Volume 39, Issue 11

[Fe(2,2'-bpy) 3 ][Fe 2 OCl 6 ] is obtained in form of red, air stable crystals by oxidation of Fe(bpy)Cl 2 with O 2 in acetonitrile. It crystallizes in the monoclinic space group P2 1 /c with Z = 4. The crystal structure contains Fe(bpy) 3 2+ and Fe 2 OCl 6 2- ions. The anion exhibits a bent oxobridge with Fe-O-Fe = 148,1° and Fe-O distances of equal length (176,5 pm). In the IR spectrum ν as Fe-O-Fe is observed at 850 cm -1 , the Fe-Cl valence vibrations at 362 and 317 cm -1 .

Triphenylphosphonium -diphenylarsinomethylide (1) and -bis-(diphenylarsino)methylide (2) are easily available through transylidation processes using Ph 3 P = CH 2 and Ph 2 AsCl as the starting materials in the appropriate molar ratio. Analytical and spectroscopic data are presented for both ylides. The structure of 2 was studied in detail by single-crystal X-ray diffraction. The basic PCAs 2 skeleton is found to deviate strongly from planarity. The Ph 2 As-substituents adopt a cis/trans conformation relative to the ylidic P = C bond with the directions of the lone pairs of electrons at the arsenic atoms in the heavy atom plane as expected for a maximum compensation of the electrostatic vectors. For 1, a cis-conformation of the lone pair of electrons and a large PCAs angle are predicted on the basis of NMR analogies with the phosphorus homologues. Single bond rotational barriers appear to be much lower for 1 and 2, however, than for the corresponding phosphino-substituted ylides.

The structure of the title com pound 5 has been investigated by X-ray crystallography in order to discern between two structural alternatives. 5 crystallizes in the monoclinic space group P2 1 /c, and almost planar B-B bonded dioxaborolane rings are present in the molecule. 5 possesses a crystallographically imposed center of inversion, and approaches the point group symmetry D 2h -

The pentachlorides MCI 5 (M = Nb, Ta) react with trithiazyl chloride in CCl 4 suspension to form the donor-acceptor com plexes MCl 5 -NSCl and (MC1 5 ) 2 • N 2 S 2 . With excess (NSCl) 3 the ionic com pounds S 4 N 4 Cl[MCl 6 ] are obtained. Reaction of the complexes MCl 5 - NSCl with SCl 2 give another ionic species N(SCl) 2 [MCl 6 ] whereas thermal cleavage is found to result in the formation of (MCl 5 ) 2 • N 2 S 2 . All products were characterized by their IR spectra.

On treatment of Na 2 B 6 H 6 with halogens in aqueous alkaline solution, the hexahalogenoborates B 6 X 6 2- , X = Cl, Br, I, are formed. Their octahedral structure is proved by 11 B NMR spectroscopy. The chemical shifts in relation to BF 3 · OEt 2 increase within the series H (-13.5) < Cl (-17.4) < Br (-18.5) < I (- 27.5 ppm ). The IR and Raman spectra are assigned according to point group O h . The internal vibrations of the B 6 -cage, observed in the range 750-1250 cm -1 at nearly unchanged positions, are distinguishable from vibrations mainly originating from motions of the X 6 -shell against the rigid B 6 -cluster.

The preparation of bis-cyanophthalocyaninatoferrates(III) with different bulky cations is described. The redox behaviour was studied by cyclic voltammetry, and the results confirmed by appropriate chemical reduction and oxidation reactions. Reactions with bases and acids as well as the redox reactions are governed by the strong trans-efiect of CN - favouring the formation of the monocyano or mixed ligand monocyano complexes. The ESR and Mössbauer spectra as well as the magnetic susceptibility studies (4 .2 -300 K) indicate a low-spin Fe(III) complex with a pseudooctahedral 2 T2-groundstate. The IR and Resonance Raman (RR) spectra were investigated. By comparison with similar electronic Raman transitions in the low-temperature Raman spectra of K 3 [Fe(CN) 6 ] and Na 2 [Fe(CN) 5 NO] • 2H 2 O the RR-enhanced band at 525 cm -1 in the 80 K RR-spectrum is assigned to the intraconfigurational Raman transitions between the groundstate spin-orbit split components Г 7g →Г 7g , Г 6g (D 4h *) yielding the spin-orbit coupling parameter ζ Fe = 350 cm -1 . In the FIR-spectrum the F e-C-stretching vibration (a 2u ) is localized at 350 cm -1 as confirmed by comparison with the FIR-spectra FeXPc(2-) (X = F. Cl. Br, I). The UV - VIS spectrum was measured together with those of the bis-cyano complexes of Fe(II) and Co(III). The splitting of the Q-band (a 2u e g ) is discussed. Extra-bands at 540. 610 and 775 nm are assigned to Pc →Fe-electron transfer. A comparison with the spectra of the H 2 S0 4 adduct and the phthalocyanine- π-cation radical is presented.

The preparation of anionic phthalocyaninato-cobaltates(III) [CoX 2 Pc(2-)] - (X = OH . F, CI, Br) is described. The UV -VIS. IR and Resonance-R am an (RR ) spectra are measured and com pared with those of the complexes [CoX 2 Pc(1 -)] (X = Cl, Br) containing the phthalocyanine-π-cation- radical.The characteristic spectroscopical differences for the Pc(1-)- and Pc(2-)-Ligands are discussed. Besides the typical B-, Q- and N-transitions of the Pc(1 -)- and Pc(2 -)-ligand additional weak bands are observed in the UV -VIS spectra for both dichloro- and dibromocomplexes. These bands are assigned to X (π , σ) → Co electron transfer a 2u (π x ), a 2u (σ x ) → a 1g (d); for the Pc(1 - )-complexes Cl(π) is at 22.9, Cl(σ) at 38.9. Br(π-) at 19.6 and Br(σ) at 36.4 kK. For the Pc(2-)-complexes these bands are slightly red-shifted by about 0.5 kK. The assignment is confirm ed by the RR-spectra. For both dichloro- and dibromo-complexes the sym. (Co-X)- stretching vibration (a 1g , ν 1 ) is strongly RR-enhanced and up to four overtones of ν 1 are observed (for Pc(2-): ν ( Co - X ) for X = Cl: 270. Br: 165 cm -1 ; for Pc ( 1 - ) : X = Cl: 280. Br: 168 cm -1 ). The antisym. (Co -X)-stretching vibration (a 2u ) is observed in the FIR spectra (for Pc(2 -): ν(Co-X) for X = F: 546. Cl: 333. Br: 243 cm -1 ; for Pc ( 1 - ) : X = Cl: 326. Br: 250 cm -1 ).

Phosphaethenes of the type (Me 3 Si) 2 C = P -NRSiMe 3 R = C 10 H 15 (7), CMe 3 (8), 2.4.6-Me 3 C 6 H 2 (10)), LiF, and Me 3 SiF are obtained in the reaction of the aminodifluorophosphanes (3-5) with the lithium salt of tris(trimethylsilyl)methane (1). 10 is isolated as by-product. The main product is F 2 PC(SiMe 3 ) 3 (9). The lithium salt of tris(trimethylsilyl)silan (2) reacts with 3 -6 to give the thermally stable substitution compounds (Me 3 Si) 3 Si -PF-NRSiMe 3 (11-14). The fluorosilylphosphane Me 3 Si(CMe 3 )P -SiFMe - N(SiMe 3 ) 2 (15) is formed in the reaction of Me 3 Si(CMe 3 )PLi and F 2 SiMeN (SiMe 3 ) 2 .

The complexes trans-[IrClL(PiPr 3 ) 2 ] (L = CO , py, CH 3 CN) were prepared from [(C 8 H 14 ) 2 lrCl] 2 via[IrCl(PiPr 3 ) 2 ] as intermediate. rrans-[IrCl(CO)(PiPr 3 ) 2 ] reacts with LiC 2 Ph to form trans- [IrC 2 Ph(CO)(PiPr 3 ) 2 ] which on treatment with HX produces [IrH X(C 2 Ph)(CO)(PiPr 3 ) 2 ] (X = Cl, CF 3 CO 2 ). The trifluoroacetate ligand is displaced by iodide to give [IrHI(C 2 Ph)(CO)(PiPr 3 ) 2 ]. trans-[IrCl(N 2 )(PiPr 3 ) 2 ] is obtained from the carbonyl complex and 2-furfurylazide.

t C 4 H 9 N = VBr 3 has been prepared by reaction of the trichloride with hydrogen bromide dissolved in benzene. The structure of the 2.2'-dipyridyl complex [ t C 4 H 9 N = VBr 3 · C 10 H 8 N 2 ] has been found to be octahedral with meridional arrangement of bromide. Syntheses of i C 3 H 7 N = V(OR) 3 and iC 3 H 7 N = V(OR) 3 are described. The properties of these compounds are studied by chemical reactions such as redistribution, transamination and alcoholysis. The 51 V NM R spectra of the alkyliminovanadium(V) compounds are discussed; the constants of 51 V , 14 N coupling have been determined. The oxovanadium (V) complex [VO (OCH 3 ) 3 -V O(OCH 3 ) 2 Cl] has been prepared; all attempts to prepare VO(OCH 3 ) 2 Cl have not been successful.

The reaction of Lithium-tris(dimethylphosphino)methanide with methyl iodide is sensitive to the choice of the solvent and reaction conditions; in pentane at room temperature and in the presence of tetramethylethylenediamine, Me 3 P = C(PMe 2 ) 2 is the major product, whereas in tetrahydrofuran, (Me 2 P) 3 C -CH 3 is formed predominantly. Under similar conditions, Lithium-bis- (dimethylphosphino)methanide reacts with Mel to give (Me 2 P) 2 C(CH 3 )H as the main product. An X-ray structure determination of the tetrahydrofuran solvate of LiC(PMe 2 ) 3 reveals this compound to be dimeric with one solvent molecule coordinating to Li. A pseudo tetrahedral coordination sphere around each Li atom is completed by two phosphino groups of one [C(PMe 2 ) 3 ] - anion and a contact ion pair interaction with the carbanionoid center of the second. The crystals are monoclinic, space group P2 1/ n, with a = 928.5(2), b = 1250.8(3), c = 1407.9(3) pm, β = 100.07(1)°, V = 1609.9 • 10 6 pm 3 D c = 1.13 g/cm 3 for Z - 4 at -40 °C. Full-matrix least-squares refinement of 249 parameters based on 2158 reflections converged at R = 0.029. The ligand properties of (Me 2 P) 3 CCH 3 are tested in its reactions with (CO) 4 Cr(C 7 H 8 ) and (CO) 5 Cr[CH 2 S(O)Me 2 ] from which and may be isolated. The latter crystallizes in the monoclinic space group P2 1 /c with a - 1218.5(3). b = 881.7(3), c = 1824.1(4) pm, β = 106.66(2)°, V = 1877.6(9) • 10 6 pm 3 , D c = 1.37 g/cm 3 for Z = 4. Least-squares refinement of 218 parameters on 1615 reflections produced R = 0.063. The structure determination confirms the molecule to contain a five-membered heterocycle in an approximate envelope conformation.

By applying the method of inverse titration [1,2] the influence of increasing concentrations of added effectors to organic and metalorganic chemical systems on the product selectivity can easily be identified. o a Wittig-type system we added LiI (change of stereoselectivity) and also triphenylphosphanoxide (removal of salt-effect). To a catalytic N (0) /butadiene system we added triphenylphosphite and then morpholine and vice versa. Ni:P(OC 6 H 5 ) 3 : morpholine in a ratio 1:1:0,1 yields more than 90% cyclodimers but in a ratio 1:0,1:20 more than 90% n-octa-1,3,6- trienes. The co-oligomerisation of two butadienes with one 2,5-dimethyl-3-aza-hex-3-en in the system Ni/triphenylphosphane/butadiene/Schiff base/toluene/effector (1:1:66:33:66: ~ 0,1) leads - within the 2 : 1-cooligomers - by adding di-n-propyl-borane to a pure octadienylated Schiff base 11 or by adding morpholine largely to an octatrienylated amine 12 ( ~ 85% 12 and ~ 15% 11).

The gas-phase pyrolysis of cyclohexeno-1,2,3-selenadiazole and cycloocteno-1,2,3-selenadiazole has been investigated by variable temperature photoelectron spectroscopy and matrix IR spectroscopy. The ring contracted, highly reactive products cyclopentylidenselenoketene (cyclopentylidenmethanselone) and cycloheptylidenselenoketene (cycloheptylidenmethanselone) - which had not been found in liquid phase thermolysis experiments - have been detected. Additionally HeI photoelectron and IR spectra of analogous ketenes and thioketenes are presented for comparative reasons.

The title compound 1,3,3,5,7,7,10,10-octaphenyl-2,4,6,8,9,11-hexoxa-1,3,5,7,11-pentagermabicyclo[3.3.3]undecane is synthesized from PhGeCl 3 /Ph 2 GeC l 2 and AgNO 3 in aqueous acetone. The 13 C NMR phenyl signals for bridges and bridge-heads are in the expected ratio of intensity 3:1. The crystal structure of Ph 8 Ge 5 O 6 ·1/2 acetone has been determined and refined to R = 0.062. The asymmetric unit contains two independent bicyclic Ph 8 Ge 5 O 6 cages and one disordered crystal acetone. The total symmetry of both Ph 8 Ge 5 O 6 molecules is near to D 3 , the symmetry of the individual 8-membered rings (GeO) 4 is near to C 2 (distances Ge -O 172-180, Ge -C 191-195 pm, angles Ge - O - Ge 128.0-133.8, O - Ge - O 107.5-110.6°).

In the Fast Atom Bombardment (FAB) mass spectra of monomeric and dimeric corrinoids, exchange of metal-bound ligands against matrix particles is observed which leads to pseudo molecular ions. Negative ion FAB mass spectra in particular, give distinct information on the intact molecular units.

Cr(CO) 2 [P(CH 3 ) 3 ] 2 (η-diene) (9-14) and Cr(CO) 2 [P(OCH 3 ) 3 ] 2 (η-diene) complexes (15-20) were prepared photochemically in high yields from Cr(CO) 4 [P(CH 3 ) 3 ] 2 (1) or Cr(CO) 4 [P(OCH 3 ) 3 ]2 (2), respectively, with the dienes 1,3-butadiene (3), trans-1,3-pentadiene (4), 2-methyl-1,3- butadiene (5), trans,trans-2,4-hexadiene (6), 2-methyl-1,3-pentadiene (7), and 2-ethyl-1,3- butadiene (8). The stereochemistry of 9-20 was determined by IR and N M R spectroscopy. In the case of dicarbonyl-η-trans-1 ,3-pentadiene-bis(trimethylphosphane)chromium(0) (10) and the corresponding trans,trans-2,4-hexadiene complex 12 the X-ray crystal and molecular structure analyses confirm the spectroscopic conclusions. The distorted octahedral complexes are obtained exclusively as af-isomers. They show a hindered, degenerate isomerization with an intramolecular mutual exchange of the donor ligands. Trigonal prismatic transition states and distorted octahedral intermediates are appropriate models for the explanation of the degenerate isomerization. The activation barriers for the ligand movement were determined by dynamic 31 P-NMR spectroscopy. The mobility of the ligand spheres distinctly depend on the position of the alkyl groups of the diene ligands. A methyl group in 1E-position increases the barrier of the ligand movement by ≈ 16 kJ/mol, in 2-position the barrier is lowered by ≈ 5 kJ/mol. This effect is caused by steric interactions between the alkyl groups and the donor ligands in the transition or ground state.

Reaction of tris(ethene)nickel(0) with dmpe at low temperature affords the crystalline compounds (dmpe)Ni 2 (C 2 H 4 ) 4 (6), (dmpe) 2 Ni 2 (C 2 H 4 ) 3 (7), and (dmpe) 3 Ni 2 (C 2 H 4 ) 2 (8), depending on the stoichiometries employed. In 7 and 8 , nickel is tetrahedrally coordinated by ethene and three phosphorus ligands. In addition, (dmpe) 4 Ni 2 (9) has been obtained with excess dmpe at 20 °C. Structural assignments were made on the basis of NMR spectra.

Diastereomeric mixtures for members of series CH 3 (t-C 4 H 9 )P(X ) -Y -(Z)P(t-C 4 H 9 )CH 3 were prepared. Pure meso- and rac-[CH 3 (t-C 4 H 9 )P (S)] 2 (8a/8b) and rac-[CH 3 (t-C 4 H 9 )P(S)] 2 S (13) were isolated. Exchange reactions leading to redistribution of sulfur between tri- and pentavalent phosphorus sites are discussed. A novel one-batch method is used for the synthesis of diphosphine disulfides.

Syntheses, separation of diastereomers, NMR studies and molecular properties in solution are reported for [CH 3 (t-C 4 H 9 )P (S)] 2 (1 and 2), and [CH 3 (t-C 4 H 9 )P(S)] 2 S (3) in the preceding paper [1], For further characterization the crystal structures of the diastereom eric disphosphane disulphides (1 and 2) as well as of the related sulphane (3) have been determ ined. 1 is triclinic (space group P1̄; Z = 1), 1792 independent reflections yielded R = 0.03. 2: monoclinic (P2 1 ; Z = 2), 973 reflections, R = 0.07. 3: orthorhombic (Pbca; Z = 8), 2607 reflections, R = 0.05. Molecules of 1 and 2 are diastereomers. The configuration of 1 is meso (point symmetry 1̄-C i , all ligands trans) whereas 2 is an enantiomeric form of the prepared racemic mixture (S atom s and methyl gauche, t-butyl trans). The distance P - P is 226.6(1) and 226.9(3) pm, respectively. Molecules of 3 are enantiomers in racemic crystals (S atoms and t-butyl close to gauche). The molecule is bent by an angle P -S -P of 104.78(5)°.

Disubstituted dibenzoheptafulvenes 4 are obtained from dibenzocycloheptene 8 via the carboxylic acid amide 10, and are characterized by spectroscopic methods and cyclic voltammetry. These dibenzoheptafulvenes are nonplanar, geometric enantiomorphy is shown by 1 H-NMR of 12-dim ethyl-am ino-12-siloxydibenzoheptafulvene 4c. Oxidation o f 12,12-bis(dim ethylamino)dibenzo[a,d]-heptafulvene 4a with Ag(I), I 2 or Cu(II) leads to the radical cation 7. In solution 7 is converted to dibenzocycloheptatriene and anthracene amidinium salts 18 and 19. The ratio o f these two amidinium salts depends on the reaction conditions. H-radical trapping from the medium is proposed for the formation of 18, while 19 must be formed under elimination of a C 1 -unit.

Reaction of a sterically hindered aniline with a sterically non-hindered arylisocyanate produces the sterically hindered aryl isocyanate in good yields besides the urea derived from the unhindered aryl isocyanate.

The conversion of the metal organyls of 1,3-benzdioxole, pyrido[2.3-d]-1.3-dioxole and pyrido[2.3-b]-1.4-dioxene using lactimethers did not prove successful. The N-alkyl-2-aryl-pyrrolidines 10a-c, 11a-c, 12a, 13a and 14a were synthesized from the aldehydes 4a-c via the γ-ketonitriles 7a-c and the 2-aryl-⊿ 1 -pyrrolidines 8 a-c; in some cases, the recovery was high.

The structure of the blue pigment obtained from the culture medium of Pseudomonas putida upon addition of Fe ++ and the nature of its redox reactions has been elucidated.

Diazoketones 2 and 4 react with the thiation agent 1 to give 1 ,2 ,3-thiadiazole derivatives 3, 5 and 6 , respectively. The action of 1 on 3-diazooxindole (8 ) yields the dimeric dithione 9. Structural assignments are based on analytical. Chemical and spectroscopic results.

3α-Acetoxy-5β-cholan-24-oic acid was transformed into 3β-acetoxy-5β-pregnan-20-one by a sequence of reactions that involves inversion o f the configuration at C-3 and degradation of the side chain of the bile acid. The procedure would allow the introduction of a label at C-21 of the final compound.

The title compound (1) has been prepared by the reaction of PNP-perthionitrate with triphenylphosphane in acetone or acetonitrile.

Redetermination o f the structure of the title complex revealed that some unusual bond lengths originally reported for this structure [1], are due to an overlooked disorder of the carbene ligand. Rerefinement with a disordered structural model results in normal bond lengths.

The hydrochloride of 2-methoxy-6-chloro-9-[(δ- diethylamino-α-methyl-butyl)amino]-acridine (Atebrine ® ) (1) reacts under the influence of UV light (λ > 290 nm) in water via N -C-clearage intermolecular to 2-methoxy-6-chloro-9-am ino-acridine (2) and 2-methoxy-6-chloro-acridine (3). Their formation is directly depend of water and partial pressure of oxygen. The reaction is controlled probably by reactive oxygen species ( 1 O 2 , · OH and · OOH), which can be formed in an energy or electron transfer process between singlet-excited Atebrine ® (1) and water/oxygen mixture.