Volume 39, Issue 2

The new compound SrSb 4 S 7 · 6 H 2 O crystallizes in the monoclinic system, space group P2 1 /n with lattice constants a = 2765,4(8) pm, b = 731,5(3) pm, c - 897,2(3) pm, ß - 90,4(1)°. In the structure there are anionic (Sb 4 S 7 2- ) ∞ -strings, which are arranged parallel in sheets and separated by the hydrated Sr 2+ ions

Single crystals of ReCl 5 • OPCl 3 were obtained by cooling a saturated solution of rheniumpentachloride in phosphorylchloride. It formes black needles, which are extremely sensitive to moisture. In the IR spectrum ν(PO) is shifted downwards by 140 cm -1 in comparison with liquid POCl 3 , indicating coordination via oxygen. The crystal structure was solved and refined from Xray diffraction data (space group Pnma, four formula units per unit cell, a = 1629, b = 790, c = 877 pm, 902 observed, independent reflexions, R = 0.040). The complex forms discrete molecules ReCl 5 • OPCl 3 , with symmetry C s (m). Bond lengths are Re -O - 214 pm and P-O = 146 pm, the angle Re -O -P is 143°

The reaction of o-phenylenebis(dichlorphosphane) (3) with Lil in benzene gives 1,2,5,6- tetraphospha-3,4-7,8-dibenzo-2,6-diiodo-bicyclo[3,3,0]octane (4a), whose structure is reported. The bicyclus is also characterized by elemental analysis, 1 H NMR, 31 P NMR, IR, mass spectroscopy

The phosphorus pseudohalogens P(CN) 3 , P(NCO) 3 and P(NCS) 3 react with (η 5 -C 5 Me 5 )Co(CO) 2 to give the complexes (η 5 -C 5 Me 5 )Co(CO)XPX 2 (X = CN, NCO, NCS). All the compounds are characterized by elemental analysis, IR. electronic and 1 H NMR spectra

The compound S 2 N 2 • 2AlBr 3 has been prepared by reaction of S 4 N 4 with AlBr 3 in 1,2-dibromoethane at room temperature. Its crystal and molecular structure have been determined by X-ray diffraction; R = 0.068. Crystal data: monoclinic, P 2 1 /n, a = 9.594(5), b = 9.975(4), c = 7.528(4) Å , β = 111.36(5)°. The S 2 N 2 ring of the centrosymmetrical complex is bonded via its nitrogen atoms to two AlBr 3 units thus completing coordination tetrahedra around the Al atoms. Bond distances and angles within the S 2 N 2 ring are d(S-N) = 1.629(13) and 1.651(13) Å, ∢ (S-N-S) = 95.8, and ∢ (N-S-N) - 84.2°. Whereas the S-N bond lengths agree closely with those of free S 2 N 2 , the angle at N is enlarged by ca. 5° and the angle at S is decreased by ca. 5°. The sulfur atoms form two close S···Br contacts of length 3.149 (intramolecular) and 3.193 (intermolecular) Å , respectively. The intermolecular attractive nonbonded S···Br interactions tie the complexes together in a way that leads to infinite chains which run parallel to the crystallographic z axis

N-Methylpyridinium-triiododicuprate(I), C 6 H 8 NCu 2 I 3 , methyltriphenylphosphonium-tetraiodotricuprate( I), (C 6 H 5 ) 3 CH 3 PCu 3 I 4 and tetrapropylammonium-tetraiodotricuprate(I), (C 3 H 7 ) 4 NCu 3 I 4 were obtained by reacting Cu with I 2 and C 6 H 8 NI, (C 6 H 5 ) 3 CH 3 PI or (C 3 H 7 ) 4 NI in acetone. The crystal structures of these compounds are built up by the cations and isolated chains of edge or face sharing Cul 4 -tetrahedra: [C 6 H 8 N ] + 1 ∞ [(CuI 2/2 I 2/4 ) - , [(C 6 H 5 ) 3 CH 3 P] + 1 ∞ [(CuI 1/2 I 2/3 I 1/4 ) 2 (CuI 2/3 I 2/4 )] - and [(C 3 H 7 ) 4 N] + 1 ∞ [(CuI 3/3 I 1/2 ) 2 (CuI 3/3 )] - . There are very short Cu···Cu distances of 246.1(5) and 250.3(5) pm in (C 3 H 7 ) 4 NCu 3 I 4 produced by face sharing of Cul 4 -tetrahedra

The impedance of teflon bonded electrodes was measured in the frequency domain. These electrodes based on activated carbon as electrocatalyst were developed for fuel cell applications. When feeding the electrode with air or oxygen the impedance spectra could be explained by two Nernst diffusion processes and a small charge transfer process. Two methods for separating the measured impedance into partial impedances related to different steps of the electrode reaction are presented. A least square fit procedure is described which has been applied successfully to the impedance analysis of porous electrodes

4,6-Di-tert-butyl-1,2,3-benzodithiazolium-chloride (1) reacts with Ph 3 P=NSi(CH 3 ) 3 (2) or Na[N(Si(CH 3 ) 3 ) 2 ] (3) in the presence of oxygen to yield 3,3',5,5'-tetrakis-tert-butyl-2,2'-bissulfinyl- amino-1,1'-diphenyl-disulfide (4), which was characterized by X-ray structure determination. Crystals of 4 are triclinic, space group P1, with a = 1043.6(4), b = 1088.8(7), c - 1451.5(7) pm, a - 76.69(5), β = 80.67(3) and γ = 77.91(4)°

The metal carbonyl hydrides HM(CO) 3 (π-C 5 H 5 ) (M = Mo, W), HMn(CO) 4 L, HCo(CO) 3 L (L - CO, PPh 3 ) react with aziridines by protonation of aziridine, nucleophilic attack of the corresponding carbonyl metallate and CO insertion to give the β-aminoacyl complexes 2-7. The ring opening of C-substituted aziridines is regiospecific. With alkyl substituted aziridines the nucleophilic attack of the carbonyl metallate occurs at the sterically less hindered carbon atom, with phenyl substituted aziridines at the phenyl substituted carbon atoms. From the reactions of HM(CO) 3 (π-C 5 H 5 ) with optically active aziridines, which afford complexes with an asymmetric metal atom, only one diastereomer could be observed. The mechanism of these reactions is discussed and the spectral data (IR, 1 H NMR, MS) of the complexes are reported. β-Aminoacyl complexes have also been obtained by addition of amines to [(π-C 5 H 5 )(CO) 3 M(alkene)] + BF 4 - (M = Mo, W). The methyl complex H 3 CMn(CO) 5 reacts with aziridine to give the acetyl complexes H 3 CC(O)Mn(CO) 4 (aziridine) and H 3 CC(O)Mn(CO) 3 (aziridine) 2 , respectively

Nickel(0) complexes of diazadienes (dad = RN = CR' - CR ' = NR ) catalyse the trimerization of esters of 2-butynoic acid, phenylpropynoic acid and butynedioic acid to give hexasubstituted benzenes with the unsymmetrical esters 2 as the main products. A primary adduct 7 of acetylene dicarboxylic acid dimethyl ester of the type (dad)Ni(alkyne) could be isolated and characterized by 1 H NMR, IR and UV spectroscopy. According to their characteristic CT absorption. 7 and its analogues are shown to persist during catalysis as an active species

Three compounds of the type Ti[M B (CN) 6 ] (M B = Co, Rh, and Ir) have been synthesized and characterized by means of their X-ray diffraction powder patterns, magnetic measurements, infrared, electronic, and X-ray photoelectron spectra. All compounds crystallize in the facecentered cubic system and form a three-dimensional framework of two octahedral coordination units M B C 6 and TiN 6 . Upon the formation of Ti[M B (CN) 6 ] from the corresponding potassium salt, the π back-donation in the [M B (CN) 6 ] 3- moiety is enhanced by the bridge formation through the cyanide ligand

Pure isomers of X n B 12 H 12-n 2- ; X = Cl, Br, I are isolated by ion exchange chromatography on diethylaminoethyl cellulose. The structures are determined by 11 B and 11 B { 1 H}NMR spectroscopy. With X = Cl, Br the signal of ipso-B atomes is shifted to lower, with X = I to higher field compared with B 12 H 12 2- . The resonances of B-atoms influenced by the antipodal effect are observed at high field, increasing within the series I<Br<Cl. The chemical shifts are explained by the anisotropy effect and by the paramagnetic term due to different -I and +M effects of the halogens. In agreement with theoretical predictions the substitution of B 12 H 12 2- with chlorine proceeds successively at vicinal positions B(1) -B(2) -B(3). The IR and Raman spectra of 1-XB 12 H 11 2- show in the region 175 - 380 cm -1 two characteristic bands shifting to lower frequencies in the series Cl, Br, I and are therefore assigned to (B 12 ) -X stretching and (B 12 ) -X bending modes, respectively

The title compound C 12 H 49 Cl 4 I 2 N 8 O 16 Pt 2 , Mr 1314.1, is monoclinic P 2 1 (from structural analysis), a = 8.74(1), b = 11.36(1), c = 8.63(1), β = 107.6(5), V = 817 Å 3 , Z = 1, D m (flotation) = 2.65 g cm -3 , D c = 2.66 g cm -3 , MoK ɑ λ = 0.71069, μ = 110.7 cm -1 , R = 0.063 for 1068 observed reflections. Rotation photographs show diffuse patterns corresponding to odd values of k together with weak Bragg reflections. Refinement of diffractometer data was carried out in space groups Pm, P2 1 /m and P2 1 ; both refinement in Pm and P2 1 give satisfactory agreement and lead to very similar crystal structures

The compound [N(CH 3 ) 4 ] 2 NaFe(CN) 6 • H 2 O crystallizes in the orthorhombic space group Pnma, Z = 4, a - 1863.9(2), b = 861.7(1), c - 1317.2(2) pm. The X-ray single crystal structure determination (2515 reflections, R - 0.04) revealed an elpasolite-related framework of slightly deformed Fe(CN) 6 3- octahedra, the mean distances in which are Fe-C = 194.0 and C-N = 113.9 pm. The strongly distorted octahedral N 6 cavities formed by six Fe(CN) 6 3- units are occupied by monohydrated sodium ions, exhibiting a very short distance Na-O = 221.8(3) pm. By approach to one of the octahedral faces within their N 6 environment the sodium ions obtain a distorted tetrahedral NaON 3 coordination, Na-N = 2 x 238.0(3) and 241.3(3) pm. One of the compound’s two tetramethylammonium ions, which are centered at mirror planes, is orientationally disordered. The reason for this is discussed

New 6π-tricarbonylchromiumpyrnftne complexes 5c and 5d could be synthesized from 2,6-di-rbutyl- and 2,4,6-tri-f-butylpyridines (3c and 3d) with chromium hexacarbonyl. They are characterized by their 1 H and 13 C NMR Spectra and their CO-frequencies which are rather similar to those of 6π-tricarbonylchromium-2,4 ,6-triphenyl [1] or 2,4,6-trw-butyl- [2] λ 3 -phosphorins. When 5d is reacted with lithiumphenyl, the phenyl residue adds to C-4, giving probably compound 7, which by methanolysis and allyl rearrangement of the hydrogen atom from position 4 to position 2 affords tricarbonylchromium-2,6-di-f-butyl-4-phenyl-1,2-dihydropyridine (8) in 56% yield. The 6π-tricarbonylchromium complexes of 2,4,6-triphenyl- or 2,4,6-tn-t-butyl-λ 3 -phosphorins react with lithiumorganic compounds by addition only to the phosphorus atom whose reaction with methyliodide lead to tricarbonylchromium-λ 5 -phosphorin-ylid complexes [2], 5 d is a well crystallized compound, the X-ray analysis of the first 6π-tricarbonylchromium pyridine derivate could be performed [3] and compared with the results of the X-ray analysis of 6π-tricarbonylchromiumx 2,4,6-triphenyl-λ 3 -phosphorin [4]

Based on single crystal X-ray diffraction data the crystal structure of tricarbonyl(2,6-dwmbutyl- pyridine)chromium(0) has been determined at 200 K: space group P 2 1 /n, Z = 4, lattice constants a = 680.6(5), b - 1383.3(10), c = 1763.0(16) pm, β = 96.53(8)°, refinement to R w - 0.048 for 1672 independent reflections with F O > 2 σ. The chromium atom is η6π6- bonded to the essentially planar pyridine ring (Cr-C: 219-222 pm, Cr-N: 221 pm). The CO ligands show “eclipsed” orientation with respect to the 2, 4 and 6 position of the pyridine ring. Two CO groups fit into the gaps formed by two methyl groups of the tert-butyl substituents in 2 and 6 position, respectively. The results are discussed in context with related arene and λ 3 -phosphorine complexes

A product study has been made of the γ-radiolysis of aqueous methane solutions that also contained nitrous oxide and oxygen. Formaldehyde (G = 2.8), hydrogen peroxide (G = 2.1), methanol (G = 1.5), methylhydroperoxide (G = 0.8), formic acid (G = 0.3), and dimethylperoxide (G = 0.1) were found. In alkaline solutions (pH 8, 10 -3 M phosphate buffer), the formaldehyde yield rises to G = 3.2, while the formic acid yield falls to almost zero (G = 0.05). The initial precursor of the carbon-containing products is the methylperoxyl radical. The methylperoxyl radicals decay through a short-lived tetroxide along various pathways. The most prominent one leads to formaldehyde, methanol and oxygen. Methoxyl radicals (and oxygen) are also formed and, after rearrangement into hydroxymethyl radicals and their conversion into hydroxymethylperoxyl radicals, eventually yield formic acid and probably further formaldehyde. A route to formaldehyd and hydrogen peroxide is also envisaged. Methylhydroperoxide is formed in the reaction of methylperoxyl radicals with HO 2 /O 2 ·̄ radicals (from radiolytic H atoms and the unimolecular decay of the hydroxymethylperoxyl radical)

Azidometal(III) porphyrins, e.g. M(TTP)N 3 1 Aa-1 Ca (M = Cr, Mn, Fe), are transformed into nitrido complexes on irradiation with ultraviolet light. Thus, Cr III or Mn III complexes, e.g. Cr(TTP)N 3 or Mn(TTP)N 3 , yield Cr v and Mn v complexes with terminal nitride ligands, e.g. Cr(TTP)N (1Ab) or Mn(TTP)N (1Bb) with concomitant liberation of 1 mol of N 2 . However, the Fe III complex Fe(TTP)N 3 produces the mixed-valence ,μ-nitrido-bis[iron(III,IV)] complex, [Fe(TTP)] 2 N (1Cg) and about 1.2 mol of N 2 per mol of Fe. The azidometal(III) porphyrins are prepared from the corresponding hydroxo- or μ-oxo-metal(III) porphyrins and hydrazoic acid in benzene

The fluorescence spectra of 42 hydroxy- and methoxyflavones in methanol solution have been investigated. The following findings are considered to be useful in structure elucidation and identification of flavonoids: (a) The maxima of the absorption and fluorescence bands give, in most cases, a unique combination; (b) flavones exhibit exceptionally large Stokes’ shifts (6,800 to 10,000 cm -1 ); (c) most flavones fluoresce blue, but flavonols fluoresce yellow or green; the fluorescence of flavonols consists frequently of two bands; (d) fluorescence is zero or very weak for 5-hydroxyflavones; (e) 5-hydroxyflavones become increasingly fluorescent with in increasing number of oxygen functions being present in the molecule; a 3-hydroxy group has a particular beneficial effect; (f) hydroxyflavones fluoresce less intense than the corresponding m ethoxyflavones; (g) fluorescence intensity is distinctly higher in polar protic than in apolar solvents. The effects of three groups of shift reagents on the spectra has also been investigated. The first group involves water, 10% and 50% sulphuric acid. The second group consists of basic reagents (sodium acetate, sodium hydrogen carbonate and sodium carbonate), and the third group of com plexing reagents such as aluminum trichloride, borax and magnesium sulphate. The following generalisations may be made: (a) Water causes a bathochromic shift in emission with 7-hydroxyflavones, but a hypsochromic shift with flavonols; (b) 50% sulphuric acid is able to protonate (and thus to longware-shift the em ission maximum) of all flavones except for the 3-, 5-, and 8-hydroxy isomers; (c) sodium acetate and hydrogen carbonate cause characteristic shifts with 7-hydroxyflavones and, occasionally, with 4 '-hydroxyflavones lacking a 7-hydroxy group; (d) aluminum trichloride produces a longware shift and an enorm ous increae in fluorescence intensity with flavonols; (e) borax can be used to detect sensitively the presence o f a 3 ',4 '-dihydroxy group

The absorption and fluorescence maxima of 20 isoflavones have been determined in methanol solution and the effect of addition of water, 50% sulfuric acid, aluminium trichloride, borax, sodium acetate, ammonia and sodium hydroxide has been studied. The following findings may be useful in the structure elucidation of naturally occurring isoflavones: (a) 5-Hydroxyisoflavones have band I absorption maxima around 335 nm. 6-hydroxyisoflavones between 310 and 330 nm, and others below 310 nm. (b) Addition of water produces practically no shift in the absorption spectra, but - unlike other hydroxyisoflavones - can give distinctly longwave shifted new fluorescence bands with 7-hydroxyisoflavones. (c) Addition of sodium acetate gives rise to anion absorption of 7-hydroxyisoflavones and to partial anion absorption of 6-hydroxyisoflavones; the spectral maxima of 5-hydroxyisoflavones remain practically unchanged, (d) Ammonia gives rise to anion absorption of both 6- and 7-hydroxyisoflavones, but not of the 5-hydroxy isomers, (e) Sodium borate is a useful reagent to identify 6,7-dihydroxyisoflavones by virtue of its ability to form a chelate complex with an absorption maximum that is different from the anion absorption, (f) Aluminium trichloride forms complexes with both 5-hydroxy- and 6,7-dihydroxyisoflavones with distinct absorption maxima, (g) 5,7-D ihydroxyisoflavones may be recognized by addition of ammonia, which does not result in a longwave shift, but rather in an intensification of the longwave absorption band, (h) 6-H ydroxyisoflavones can be differentiated from the 7-hydroxy isomers by their longwave shifts (4 0-60 nm) following addition of ammonia. The respective shifts of the 7-hydroxy isomers are smaller, (i) 5-H ydroxyisoflavones are practically non-fluorescent. while others have fairly strong fluorescences, (j) The absorption and fluorescence maxima of isoflavones give unique combinations which may be useful in their identification, (k) Addition of aluminium chloride makes the non-fluorescent 5-hydroxyisoflavones fluorescent. (1) As in the case of absorption, 6,7-dihydroxyisoflavones form complexes with borate possessing fluorescence bands with maxima different from those of the anion bands

Desapogossypolone tetraethyl (2b), a degradation product of gossypol (1), was obtained in a simple way by oxidative coupling of 6,7-diethoxy-4-methoxy-1-naphthol (7c) and C-methylation with diazomethane

Hydrogenobalam in (metal-free vitamin B 12 ) and cupribalamin are characterized by their fast atom bombardment (FAB) mass spectra which show molecular ion and characteristic fragment ion peaks. These spectra and the high-resolution FAB mass spectrum of cobalamin (vitamin B 12 ) show that the (M+H) + -CN-59 peak for the latter is due to loss of acetamide and not of the central cobalt atom. In the FAB mass spectrum of cupribalamin metal clusters are observed

2-Amino-5-nitro-6-(1'-D -ribityl)amino-4(3H)-pyrim idinone (6a) was converted to the dimethoxytrityl derivative, which was subsequently acetylated. The trityl residue was then removed, and the com pound was phosphorylated by the cyanoethyl method. Removal of the protecting groups yielded 2-am ino-5-nitro-6-(1'-D -ribityl) aminopyrimidinone 5'-phosphate (11a). Catalytic hydrogenation yielded the labile 2,5-diam ino-6-(T -D -ribityl) amino-4(3H )-pyrimidinone 5'-phosphate (3a) which is the substrate for a deaminase from yeast. 5-Amino-6-(1'-D -ribityl) amino- 2,4(1 H ,3H )-pyrim idinedione 5'-phosphate (3b) was prepared by an analogous sequence of reactions. It was further converted to 6,7-dimethyl-8-(1'-D -ribityl) lumazine 5'-phosphate (12b). The phosphoric acid esters prepared by the present procedures contained about 20% of an undesired isomer as a consequence of insufficient selectivity of the tritylation reaction

AsPh 4 [OsO 4 ] is prepared by reaction of OsO 4 with AsPh 4 I in CH 2 C 12 solution. According to the IR spectrum , the [OsO 4 ] ⊖ ion adopts a distorted tetrahedral structure. The reciprocal magnetic susceptibility displays linear temperature dependence in the range of 4.2 to 140 K (μ eff ( = 1.25 B.M., 0 - 2.6°). The results of cyclo-voltammetric measurements are in accordance with a reversible oneelectron process OsO 4 /OsO 4 ⊖ ; the redoxpotential was found to be 104(2) and 100(3) mV resp. versus SCE

Osmium pentachloride reacts with NO forming the complex NO [Os(NO)Cl 5 ], which when treated with (PPh 3 Me)Cl yields PPh 3 Me[Os(NO)Cl 5 ] and nitrosyl chloride. The thionitrosyl complex AsPh 4 [Os(NS)Cl 5 ] is prepared by the reaction of OsCl 5 • POCl 3 with trithiazyl chloride, followed by the reaction of the resulting complex [Os(NS)Cl 4 • POCl 3 ] with AsPh 4 Cl. The complexes are characterized by their IR spectra

The preparation of cyanide containing phthalocyaninatoiron(II) or -iron(III) derivatives either with terminal or bridging cyanide is described. With help of the C≡N valence frequency (IR) and the magnetism of the compounds the oxidation state of the iron is determined. Thermoanalytical and electrical conductivity data are reported