnitudes of the Cu(II)-M(II) interactions with M = Ni and Mn have been compared and qualitatively justified.

Addition of an excess of lithiated alkoxyallenes to phthalimide 5 provided the expected primary adducts 7a-c, which could be cyclized via their oxygen moiety to furnish spirofuran derivatives 8a-c. After selective protection of the hydroxyl function of 7a-c the resulting siloxy derivatives lla-c were transformed by gold(III) catalysis into pyrroloisoindolones 13a-c in moderate yields. This establishes a new approach to this class of heterocycles in a [3+2] fashion with the alkoxyallenes as functionalized C-3 unit and phthalimide 5 providing the CN moiety. Treatment of primary adducts 7a-c with aqueous sulfuric acid surprisingly led to compounds 14a-c in good yields. The constitution of these products was proved by an X-ray analysis of derivative 15a. Aqueous hydrochloric acid converted 7a into a similar product 17 containing a chlorine substituent. These reactions can be considered as olefination reactions of phthalimide.

Polydentate bridging ligands can be used to link small polyoxo-alkoxo-metalate units to form supramolecular clusters. In the title compound, twelve μ4 -bridging squarato groups connect eight trinuclear methoxo-oxo-vanadate units to form a tetradodecanuclear cubic framework, in whose cavity six n-butyl groups of the tetra-n-butylammonium cations are anchored.

Polydentate bridging ligands can be used to link small polyoxo-alkoxo-metalate units to form supramolecular clusters. In the title compound, twelve μ

C34H26F6N2O4, monoclinic, C12/c1 (no. 15), a = 23.313(5) A, b = 9.153(2) A, c = 14.571(3) A, 0 = 110.824(5)°, V = 2906.1 A, Z = 4, Rgt(F) = 0.048, wRref(F ) = 0.147, T = 173 K. Source of material The synthesis starts with a one pot procedure [1] of lithiated methoxyallene, 1,4-dicyanobenzene and trifluoroacetic acid to provide the corresponding 4-pyridinol derivative. The title compoundwas obtained after conversion of the 4-pyridinol derivative into 6,6'-(1,4-phenylene)bis[5-methoxy-2-(trifluoromethyl)pyridin-6,4-diyl] bis(1,1,2,2,3,3,4,4,4-nonafluorobutan-1sulfonate) and a Suzuki coupling with 4-methoxyphenyl boronic acid [2]. Purification by chromatography on silica gel as described in [2] and recrystallization frommethanol afforded colorless crystals (m.p. 516 518 K). Discussion The two pyridine substituents in the crystal structure of the title compound prefer a transoid arrangement with respect to the central phenylene moiety, which leads to an extended conformation of themoleculewithC2 symmetry (overall length: ca. 2.0 nm).As expected the five (het)aryl rings are not in a plane. The dihedral angles between the 4-methoxyphenyl ring and the pyridine ring are ca. 32°whereas the dihedral angles between the pyridinemoiety and the central phenyl ring are ca. 24°. Z. Kristallogr. NCS 223 (2008) 347-348 / DOI 10.1524/ncrs.2008.0151 347 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: yellow prism, size 0.07 × 0.25 × 0.4 mm Wavelength: Mo K2 radiation (0.71073 A) ': 1.22 cm−1 Diffractometer, scan mode: Bruker APEX-II CCD, +/3 2#max: 61.1° N(hkl)measured, N(hkl)unique: 12412, 4444 Criterion for Iobs, N(hkl)gt: Iobs > 2 "(Iobs), 3302 N(param)refined: 210 Programs: SHELX-90 [3], SHELXS-97 [4], SHELXL-97 [5] Table 1. Data collection and handling. H(3) 8f 0.5114 0.6127 0.1541 0.029 H(8A) 8f 0.3854 0.1780 −0.0775 0.074 H(8B) 8f 0.4262 0.0352 −0.0372 0.074 H(8C) 8f 0.4585 0.1873 −0.0434 0.074 H(10) 8f 0.3368 0.1076 0.0785 0.034 H(11) 8f 0.2598 0.4991 −0.0232 0.035 H(13) 8f 0.5246 0.1362 0.1899 0.031 H(14) 8f 0.6227 0.0402 0.2328 0.035 H(16) 8f 0.6820 0.4157 0.1490 0.040 H(17) 8f 0.5833 0.5125 0.1069 0.035 H(18A) 8f 0.7534 0.2518 0.1337 0.115 H(18B) 8f 0.8018 0.1605 0.2206 0.115 H(18C) 8f 0.7756 0.3120 0.2439 0.115 Table 2. Atomic coordinates and displacement parameters (in A). Atom Site x y z Uiso

The largest isopolyoxotunstate ion known to date, W

C22H49NO5Si2, monoclinic, P1211 (no. 4), a = 10.529(2) Å, b = 8.152(1) Å, c = 16.554(3) Å, β = 98.015(4)°, V = 1406.9Å3, Z = 2, Rgt(F) = 0.064, wRref(F2) = 0.188, T = 173 K.