Volume 38, Issue 6

Single crystals of HT-Li 2 PbO 3 have been prepared by heating of mixtures of Rb 2 PbO 3 and Li 2 O [Ag-cylinders, 600 °C, 100 d]. The structure determination [1005 symmetry independent l 0 (hkl), R = 5.85%, Rw = 5.35%, confirms space group C2/c with a = 548.60(16), b = 949.51(22), c = 1027.35(27) pm, β = 100.11(3)°, d rö = 6.78 g · cm -3 , dpyk = 6.80 g · cm -3 , Z - 8. The NaCl-type structure variant is characterized by alter-nating layers of Li + and Pb4 + /Li + cations, which are all octahedrally coordinated. Effective Coordination Numbers, ECoN are calculated via Mean Fictive Ionic Radii, MEFIR.

(Ph 2 Ge 5 ) can be obtained from solutions in five crystalline phases, two pure and three including solvent of crystallization. This is lost at 70 °C. At 190 °C all phases transform into a plastic crystalline phase. For this tetragonal phase a gear wheel model for librations of the molecules is developed. The crystal structure of triclinic (Ph 2 Ge) 5 has been determined and refined to R = 0.050. The molecule has a flexible conformation in accordance with a better solubility than exhibited by the homologous rings (Ph 2 Ge) 4 and (Ph 2 Ge) 6 containing rigid normal conformations. The arrangement of phenyl groups is either parallel or perpendicular for both cases intra- and intermolecular. The compound (Ph 2 Ge) 6 attains a plastic crystalline state at 346 °C.

The new compounds (N 2 H 5 ) 2 PtI 6 and (N 2 H 5 ) 2 PtI 5 · H 2 O were obtained by reaction of H 2 PtCl 6 with N 2 H 5 CI and HI in aqueous solutions. In the crystal structure of the ortho - rhombic bis[hydrazinium(+I)]hexaiodoplatinate(IV) (N 2 H 5 ) 2 PtI 6 the N 2 H 5 + cations and PtI 6 2- anions build up a K 2 PtCl 6 - like arrangement. Bis[hydrazinium(+I)]pentaiodoplatinate( II,IV)hydrate, (N 2 H 5 ) 2 Ptl 5 · H 2 O, is classed with the group of linear chain mixed-valence platinum complexes which have highly anisotropic properties. In the crystal structure are structurally undistinguishable PtI 4 -units (Pt-I = 264 pm) connected by asymmetric I-bridges (Pt-I = 270 pm and 338 pm) to 1 [PtI 4 I 2/2 ] chains.

(TEA)[O S Cl 6 ] is formed quantitatively by heating solid trans-(TEA)[OsX 4 (CO) 2 ] (X = Br, I) in a stream of chlorine at 120 °C, and can be purified by recrystallisation from CH 2 Cl 2 without decomposition. It is reduced immediately by acetone, methanol, Cl - , Br - , I - to give [OsCl 6 ] 2- . The standard potential [OsCl 6 ]-/[OsCl 6 ] 2- in acetonitrile referred to the saturated mercury-mercurous sulphate electrode is 0.840 V. The IR and Ra bands of (TEA)[OsCl 6 ], assigned according to point group Oh, are shifted to higher frequencies compared with (TEA)2[OsCl 6 ]. The excitation at 488.0 nm gives a resonance Raman spectrum exhibiting 6 overtones of vi and combination tones up to 4ν 1 + v 5 . The electronic absorption spectrum shows five spin-forbidden intraconfigurational transitions coupled with odd vibrational modes in the near infrared region. The spin-allowed 4 A 2g → 4 T 2g , 4 T 1g -transitions are observed at 347 and 305 nm. The excited levels can be fitted with the parameters ⊿ = 28500 cm -1 , B = 340 cm -1 , ξ = 2500 cm -1 , allowing to calculate the nephelauxetic ratio β 55 to 0.47. In the visible region extensive charge transfer transitions are observed. Based on the strong oxidizing character of Os(V) there is a bathochromic shift of corresponding bands of [OsCl 6 ]- in relation to [OsCl 6 ] 2- of about 6600 cm -1 and to the isoelectronic [ReCl 6 ] 2- of about 13700 cm -1 , respectively. From πt 1u →dt 2g the optical electronegativity is calculated to X opt (Os v ) = 2.49.

Prussian Blue analogs of the type Fe[M B (CN) 6 ] (M B = Pd and Pt) crystallize in the face-centered cubic system: space group F m3m -O h 5 , Z = 4. Magnetochemical and Mößbauer spectroscopic measurements have revealed that nitrogen-coordinated iron(II) ions and carbon-coordinated M B (IV) ions are in the high spin state and in the low spin state, respectively, in the temperature range 4.2 to 300 K. Upon the formation of Fe[M B (CN) 6 ] from K 2 [M B (CN) 6 ], the binding energies of N 1s, Pd 3d 5/2 and Pt 4f 7/2 increase while the C 1 s binding energy decreases. This tendency could be interpreted in terms of the inductive effect of iron(II) ions attached to the nitrogen end of cyanide ligands.

The title compound crystallizes in the rhombohedral space group R3, Z = 1. The boron atom occupies a special position on the threefold axis therefore imposing C 3 symmetry to the molecule. The C 2 BN plane is twisted relative to the BN 3 plane by 37.1°, and the BN bond length of 144.8(3) pm is on the upper limit of BN bond lengths found for other triaminoborane systems.

A new procedure for a specific micro-synthesis of p-iodo-aniline has been developed. It consists of the reaction of aniline with tliallium(III)-trifluoroacetate followed by the iodination with aqueous potassium iodide.

Colourless crystals of HSb 3 O 8 were prepared by hydrothermal methods from Sb 2 O 5 . The crystal structure [P2/n, a = 945.6(2), b = 869.1(2), c = 990.9(2) pm, β = 90.25(2)°, Z = 6. R = 0.045] was determined from diffractometer measurements. Distorted SbO 6 octahedra are linked through vertices and edges to form a three-dimensional polymer of pseudo-orthorhombic symmetry. The hydrogen atoms could not be located.

The synthesis of a λ 3 P-substituted phosphorane involving direct substitution of a Ph 2 P group at λ 5 P by the reaction of a chlorophosphorane with Ph 2 PSiMe 3 is described; the identity of this novel compound is established by NMR and mass spectroscopy, and by a single crystal X-ray diffraction study.

The reactions of dicarbonyl dinitrosyl iron with tri-tert-butylphosphine, di(feri-butyl)-trimethylsilyl-, -germyl-, -stannyl-phosphine, tert-butyl-bis(trimethylsilyl)-, -(germyl)-, -(stannyl)phosphine, as well as with tris(trimethylsilyl)-, -(germyl)-, and -(stannyl)phosphine result in the elimination of one CO ligand and the formation of the corresponding carbonyl dinitrosyl organometalphosphine iron complexes. The IR, 1 H, 31 P, 13 C, and 119 Sn NMR spectra of the new complexes are reported and discussed.

The reaction of Cp(CO) 2 (NO)Cr with Me 3 P = CH 2 yields the tetramethylphosphonium -[(trimethylphosphoranyliden)acetyl-Chromate] Me 4 P[Cp(CO)(NO)Cr-C(O)-CH = PMe 3 ] (1) via ylide addition at the carbonyl carbon and transylidation. A reversible equilibrium is established between 1 and the starting materials, which is responsible for the facile conversion of 1 into the ylide complex Cp(CO)(NO)Cr-CH 2 PMe 3 (2) on photolysis. In the presence of Mel, 1 is degradated to [Me 4 P]I, [Me 3 PEt]I, [Me 2 PEt 2 ]I and Cp(CO) 2 (NO)Cr. Treatment of 1 with an equimolar amount of MeOSO 2 F leads to the formation of the "zwitterionic" phosphoniovinyl complexes Cp(CO)(NO)Cr-C(OMe) = CH-PMe 3 (3a) and Cp(CO)(NO)Cr-C(OMe) = C(Me)-PMe 3 (3b). With excess MeOSO 2 F the phosphoniocarbene complex [Cp(CO)(NO)Cr = C(OMe)-CH(Me)-PMe 3 ]SO 3 F (4a) is obtained. Me 3 P = CH 2 de-protonates 4a to 3b, which adds HCl to give [Cp(CO)(NO)Cr=C(OMe)-CH(Me)-PMe 3 ]Cl (4b). The phosphonium cobaltacylates Me 4 P[(CO)(NO)(L)CO-C(O)-CH = PMe 3 ] (5a, b), generated from the cobalt complex (CO) 2 (NO)(L)Co (L = CO, Me 3 P) and Me 3 P = CH 2 , readily transform to the ylide complexes (CO)(NO)(L)Co-CH 2 -PMe 3 (6a, b). MeX (X = I, SO 3 F) cleaves 6b to give (CO) 2 (NO)(Me-P)Co and [Me 3 PEt]X. The new complexes are characterized by elementary analysis and spectroscopy.

The Separation of a number of cyclic methylene sulfides and selenides by reversed-phase high-pressure liquid chromatography is reported. The retention times as well as the capacity factors depend in a systematic way on the ring size, the number and kind of chalcogen atoms, and the number of heteronuclear bonds within the ring. These relation-ships are used to assign the chromatograms of cyclic selenium sulfides of type Se n S 8-n (n = 1-8) prepared in a new reaction from Se 2 Cl 2 , SCl 2 and potassium iodide and containing all selenium atoms in neighboring positions.

The unsaturated acylphosphanes RC(O)PPh 2 (4a, b') [R = Ph-CH = CH (a), C 3 H 4 N 2 (Cl)-C(Ph) = CH (b')] are obtained by reaction of RC(O)Cl (3a, b') with (CH 3 ) 3 SiPPh 2 . The preparation of 3b' is possible by addition of imidazole to the triple bond of Ph-C=C-C(O)OC 2 H 5 and subsequent hydrolysis of RC(O)OC 2 H 5 (lb) [R = C 3 H 3 N 2 -C(Ph) = CH (b)] and chlorination of RCO 2 H (2b'). From 4a and imidazole the imidazolide Ph 2 P(Ph)CH-CH 2 -C(O)-N 2 C 3 H 3 (5) is formed which can be oxidized to give Ph 2 (O)P(Ph)CH-CH 2 -C(O)-N 2 C 3 H 3 (6). 4a is coordinated in two different ways to transition metals. A 1:1 molar ratio of 4 a and L n MnTHF [L n Mn = (η 5 -C 5 H 5 )Mn(CO) 2 ] yields the P-coordinated complex RC(O)P(Ph 2 )-MnL n (7a). Excess of L n Mn·THF results in the formation of P- and η 2 -coordinated L n Mn-P(Ph 2 )C(O)(η 2 -C 2 H 2 Ph)MnL n (8a). In the presence of HP(O)Ph 2 , 4a is oxidized with molecular oxygen to give the phosphorylated alcohol RC[P(O)Ph 2 ] 2 OH (9a). Via the oxide 10 a and the enol ether Ph 2 (O)P-CHPh-CH = C(OCH 3 )P(O)Ph 2 (11a) the ester Ph 2 (O)P-CHPh-CH = C[OC(O)R]P(O)Ph 2 (12 a) can be isolated from the Arbusov reaction of 3a and CH 3 OPPh 2 .

The complexes C 5 Me 5 Pd(PR 3 )X (1-4) are prepared from [Cl(PR 3 )Pd] 2 (μ-OCOCH 3 ) 2 and TIC 5 Me 5 . Attempts to replace the halide ligand by a second C 5 Me 5 or a C 5 H 5 unit remained unsuccessful. The X-ray structure analysis of C 5 Me 5 Pd[P(i-Pr) 3 ]Cl (3) indicates that the five-membered ring shows a tendency of η 1 -bonding towards the metal.

In the course of systematic investigations on sila-substituted parasympatholytics the diphenyl(2-aminoethoxymethyl)silanols 3b and 4b (and its carbon analogue 4a) were synthesized and characterized by their physical and chemical properties. In the solid state 4a and 4b form strong O-H---N hydrogen bonds, which are intramolecular (4a) and intermolecular (4b), respectively. 4a and 4b were found to be weak antimuscarinic agents (4b >4a) and strong papaverine-like spasmolytics (4a ≈4b).

The isomorphous crystal structures of the manganese and rhenium bromotricarbonyl complexes 2 a, b have been determined at room temperature (Mn) and at -110 °C (Mn, Re; P2 1 /c, Z - 4). At room temperature, data collection is accompanied by crystal decomposi-tion, and a cleavage of the PPh3 group is suggested by the results as the primary process. The same initial step is thought to be valid for the photodecomposition in solution. The main structural difference between the free and coordinated betaine ligand 1 is the reduced electrostatic interaction of P and S in the complexed form.

Treatment of the subst. 4,5-Dihydroxy-1,3-benzdioxoles (1a-1m) with silver(I)-carbonate/Celite resp. tetrachloro-1,2-benzoquinone as dehydrogenation agent yields the 1,3-benzdioxol-4,5-quinones (2a-2m). These are darkblue or black coloured compounds with a different stability.

A convenient method for the preparation of 12a-hydroxymethyl derivatives of rotenone 1 and amorphigenin 2, possibly applicable to other rotenoids with activated 12a-hydrogen atom is described. The stereochemistry of the products is discussed.

Heterocyclic Synthesis, Pyrrolones The behaviour of 4-benzylidene-2-oxazolin-5-one (2) and of 4-phenylazo-2-oxazolin-5-one (3) toward a variety of active methylene reagents is reported. Cleavage of the oxazolin-5-one ring was observed in most cases. A variety of new, otherwise, difficult accessible, azolyl derivatives could be prepared.

2,2,2-Trimethoxy-3,3-bis(trifluoromethyl)-2,2-dihydro-1,4,2-oxazaphosphol-4-enes on thermolysis undergo a 1,3-dipolar cycloreversion reaction with formation of bis(trifluoro-methyl) substituted nitrile ylides. Trapping reactions of the 1,3-dipolar species with α,β-unsaturated carboxylic acid esters and nitriles are described. 2-Aryl-3-carbethoxy-5,5-bis(trifluoromethyl)-1-pyrrolines obtained undergo an uncatalyzed autoxidation pro-cess to give 2-aryl-3-carbethoxy-3-hydroxy-5,5-bis(trifluoromethyl)-1-pyrrolines. 5,5-Di-fluoro-4-trifluoromethyl-2-oxazolines and 5-fluoro-4-trifluoromethyl-oxazoles formed as by-products indicate that the thermal induced [3+2]-cycloreversion reaction of 2,2,2-tri-methoxy-3,3-bis(trifluoromethyl)-2,2-dihydro-1,4,2-oxazaphosphol-4-enes is most likely a stepwise process.

Several new thiazolo[2,3-a]pyridine derivatives were obtained via the reaction of mercaptocinnamic acid and thioglycollic acid with some activated nitriles and treatment of the resulting 2-thiazolin-4-ones with cinnamonitrile derivatives.

DTA, X-ray and microprobe measurements show, that the compound "Ag 8 SnTe 6 " seems not to be a stable argyrodite.

The compound CS 3 V 2 O 4 F 5 with statistically distributed [V 2 O 4 F 5 ] 3- complexes shows a weak, red emission at low temperatures. This emission is discussed in relation to similar luminescent compounds.

Oxidation of Oxalyl-bis(diphenylphosphane), Mechanism In dependence of the solvent, oxalyl-bis-(diphenylphosphane) (1) is oxidized with mole-cular oxygen either in a radical or an ionic mechanism to give -via the radicals· PPh 2 and the recombination products [-PPh 2 ] 2 (3) -the oxide [Ph 2 P(O)] 2 (4) and [Ph 2 P(O)] 2 O (6), respectively. In both cases CO and CO 2 are eliminated in nearly equal amounts.

Tetramethylsilane reacts with HN(SO 2 Cl) 2 (1) in a complex manner, the nature of the product mixture depending strongly on the reaction conditions. Refluxing 1 with TMS in excess, using CH 2 Cl 2 as a diluent, affords in high yield the new compound HN(SO 2 Cl)(SO 2 Me) (2) according to eq. (3). Hydrolysis of the crystal-line, moisture sensitive compound 2 is described by eq. (4).