Volume 43, Issue 8

Several fortuitous preparations and high yield rational syntheses for [(Me 3 P) 2 M(PMe 2 )]: (1: M = Co; 2: M = Ni) are described. 1 crystallizes in the space group P1̄ (no. 2); a = 975.6(5). b = 943.6(5), c - 904.2(5) pm. α= 63.8(1)°, β = 79.1(1)°, γ = 72.8(1)°. Mixed metal complexes L 2 Co(PR 2 ) 2 NiL 2 (L = PMe 3 ; R = Me, Ph) evaded detection giving symmetric products exclusively. An improved synthesis of LiP(C 6 H 5 ) 2 ·dioxane is also described.

Me 2 SN 2 P 2 Ph 4 M(CO) 4 complexes (1) (M: 1 a Cr, 1 b Mo, 1 c W) have been synthesized from Me 2 S(NPPh 2 ) 2 and C 7 H 8 M(CO) 4 . 1a-1c are stable at room temperature, 1 b crystallizes in the space group P2 1 2 1 2 with cell constants a = 2486.3(2); b = 1488.8(1); c = 882.0(1) pm.

The new ligand (Me 3 Si) 2 NC(Ph)NP(Ph) 2 N(SiMe 3 ) (1) reacts with MOOCl 4 to yield the green metallacycle 4. 4 was characterized by X-ray diffraction. Crystals of 4 are monoclinic, space group P2 1 /n with a = 1061.2(10). b = 1590.5(10), c = 1737.4(20) pm, β = 104.84(7)° and Z = 4. Mo is coordinated octahedrally by two nitrogens of the bifunctional ligand. by one oxygen and three chlorine atoms. The ligand undergoes cyclization, a bond being formed between N and one phenylic o-position.

(Et 2 N) 3 P=CH 2 reacts with NbCl 5 , WCl 6 or WF 6 under C-C bond formation to give the phosphonium cation [(Et 2 N) 3 PCH 2 ] 2 2+ · [(Et 2 N) 3 PCH 2 ] 2 2+ [WCl 6 ] 2 - was isolated in a crystalline form and investigated by X-ray analysis. The reaction of (Et 2 N) 3 P=CH 2 with MOCl 4 in a solvent proceeds with formation of the [(Et 2 N) 3 PCH ] + cation.

The crystal structure of the carbamoyl complex [(CO) 4 FeC(O)NMe 2 ][C(NMe 2 ) 3 ] (1) is described. It crystallizes in the triclinic space group PI (a = 7.876(3), b = 10.098(3), c = 12.067(5)Å, α = 94.25(3), β = 90.94(3), γ = 97.30(3)°, Z = 2) and consists of independent ions. The cation has a planar CN 3 array with sp 2 hybridized C and N atoms. The carbamoyl group of the anion occupies an axial position in the trigonal bipyramidal environment of the iron atom.

Cd[AsF 6 ] 2 (1) reacts with cyanogen to yield [Cd{(CN) 2 } 2 SO 2 ][AsF 6 ] 2 (2). 2 crystallizes in the space group Pnma with cell constants a = 1475.2(3); b = 821.7(3); c = 1321.2(9) pm. The coordination sphere of cadmium consists of nine atoms (one oxygen, four fluorines and four nitrogens). Cyanogen forms polymeric links.

The molecular and crystal structures of the isotypic compounds tetramethyldiphosphane 1 and -diarsane 2 have been determined by single crystal X-ray diffraction (monoclinic; C2/m; Z = 2; 1/2: -155/-144 °C\a = 540.6(2)/555.8(2); b = 1131.0(6)/l 136.7(6); c -602.5(2)/612.8(2) pm;β = 97.31(3)/95.24(3)°;P-P 221.2(1)/As-As 242.9(1) pm). In accordance with the crystallographically imposed symmetry 2/m, the molecules adopt antiperiplanar conformation. Their crystal structures are closely related to those of the homologues tetramethyldistibane 3 [1] and -dibismuthane 4 [3]. As found for the latter compounds, the E -E units (E = P, As) are also aligned in linear chains, but the intermolecular E···E contacts (P···P 381/As···As 370 pm) do not allow any extended interaction between molecules, which otherwise would result in thermochromic effects.

The 1,4-dithia-2,6-diaza-3,5-diborinanes 1a-d react with elemental sodium with formation of the 1,3-diaza-2,4-diboretidines 2a-d. By use of more sodium in case of 1 d or 3,5-bis(diethylamino)- 2-cyclohexyl-6-trimethylsilyldiborinane, the 1,3-thiaza-2,4-diboretidines 3 were formed. 3.5-Dimethyl-2,6-bis(trimethylsilyl)-1,4-dithia-2,6-diaza-3,5-diborinane gives the borazine 4, The reaction of di-t-butyl-sulfurdiimide with 2,6-di-t-butyl-3,5-dimethyl-1,4-dithia-2,6-diaza-3,5-diborinane leads by ring contraction to the four-membered ring system 5. 1 H, 11 B, 13 C NMR and mass spectra are reported and discussed.

The compound [(PyH) 3 Br][AlBr 4 ] 2 is formed by melting stoichiometric amounts of AlBr/PyHBr in a ratio of 2:3. It crystallizes in the orthorhombic space group Pbca with lattice constants a = 1365.5(2), b = 1616.0(2), c = 2783.7(3) pm, Z = 8, D c = 2.21 g/cm 3 . The structure was solved from 2810 diffractometer measured intensities (Cu -K α radiation) and refined to R w (F) = 0.071. The cation shows three pyridinium ions attached via N - H - Br hydrogen bonds to a central bromide ion. The N - Br distances are 321(1), 321(2) and 332(2) pm.

Idiomorphous crystals of five different polymorphic modifications (α-ε) of TeI 4 are simultaneously grown from solutions of TeI 4 and concentrated HI in methanol by evaporating the solvent at room temperature. δ-TeI 4 is the only stable phase at normal conditions. Phase transformations of α-, β-, γ-and ε-TeI 4 to the final stage δ-TeI 4 take place by heating and run through discrete intermediates. The observed graduations lead to a sequence γ-, β-, α-,ε-TeI 4 which indicates “increasing metastability”. The crystal structures of α-TeI 4 (trigonal; P3̄ml; a = 4.228(2), c - 6.684(6)Å, Z = 0.5; D x = 5.10 g/cm 3 ), β-TeI 4 (orthorhombic; Pn2 1 m; a = 6.888(2), b = 14.539(3), c = 16.753(4) Å, Z = 8; D x = 5.03 g/cm 3 ) and γ-TeI 4 (monoclinic; P2 1 /c; a = 11.199(4), b = 13.599(4), c = 22.158(6) Å,β = 98.10(3)°, Z = 16; D, = 5.05 g/cm 3 ) are related to the known crystal structure of δ-TeI 4 . α-TeI 4 (“Te 0.5 I 2 ”) is an isotype of the 2H-CdI : structure with random distribution of Te over the Cd-positions. The crystal structures of β-, γ-and δ-TeI 4 contain discrete tetrameric molecules “(TeI 4 ) 2 (TeI 3 + I - ) 2 ” which are generated by ordered distributions of Te over 1/4 of the octahedral holes of a 2H-(β) and a 4H-sequence (y,δ ) of the nearly close packed iodine layers. A nearly cubic close packing of Iodine atoms is observed in the crystal structure of ε-TeI 4 (tetragonal; I4 1 /amd; a = 16.875(6), c -11.829(5) Å, Z = 16; D x = 5.01 g/cm 3 ). The ordered distribution of Te in 1/4 of the octahedral holes leads to tetrameric molecules “(TeI 3 + I - ) 4 ” in a cubanelike arrangement which, thus far, has been observed only in the crystal structures of TeCl 4 and TeBr 4 . The Madelung Parts of Lattice Energies, MAPLE, of β-, γ-, δ-and ε-TeI 4 are calculated.

(NH 4 )NbOBr 4 is obtained as air sensitive, light red crystals from NH 4 Br and NbBr 5 in a sealed glass ampoule at 420 °C, whereby the oxygen presumably originates from the glass surface. The compound crystallizes in the monoclinic space group C2/m with a = 1269.9(1), b = 1384.7(2). c = 773.0(2) pm, β = 114.44(2)° and Z = 6. The structure is built up by NH 4+ cations and polymeric NbOBr 4 anions. Symmetrical linear oxo bridges with Nb-O = 199 pm connect square planar NbBr 4 units to form endless chains arranged in planes parallel (010). Neighbouring NbBr 4 units are in eclipsed as well as staggered orientations. The NH 4 + cations are located between the planes of parallel NbOBr 4 - chains. The vibrational frequencies of the IR and Raman spectrum are assigned.

The phosphino-substituted sulfur diimides S(N-P t Bu 2 ) 2 (1), t Bu;P(NSN)PRR′ (R = R′ - phenyl (2a), cyclohexyl (2b), isopropyl (2c), ethyl (2d); R = phenyl, R′ = tert-butyl (2e)) and t Bu 2 P(NSN) t Bu (3) were studied in solution by 1 H, 13 C and 31 P NMR spectroscopy**. The coupling constants 4 J( 31 P 31 P) of the compounds containing different phosphino groups, 2a-e, depend both on the nature of the solvent and the temperature. The NMR results are interpreted in accord with a rapid Z/E⇄ E/Z interconversion at room temperature and the predominance of a single configurational isomer at low temperatures. There is no indication for the presence of the “symmetrical” configurations, Z/Z or E/E respectively, in solution in appreciable amounts. 15 N NMR data are also reported for a series of sulfur diimides.

Single crystals of Ca 2 [C 6 H 2 (COO) 4 ]·6H 2 O were grown in aqueous silica gel. Ca 2+ has CN 6+2. The coordination polyhedron is formed by three water molecules and five oxygen atoms of carboxylate groups. Six oxygen atoms are closely bound (235,9-243,9 pm), the two remaining coordination partners are considerably more remote from Ca 2+ (268,2 and 273,8 pm). COO - groups chelate Ca 2+ in an asymmetric manner, but the C -O bond lengths do not differ markedly (125,2-126,3 pm). The connection of Ca 2+ with [C 6 H 2 (COO) 4 ] 4- leads to rigid layers. Adjacent layers are interlinked by hydrogen bonds. Those oxygen atoms which are weakly bound to Ca 2+ are favoured as proton acceptors in hydrogen bonds. The COO groups are tilted differently against the C 6 -ring plane. One is approximately coplanar, but the other is oriented almost perpendicularly.

Dichalcogenostibanes of the type RSb(ER′) 2 (R = CH 3 ,C 2 H 5 ; E = S. Se; R′ = CH 3 . C 6 H 5 ) and trialkylstibanes R 3 Sb have been prepared by redistribution reactions of stibanes of the type R 2 SbER′.

Using 293 K diffractometer intensity data, the crystal structures of [H 3 N(CH 2 ) 3 NH 3 ] 3 (BiX 6 ) 2 (H 2 O) 2 with X - Cl, Br have been determined by single crystal X-ray technique and refined to a final R w of 0.027 and 0.043, respectively. The structures are isotypic, space group P2 1 /c, Z = 2 with a = 14.415(1). b = 9.7401(7), c = 12.4609(9)Å, β = 105.997(8)°for X - Cl and a = 14.794(2), b = 10.127(2), c = 12.853(2)Å, β = 105.68(2)° for X - Br. Statically distorted BiX 6 3- octahedra confirm the symmetry rules for the stereochemistry of the lone pair electrons in AX 6 E-systems. Basic structural data for all compounds containing BiX 6 3- and SbXh 3 ions (X = Cl, Br, I) known to date are given including the ⊿-values as a measure for the distortion of the octahedral coordination polyhedron.

2,2-Dichloro-triazaphosphinine (2) reacts with SbF 3 in the molar ratio 3:1 to give the mixed halogenated triazaphosphinine (3). New addition compounds 5 and 6 can be formed in the reaction of the zwitter ion 4 and amines or in the reaction of 2.2-difluoro-triazaphosphinine (1) with KCN. Phosphorus-boron-exchange is observed in the reactions of 4 or 2 with BF 3 · OEt 2 . The new C-B -N-heterocycles 8 and 9 are obtained. The gas-phase structure of 1 has been determined by electron diffraction. The scattering intensities are compatible with a planar ring conformation with C 2v symmetry and with equivalent NC bond lengths (PN = 1.579(10) Å, NC = 1.299(7) Å, NPN = 109.2(7)°, PNC - 118.1(9)°, CNC - 119.6(7)° and NCN = 127.5(12)°).

NaGaSn, (trigonal; P3 1 12 (No. 151); a = 632.8(4), c = 617.0(3) pm, Z - 1; d x = 5.33 g/cm 3 ) was grown from the melt. The crystal structure contains Ga and Sn atoms in a helical arrangement (six atoms per turn) along the c-axis direction. Interatomic bonding between neighbouring helices completes a distorted [2+2]-tetrahedral environment for every Ga/Sn position. The compound is classified in terms of the Zintl concept.

tert-Butyltriiodosilane (1) has been prepared in its pure form by heating tert-butylsilane (2) with iodine. Compound 1 has been characterized by elemental analysis as well as by spectroscopic methods.

3 different modifications of TbCl 3 were synthesized. TbCl, (UCl 3 -type), probably in a metastable state, crystallizes in space group P6 3 /m with a = 737.63(2) pm, c = 405.71(2) pm and Z - 2. TbCl 3 (PuB 3 -type) crystallizes in space group Cmcm with a = 384.71(6) pm, b = 1177.37(7) pm. c = 851.77(4) pm and Z = 4. h-TbCl 3 , the high temperature phase being stable above 790 K. crystallizes in space group P4 2 /mnm with a = 642.51(4) pm, c = 1177.14(18) pm and Z = 4.

(Cp)Mo(CO) 2 (tolN 5 tol) is formed in the reaction of (Cp)Mo(CO) 3 Cl with tolNN(NH)NNtol and NaOH in ethanol. It forms red platelike crystals from THF/hexane which crystallize in the monoclinic space group P2 1 /n with the lattice parameters a = 765.6(2), b = 2372.3(3), c = 1149.4(2) pm, β = 97.06(2)°, Z = 4. The structure consists of monomeric complexes. The pentaazadienido ligand chelates with its nitrogen atoms N1 and N3 the Mo atom of a (Cp)Mo(CO) 2 unit. The nitrogen atom N 5 is not coordinated to the metal atom. Although asymmetrically bonded, the all trans N 5 zig zag chain is planar. The N -N distances in the four membered chelate ring are nearly equal (N 1 - N 2 = 131.0 and N 2 - N 3 = 132.6 pm)

Reaction of [Fe(phen) 3 ]I 2 (phen = 1.10-Phenanthrolin) with Sbl 3 in acetonitrile leads to [Fe(phen) 3 ] 2 Sb 6 I 22 ·2CH 3 CN (1). The structure of 1 was determined from single crystal X-ray diffraction data. 1 crystallizes in the triclinic space group P1̄ with a = 1352.4(1). b - 1376.8(1), c - 1597.7(1) pm, α = 105.85(1). β = 92.09(1). γ = 97.94(1)°. Z = 1. The structure of 1 consists of isolated anions and cations. The centrosymmetric Sb 6 I 22 4- ion exhibits a double cube-like structure with Sb and I occupying alternating corners of the skeleton.

From geranylacetone and by the use of a variety of reagents, twelve analogues of the juvenile hormone III were synthesized. The compounds (5-16) have an isoprenic structure bearing at the extreme of the chain functional groups as carbonate, carbamate, thiolcarbonate, thiolcarbamate, carbonyloxyimino and thiol carbonyloxyimino. Compounds 5-9 present the normal unsaturated isoprenic chain while compounds 10-16 have a monoepoxide function. All the compounds were tested for their respective juvenile hormone activity for Triatoma infestans and Rhodniusprolixus. The most active compounds were those having a thiol carbonate group independently of the oxidation state of the molecule. The synthetic procedures and the biological results are discussed.

2-Pyrryl-(m-terphenyl)-carbinol and 2-pyrryl-(3,3″,5.5″-tetra-t-butyl-m-terphenyl)-carbinol are cyclized in acidic medium to the corresponding raeso-tetraarylporphyrins. The meso-tetraarylporphyrins are transferred to the iron and manganese complexes. The reactions of the iron porphyrins with OH - are studied and the products of these reactions are characterized.

The crystal structure of potassium nickel arsenate. KNiAsO 4 has been determined by high resolution powder neutron diffraction at 30 K. The unit cell of KNiAsO 4 is rhombohedral. space group R3̄, with hexagonal cell constants, a = 4.97208(2) (Å). c = 28.52606(10) (Å). The compound is isomorphous with NaNiAsO 4 .

The ratios of reduced and oxidized nicotinamide nucleotides (NADH/NAD + and NADPH/ NADP + ) were indirectly determined at various stages of cataractogenesis by estimating the concentrations of metabolites (lactate, pyruvate and malate) of the lens. The ratios of NADH/NAD + and NADPH/NADP + decreased significantly from immature to mature (P<.001, P<.05). to hypermature (P<.001, P<.05), to Morgagnian (Pc.001. Pc.001) and diabetic types (Pc.001, P < .001) of cataractous lenses respectively. Ratios of nicotinamide nucleotides in diabetic lenses were lower in comparison to those of other types studied. As the opacity progressed, the ratios decreased with increase in blood glucose levels.

The structure and absolute configuration of “cyclotirucanenol” a new triterpene isolated from Euphorbia tirucalli has been established as 24β-methyl-9β-19-cyclolanost-20-en-3β-ol through chemical and spectroscopic studies including 2D-NMR.

The structures of six ceramide-1-phosphoethanolamines have been elucidated which differ in the long chain base as well as in the fatty acid component

PPh 3 Me[HSO 4 ] was prepared by the reaction of (PPh 3 Me)I with silver sulfate in aqueous solution. OPPh 2 Me and benzene being the by-products. The title compound was characterized by its IR spectrum as well as by an X-ray structure determination (1730 observed independent reflexions, R = 0.043). Crystal data: a = 910.4(3). b = 1587.8(4), c = 1294.2(6) pm, β = 105.52(3)°. space group P2 1 /c, Z = 4. The structure consists of PPh3Me ⊕ cations and of HOSO 3 ⊖ ions that are associated via strong hydrogen bonds to dimeric centrosymmetric units.

The 1 H NMR spectra (in DMSO solution at 300 K) of retinoic acids (cis- and trans-isomers) and new arotinoids were run at 500 MHz and assigned by using homo- and heteronuclear two-dimensional (2D) chemical shift correlation experiments. Spectral analysis was indicating, on the basis of 7 values, that the ring C(l)-C(2)-C(3)-C(4)-C(5)-C(6) adopts, in all compounds, a chair conformation.