Volume 44, Issue 2

From a saturated solution of EtOC 6 H 4 N 2 NHN 2 C 6 H 4 OEt in aqueous ammonia and Cu(NH 3 ) 4 2+ dark brown Cu(EtOC 6 H 4 N 5 C 6 H 4 OEt) 2 (1) is obtained as an explosive precipitate. Upon heating in pyridine 1 is reduced to trimeric 1,5-bis(p-ethoxyphenyl)pentaazadienido copper(I) (2). 2 forms air-stable red crystals with the rhombohedral space group R3̄̄ and the lattice constants a = 1371.2(4) pm, α = 86.88(3)° and Z = 2. In 2 a linear Cu 3 3+ chain is coordinated by the atoms N 1, N 3 and N 5 of three pentaazadienido ligands, such that each Cu atom obtains a trigonal planar coordination by three N atoms. As 2 is located on the threefold axis of the space group R3̄̄, it has the Symmetrie C 3 . The distances Cu 2-N 3 = 192.7 pm to the more basic central atoms N 3 are shorter than the distances Cu 1-N 1 = 205.7 and Cu 3-N 5 = 201.5 pm to the outer N atoms of the N 5 chains. The pentaazadienido ligand forms a planar N 5 zig-zag chain with distances in the range of 127.8 to 135.4 pm. The very short Cu-Cu distances of 234.8 and 236.1 pm can be explained by bonding interactions between the d 10 centers.

dioxo-bis(phthaIocyaninato-niob(V))tribromid, [(PcNb)20 2Br]+BrJ, einem zweikernigen Phthalocyaninatokomplex Synthesis and Structure of i w-Bromo-/ i/-dioxo-bis(phthalocyaninato-niobium(V))tribromide, [(PcNb)20 2Br]~Br3 , i w -Brom o-^-dioxo-bis(phthalocyaninato-niobium (V))tribrom ide. Synthesis. Crystal Structure [(PcNb) 2 O 2 Br] + Br 3 - (1) is obtained by the reaction of NbOBr 3 with phthalodinitrile in 1-chloronaphthalene at 230 °C in the form of the solvate 1 · 1-chloronaphthalene or without solvent at 200 °C as 1 · phthalodinitrile. Both com pounds crystallize in almost identical structures in space group P 2 1 /c with the lattice constants: 1 · ClC 10 H 7 : a = 1556.3(2), b = 2394.8(5), c = 1841.5(2) pm, β = 109.06(1)°, V = 6487.1 · 10 6 pm 3 , Z = 4; 1 · C 6 H 4 (CN ) 2 : a = 1557.3(8), b = 2330.5(9), c = 1851.1(6) pm, β = 108.18(4)°, V = 6382.4 ·10 6 pm 3 , Z = 4. In the cation of 1 two PcNb units (H 2 Pc = phthalocyanine) are linked together by two asymmetric Nb-O- Nb bridges and one almost symmetric Nb-Br-Nb bridge, with distances Nb-O = 183.1 and 207.2 pm and Nb-Br = 280.5 and 284.5 pm. A s the Nb-Br-Nb bridge is longer the planes of the two Pc 2- ligands form an angle of 25.1°. Each Nb atom is coordinated to four N atoms of the Pc 2- ion with distances of approximately 214.2 pm and to the bridging oxo and bromo ligands resulting in the coordination number seven in the form of a monocapped trigonal prism with the Br atom as the cap. The counter ion Br 3 - is almost symmetric with Br-Br = 250.9 and 253.2 pm in 1 • C 6 H 4 (CN) 2 but in 1·ClC 10 H 7 it is more asymmetric with Br-Br = 247.6 and 255.6 pm.

[Na-15-crown-5][WF 5 (NCl)] has been prepared as yellow crystals by the reaction of NaF with WC 14 (NCl) in the presence of 15-crown-5 in acetonitrile solution. The compound was characterized by its IR spectrum as well as by an X-ray structure determination. Crystal data: space group P 2 1 /n, Z = 4 (2945 observed, independent reflexions, R = 0.035). Lattice dimensions at - 65 °C: a = 827.2(8); b = 1617.3(13); c = 1372.2(10) pm; β = 99.42(5)°. The com pound forms ion pairs, in which the sodium ion is seven-coordinated by the oxygen atoms of the crown ether m olecule, and by two fluorine ligands of the [WF 5 (NCl)] - unit with Na -F distances of 228.3(6) and 251.3(6) pm. The W ≡ N-Cl group of the anion is nearly linear (bond angle 176.1(5)°) with bond lengths WN = 173.3(6) and NCI = 162.2(7) pm.

The low temperature Raman spectra (10 K) of Cs 2 B 6 H 6 and its 11 B and 10 B enriched derivatives prepared for the first time show well resolved signals o f the B 6 -cage vibrations υ 1 (A 1g ), υ 3 (E g ) and υ 9 (T 2g ) for all isotopomers 11 B 10 B 6-n H 6 2 - , n = 0-6. The intensities o f the sharp peaks correlate exactly with the statistical abundance ratio. W hereas the frequency decreases by nearly equidistant steps of 7 cm -1 with increasing n values, the geometric isomers for n = 2, 3 and 4 are separated by only about 2 cm -1 . The band assignments are verified by Teller-Redlich calculations.

The polar metal-metal bond of [Ph 3 PAu 1 -Co -1 (CO) 4 ] was cleaved photochemically by metal to metal (Co -1 ￫ Au +1 ) charge transfer excitation. Metallic gold, Ph 3 P, and [Co 2 (CO) 8 ] were formed as products.

The crystal structure of calcium azide dihydrate trans-bicyclo-[4.4.0]-1,4,6.9-tetraazadecane has been determined by single crystal X-ray diffraction at 100 K. [Ca(N 3 ) 2 (H 2 O) 2 (C 6 H 14 N 4 crystallizes in the orthorhombic space group Pnma, Z = 4. with a - 1396.6(5), b = 1407.1(5), c = 712.2(2) pm. Calcium is hexacoordinated to four azide groups and two water molecules. The elongated octahedra are linked via μ(1,3)-bridging azide ions to form monolayers parallel to the ac-plane. The C 6 H 14 N 4 molecules are arranged between these layers.

The phosphinidene bridged clusters FeCo 2 (CO) 9 (PMe) and FeCoWCp(CO) 8 (PM e) add the diphosphinomethane ligands dmpm and dppm with concomitant opening of two metal-metal bonds. The crystal structure determination of the addition product (Me 2 P-CH 2 -PMe 2 )FeCoWCp(CO) 8 (PMe) has shown that the Fe -W and Fe -Co bonds have been opened and the chelating diphosphine spans the Co -W bond. This is in contrast to the reaction with monodentate phosphines where the Co -W and Co -Fe bonds are broken. Upon heating the addition products eliminate two moles of CO with formation of the diphos­ phinom ethane substituted starting clusters, which in turn add CO under pressure to re-form the addition products.

Incomplexes of the type [(NC) 2 Hg II N CFe II (CN) 5 ] 4- which are formed in aqueous mixtures of Hg(CN) 2 and [Fe(CN) 6 ] 4- both metals are weakly coupled. Optical metal to metal charge transfer (MMCT) excitation from Fe II to Hg II leads to the reduction of Hg II to Hg 0 an the oxidation of [Fe(CN) 6 ] 4- to [Fe(CN) 6 ] 3- . In the complex [(NC) 5 Co I -Hg II -Co I (CN) 5 ] 6- the m etals are strongly coupled by direct but polar metal metal bonds. MMCT (Co I ￫ Hg II ) excitation induces the photoredox reaction: [HgCo 2 (CN) 10 ] 6- ￫Hg 0 + 2[Co(CN) 5 ] 3- .

A second modification o f the title com pound has been isolated and characterized by an X-ray structure analysis. It crystallizes in the monoclinic space group P2 1 /c. The indium atom is hexacoordinated and surrounded by three sulfur and three oxygen atoms in a facial arrangement as has been found for a previously known isomer. However, the phenyl groups adopt a different orientation, hence it is a rotamer.

The reaction of piperidinium and potassium phosphorodithioates with 2-chloro-1-methyl-pyridinium salts afforded the corresponding bis(phosphorothioyl) sulfides in good yields. The similar reaction with potassium diphenylphosphorothioate gave exclusively bis(diphenylphos-phorothioyl) oxide.

The two-electron reduction of [(DAD)Ru(CO) 2 I 2 ] (DAD = RN = CH -CH = NR ) gives the reactive ruthenates(O) [(DAD Ru(CO ) 2 I] - , which add organic electrophiles to afford iodoruthenium organic com pounds such as [(DAD)Ru(CO) 2 (CH 3 )I] 3. Their electrochemical behaviour depends on the steric requirem ents of the D A D involved. With a small DAD (R = ipr) the oneelectron reduction gives a Ru(I) interm ediate, which finally yields a stable Ru-Ru-bonded dimer 4. With a bulky DAD(R - CH (ipr) 2 ) the reduction proceeds to the organoruthenates [(DAD)Ru(CO) 2 R] - . The structure of the dimer 4 was determined by a single crystal X-rax diffraction study: C 22 H 38 N 4 O 4 Ru 2 (624.69), space group F2dd, a = 9.944(2), b = 20.414(3), c = 27.644(5) Å , V = 5611,3(3) Å 3 , Z = 8; final R-value 0.034 from 2011 reflections. The molecule shows two almost planar (DAD )Ru(CO) 2 units, which are staggered with respect to the Ru -Ru single bond. The methyl groups occupy the positions trans to this M-M bond. 4 represents a new type of chromophore with only one very intense and rather narrow absorption band near the infrared (λ max = 745 , ε = 30000 cm 2 mmol -1 ), arising from the presence of a high-lying a-orbital, an antibonding combination of occupied d-orbitals and low-lying D A D π*-orbitals of proper symmetry.

The crystal and molecular structure of the dithallium salt of the 1,2-dicyanim inocyclobuten-3,4-dione dianion and of 1,2-diiodocyclobuten-3,4-dione, determined by X-ray diffraction, are reported and discussed. Results of FT-IR and calorimetric measurements are also presented.

A study of the dienophilic properties of F 3 CP = C(H)F (1) and F 3 CP = C (D)F (4) has been performed by using Me 3 SnP(CF 3 )CF 2 H (2) and Me 3 SnP(CF 3 )CF 2 D (3), respectively, as precur­ sors for the in situ generation of 1 and 4 in the presence of 2 ,3-dim ethyl-1,3-butadiene, 1,3-cyclohexadiene or 9,10-dimethylanthracene. Slow elimination of Me 3 SnF occurs at 55 °C yielding the cycloadducts of 1 and 4, respectively, within 5 or 7 days. Polymerization is observed as the main stabilizing reaction of 1 and 4, thus reducing the yields o f the [2+4]-cycloadducts 5 to 9 to about 20%. They are formed as mixtures o f diastereomers in the ratio a:b ≈ 90:10. In the preferred isomer a according to NMR data CF 3 and F have anti positions. Since NMDO calculations yield energy barriers of about 40 kcal/mol for E/Z isomerization, and literature values for inversion barriers of trialkyl phosphanes are of the same magnitude, the formation of isomers most likely has to be explained by a nonconcerted mechanism of the [2 + 4]-cycloaddition.

Dimcarb, a liquid distillable 1 .8 :1-dimethylamine-carbondioxide complex which can be used as a preparatively profitable dimethylamine source, displays unusual properties in view of a salt ("dimethylammonium dimethylcarbamate"). The dynamic structure behaviour has been investigated by 1 'H, 13 C, and 15 N NMR spectroscopy: At ambient temperature dimcarb underlies a rapid dimethylamine change between ammonium and carbamate functionality (⊿G ≠ about 58 kJ/mol). On further temperature decreasing prototropic interactions between dimethylammonium and dimethylamine as well as dimethylcarbamate and dimethylcarbamic acid species are additionally revealed. Timely averaged, ionic structures predominate, obviously dimethylammonium dimethylcarbamate combinations as intimate ion pairs. Involved dimethylcarbamic acid can be trapped as methylester in high yield by reaction of dimcarb with diazomethane. Moreover, the dimethylcarbamic acid trimethylsilylester, obtained from dimcarb with the aid of trimethyl-chlorosilane, affords a crystalline product by methanolysis at -78 °C. probably dimethylcarbamic acid, which decomposes above -50 °C under carbondioxide elimination and regeneration of dimcarb.

Conditions for ENDOR measurem ents of organosulfur radical cations are discussed and tested. The one electron oxidation of a variety of aromatic sulfur com pounds comprising benzene-1,2-dithiole, 1,4-dithiine, thianthrene and diphenylsulfide derivatives as well as 33 S isotope-marked bis(2,5-dimethoxyphenyl)disulfide is accomplished using the oxygen-free, powerful and selective AlCl 3 /H 2 CCl 2 reagent. Partly with substantial structural changes, paramagnetic M ⊕ species of 1,2-benzodithiete, 1,4-dithiine, thianthrene and diphenyl sulfide result. Their temperature-dependent ENDOR signal patterns provide numerous information e.g. on radical cation structure and dynamics, on the rather high sulfur spin populations or on the spin rotation interaction dominated relaxation behaviour. Accordingly, to obtain optimum ENDOR effects in organosulfur radical cations low temperature measurements are required, and especially for still undiscovered 33 S ENDOR couplings, small g factor anisotropies and 33 S spin densities appear to be necessary.

The title com pound has been prepared by the reaction o f N ,N ,N '-tris(trimethylsilyl)-benzamidine with tellurium tetrachloride in CH 2 Cl 2 solution. The complex was characterized by an X-ray structure determination. Crystal data: space group P 1̄ , Z = 2, (2428 observed independent reflexions, R = 0.031). Lattice dimensions (19 °C): a = 946.7(1), b = 1031.5(1), c = 1337.1(1) pm; α = 67.411(8)°, β = 68.508(9)°, γ = 67.195(8)°. Ph-C(NSiMe 3 ) 2 TeCl 3 forms monomeric molecules, in which the tellurium atom is ϕ-octahedrally surrounded by three chlorine atoms and by the two nitrogen atoms of the amidinato chelate (bond lengths Te -N = 209.6 and 219.2 pm). The lone pair at the tellurium (IV) center and the small bite angle of the ligand cause a strong distortion of the octahedral geometry.

We report the use of iminiumtetrachloro-aluminates 1a , 2a, and 3a in Mannich reactions. These salts are easily synthesized and offer some important advantages compared to iminium salts 1 b -e.

The CT complexes 2Vn 2 EE'·TCNE (1, E = E' = S; 2, E = E' = Se; 3, E = S, E' = Se) are prepared by combining the solutions of the components in acetonitrile. The three com pounds are isostructural and built up by Vn 2 EE'/TCNE/Vn 2 EE' units in which a TCNE molecule is inserted into the cavity formed by two of the folded, oppositely arranged Vn 2 EE' molecules. In this arrangement of donor and acceptor molecules an optimum overlap of the corresponding HOMOs and LUMOs is guaranteed as can be seen from the CNDOand HAM 3 calculations. The temperature dependence of the electrical conductivities shows the com pounds 1-3 to be semiconductors with gap energies of 1.27, 1.17 and 1.19 eV , resp.

Base induced isomerization of 1-benzoxepin-5(2H )-one (1a ) yields 1-benzoxepin-5(4H )-one (4a) which gives the unsaturated alcohol 5a on treatment with Ce(III)chloride/sodiumboranate. Subsequent reaction of 5a with p-toluenesulfonylchloride and then, without isolation of the intermediate, with base yields 1-benzoxepine (6 a). With tetracyanoethylene 6a forms the corresponding diene-adduct. The same reaction sequence was realized in the analogous sulfur series, yielding 1-benzothiepine (6 b).

Abstract 5-Dimethylamino-1-naphthalene-carbonic acid chloride (1), the analog of dansylchloride, is synthesized. With diazomethane the diazoketone 2 is obtained. The modified aerosil A is formed by the interaction of 1 with amino-aerosil. The density of the coverage is available a) chemically by dissolving the inorganic matrix of A with H 2 F 2 and spectroscopic determination of the formed n-butylamide 9, b) by fluorescence spectroscopy and c) by U V spectroscopy. Silanole groups both in organic substituted compounds and in aerosil react with the fluorescent silanes 6 and 7 using CsF/imidazole-catalysis forming the corresponding siloxanes according to (4 b) and (8). The modified aerosils C, D and E are prepared in this way and characterized. The functionalization of amino-aerosil with 7-chloro-4-nitrobenzeno furazane (10) leading to the modified aerosil B is unsatisfactory.

Several new pyrroline derivatives were prepared from 4-amino-1-benzoyl-3-benzylidene-4-pyrroline- 2-one (4).

K 2 Au 3 is obtained from the elements in a sealed Ta am poule as air-sensitive needles with a golden lustre. It crystallizes in the orthorhombic space group Immm with the lattice constants a = 487.5(2), b = 545.4(2), c - 1000.4(4) pm; Z = 2. The structure is com posed of planar layers of Au atoms at z = 0 and 0.5 and intercalated K atoms. The layers consist of triangles and hexagons with Au -Au distances between 268.8 and 280.2 pm. The K atoms have ten Au neighbours with distances from 334 to 389 pm.

Hydrazones of chiral and achiral ketones with enantiomerically pure phosphorylhydrazine 4 are prepared and analysed by 31 P NMR spectroscopy and HPLC for their diastereoisomeric purity.

The space group of the title compound is probably C2/m rather than the previously reported C2.

Some vanadium(V) oxo-polymers such as cis- V 2 W 4 O 19 4- and V 10 O 28 6- exhibit high catalytic activity for the oxidative cleavage of 3,5-di-t-butylcatechol. A chelated species of catechol to two vanadium atoms has been assumed as an active intermediate based on the spectroscopic results.