Volume 37, Issue 10

The new compounds Ba 2 GeP 2 and Ba 2 GeAs 2 crystallize in the monoclinic system (space group P2 1 /c) with lattice constants: Ba 2 GeP 2 : a = 855.3 ± 0.5 pm, b = 951.5 ± 0.5 pm, c = 748.1 ± 0.5 pm, β = 105.95 ± 0.08°. Ba 2 GeAs 2 : a = 875.7 ± 0.5 pm, b = 970.0 ± 0.5 pm, c = 700.7 ± 0.5 pm, β = 100.03 ± 0.08'. There are characteristic isolated Ge 2 P 4 8- and Ge 2 As 4 8- anions, which are arranged in sheets.

In the systems NbZn 2-x AL x and TaZn 2-x Al x a great number of samples was prepared and investigated by means of X-ray powder diffraction. In both systems at the equiatomic composition two new ternary phases were found. Their crystal structures were determined and found to belong to the Friauf-Laves type (MgZn 2 prototype, S. G. P 6 3 /mmc). The unit cell parameters of NbZnAl are a = 506.4 ± 0.2 pm, c = 829.9 ± 0.8 pm, c/a = 1.639, and for TaZnAl a = 503.8 ± 0.2 pm, c = 827.9 ± 0.3 pm, c/a= 1.643. In the system NbZn 2-x -Al x , at the composition NbZn 1.25 Al 0.75 , a ternary phase of the AuCu 3 structure (a= 394.4 i 0.3 pm, S. G. Pm3m) was also observed, while in the system NbZn 3-x Al x a single phase region, having the AuCu 3 structure, was found to exist up to the composition NbZ 2 Al. The stability of these Friauf-Laves phases and those found previously in the systems ZrZn 2-x Al x and HfZn 2-x Al x is discussed in terms of atomic sizes and valence electron concentration.

Tris(dimethylamino)borane, X-ray The crystal and molecular structure of tris(dimethylamino)borane, a liquid at room temperature, has been determined by single-crystal X-ray diffraction methods at - 116°C. The single-crystal growth was accomplished by means of a miniature zone melting process on the diffractometer. The structure data are compared with those of other aminoboranes.

The cationic sulfur dioxide complexes [CpFe(CO) 2 SO 2 ] + AsF 6 - (7) and [CpCr(NO) 2 SO 2 ] + AsF 6 - (9) are obtained in almost quantitative yield from CpFe(CO) 2 I(CpCr(NO) 2 Cl) and AgAsF 6 in liquid SO 2 . With excess transition metal halide dinuclear halogen-bridged cations ([CpFe(CO) 2 IFe(CO) 2 Cp] + and [CpCr(NO) 2 ClCr(NO) 2 Cp] + ) are formed. The crystal structure of 7 is reported, and the bonding in the complexes is discussed in the light of spectroscopic data.

The structure of the heteropoly periodate ion [H 2 V 2 I 2 O 16 ] 6- has been determined in its Na salt at -150 °C by single crystal X-ray diffraction with 1909 reflections and refined to F = 0.022 (R′= 0.028). Na 6 [H 2 V 2 I 2 O 16 ]·10H 2 O crystallizes in the triclinic space group P1 with a = 11.407(5), b = 8.865(3), c = 6.105(3) Å, α = 82.07(3)°, β = 84.24(4)° γ = 70.23(3)°, V = 574.5 Å 3 , Z = 1. The [H 2 V 2 I 2 O 16 ] 6- anion consists of edge and corner sharing IO 6 octahedra and VO 5 square pyramids. The vibrational spectra clearly indicate the presence of VO(terminal) 2 groups.

Ba metal and Se powder react in dry ethylendiamine (≙ en) in the presence of 222-Crypt to [Ba-4en]Se 4 ·en. The new compound crystallizes in the monoclinic system, space group C2/c with the lattice constants: a = 1187.9(7) pm, b= 1546.9(7) pm, c= 1497.9(7) pm, β = 105.82(8)°. Significant structure units are Se 4 2- chain anions.

The stoicheiometrically 1:1 adduct of 1,4,7,10,13,16-hexaoxa-cyclooctadecane with m-nitroaniline, C 18 H 30 N 2 O 8 , Mr = 402.45, crystallises from toluene in red-orange prisms, (probable) space group P1̄, a = 801.8(3), b = 920.4(3), c = 1403.3(4) pm, α = 80.40(4), β = 79.79(4), γ = 85.95(3)°, V = 1.07910 nm 3 , Z = 2, d calc. = 1.238 Mgm -3 . Structure refinement converged at R = 0.060 (R w = 0.002) for 2915 diffractometer data.

Malonenamide oxime [HONC(NH 2 )CH 2 C(NH 2 )NOH = C 3 H 8 N 4 O 2 ] (1), its bis-chelate complex with Ni(II) [Ni(C 3 H 7 N 4 O 2 ) 2 ] (2) and an ethanol solvate of this complex [Ni(C 3 H 7 N 4 O 2 ) 2 · 0.6 C 2 H 5 OH] (3) are characterized by X-ray structure analysis, as well as a paramagnetic tris-complex [Ni(C 3 H 7 N 4 O 2 ) 2 (C 3 H 8 N 4 O 2 )] (4), which forms a catena structure in the crystal. The molecular structures of two reaction products of 2 with air are described: [Ni(C 3 H 5 N 4 O 3 ) 2 (H 2 O) 2 ] · 4 H 2 O (5) has formed by oxidation of the methylene groups and may be taken as a complex of mesoxalamide oxime; [NiC 8 H 16 N 8 O 8 ] · 6 H 2 O (6) has a macrocyclic ligand which is a derivative of orthocarbonic acid, formed by addition of carbon dioxide to the oxime groups.

The tridentate mono-basic Schiff base N-(2-diethylaminoethyl)salicylaldimine ≙Hsal-en-NEt 2 forms complexes 1 = [(sal-en-NEt 2 )MY] with divalent metals M (Y = halide). The preparation of three copper(II) complexes 1a (Y=Br), 1b (Y=Cl), and 1c (Y=SCN) and one palladium(II) complex 1(1 (Y=Cl) is described and the UV/VIS spectra of these complexes in methanol and chloroform are compared and discussed. The crystals of 1a · CHCl 3 , 1b · CHCl 3 , and 1d · CHCl 3 are all isotypic and crystallize in the orthorhombic space group Pbca, whereas the solvent-free crystals of 1 b (and also 1 a) are monoclinic with the space group P2 1 /c. The metal is 4-coordinate with an almost planar ONNY donor atom arrangement around the palladium and with a distorted arrangement around the copper. The crystals consist of separate non-bridged complex units and the chloroform is not coordinated.

The reaction of trans-bromotetracarbonyl(phenylcarbyne)chromium (1) with lithium phenylselenolate and subsequent protonation with aqueous hydrochloric acid leads to (CO) 5 Cr[Se 2 (C 6 H 5 ) 2 ] (3) and (CO) 4 Cr(μ-SeC 6 H 5 ) 2 Cr(CO) 4 (4). From 1 and lithium 4-methylphenylthiolate (CO) 5 CrC(C 6 H 5 )SC 6 H 4 CH 3 (5) and (CO) 5 CrS(C 2 H 5 )(4-CH 3 C 6 H 4 ) (6) are obtained, if triethyloxonium tetrafluoroborate is used instead of hydrochloric acid. The analoguous reaction of 1 with lithium phenylselenolate yields the seleno ether complex (7). Reaction conditions, properties, spectroscopic data and the results of an X-ray structure determination of the binuclear complex (4) are reported.

The reaction of Re 2 (CO) 10 with LiSi(C 6 H 5 ) 3 and subsequent alkylation by CH 3 FSO 3 yields - besides eq-(CO) 9 Re 2 C(OCH 3 )Si(C 6 H 5 ) 3 (1) and (CO) 8 Re 1 eq,Re 2 ax-[C(OCH 3 )Si(C 6 H 5 ) 3 ] 2 Re 2 (2) - (CO) 13 Re 3 COSi(C 6 H 5 ) 3 (3) in small yields. In this trinuclear complex 3 Rel and Re2 are bridged by a (CeHs^SiCO-group, which is coordinated to Re 1 as an η 2 -acyl ligand and to Re 2 through oxygen only. Reaction conditions, properties and spectroscopic data of the new compound as well as an X-ray structure of 3 are reported.

Symmetrical anhydrides of hydroxycarbene complexes of manganese and rhenium, [π-C 5 H 5 (CO) 2 MC(R)] 2 O, (M = Mn, Re) are prepared by reaction of cationic carbyne complexes [π-C 5 H 5 (CO) 2 MCR]BX 4 with the corresponding metal carbonyl acylates Li[π-C 5 H 5 (CO) 2 MC(O)R]. [π-C 5 H 5 (CO) 2 MnC(C 6 H 5 )] 2 O is also obtained by controlled hydrolysis of π-C 5 H 5 (CO) 2 MnCX(Br)Ce 6 H 5 . The new complexes are characterized spectroscopically and by an X-ray structure analysis of [π-C 5 H 5 (CO) 2 MnC(C 6 H 5 ) 2 O.

The phosphinothioformimidato complex (1) crystallizes triclinic in the space group P1̄ with lattice constants a = 989.4(9) pm, b - 1042.0(8) pm, c = 1088.5(8) pm, α = 91.45(4)°, β = 97.10(4)°, γ = 100.53(5)°. The four-membered chelate ring is folded over the P-S edge by a dihedral angle of 167.1°. The crystal system of the thiophosphoryl thioformimidato complex (2) is monoclinic with the space group P2 1 /c, and the lattice parameters are a = 1109.5(3) pm, b = 966.0(3) pm, c = 2256.7(3) pm, β=103.11(2)°. The chelate ligand is linked to the metal by two S atoms forming a five-membered ring in the “envelope” conformation with the thiophosphoryl S atom at the apical position.

The compounds Pd(PPr i 3) n (n = 2 or 3) and Pd(PMePh 2 )4 react with CS 2 to give the mononuclear complexes (PR 3 ) 2 Pd(η 2 -CS 2 ). In the reactions of Pd(PMe 3 ) 4 and Pd(PMe 2 Ph) 4 with CS 2 binuclear complexes [(PR 3 )Pd(S 2 CPR 3 )] 2 containing bridging phosphoniodithio-carboxylates as ligands are formed. [(PMe 3 )Pd(S 2 CPMe 3 )] 2 is also obtained from (PR 3 ) 2 Pd(η 2 -CS 2 ) (PR 3 = PPr i 3 , PMePh 2 , PPh 3 ) and PMe 3 . The reactions of Pd(PR 3 ) n with the zwitter ions PMe 3 CS 2 and PMe 2 PhCS 2 lead to binuclear compounds [(PR 3 )Pd(S 2 CPR′ 3 )] 2 (PR 3 = PPr i 3 , PMe 2 Ph, PMePh 2 , PPh 3 ; PR′ 3 = PMe 3 , and PR 3 = PMePh 2 ; PR′ 3 = PMe 2 Ph). [(PMe 3 )Pd(S 2 CPMe 3 )] 2 reacts with PMe 3 with cleavage of the phosphoniodithiocarboxylate bridges to give (PMe 3 ) 2 Pd(S 2 CPMe 3 ). The formation of [(PMe 3 )Ni(S 2 CPMe 3 )] 2 from Ni(PMe 3 ) 4 and PMe 3 CS 2 is also described.

The colourless five-and six-membered arsamanganacycloalkanes (4a, a′, b, b′) are formed by reductive cycloelimination of (OC) 4 BrMn-AsPh 2 -[CH 2 ] n -Cl (3a,b) with sodium amalgam and a one step reaction of (OC) 5 MnBr (1) with Me 2 As-[CH 2 ] n -MgCl (2a′,b′), respectively. 3a,b are accessible in substituting CO by the arsanes Ph 2 As-[CH 2 ] n -Cl (2a,b) in 1. In respect of thermal stability and reactivity 4a,a′, b,b′ are comparable with their phosphorus analogues. 4a crystallizes in the morioclinic space group C2/c with Z = 8 and has an envelope conformation. Into the reactive Mn-Cσ bond SO 2 or CO can be inserted to give the cyclic sulfinato-S complexes (5a,a′,b,b′) and acyl compounds (6a,b′) respectively.

A new X-ray diffraction study of p-nitroaniline shows that through-conjugation has highly significant effects on the geometry of the molecule, as compared to aniline and p-nitrobenzoic acid. The effects include a moderate decrease of the internal angles of the ring at substituted carbons, with respect to values derived by superimposing independent angular distortions from each substituent.

Crystals of [Al(C 5 H 5 N) 4 Cl 2 ][AlCl 4 ] are orthorhombic, Pna2 1 , Z = 4, a = 18.522(7), b = 15.141(5), c = 9.593(3) Å, V = 2690(2) Å 3 , D c = 1.440 g/cm 3 . The structure has been solved from 5968 diffractometer measured intensities and refined by full-matrix least squares to R w (F) = 0.032. The crystal structure shows the complex to be trans-dichloro-tetrakis(pyridine)aluminium(III) tetrachloroaluminat(III). The mean trans Al-Cl-and trans Al-N-distances in the octahedron are 2.279(3) and 2.070(4) Å, respectively. Crystals of Al(C 5 H 5 N) 3 Cl 3 are monoclinic, P2 1 /c, Z = 4, a = 7.261(2), b = 29.961(4), c = 8.624(1) Å, β = 98.12(2)°, V -1857(1) Å 3 , D C = 1.326 g/cm 3 . The structure has been solved from 4707 diffractometer measured intensities and refined to R w (F) = 0.028. The crystal structure shows octahedral complexes AlCl 3 ·3 (C 5 H 5 N) with trans geometry. The Al-N-distance trans to chlorine (2.096(2) Å) is significantly longer than the two other Al-N-distances (mean 2.072(2) Å).

Trimesityltin bromide reacts with concentrated aqueous ammonia to give trimesityltin hydroxide. This compound eliminates mesitylen and yields dimesityltin oxide. The product was investigated bv 13 C NMR, mass spectroscopy and X-ray diffractions. Di-mesityltinoxide crystallizes in the space group P2 1 /w with a = 25.38(1) Å, b = 12.525(5) Å, c= 32.91(1) Å, β= 91.37(3)° and two molecules in the asymmetric unit (Z=8). The R-factor is 0.049 for 4688 symmetry-independent reflections. The trimeric molecules have six-membered tin-oxygen heterocycles in a twist conformation.

The stereochemistry of the photo reaction products of tricarbonyl-η-6,6-dimethyl-fulvene-chromium(O) (1) with 7-methyl-and 7-methoxycycloheptatriene was studied by NMR-spectroscopy. Both trienes add to 1, displace a CO ligand, and form substituted dicarbonyl-η 3 -2-cycloheptadienylene-η 5 -2-cyclopentadienylidene-propane-chromium(0) complexes. With C 7 H 7 CH 3 only one isomer (3) is formed with the methyl-group in endo-position and the enyl system encompassing C(1′)-C(3′) of the seven membered ring. C 7 H 7 OCH 3 yields 3 isomers which were separated by column chromatography. 5 has the same constitution as 3. The isomers 4 and 5 bear the OCH 3 -group in e^o-position. The enyl system of 4 is located on C(1′)-C(3′), that of 6 on C(3′)-C(5′). 6 rearranges at room temperature to 4.

Condensation of benzoylacetonitrile (1a) and benziminoacetonitriles (1b, c), resp., with tho hydrazines 2a-f leads to benzoylacetonitrile-hydrazones (3a-i), which react with tetracyanoethylene to give pyrazolo[3,4-b]pyridines (6a-d) and polymethines (7a, b, 8), resp.

Aryl-mono- and -disulfonic acid derivatives (Ar(SO 2 Y) n n= 1,2; Y = OR, NR, R′) were converted to aryl sulfinic acids by electroreductive fission according to the steps shown in Scheme (1). Determination of the electron-transfer during the electroreduction (Ilkovič, n < 1) indicates the irreversibility of the reaction sequence given. Cyclovoltammetric measurements on benzene-1,4-disulfonicacid-di-n-hexylester indicate that the first reduction step (the formation of the radical anion A or B) is reversible.

The preparation of the nematic 4-(4-n-pentyl-1-piperidyl)cyclohexane-1-carbonitrile (1b) via the enamine 2b and the N-Cyclohexylpiperidines 5a-c is described. The nematic range of 1b was found to be 8 °C.

a-Hydrogens a-Hydrogens of R-C ≡ C-and N ≡ C-substituted cyclopropanes are more acidic than their open chain analogs, as expected from the higher acidity of cyclopropane versus propane. In the case of the carbonyl substituted species, however, this order is reversed. Furthermore, in H/D exchange reactions of optically active compounds, only cyclopropyl cyanides retain their configuration; aliphatic and cyclopropyl ketones exchange and racemize essentually at the same rate. This behaviour has been rationalized qualitatively in the following manner: RC = C-and N ≡ C-substituents stabilize a negative charge mostly inductively; on the other hand, with carbonyl groups, delocalisation of the negative charge (resonance) is more important than the inductive effect. Thus the unfavourable configuration (I-strain) of the planar cyclopropyl enolate anions is in agreement both with the low acidity of the corresponding cyclopropanes and with the loss of optical activity in H/D-exchange reactions. In order to put this explanation on a more quantitative basis, we calculated the relative proton affinities of isopropyl-and cyclopropyl-carbanions by means of the ab-initio STO-3G method. In the case of X = H, CF 3 and C ≡ N, the cyclic anion (CH 2 ) 2 C ⊖ X is more stabilized by the substituent X than in the anion (CH 3 ) 2 C ⊖ X; with X = CHO, COOH and NO 2 the order is reversed. Cyclopropyl anions should have a pyramidal configuration with X = H, CF 3 , C ≡ N and NO 2 , which indicates a strong inductive effect also of the nitro group. In summary: STO-3G calculations support the qualitative explanations of the experimental results with regard to the acidities of substituted cyclopropanes.

The photoreaction of the 2-methyl-4-phenyl-1-benzothiepins 1a und 1b leads first to the not isolated primary pliotoproducts 2 a and 2 b. These were entirely transformed to the secondary pliotoproducts 3a and 3b in the course of the irridation.

From the methanol extract of Catharanthus roseus tissue cultures sitsirikine (2), isositsirikine (3), dihydrositsirikine (4), yohimbine (5), 3-iso-19-epiajmalicine (6), pleio-carpamine (7), antirhin (8) and two up to now unknown alkaloids have been isolated in addition to the compounds previously found in the hexane extract. The structures belonging to lieteroyohimbane, vallesiachotamine, corynanthe and related types were deduced by UV, NMR and mass spectroscopy.

The dehalogenation of the 1-aryl-3-chloro-4-oxo-azetidine-2-carboxylicacid-ester (3a-d) and (4a-d), which may be obtained by the addition of chloroketene to the aniles (2 a-d) leads to the title compounds in good yield.

By reaction of solutions of CuCl 2 ·2H 2 O and hexamethylenetetramine, C 6 H 12 N 4 , in acetone, a complex [Cu 4 Cl 6 O(C 6 H 12 N 4 )] could be obtained as single crystals. An X-ray analysis shows that the complex has a structure related to that of basic beryllium acetate. An oxygen atom is tetrahedrally surrounded by four cop-per atoms which, together with six chlorine atoms, form an adamantane-like core. Each copper atom is bonded via a nitrogen atom to a hexamethylenetetramine molecule.

The complex [L 2 IrCl] (L = η 4 -2,3-dimethylbutadiene- 1,3) reacts with AgBF 4 in CH 2 Cl 2 to yield [L 2 Ir] + BF 4 - (1). If 1 is dissolved in dimethylsulfoxide (DMSO) the stable adduct [L 2 Ir(DMSO)] + BF 4 - (2) can be isolated. In 2 the DMSO ligand coordinates to iridium via oxygen. The compounds 1 and 2 were characterized by elemental analysis, infrared, and 1 H NMR spectra.