Volume 40, Issue 11

The new compounds K 2 CuP, NaZnP and K 4 CdP 2 have been prepared and structurally charac­terized. The crystallographic data are: K 2 CuP: orthorhombic, space group Cmcm (No. 63). Na 2 CuAs structure type with a = 983.9(5) pm. b = 739.7(4) pm, c = 579.5(3) pm. There are CuP 2- zigzag chains, which are isosteric to the chains in HgO. NaZnP: tetragonal, space group P4/nmm (No. 129). PbFCl structure type with a = 406.6(2) pm. c = 689.3(3) pm, c/a = 1.695. K 4 CdP 2 : monoclinic, space group C2/m (No. 12). New structure type with a = 984.0(5) pm, b = 568.1(3) pm. c = 957.5(5) pm. β = 110.0(1)°. There are discrete [P−Cu−P] 4- anions, which are isosteric to the HgCl 2 molecules.

Heptaphosphane(3) (1) is obtained pure by the reaction of (Me 3 Si) 3 P 7 with methanol and has been characterized NMR spectroscopically (in nascent state). It turned out to be a mixture of two diastereomers P 7 H 3sym and P 7 H 3asym , which differ in the spatial arrangement of the hydrogen atoms. Both isomers were proven to possess the earlier reported structure of a tri-cyclo[2.2.1.0 2,6 ]heptaphosphane, which in the case of P 7 H 3sym was ascertained by a complete analysis of its 31 P{ 1 H} NMR spectrum. As shown by the chemical shifts, the P 7 cage in P 7 H 3sym is clearly stretched compared with P 7 Me 3sym and (Me 3 Si) 3 P 7 .

Stibanes RSbHal 2 are reductivly coupled by interaction with Na 2 M 2 (CO) 10 (M = Cr, W) or Cp(CO) 2 MnTHF. The resulting distibanes RS̲b̲(Hal)-(Hal)S̲b̲R are coordinated to sixteen elec­tron L n M-fragments (L n M=M(CO) 5 , Cp(CO) 2 Mn). Both the meso and d/l stereoisomeres are structurally characterised by X-ray analyses.

Crystals of Rb 2 VOF 4 have been obtained under hydrothermal conditions. The crystal structure (orthorhombic, space group Pnma, a = 759.9(2) pm. b = 579.1(2) pm, c = 1193.8(4) pm, Z = 4, d c = 3.96 gcm -3 , d m = 3.90 gcm -3 , R = 0.019 for 655 independent reflections) shows infinite zig-­zag-chains of VOF 5 -octahedra along the b-axis, linked by cis-bridging F-atoms. Despite of orien­tational disorder, clear evidence for a trans-effect could be established: d(V−O) 165.8(2), d(V−F trans brjdge ) 221.1(1), d(V−F cis bridge ) 203.6(1), d(V-F terminal ) 185.2(2), 187.8(2), 193.2(2) pm.

Rb 2 Li 2 Si0 4 and Rb 2 Li 2 Ge0 4 were prepared from the binary oxides in closed Ni-tubes at 800 and 850 °C, respectively. Crystal structures of the isotypic compounds were determined from four-circle diffractometer data (2018 and 1509 I o (hkl), R = 8.37%, R w = 6.39% and R = R w = 13.68%). They crystallize triclinically, P1̄, a = 897.92(11), b = 564.73(5), c = 546.99(6) pm, α = 93.95(10), β = 111.24(9), γ = 93.75(10)° (Rb 2 Li 2 SiO 4 ) and a = 905.4(9), b = 575.4(7), c = 560.6(7) pm, α = 94.67(9), β = 110.82(10), γ = 93.60(9)° (Rb 2 Li 2 GeO 4 ) (Guinier-Simon-data). Z = 2. Effective Coordination Number (ECoN) and Madelung Part of Lattice Energy (MAPLE) values were calculated. The structure is described using Schlegel-diagrams.

The reactions of tri-t-butylphosphane 1 with selenium and tellurium proceed quantitatively with formation of seleno- and the telluro-tri-t-butylphosphorane. respectively (3, 4). Tri-t-butylarsane 2 reacts with selenium to give seleno-tri-t-butylarsorane (5), but no significant interaction is observed between 2 and elemental tellurium. 1 H and 31 P NMR spectra provide evidence for rapid tellurium transfer between telluro-tri-t-butylphosphorane (4) and tri-t-butylphosphane (1), tri-t-butylarsane (2) or tris(dimethylamino)phosphane. Selenium transfer between seleno-tri-t-butylarsorane (5) and tri-t-butylarsane (2) leads to 1 H and 13 C NMR line broadening. Vibrational spectra of t-Bu 3 E−Y (3: E = P, Y = Se; 4: E = P, Y = Te; 5: E = As, X = Se) indicate coupling of E−C and E−Y stretching vibrations in 3 and 4.

VBr 2 (N 3 S 2 ) was synthesized by reaction of VCl 2 (N 3 S 2 ) with Me 3 SiBr. It reacts with PPh 4 Br in dibromomethane solution to form (PPh 4 ) 2 [VBr 3 (N 3 S 2 )] 2 . The compounds were characterized by their IR and 51 V NMR spectra. The crystal structure of VBr 2 (N 3 S 2 ) was determined by X-ray diffraction (2060 reflexions. R = 0.114). Crystal data: triclinic, space group P1̄, a = 586.4, b = 794.2, c = 744.6 pm. α - 89.25, β - 108.58, γ = 99.67°. Z = 2. The vanadium atoms form planar, six-membered rings wjith the N 3 S 2 groups, with short VN distances (172 and 185 pm). Bromine- bridged dimers are associated via V−N links to form chains in a similar way as in some tetrahalides. The structure is similar to that of VCl 2 (N 3 S 2 ), but the chains are rotated by 17° along their axes.

The reduction potentials of 40 aromatic nitro compounds R π (NO 2 ) n with R π = benzene, naphthalene, anthracene, fluorene and carbazole and n = 1 to 4 nitro groups are determined by cyclic voltammetry in DMF under aprotic conditions. The perturbation by the strongly electron accepting substituents can be rationalized via correlation with HMO eigenvalues. Based on reversibility criteria, the electrochemical behaviour is discussed and the compounds are classified with respect to reversible or irreversible one-electron transfer as well as up to 4 (quasi)-reversible reduction steps. The CV data measured can be used to predict redox reactions of aromatic nitro compounds in inert solvents.

Sodium dimethylbismuthide, generated from dimethylbismuth bromide and sodium in liquid ammonia, was treated with alkyl halides to produce dimethylalkylbismuthanes, Me 2 Bi(alk) (alk = C 2 H 5 , n-C 3 H 7 , n-C 4 H 9 , C 3 H 5 , i-C 3 H 7 ) as thermolabile liquids in yields ranging from 70 to 90%. With methylene chloride bis(dimethylbismutho)methane, (Me 2 Bi) 2 CH 2 , was obtained. Aryldimethylbismuthanes, (aryl)BiMe 2 , were prepared by treating dimethylbismuth bromide in THF with elemental lithium (-78 °C) and subsequent reaction with aryl halides (aryl = 4-C 6 H 4 CH 3 , 4-C 6 H 4 OCH 3 , 2,4,6-C 6 H 2 (CH 3 ) 3 ). At 90 °C in an N 2 -stream, the thermolabile compounds react quantitatively to form diarylmethylbismuthanes, (aryl) 2 BiMe and Me 3 Bi.

The reaction of [dppmPtCl 2 ] (dppm = bis(diphenylphosphino)methane) with bis(alkynyl)-dimethylstannanes leads to monomeric complexes [dppmPt(C≡C−R) 2 ], 2 (R = H, CH 3 , C 4 H 9 t , C 6 H 5 ) in >90% yield. Rearrangement of 2 into the dimeric complexes 3, trans,trans- [Pt 2 (C≡C−R) 4 (dppm) 2 ] is catalyzed by traces of various phosphanes. All products are characterized by 1 H, 13 C, 31 P and 195 Pt NMR spectroscopy.

The iron(II) complexes FeX 2 [P(CH 2 CH 2 CH 2 PMe 2 ) 3 ] with X = CN (4), N 3 (5). and NCS (6) have been prepared by metathetical reaction of FeCl 2 [P(CH 2 CH 2 CH 2 PMe 2 ) 3 ] (1) with the corresponding sodium pseudohalide. Treatment of the dihalo compounds FeX 2 [P(CH 2 CH 2 CH 2 PMe 2 ) 3 ] (X 2 = Cl 2 (1). Br 2 (2), I 2 (3)) with LiAlH 4 gave the halohydro derivatives FeHX[P(CH 2 CH 2 CH 2 PMe 2 ) 3 ], where HX = HCl (7). HBr (8). and HI (9). Consistent with a cis-octahedral coordination geometry, the 31 P NMR spectra of 1−9 exhibit AMX 2 type splitting. The halohydro complexes 7−9 have also been studied by IR and 1 H NMR spectroscopy. 57 Fe Möβbauer data have been collected for compounds 1, 4, and 5.

Tricyclopentadienylneodymium and -lutetium react with sec-butyl lithium and terf-butyl lithium to form sec-butyl- and tert-butyl(dicyclopentadienyl)neodymium and -lutetium, which decompose to the corresponding dicyclopentadienyllanthanide hydride complexes. Dicyclopentadienyl-bis-(trimethylsilyl)methylsamarium and -lutetium are made from dicyclopentadienylsamarium or -lutetium chloride and bis(trimethylsilyl)methyl lithium. They react with hydrogen to form the corresponding dicyclopentadienyllanthanide hydride complexes.

A series of pentacyanoferrate complexes, Na 3 [Fe(CN) 5 L] ·nH 2 O, where L = (CH 3 ) 2 NH, (C 2 H 5 ) 2 NH, (C 2 H 5 ) 3 N, (C 3 H 7 ) 2 NH, (C 4 H 9 ) 2 NH, (C 4 H 9 ) 3 N and (C 6 H 5 ) 2 NH were studied by Mössbauer and infrared spectroscopy. All the complexes exhibited two line spectra with ⊿ E Q = 0.73-1.92 mms -1 and δ = −0.04−0.49 mms -1 (w.r.t. SNP) and can be divided into two groups with well defined parameters. Partial isomer shift and partial quadrupole splitting values were correlated with bonding characteristics.

Carbonyl(η 5 -cyclopentadienyl)(η 2 -4-methylphenylketenyl)trimethylphosphinetungsten reacts with decaborane(14) under conversion of the η 2 -ketenyl into a η 2 -alkyne complex. Reaction conditions, spectroscopic data and the X-ray structure of the new compound are reported.

In magnesium as well as in aluminium derivatives of anthracene (1−4, 8) and its trimethylsilyl derivatives (5, 6 and 11), the metals occupy the axial positions at C9 and CIO, to form five-, seven- or ten-membered metallacycles, respectively, in 1−3, 5, 6 and 11. It appears that the metalla-ring size, and thus the coordination geometry of the bridging metal is of influence upon the chemical behaviour.

Methylphenyl oxadithia and trithiastannocane have been synthesized from MePhSnCl 2 and the respective disodium dithiolate. The crystal structure of the oxadithiastannocane has been deter­mined (R = 0.0535). The coordination geometry is midway between a tetrahedron and a trigonal bipyramid (equatorial Sn−S 241.4(3) and 240.5(3). Sn−Me 212.7(8) pm; axial Sn−Ph 215.0(6). Sn···O 267.6(6) pm). By using the bond angles this coordination case is inserted in a series of analogous compounds and compared with vibrational data.

The structure of the dinitrone formed on reaction of nitrosobenzene with 1,4-benzoquinone has been confirmed by spectroscopic measurements. An electron transfer radical-anion mechanism is suggested to account for its formation.

The bulk of the radiation-induced degradation products of 2′-deoxyguanosine in oxygen-free aqueous solution have been separated by high performance liquid chromatography and charac­terized by various spectroscopic techniques including fast atom bombardment mass spectrometry, 1 H NMR and circular dichroism. The two main decomposition products result from the opening of the imidazole ring and further rearrangement of the sugar moiety. In addition, the formation of six other nucleosides was shown to involve sugar radicals with subsequent epimerization, re­arrangement or cyclization reactions.

The syntheses of 3, 4a, 4b by reaction of Methylenebis(dichlorphosphane) (1) with silylated substituted ureas are described as well as their spectroscopic properties; an X-ray structure analysis of 3 is reported.

Malononitrile reacts with ethyl cyanoacetate to give a polyfunctional substituted pyridine derivative 5. The latter compound reacts with aniline, hydrazines and aromatic aldehydes to give condensated products. The active methylene of 5 couples with benzenediazonium chloride to give the phenylhydrazone derivative which cyclises readily to give a pyrido[2,3-d]pyridazine deriva­tive. 5 reacts with trichloroacetonitrile, and carbon disulphide to give fused heterocyclic deriva­tives.

The Dichlorination of methyl isoeverninate 7a gave the geminal dichloroketone 12 as the major product. The title compound 1 was therefore synthesized via dichlorination of 4-protected methyl orsellinate 5a using the pivaloyloxy-function as a new protecting group in resorcyclic acids chemistry.

Reactions of L-arabinose, D-xylose. D-galactose and D-glucose with N-methylaniline and its p-methyl and p-methoxy derivatives were studied in methanol, in the presence and absence of an acidic catalyst, by employing the thin-layer chromatographic technique. Appropriate N-aryl- N-methyl-N-glycopyranosylamines found in the products underwent rapid transformations in the reaction medium.

Various alkyl- or aryl-substituted N-(1-indanyl)-pyridinium perchlorates present evidence for restricted rotation around the C(sp 3 )-N + (sp 2 ) single bond giving rise to chiral rotamers as shown by their 1 H NMR spectra.

Spin labeled EDTA, CDTA and DTPA chelating agents and their gadolinium complexes were synthesized and evaluated for their effects on the spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation times of water, plasma, and blood. It was found that the spin labeled chelating agents are effective proton relaxation agents. Although, the gadolinium complexes of these agents have superior relaxation properties, the differences in relaxivitv between the spin labeled complexes and the non-spin labeled gadolinium complexes are marginal. The spin labeled agents and their gadolinium complexes are expected to be very useful in designing paramagnetic conjugates with biomolecules. In particular, the latter type possesses high proton relaxivity combined with a nitroxvl marker which can be followed pharmacokinetically by EPR.

From the culture medium of Pseudomonas putida three pyridine derivatives were isolated which contain the (methoxythio)carbonyl (CO−S-OCH 3 ) group thus far not described in the literature. Characterization and structure elucidation are reported.

Cyclic mononucleotides − 2′,3′ cAMP and 2′,3′ cGMP − were found in several higher plants. They seem to be widespread, naturally occurring compounds. 2′ AMP, 3′ AMP, 2′ GMP and 3′ GMP, which were also isolated from several plants, are possibly artifacts of the cyclic nucleo­tides. In small amounts ApA was isolated from Abutilon grandiflorum, UpA and UpG from Mimosa pudica L. The biological influence of 2′,3′ cAMP and 2′,3′ cGMP on the nyctinastic leaf movement was tested. There is some evidence that both substances shift and dampen the circadian rhythm of Albizia lophanta.

The synthesis of Substance P (SP) bound at the C-terminal methionine to polyethylene glycol monomethyl ether (M-PEG) is described. SP-PEG-M is obtained in good yield by the liquidphase peptide synthesis. Gel permeation chromatography reveals that aggregated forms of the PEG-bound peptides are absent in CHCl 3 . CD and IR spectra point to a β-turn located at the N-terminal part of SP-PEG-M. In binding studies and in vivo assays the described compounds are devoid of biological activity.

4-Cyano- and 4-Carbomethoxy-3,4-dihydro-2H-l,5-benzodioxepin-3-one (1a and 1b) have been converted to the corresponding enol-toluenesulfonates 2a and 2b, respectively. Reaction of 2a and 2b with base led to the heterocyclic allenes 3a resp. 3b, which could be trapped by Diels-Alder-reaction with furane, yielding the cycloadducts 4a and 4b.

Reaction of the acid chlorides X 1 X 2 X 3 CC(O)CI (1ax-bz) with the silylphosphanes Me 3 SiPR 2 (2a, b) [R = 4-CH 3 C 6 H 4 (a), c-C 6 H 11 (b)] results in the for­mation of the mono-, di- and trichloroacetylditolyl- and -dicyclohexylphosphanes X 1 X 2 X 3 CC(O)PR 2 (3ax-bz). 3bx-bz are thermally unstable and decompose at 20 °C to give ClP(c-C 6 H 11 ) 2 . Stereochemical effects cause the 31 P signal in the spectra of the series 3 ax-az and 3bx-bz to shift to higher fields with increasing content of chlorine in the acetyl group.

Salts of the types (NR 4 ) 2 S 2 O 8 and NR 4 HSO 5 can be prepared easily by ion pair extraction. The lipophilicity of persulfate anions is classified. Phase transfer catalyzed peroxodisulfate oxidation of 2,6- disubstituted phenols yields diphenoquinones.

Four novel spin labeled azacrown ethers contain­ing either endo- or exo-cyclic nitroxyl moieties were synthesized by short and convenient routes. These compounds should be of interest in biological studies of membranes using ESR spectroscopy.

Hydrophosphorane 1 reacts with elementary sul­fur in the presence of triethylamine to yield phosphorane sulfide 4 which is converted by hydrogen chloride into the corresponding acid, thiohydroxy- phosphorane 5. The X-ray structure determination exhibits an almost undistorted trigonal bipyramide, the five membered rings in axial/equatorial positions and the hydrogen in close contact to one axial oxygen.

Chlorodiphenylphosphane and triethylammonium perfluoropinacolate yield the monocyclic hydrophosphorane 3. The X-ray structure analysis reveals that hydrogen is bonded in the axial position of a trigonal bipyramide. With dimethyl sulfoxide 3 undergoes a ring opening reaction to give phosphinate 5.

A reinvestigation of Iphiona mucronata gave in addition to the known compound a new dehydrothymol derivative. Its structure was determined by spectroscopic methods.