Volume 46, Issue 2

Substituted 1,3-dithiole-2-ones 2 a - f are obtained by reaction of 1,3-dithiole-2-thiones 1 a - f with mercuric acetate. The thiones 3 react with triethyloxoniumtetrafluoroborate giving 1.3-dithiolium salts 4 a - h . The cyclocondensation of compounds 3 to thieno[2,3-d]-1,3-dithiole- 2-thiones 6 a - c is described. The first synthesis of 5-methylthio-2-thioxo-1,3-dithiole- 4-carboxylic acid is reported.

The oxidation of dialkoxymethylstibine with hydrogen peroxide in the presence of sodium hydroxide leads to the formation of disodium-di-μ-oxo-bis[trihydroxo-methylantimonate(V)]. The salt can be synthesized also by dissolving methanestibonic acid in an aqueous solution of sodium hydroxide. The crystal structure has been determined; it shows a dimeric molecule containing a four-membered ring with Sb -O -Sb linkages. Thermal decomposition and spectroscopic properties o f the com pound are discussed.

The reaction of lithiated catechol ligands with W (0)Cl 4 produces LiCl as a side product. The lithium chloride from this reaction crystallizes as (THF) 2 Li(μ-Cl)-,Li(THF) 2 . The X -ray analysis shows lithium in the center of a distorted tetrahedron made up from two THF molecules and two bridging chlorides with d(Li-Cl) = 2.342(3) and 2.308(3)Å.

Dinitrogen bridged cobalt(I) hydride compounds (L 3 CoH) 2 N 2 (1: L = PMe 3 , 2: 3L = CH 3 C(CH 2 PMe 2 ) 3 have been synthesized by protonation of dinitrogen cobaltates. 1 crystallizes in the monoclinic space group C 2/m . a = 965, b = 1653, c = 1148 pm ,β = 106.88°, Z = 2. In solution 1 takes up N 2 reversibly forming CoH(N 2 )(PMe 3 ) 3 (1 a) . Infrared data including isotope labeling ( 15 N , 2 H) and assignment of vN = N and vCoH bands are presented. 1 reacts with aryl alkynes to give dialkynylcobalt(III) complexes CoH(C 2 ,R 1 )(C 2 ,R 2 )(PMe 3 ) 3 (5: R 1 = R 2 = C 6 H 5 ; 6 : R 1 = R 2 = 4 -CH 3 C 6 H 4 ; 7: R 1 = R 2 = 4-C lC 6 H 4; 8 : R 1 = C 6 H 5, R 2 = 4-ClC 6 H 4 ) that are also obtained in a more convenient synthesis involving cobalt(I) intermediates Co(C 2 R 1 )(PMe 3 ) 4 (10: R 1 = 4 -CH 3 C 6 H 4 , 11: R 1 = 4-ClC 6 H 4 ). Three metastable isomers of 5 have been characterized, the stable configuration is mer-trans as shown by a crystal structure determination: Space group P 2 1 , a = 933.5(5), b = 1636.7(6), c = 901.1(3) pm, β = 97.4(1)°, Z = 2.

The reaction of hexafluoroacetone with triphenylphosphane selenide proceeds with elimination of triphenylphosphane oxide to yield 2,2,4,4-tetrakis(trifluormethyl)-1,3-diselenetane (1). Crystals of 1 that are suitable for X -ray crystal structure analysis have been obtained by recrystallization from hexane.

The tetragonal K 2 NiF 4 type crystal structure (I4/mmm , Z = 2) has been refined at isostructural Rb 2 MgF 4 (a = 405.5, c = 1379.0 pm , w R = 0.083), Rb 2 CoF 4 (a = 414.9, c = 1369.6 pm, w R = 0.045) and Rb 2 NiF 4 (a = 408.6, c = 1370.8 pm , w R = 0.023), using between 169 and 313 independent single crystal X-ray reflections. In contrast to the anomaly of nearly undistorted MF 6 octahedra in the potassium compounds K 2 MF 4 , significant shortening o f the terminal vs. bridging bonds is observed in Rb 2 MF 4 : Mg - F = 199.3/202.8, C o - F = 202.8/207.5, Ni - F = 200.7/204.3 pm .

The structure of hydro-trans-diiodobis(2,3-butanedione dioximato)cobaltate(III), H(CoI 2 (dmg) 2 ) (dmg - = dimethylglyoximate) has been determined by single crystal X -ray diffraction at ambient temperature. The crystals are monoclinic, space group C 2/c, C 8 H 15 CoI 2 N 4 O 4 , M r = 543.98; a = 15.714(6), b = 7.408(3), c = 13.944(5) Å; β = 107.76(3)°; V = 1545.85 Å 3 ; Z = 4; D c = 2.34 Mg m -3 . The com pound is best visualized as a monobasic acid. The molecules are linked together into two-dimensional network, where linkage parallel to the ac plane is effected by weak intermolecular iodine interactions (I ···I = 3.826 Å), and linkage along the b axis by symmetric intermolecular O - H - O bridges (O - O intermol = 2.499 Å) involving the acidic protons. Each molecule contains two equivalent intramolecular O - H - O bridges (O ··· O intrarnol = 2.603 Å). The coordination geometry around Co is a distorted (4+2) octahedron of four chelating equatorial N atoms and two apical iodine atoms. The rectilinear I- Co- I triads are arranged in infinite, faintly zigzagged heteroatomic chains propagating parallel to the ac plane.

The metathetical reactions of potassium thionylimide, KNSO, with arsenic and antimony halides in acetonitrile solution have been used to prepare two series of arsenic and antimony thionylimides, t Bu 3-n As(NSO) n and t Bu 3-n Sb(NSO) n , respectively, (n = 3, 2, 1). The tert-butyl- substituted compounds are moisture-sensitive oils. The half-sandwich hydrido-metal complexes CpM(CO) 3 H react with t BuAs(NSO) 2 in THF solution to give the metallo-arsanes [Cp(CO) 3 M]As( t Bu)(NSO) (M = Cr, M o, W).

The title compounds have been prepared by reactions of sodium polyselenide solutions in DMF with FeCp(CO) 2 I, and CoCl 2 · 6H 2 O , respectively, in the presence of (Ph 3 PNPPh 3 )Cl. They form black crystals, which were characterized by X-ray structure determinations. [Ph 3 PNPPh 3 ] 2 [Fe 2 Se 2 (Se 5 ) 2 ] · 2 DMF: Space group P2 1 /c, Z = 2, 2801 observed unique reflexions, R = 0.077. Lattice dimensions at 20 °C: a = 1091.6(7), b = 1247.3(5), c = 3070(2) pm, β = 90.77(4)°. In the dimeric anion the Fe atoms are linked via two bridging Se atoms, and each Fe atom is chelated by an Se 5 group. In the crystals, there are alternating layers o f cations and anions. [Ph 3 PNPPh 3 ] 3 [Co 3 (Se 4 ) 6 ] · 2 DMF : Space group P1̄, Z = 1, 3549 observed unique reflexions, R = 0.108. Lattice dimensions at 20 °C: a = 1496.2(5), b = 1504.8(5), c = 1904.1(6) pm, α = 100.31(2)°,β = 100.60(2)°, γ= 117.18(2)°. In the [Co 3 (Se 4 ) 6 ] 3- ion two [Co(Se 4 ) 3 ] 3- units, each with three chelating Se 4 groups, are linked to a central Co 3+ cation.

(TeCl 3 )(MoOCl 4 ) is obtained by the reaction of TeCl 4 and MoOCl 3 in a sealed ampoule at 180 °C. It forms yellow-green moisture sensitive crystals. The crystal structure determination (lattice constants a = 734.8(1), b = 1281.5(3), c = 1172.2(2) pm, β = 94.62(2)°, monoclinic space group P 2 1 /c, 2808 unique reflections for 92 parameters, final R = 0.029) shows that (TeCl 3 )(MoOCl 4 ) consists of square pyramidal (MoOCl 4 - ) anions and (TeCl 3 + ) cations. The (MoOCl 4 - ) anions are linked by asymmetric chlorine bridges and form centrosymmetric dimers (MoOCl 4 - ) 2 2- with the oxygen atoms located in the trans positions of the chlorine bridges. The coordination sphere for the Mo atom is a deformed octahedron of one oxygen and five chlorine atoms. Each trigonal pyramidal (TeCl 3 + ) cation is connected by chlorine bridges to two neighboured (MoOCl 4 ) 2 2- anions resulting in a strongly deformed octahedral environment of six chlorine atoms for the Te atom. The MoOCl 5 and TeCl 6 octahedra are linked by edges and corners and form layers parallel to the be plane. Alternatively the structure can be regarded as a close packing of Cl and O atoms with the layer sequence ABAC, A ··· and Mo and Te atoms located in one quater of the octahedral holes.

The crystal structures of the compounds [Cl 3 SnCo(CO) 4 ] 1, [Cl 2 Sn{Co(CO) 4 } 2 ] 2 , and [ClSn{Co(CO) 4 } 3 ] 3 , have been determined by X-ray crystallography. Sn is co-ordinated tetrahedrally by Cl- and Co-substituents, the co-ordination polyhedron of Co is a distorted trigonal bipyramid. The Sn -Cl- and the Sn-Co-distances both increase from 1 to 3 (Sn -Co: 247.7 in 1, 253.2 in 2, and 260.6 pm in 3).

The synthesis of 6 α-n-hexyl-1 α-hydroxymethyl-(4aβ, 8aα)-decahydronaphthalene-2β-ol using a Robinson-Nazarow-anellation followed by a Birch-reduction is described. This compound exhibits liquid crystalline behaviour in the presence of water. No mesomorphic properties were observed in the absence of water.

The reaction of acetylene-bis(phosphonous-bisdimethylamide) (1) with tetraphenyl-cyclopentadienone (2) yields a 1-phospha-1,6a-dihydropentalene (4), which can be sulfurized with CS 2 to give the 1-thio-compound 5, and oxidized with H 2 O 2 to give the 1-oxo-compound 6. With dimethyl-acetylenedicarboxylate (7) an amazingly stable l (λ 5 ),4(λ 5 )-diphosphapentalene (8) is generated, which reacts further with 7 to yield a l(λ 5 ),4(λ 5 )-diphosphaazulene (9). The preparation of the new molecules 4, 5, 6, 9 and the crystal structures of 5 and 9 are reported.

1,1,3,3-Tetrakis(dimethylamino)-diphosphete (3) reacts with diphenylacetylene and bis(trimethylsilyl)butadiin-1 ,3 to give 1,1,3,3-tetrakis(dimethylamino)-4,5-diphenyl-1 λ 5 ,3λ 5 - diphosphorine (8) and 1,1,3,3-tetrakis(dimethylamino)-5-trimethylsilyl-4-(trimethylsilyl-ethinyl)-1λ 5 ,3 λ 5 -diphosphorine (9). The new compounds are characterized by their NMR , mass and IR spectra. In addition, the results of an X-ray structure analysis of 9 are reported.

The octadendate thioetherthiol ′S 8 ′ - H 2 was synthesized by alkylation of the tetradendate thioetherthiol ′S 4 ′ - H 2 . Further products were the disulfide ′S 8 ′, resulting from the oxidation of ′S 8 ′ - H 2 , and the crown thioethers Bzo 2 -12S4, Bzo 4 -24S8 and Bzo 6 -36S12. Bzo 4 -24S8 was characterized by X-ray structure determination.

Reactions of the electron-rich, homoleptic alkylisocyanide complexes M(R N C) 6 (1a-2b) (1: M = Mo, 2: M = W; a: R = Et, b: R = t Bu) with electrophiles have been studied. A coupling of two isocyanide ligands to a complexed alkyne ligand is observed, when M(R N C) 6 is treated with two equivalents of HX(X = Br, I) and leads to the bis(alkylamino)acetylene complexes [X (R N C ) 4 M[η 2 -R(H)NC ≡ CN(H)R]]X (3a′-4b″) (3: M = Mo, 4: M = W). Treatment of W (EtNC) 6 (2a) and W ( t BuNC) 6 (2b) with one equivalent of Me 3 SiOTf results in the quantitative formation of the aminocarbyne complexes [(EtNC) 5 W ≡ CN (SiMe 3 )Et]OTf (6c) and [( t BuNC) 5 W ≡ C N (SiMe 3 ) t Bu]OTf (6d), respectively. In comparison, an equilibrium between W( t BuNC) 6 (2b) and the aminocarbyne complex [( t BuNC) 5 W ≡ C N (SiMe 3 ) t Bu]Cl (6e) is found, when 2b is treated with Me 3 SiCl. The compounds 6c and 6d are structurally related to the aminocarbyne complexes [(EtNC) 5 M ≡ C N E t 2 ]BF 4 (5a: M = Mo, 6a: M = W) and [( t BuNC) 5 W ≡ C N (Et) Bu]BF 4 (6b), which are obtained from ethylation of M (EtNC) 6 (1a, 2a) and W ( t BuNC) 6 (2b) with Et 3 OBF 4 . 5a and 6a undergo with HI a carbyne-isocyanide coupling reaction to give the alkyne complexes [I(EtNC) 4 Mo[η 2 -Et 2 NC≡CN(H)Et]]BF 4 (7a) and [I(EtNC) 4 W[η 2 -Et 2 NC≡CN(H)Et]]BF 4 (8a), respectively. Similar reactivity is exhibited by 6b, which yields with HI the alkyne complex [I( t BuNC) 4 W[η 2 - t Bu(Et)N C ≡ C N (H) t Bu]]BF 4 (8b). The reported transformation of a complexed isocyanide to an aminocarbyne and the acid-induced aminocarbyne-isocyanide coupling reaction are experimentally verified to be important steps in the reductive coupling of isocyanide ligands in [M(RNC) 6 X] + -complexes yielding the bis(alkylamino)acetylene compounds [X(R N C) 4 M[η 2 -R (H )N C ≡ C N (H )R ]] + .

Spectroscopic and ESR studies have revealed that redox interaction occurs between binuclear Mn 2 (III/IV) complex, [Mn 2 O 2 (2,2′-bipyridine) 4 ] 3+ and binuclear Mn 2 (II/II) complexes, [Mn 2 (L-py)(CH 3 COO) 2 ] + and [Mn 2 (L-py)Cl 2 ] + , in a dilute acetonitrile solution. Electrochemical data suggest that the chloride ion plays an additional important role in the above reaction.

PhNCO reacts with oxo ligands at metal centers to form phenyl nitrene complexes. As an intermediate of this reaction we obtained with ReO 2 I(PPh 3 ) 2 (1) the trimeric complex [ORe(OCONPh)I(PPh 3 )] 3 (2) in which the PhNCO moiety was added to an oxo ligand to form an N -phenyl carbamato group. This group acts as a bridging ligand chelating one Re atom via its N and one O atom and coordinating an other Re atom by its second O atom . 2 crystallizes as 2 · 2 CHCl 3 in the triclinic space group P1̄ with a = 1423.1(5), b = 2443.3(7), c = 1403.8(6) pm , α = 92.31(3), β = 94.76(3), γ = 81.48(3)°, and Z = 2. From the mother liquor of 2 after a few days Re(NPh)(NH 2 Ph)I 2 (PPh 3 )(OCONHPh) (3) is formed as a partial hydrolysis product. 3 is monoclinic with the space group P2 1 /n and a = 1163.0(4), b = 2527.0(3), c = 1243.9(5) pm, β = 98.04°, Z = 4. The Re atom exhibits an octahedral coordination w ith the two I atom s in a ?ra«s-arrangem ent and the phenyl nitrene ligand trans to the m onodentate PhN HCO 2 group. The coordination is completed by a phosphine and an aniline ligand. Reaction of 2 with excess PPh 3 yields 1. It crystallizes from CHCl 3 as 1 · CHCl 3 in the monoclinic space group P2 1 /n with a = 975.9(3), b = 2731(1), c = 1417.3(6) pm , β = 93.35° and Z = 4. In 1 the Re atom is pentacoordinated in form of a trigonal bipyram id with the two phosphine ligands in axial positions. A solution of 2 in THF forms Re(NPh)(NH 2 Ph)I 2 (PPh 3 ) (OReO 3 ) (4) upon exposure to air at room temperature. 4 is obtained as orthorhombic crystals with the space group Pca2 1 and a = 1727(1), b = 1064.2(4), c = 1765.7(9) pm , Z = 4, and is an analogue of 3 from which it can be derived by substituting the carbamato ligand by a perrhenat ion. In 3 and 4 the phenyl nitrene ligand is bound by a Re = N triple bond of 172 pm in a linear arrangement Re = N - Ph .

Azobenzene and stilbene derivatives with azomethine and ester groups and polymers of corresponding structures with mesogens possessing three to four aromatic systems in their mesogenic units have been synthesized, characterized and studied for their liquid crystalline properties by DSC measurements and observation by polarizing microscopy.

The action of diazomethane on 3,4-dioxodiisophoranes yields 3-oxodiisophorane-4-spiro- 2′-(oxiranes). Their reactions, spectral properties and fragmentation patterns under electron impact, and those of compounds derived from them , conform to their proposed structures.