Volume 36, Issue 1

The electrochemical synthesis of iron, cobalt, and nickel carbonyl compounds from metal acetylacetonates of oxidation state + II or + III and from metal anodes is described, solvent effects and the problem of cluster formation are discussed.

The electrochemical synthesis of iron, cobalt, and nickel carbonyl derivatives with phosphane ligands from metal anodes is described.

BaSe 2 crystallizes with a monoclinic cell, a = 9.820(5), 6 = 4.929(3), c = 9.335(5) Å, β= 118.48(5)°; Z = 4, space group C 2/c. BaSe 3 is tetragonal, a = 7.2802(5), c = 4.2495(4) Å; Z = 2, space group P4̄2 1 m. Both polyselenides are isotypic with the corresponding poly sulfides.

In the presence of small amounts of solid sodium hydroxide, [2,2-dimethyl-l-(trimethylsiloxy)propylidene]-trimethylsilylphosphine reacts at + 20 °C to give hexamethyldisiloxane and 2,2-dimethylpropylidynephosphine (2). In contrast to similar alkylidynephosphines this compound is stable at room temperature. The IR and mass spectrum are discussed, and 1 H, 13 C and 31 P NMR spectral data are given.

The IR and NMR spectra of the complexes [M(CO) 6 ]Cl · HCl (M = Mn: 1, M = Re: 2), M(C0) 5 C0 2 Et (M = Mn: 3, M = Re: 4), [Mn(CO) 5 PR 3 ][PF 6 ] (5; PR 3 = PPh(OPh) 2 : a, P(n-Pr) 3 : b, PHPh 2 : c, PPh(NEt 2 ) 2 : d, P(p-C 6 H 4 F) 3 : e), [Re(CO) 5 PHPh 2 ][PF 6 ] (6 c), Mn 2 (CO) 8 (PR 3 ) 2 (7) and Re 2 (CO) 8 (PHPh 2 ) 2 (8c) are discussed in the context of σ-and π-interactions in the metal-ligand system and compared with 51 V NMR data of the analogous isoelectronic and isostructural carbonylvanadates (-I). On the basis of these results, the phosphines are arranged in the order of decreasing integral ligand strength according to a>b>c>d. The 55 Mn shielding of 5 is greater than that of 1, which is explained by strong σ-interactions and correspondingly large e-a 1* splitting dominating the paramagnetic deshielding term in the pseudooctahedral complexes of type 5. The only rhenium compound accessible to NMR is 2, for which the 185 Re and 187 Re resonances were obtained. 31 P coordination shifts are positive for all complexes. Spectroscopic data for 7c show that this complex presumably has the structure (CO) 5 Mn-Mn(CO) 3 (PHPh 2 ) 2 , contrasting 7a, 7b, 7d and 7e (local D 4d symmetry).

The new oxide pnictides Ba 2 Mn 2 Sb 2 O and Ba 2 Mn 2 Bi 2 O crystallize in the hexagonal system (space group P6 3 /mmc) with the following constants: Ba 2 Mn 2 Sb 2 O: a = 471 ± 1 pm, c = 2004 ± 2 pm, c/a = 4.255, Ba 2 Mn 2 Bi 2 O: a = 480.3 ± 0.5pm, c = 2009.7 ± 1.0pm, c/a = 4.184. The Mn and Sb(Bi) atoms form corrugated hexagonal nets. These nets are bridged between the Mn atoms by O atoms to double layers separated by Ba atoms.

Solutions of LiAlH 4 in tetrahydrofuran (THF), glycoldimethylether (monoglyme), diglycoldimethylether (diglyme) and triglycoldimethylether (triglyme) as well as solutions of LiAlH 4 /THF in toluene have been investigated by 7 Li and 27 Al NMR. It was found that δ 27 Al is nearly independent of the solvent as is 1 J(AlH). However, the line width of the 27 A1 NMR signal shows strong solvent influences and, in addition, concentration and temperature dependence. Intermolecular hydride exchange becomes rapid in solutions of monoglyme and triglyme at room temperature. This can also be shown by the H/D exchange between LiAlH 4 and LiAlD 4 . δ 7 Li data indicate that Li is hexacoordinated in the series of glycoldimethylethers, and LiAlH 4 in diglyme seems to be the system in which the AlH 4 moiety is least affected by ion pair or triple ion formation.

Bis(2,4-pentanedionato) Copper(II) reacts with some oxygen donor organic solvents to form addition complexes with general formula, Cu(2,4-pentanedionato)2. L (where L = MeOH, EtOH, Pr i OH, Bu t OH, THF, MeCOMe, MeCOEt and MeCOPr n ). The complexes were recrystallized and characterized by the elemental analyses, infrared and electronic spectra, molecular weight and magnetic measurements.

Tris(diethylphosphitoborane) (2) can be synthesized by the reaction of BF 3·O (C 2 H 5 ) 2 with sodium diethylphosphite. The chemical behaviour of this new compound and its NMR data are reported.

A systematic study of the cleavage of element-element bonds in compounds of the type R n E-ER m (R = CH 3 , CF 3 ; E = P, As, S, Se, Te; n,m = 1, 2) by the group IV A element hydrides Me 3 M′H (M′ = Si, Ge, Sn; Me - CH 3 ) has been carried out. To evaluate the reaction pathway, for a number of compounds the attack of H 2 O, CH 3 OH, HBr and HI has been investigated. Possible reaction intermediates have been synthesized by independent routes and tested under comparable conditions.

The darkred compound SbCl 3 · I 2 · S 2 C 4 H 8 has been prepared and its crystal structure determined. This new compound crystallizes in the monoclinic system, space group P2 1 , with a = 849.2 pm, b = 904.2 pm, c = 923.6 pm and β = 106.1° at a temperature of 113 K, and with a = 858.8(2) pm, b = 914.7(3) pm, c = 934.0(4) pm and β = 106.62(3)° at a temperature of 293 K, respectively. The structure is built up from chains (SC 2 H 4 S ··· I-I-ClSbCl 2 )∞ with a ψ-trigonal bipyramid around Sb.

A series of compounds Na 3 [Fe(CN) 5 RNH 2 ] · nH 2 O where R = -H, -CH 3 , -C 2 H 5 , n-C 3 H 7 , n-C 4 H 9 and -CH 2 C 6 H 5 and RNH 2 = C 5 H 5 N have been studied by Mössbauer spectroscopy. Quadrupole splitting (⊿EQ) values vary in a limited range (0.68-0.80 mm/sec) indicating only small distortions in the octahedral geometry of the compounds with the substitution of various amino groups. Isomer shift (δ) values remain almost constant suggesting that s-electron density is not affected by substitution.

On treatment of [OsI 4 ox] 2- with Cl - the mixed complexes [OsCl n I 4-n ox] 2- , n = 1, 2, 3, are formed. The isolation and complete separation of the differently coloured geometric isomers is achieved by ion exchange chromatography on diethylaminoethyl cellulose. The IR and Ra spectra are assigned according to point groups C 2v , C s , C 1 . The mutual influence of ligands, especially by the high trans effect of I, is indicated by shifts of the distinct vibrational and electronic bands. The observed splittings of I→Os transitions are attributed to the different groupings I-Os-I, I-Os-Cl, and I-Os-O, important for the distinction of stereoisomers. The CT-bands as well as the d-d-transitions show batho-chromic shifts with increasing number of I-ligands. Up to five spin-orbit components in the NIR region are well resolved. The assignment is improved by the electronic Ra spectra. The fine structure of some d-d-bands originates from coupling with symmetric vibrational modes.

Cleavage of Bi-C-bonds in Ph 3 Bi (Ph = C 6 H 5 ) by mercaptocarboxylic acids (H 2 Mc) depends on solvents and concentration. Ph 3 Bi in CHl 3 and H 2 MC (= mercaptoacetic, 3-and 2-mercaptopropionic, 2-mercaptobenzoic acid) reacted to give Bi(Mc)(HMc); in acetone at lower concentrations PhBi(Mc) (H 2 Mc =2-mercaptopropionic, 2-mercaptobenzoic acid) was obtained. Me 3 Bi (Me = CH 3 ) and H 2 Mc gave MeBi(Mc) at all concentrations used. Polymeric structures with bridging Mc-groups and four-coordinated Bi are proposed.

Comparative structure investigations of simple gaseous ions formed by electron impact of organometallic π-complexes have been carried out by use of the collisional activation (CA) technique. The CA mass spectra of C 6 H 6 M + ions (M = V, Cr, Fe) arising either from benzene or from methylcyclopentadienyl metal compounds show significant differences indicating different structures of these fragments. Similar observations were made with C 7 H 7 M + ions produced from benzyl or cycloheptatrienyl chromium tricarbonyl derivatives, although the metal-free ligand ions exhibit identical CA mass spectra. The C 6 H 6 V + -ion arising from C 5 H 5 VC 7 H 7 by a rearrangement fragmentation was shown to have the π-benzene vanadium structure.

Single crystals of the title compound, A, have been prepared and studied structurally by X-ray analysis. A crystallizes in the space group P2 1 /n with Z = 4 and lattice parameters a = 11.174(3), b= 15.627(5), c= 8.148(3) Å and β = 92.82(3)°. Within the limits of error the π-bonded cyclobutadiene ring is a square with an average C-C-bond distance of 1.465 Å ; the methyl groups are displaced away from the nickel atom, the average distance between the ring plane and the methyl C-atoms being 0.15 Å. The sulfur containing five membered ring has a cyclic delocalized electron distribution.

Some new mixed valence compounds of the type [M(L-L) 2 M(L-L) 2 X 2 ]Y 4 (where M = Pt or Pd, L-L = 2 NH 3 or ethylenediamine, X = Cl, Br or I and Y = HSO 4 , 1/2 SO 4 , ClO 4 or 1/2 PtCl 4 ) have been synthesized. The polarized Raman spectra of single crystals show the anisotropic character and the presence of ---M(II)---X-M(IV)-X chains. The method of preparation and the chemical behaviour correspond to the mechanism of the formation of Magnus green salt oxidized product.

Complexes of the general formula M(LH 2 )Cl 2 · 2 H 2 O, where LH 2 = N,N′-(dipicolyl)-1,8-naphthylenediamine and M = Mn, Ni and Cu, have been prepared. None of the metal ions used promote amide deprotonation on coordination: LH 2 acts as a tetradentate ligand. Distorted octahedral stereochemistries for the complexes in the solid state have been proposed utilising microanalyses, magnetic susceptibilities, molar conductance measurements and IR and visible spectral data. The Ni(II) complex exhibits evidence of a polymeric structure.

The thioanisole-π-complexes (methylthio-η-benzene)-(η-benzene)-chromium (2) and bis(methylthio-η-benzene)chromium (3) have been prepared via lithiation of bis(η-benzene)-chromium and consecutive reaction with dimethyldisulfide. 1 H NMR and 13 C NMR spectra of 2 and 3 as well as ESR-spectra of the corresponding radical cations 2. + and 3. + were recorded and analyzed. In contrast to C( η-arene )-Si and C( η-arene )-P bonds, C( y-arene )-S bonds are stable to solvolysis. With (norbornadiene)tetracarbonylmolybdenum, 3 readily forms [bis(methylthio-η-benzene)chromium]tetracarbonylmolybdenum (6) wherein 3 functions as a chelating ligand. 1 H and 13 C NMR evidence suggests, that at room temperature 6 undergoes rapid conformational interconversions.

The title compound, C 19 H 23 NO 6 · NaClO 4 , crystallizes in the monoclinic space group P2 1 /c with cell dimensions a = 16.374(5), b = 9.856(4), c = 27.245(8) Å, β = 91.88(5)° and Z = 8. The structure of this polyether complex was solved on the basis of 4501 diffractometer measured reflections and refined to an R w of 0.091. There are two molecules per asymmetric unit which are related to each other by an approximate non-crystallographic centre of symmetry. Both complex molecules exist in the favourable zwitterion configuration with ion pair attraction between the amino (NH 3 + ) and carboxyl(COO - ) end groups of the polyether ligand. The Na + ion is circulary coordinated to all except the oxygen atoms of the aminophenoxy end group of the polyether ligand suggesting that this oxygen has reduced electronegativity. All C-C and C-O bonds of the ligand exist in favourable gauche and trans conformations.

A number of 6-substituted arylaminobenzthiazoles (5-8 and 16-18), 6-(substituted -1-benzimidazolyl)benzthiazoles (9-15) and 6-(3-quinazolyl)benzthiazoles (19) have been synthesized starting from corresponding 6-aminobenzthiazoles. None of the compounds showed significant anthelmintic activity.

Two new furanoid diterpenes of clerodane type, 6-ketoteuscordin (1) and 6α-hydroxy-teuscordin (2) have been isolated from Teucrium scordium var. scordium, Lamiaceae. Their structures and stereochemistry have been determined.

The stereochemistry of α-bisabolol is discussed. The chiralities of the different α-bisabolols from Myoporum crassifolium, Populus balsamifera and Vanillosmopsis erythropappa are deduced from the absolute configuration of natural bisabolol from chamomile, which has to be considered as being (1′S,2S)-configurated according to most recent investigations. Based on this assumption, (1′S, 2R)-configuration has to be ascribed to (-)-α-bisabolol from Myoporum crassifolium, whereas (1′R,2R)-resp. (1′S,2S)-structure is present in (+)-α-bisabolol from Populus balsamifera and (-)-α-bisabolol from Vanillosmopsis erythropappa being therefore enantiomeric to the latter. Consequently, the (-)-α-bisabolols from Matricaria chamomilla and Vanillosmopsis erythropappa turn out to be identical in all respects. Synthetic α-bisabolols, however, featuring approximately equal amounts of all the four possible stereoisomers, differ not only optically but also in their stereochemical uniformity from natural α-bisabolols. By means of NMR spectrometric methods the identity of the native active agent can be established in chamomile specialities; as a consequence possible admixtures of synthetic racemates of α-bisabolol thus can be identified and quantified.

A series of ferrocenyl chalcones (1-7) have been prepared by the interaction of acetylferrocene with aromatic aldehydes. Reaction of these ferrocenyl chalcones with hydrazines gave ferrocenyl pyrazolines (8-21). Also, the reaction of chalcones with bromine yielded the corresponding dibromides (22-25). Fusion of dibromides (22-25) with 2-naphthol and 1-naphthylamine gave the corresponding substituted ferrocenylbenzofuranes (26-29) and ferrocenyl endoles (30-33) respectively.

The preparation of a non-cubic modification of water-free hexacyanometalates(III) Zn 3 [M(CN) 6 ] 2 (M = Cr, Fe, Co) is described. The X-ray powder diagrams of these compounds have been indexed rhombohedrally, space group D 6 3d -R3̄c, Z = 2.

Photoreactions of 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo, endo-5,8-dimethano-naphthaline (1) were studied in acetone with wavelengths above 290 nm. With the help of column chromatography an unusual isomerisation product (4) could be isolated, whose structure was established by spectral data obtained by mass spectrometry infrared spectroscopy, 1 H and 13 C nuclear magnetic resonance measurements.