Volume 56, Issue 2

With 1,4-dioxane as the constant donor, five new donor/acceptor complexes with the polyiodine compounds I-I, I 2 C=CI 2 , tetraiodothiophene and two tetraiodopyrrole derivatives could be crystallized and their structures determined despite their decomposition in air. They provide interesting facets for selforganisation on crystallization: The 1,4-dioxane addition causes at best small structural changes of the polyiodine compounds. All adducts crystallize in chains of alternating donors and acceptors, which also staple separatedly. The direction of the contacts O···I depends on the incorporation of the 1,4-dioxane molecules into the iodine acceptor layers. The structural results correlate with those obtained for donor/acceptor complexes with organosulfur donors and, therefore, add to the rationalization of intermolecular interactions.

The reaction of Y(NO 3 ) 3 · 5H 2 O and 2,2':6',2"-terpyridine (terpy) in MeCN leads to [Y(N0 3 ) 3 (terpy)(H 2 O )] (1) and [Y(N0 3 ) 3 (terpy)(H 2 O )] terpy-3MeCN (2) in good yields depending on the isolation conditions. The structures of both complexes were determined by single-crystal X-ray crystallography. The Y III atom in 1 is 9-coordinate and ligation is provided by one terdentate terpy molecule, two chelating nitrates, one monodentate nitrate and one terminal H 2 O molecule; the coordination polyhedron about the metal may be viewed as a tricapped trigonal prism. The Y III atom in 2 is 10-coordinate and its coordination sphere consists of three nitrogen atoms from the terdentate terpy, six oxygen atoms from the three chelating nitrates (one of them being “anisobidentate”) and one oxygen atom from a terminal H 2 O molecule; the polyhedron about the metal may be viewed as a distorted sphenocorona. The interstitial terpy is strongly hydrogen-bonded to the O atom of the coordinated H 2 O molecule to form [Y(NO 3 ) 3 (terpy)(H 2 0)] ··· terpy pairs. The new complexes were characterized by IR and 1 H NMR spectroscopies. The Y III /NO 3 - /terpy chemistry is compared to the already well-developed Ln III /NO 3 - /terpy chemistry (Ln = lanthanide).

Acylation, Heterocycles, Imidazoles 2,3-Dihydro-l,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (2, Im) reacts with PhC(O)X to give the imidazolium salts [PhC(O)Im]F (3) and [PhC(O)Im]Cl (5). From 3 and the corre­ sponding fluoro compounds, the salts [PhC(O)Im][BF 4 ] (4a), [PhC(O)Im][Ph 3 SiF 2 ] (4b) and [PhC(O)Im] [Ph 3 SnF 2 ] (4c) are obtained. 2 reacts with oxalylic chloride under CO elimination to give the salt [Im 2 CO]Cl 2 (7). The X-ray data of 4c and 7 · 4 H 2 0 · 2 HCl ([Im 2 CO][Cl 4 H 10 O 4 ]) are reported.

Germanium, Azagermatranes The reaction of tris(dimethylamino)halogermanes, (Me 2 N) 3 GeHal (7, Hal = Cl; 8 , Hal = Br), with tris(2-aminoethyl)amines, N(CH 2 CH 2 NHR) 3 (5, R = H; 6 , R = Me), yield l-halo-N,N',N"-azagermatranes (1, X = Cl, R = H; 2, X = Br, R = H; 3, X = Cl, R = Me; 4, X = Br, R = Me). Treatment of 4 with n-butyllithium affords l-n-butyl-N,N',N"-trimethylazagermatrane (14) in high yield. Reactions of n-BuLi with 7 or (Me 2 N) 4 Ge (13) lead to the formation of (Me 2 N) 3 Ge-n-Bu (15). On treatment of 15 with 5 the 1 -n-butylazagermatrane 16 was obtained. The molecular composition and the structures of all new compounds were established by elemental analyses, 1 H and 13 C NMR spectroscopy and mass spectrometry.

The reactions of Cp 2 HfCl 2 with some higher monocarboxylic acids having straight chains, caprylic (C 8 H 16 O 2 ), lauric (C 12 H 24 O 2 ), myristic (C 14 H 28 O 2 ), palmitic (C 16 H 32 O 2 ), stearic (C 18 H 36 O 2 ), and behenic (C 22 H 44 O 2 ) acid, have been studied in anhydrous tetrahydrofuran in 1:1 and 1:2 molar ratios, respectively. The reaction products isolated, of types Cp 2 Hf(L)Cl, CpHf(L) 2 Cl (LH represents different carboxylic acids), have been characterised by conductivity and magnetic susceptibility measurements and spectral (infrared, electronic, 1 HNMR and 13 C NMR) data. The bonding of the carboxylato ligand in these complexes has been discussed and plausible structures have been established.

The 31 P and 13 C NMR spectra of the heteroatom-substituted λ 3 -phosphaalkynes (Me 3 Si)- i PrNCP (1), K + [ i PrNCPl - (2) and KOCP · 2 DME (3) are described (Me = methyl; i Pr = isopropyl). In addition, 15 N NMR data of 1 and 2 as well as further NMR results of all accessible nuclei of 1 to 3 are reported. The absolute values of the coupling constants 1 J( 31 P 13 C) of 1, 2 and 3, 18.2, 45.7 and 57.2 Hz, respectively, are considerably different; the geminal coupling constants 2 J( 31 P 15 N) of the first two compounds show a decrease in the reverse order, 15.1 and 3.3 Hz. 13 C, 29 Si, 15 N, and 18 O isotope effects on the nuclear shielding of the 31 P nucleus in the non isotope-enriched compounds 1, 2 or 3 are presented and discussed. The [mono-13C]isotopomers of 1, 2 and 3 exhibit extremely negative 31 P 13 C one-bond isotope shifts varying from -211 to -223 ppb. Remarkably, for 1 and 2 large two-bond 31 P 15 N isotope shifts of -32 and -84 ppb, respectively, are observed. An unexpectedly large two-bond 31 P 18 0 isotope effect of -124 ppb was assigned to the [mono- 18 0]isotopomer of compound 3. A three-bond 31 P 13 C isotope shift of -27 ppb was found in 2.

Three donor/acceptor complexes between halide anion donors and the triiodomethane acceptor with tetraphenylphosphonium countercations, {(H 5 C 6 ) 4 P ⊕ X ⊖ ··· I 3 CH)} (X ⊖ = Cl ⊖ , Br ⊖ , I ⊖ ) could be crystallized and their structures determined at low temperature. Their crystal packing motifs are donor/acceptor layers of halide anion/triiodomethane patterns and phenyl/ phenyl interacting tetraphenylphosphonium cation chains. Structure comparison and discussion are based on literature-known analogous adducts with organoammonium salts as well as the phenyl/phenyl interactions in the numerous tetraphenylphosphonium salts registered in the Cambridge Structural Database. The results add novel facets to the selforganization phenomena observed on crystallization of halogen compounds and halide salts.

Bis(trichlorsilyl)phenylamine (1) and 2,2,4,4-tetrachlor-l,3-diphenyl-[l,3,2,4]diazadisiletid-ine (2) have been synthesized as potential precursors for the preparation of porous oxygen-free solids by the reaction of tetrachlorosilane with dilithiated aniline. Both compounds were characterized by crystal structure analysis. 1 crystallizes monoclinically, P2/n, a = 10.124(2), b = 12.701(2), c = 11.425(3) Å, β = 109.34(2)° and Z = 4 (R 1 = 4.6%, wR 2 = 11.6%, 1297 independent reflections). 2 crystallizes orthorhombically, Pbca, a = 11.42(1), b = 8.17(1), c = 17.05(1)Å, and Z = 4 (R 1 = 3.7%, wR 2 = 8.2%, 1923 independent reflections). Ammonolyses and polycondensation of 1 and 2 yield amorphous solids with low porosities.

The oxoantimonates(V) Cs 2 Sb 4 O 11 (monoclinic, C2/m, a=1964.5(5), b=762.8(2), c=730.2(2) pm, β=96.276(5)°, Z=4) and A 3 Sb 5 0 14 (A=Rb/Cs; orthorhombic, Pbam, a=718.81 (9)/ 743.37(13), b=2447.8(2)/2625.1(5), c=733.1(2)/739.6(3) pm, Z=4) were synthesized from Sb 2 0 5 and the peroxides AO 2 (A=Rb, Cs). Their crystal structures were determined on the basis of single crystal diffractometer data. The structures are composed of three-dimensional nets of [SbO 6 ]octahedra connected via common corners and edges, with the A cations incorporated in the resulting channel systems. The Raman spectra of the compounds are discussed in relation with the different type of oxide connectivites in the oxoantimonate anions.

cis- and trans-Dicyclohexyl-3,3′,4,4′-tetracarboxylic acid and their dianhydrides were prepared from tetramethyl dicyclohexyl-3,3′,4,4′-tetra-carboxylates by hydrolysis and subsequent dehydration. The trans dianhydride 2b was found to be sensitive to temperature. However, once the imide ring is formed in the reaction with an amine, the model compound is thermostable. The products were characterized by 1 H and 13 C NMR, and also by two-dimensional COSY spectroscopy. In the hydrolysis of cis-tetramethyl dicyclohexyl-3,3′,4,4′-tetracarboxylates in steam under high-pressure, trans-dicyclohexyl-3,3′,4,4′-tetracarboxylic acid was formed, while the treatment of cis-dicyclohexyl-3,3′,4,4′-tetracarboxylic acid in steam under high-pressure afforded also trans-dicyclohexyl-3,3′,4,4′-tetracarboxylic acid. In a deuterium tracer experiment of cis-1a, the 3,3′,4,4′-tetradeuterated dicyclohexyl-3,3′,4,4′-tetracarboxylic acid 2a was formed. An isomerization mechanism was postulated from this findings.

In the catalytic hydrogenation of tetramethyl biphenyl-3,3′,4,4′-tetracarboxylate, tetramethyl dicyclohexyl-3,3′,4,4′-tetracarboxylates were obtained, from which we have isolated cis isomers as crystals. The base-catalyzed isomerization afforded the trans isomers. The structure of the products isolated was determined by single-crystal x-ray diffraction, which clearly reveals the axial and equatorial positions of the methoxycarbonyl group. The structures in solution are supported by 1 H and 13 C NMR data, and also by two-dimensional COSY techniques.

The electrochemical behaviour of Na(Et 2 NCS 2 ) and M(Et 2 NCS 2 ) 2 (M= Ni(II), Pd(II) and Pt(II); Et 2 NCS 2 - = diethyldithiocarbamate) as studied by cyclic voltammetry in the acetonitrile-( n-Bu) 4 NBF 4 solvent-electrolyte couple at room temperature vs. Ag/Ag + reference electrode. Constant potential electrolyses of the complexes were carried out at their first oxidation peak potentials and monitored in situ by UV-VIS spectrophotometry. The electrolysis of Ni(Et 2 NCS 2 ) 2 in solution yielded the dimer of the ligand, (Et 2 NCS 2 ) 2 , and Ni 2+ (sol) as final products. During this electrochemical process the formation of a Ni(III) complex species as an intermediate has been observed. The electrochemical oxidation of bis(diethyldithiocarbamato) complexes of Pd(II) and Pt(II) yielded [Pd(Et 2 NCS 2 ) 3 ] + and [Pt(Et 2 NCS 2 ) 3 ] + , respectively.

The solid state synthesis and the crystal structure of Cs 6 Cl 4 O(Pearson-code hR22, R3c, a = 1324.7(6), c = 1658(1) pm, Z = 6, 931 reflections with I o > 2σ(I), R 1 = 0.040, wR 2 = 0.114) are reported. The compound crystallises isotypically with Rb 6 Cl 4 O in the anti-K 4 CdCl 6 type of structure. The structure consists of infinite chains of alternating face-sharing OCs 6 octahedra and ClCs 6 trigonal prisms which are separated by chloride anions. The underlying structural concept and the analogy to perovskites are outlined.

Using 4-[4-(dimethylamino)styryl]-l-methyl-pyridinium iodide, lead iodide, tetrabutylammon-ium bromide and lead bromide as starting materi­ als, the title compounds were prepared and characterized analytically and spectroscopically.

The formation and the crystal and molecular structure of (μ-oxo)bis{chloro(methyl)thienyl-tellurium(IV)}, [Me(Th)TeCl] 2 0 , are described. The compound is orthorhombic, space group Pbcn, a = 1893.30(2), b = 891.96(2), c = 966.24(5) pm; Z =4. The tellurium atom shows trigonal bi-pyramidal coordination with chlorine and the bridging oxygen atoms in axial, and methyl and thienyl groups in equatorial positions. The two close intermolecular Te(1) ···Cl(1) contacts ex­pand the coordination sphere around tellurium to an almost regular octahedron.