Volume 43, Issue 3

The potassium selenostannate(IV) K 4 Sn 3 Se 8 has been prepared by methanolothermal reaction of K 2 CO 3 with elemental Sn and Se at 190 °C and its structure established by X-ray structural analysis. The unit cell contains isolated [Sn 3 Se 8 ] 4- anions consisting of a central SnSe 4 -tetrahedron edge-bridged to two further tetrahedra. Crystallographic D 2 -symmetry is observed for these anions. The four-membered rings are markedly distorted with Sn -Se bond distances of 2.520(1) to the central tin atom as compared to long Sn-Se distances of 2.622(1) Å to the tin atoms of the outer tetrahedra. The terminal Sn -Se bonds have a length of 2.473(1) Å.

Zinc azide · 4-methylpyridine (1) is formed by the reaction of zinc azide with the corresponding pyridine in aqueous solution. The crystal structure was determined by single crystal X-ray diffraction methods. The crystals of 1 are monoclinic, space group C2/c, Z = 4, a = 1085.5(2), b = 1692.7(11), c = 619.7(6) pm, β = 113.47(5)°. Each zinc atom is surrounded by five nitrogen atoms (four from azide groups and one from the pyridine adduct) in a distorted trigonal bipyramidal fashion. The ZnN 5 -polyhedra share common edges to form chains along the crystallographic c-axis.

The methylthio-chlorophosphanes RP(Cl)SMe [R = Me (1). Et (2). Ph (3)] are prepared in good yields (62-65%) by condensation reactions of the corresponding dichlorophosphanes RPC12 with methanethiol in the presence of trimethylamine (molar ratio 1:1:1). 1 and 3 have been used to produce 3-phospholene sulfides in a one-pot process by reaction with 1,3-dienes at 70 to 100 °C. Reaction proceeds via [1+4]-cycloadducts, which in suitable cases can be isolated and used for the preparation of the corresponding 3-phospholene oxides. New compounds were characterized by elemental analysis and spectroscopic investigations (NMR. MS).

The reaction of PdAc 2 and K 2 PtCl 4 with the ligand 1-thia-4,7-diazacyclononan (C 6 H 14 N 2 S - L) yield crystals of [PdL 2 ](PF 6 ) 2 (4) and [PtL 2 ]Br 2 -H 2 O (5), respectively. The structures of 4 and 5 have been determined. Crystal data: 4, monoclinic, space group P2 1 /c, a = 719.2(1), b = 1712.5(3), c = 936.8(2) pm. β = 99.15°, Z = 2; 1708 reflections, R = 0.029. 5, monoclinic, space group P2 1 /c, a = 1682(2). b = 786(1), c = 1573(1) pm. β = 108.1(1)°, Z - 4; 1706 reflections, R = 0.070. 4 contains octahedrally coordinated Pd(II); in addition to the square planar PdN 4 group (mean Pd -N bond length 206 pm) the S-donor atoms are weakly coordinated in the axial positions (Pd-S: 303.4(1) pm). In 5, however, Pt(II) is in a square planar ligand environment. The S-donor atoms are bent away from the axial positions of the central atom.

Reaction of 1,3,5-tris(dimethylamino)benzene (TDMAB) with iodine in solution gives dark red needles of a compound (1) with stoichiometry C 24 H 42 I 6 N 6 , Mr = 1176.07, orthorhombic, Cmca, Z = 4, a = 10.865(2) Å, b = 16.737(6) Å. c = 20.511(9) Å, V = 3730 Å 3 , d c = 2.1 g·cm -3 measured at room temperature, R = 0.062 for 744 independent reflections and 100 L. S.-parameters. The solid contains bis[tris(dimethylamino)cyclohexadienylium]dications - obtained by dimerization of TDMAB + radical cations - and triiodide counter anions. The solid is diamagnetic. Reaction of TDMAB with 1,3,5-tricyanobenzene (TCB) leads to orange platelets of 2 with stoichiometry C 21 H 24 N 6 , M r = 360.4, orthorhombic, Pna2 1 Z = 4, a = 11.074(4) Å, b = 11.568(4) Å, c = 16.100(7) Å, V = 2060 Å 3 , d c = 1.18 g·cm -3 , measured at room temperature, R = 0.065 for 921 independent reflections and 156 parameters. The solid consists of donor (TDMAB) - acceptor (TCB) pairs. The compound is diamagnetic at room temperature.

The structure of the quinuclidine-stabilized mesyl sulfene H 3 C-SO 2 -CH=SO 2 ←N(CH 2 CH 2 ) 3 CH (3) was determined by X-ray analysis, which indicates a double-bond in the C=SO 2 group, while the quinuclidine is coordinated at a distance to the sulfur atom longer than a S-N single bond.

Trapping of methyleneborane 7a with 3-hexine yields the stable 1,2-dihydroborete 1a . Strong folding (148.8°) along the 1,3-diagonal. the short 1.3-distance (191.5 pm), a lengthened 3,4- and a shortened 1,4-bond prove the homoborirene nature of 1a.

Compounds RPBr 2 Cr(CO) 5 (R = Me, Et, i-Pr. t-Bu, c-Hex. (-)Menthyl. Ph) and RPBr 2 W(CO) 5 (R = (-)Menthyl, Ph) are obtained from M(CO) 5 THF and organodibromophosphane. Dehalogenation of the chromium complexes with magnesium in THF leads to (RP) 3 [Cr(CO) 5 ]m (m = 1. 2, 3) with m depending on the bulkiness of R. When dissolved in THF the binuclear complexes (m = 2) are gradually converted into mononuclear compounds. The isomeric structure of the cyclotriphosphane complexes is deduced from their 31 P{ 1 H} NMR spectra.

The reaction of FeI 2 , with (Me 3 NCH 2 Ph)I in CH 2 Cl 2 and with Ph 3 PS in toluene (molar ratios 1:1) yields (Me 3 NCH 2 Ph) 2 Fe 2 I6 (1) and Fe 2 I 6 (SPPh 3 ) 2 ·C 6 H 5 CH 3 (2), respectively. The structures of 1 and 2 were determined from single crystal X-ray diffraction data. 1 crystallizes in the monoclinic space group P2 1 /n with a = 895.7(2), b = 1400.5(2), c = 1360.6(3) pm. β = 95.82(2)°, Z = 2. The anion of 1, Fe 2 I 6 2- , has edge-sharing double-tetrahedra. The bridging and terminal F e - I bond lengths were found to be 269.9/270.7 and 260.3/258.6 pm, respectively (Fe-Fe: 358.2 pm). 2 crystallizes in the triclinic space group P1̄ with a = 987.6(1), b = 1119.3(1), c = 1159.4(1) pm, α = 101.10(1), β = 99.15(1), γ = 102.83(1)°, Z = 1. The molecules of 2 consist of centrosymmetric dinuclear Fe 2 I 2 units (like for Fe 2 I 6 2- in 1), with F e - I distances of 266.4 and 273.4 pm. The distorted tetrahedra around Fe are completed by an iodide ion (Fe-I: 256.9 pm) and Ph 3 PS with the sulfur as donor atom. The Fe-Fe distance was found to be 339.7 pm.

The reaction of C 6 H 5 (CH 3 )PNa with some alkyl halides in liquid ammonia was studied. The resulting phosphines were characterized by elemental analyses, NMR spectra, and by the reaction with trimethylsilyl azide giving trimethylsilylimino triorganophosphoranes.

The tridentate macrocyclic ligands 1,4,7-triazacyclononane, its thia analogue 1,4,7-trithiacyclononane, 1-oxa-4,7-diazacyclononane, and N,N′,N″-trimethyl-1 ,4,7-triazacyclononane react with Re(CO) 5 Br in dimethylformamide to yield colorless, air-stable [LRe(CO) 3 ]Br complexes (L = tridentate macrocycle). With Mn(CO) 5 Br only the cyclic amines react to afford yellow-orange [LMn(CO) 3 ]Br complexes whereas 1,4,7-trithiacyclononane does not give stable complexes of manganese. The crystal structures of [([9]aneN 3 )Re(CO) 3 ](NCS) and [([9]aneS 3 )Re(CO) 3 ]Br · 1/2 H 2 O have been determined. The former crystallizes in the orthorhombic space group P bca (a = 12/763(4), b = 12.662(5), c = 17.472(9) Å; Z = 8); whereas the latter crystallizes in the monoclinic space group P2 1 /c (a = 9.444(1). b = 11.797(2), c = 28.095(3) Å. β = 90,86(1); Z = 8).

Reaction between Cl 2 AlCH 2 CH 2 AlCl 2 and BCl 3 leads to Cl 2 BCH 2 CH 2 BCl 2, in which halogen exchange is achieved by Bl 3 to yield I 2 BCH 2 CH 2 BI 2 (5). Redox reaction between butyne-2 and 5 results in the formation of 1,4-diiodo-2,3-dimethyl-1,4-diboracyclohexene-2 (1a) and iodine. Methylation of 1 a with AlMe 3 leads to the title compound 1 d , established by 1 H, 11 B, 13 C NMR. Heating of 1 d in toluene at 160 °C in a sealed tube results in an intramolecular isomerization to give 1,2,3,4,5-pentamethyl-2,3-dihydro-1,3-diborole (2d) in 90% yield.

The thermal decomposition of ammonium metavanadate(V) has been studied at atmospheric pressure, at hydrothermal, and high-pressure conditions, respectively. In a closed high-pressure system a redox reaction between vanadium(V) and ammonia takes place, to yield with increasing temperature the compounds (NH 4 ) 2 V 6 O 12 (OH) 2 , VO 2-δ (OH) δ , and V 2n O 2n-1 the composition of the product eventually approaching V 2 O 3 at 1100 °C. All these compounds can easily be converted into V 2 O 5 by heating in air. The mid-infrared spectra of the decomposition products obtained by slow heating of NH 4 VO 3 in air, are virtually identical and show that ammonium hexavanadate(V), (NH 4 ) 2 V 6 O 16 , is the most important, and perhaps only, intermediate in the “non-reduction” case. On further heating, (NH 4 ) 2 V 6 O 16 may not only loose ammonia and water to form V 2 O 5 but could as well partially be reduced by ammonia. This could explain the diversity of intermediate “compounds” described in the literature. Hydrothermal reaction of NH 4 VO 3 yielded (NH 4 ) 0 . 5 V 2 O 5 , (NH 4 )2V 3 O 8 , and V 2 O 3 at rather low temperatures.

Organomercury(II) complexes involving isoniacinamide(I) of the type. RHgCl(L)(II) [R = phenyl, o-, p-hydroxyphenyl ( o-, p-HOC 6 H 4 ) , p-acetoxyphenyl (p-AcOC 6 H 4 ), 2-furyl (2-C 4 H 3 O); L = isoniacinamide] have been synthesized and characterized. Conductance measurements indicate that the complexes are non-electrolytes. From IR and UV spectral studies it is concluded that isoniacinamide is coordinated to the mercury(II) ion through the ring nitrogen atom. 1 H and 13 C NMR support the stoichiometry of the complexes. Fluorescence studies have been made for o-, p-HOC 6 H 4 HgCl(L) complexes. For C 6 H 5 HgCl(L), p-HOC 6 H 4 HgCl(L) and p-AcOC 6 H 4 HgCl(L) complexes, thermal studies (TG and DSC) have been carried out and relevant kinetic and thermodynamic parameters for thermal degradation have been enumerated. The fragmentation pattern of the complexes has been analysed on the basis of mass spectra. The C 6 H 5 HgCl(L) and p-AcOC 6 H 4 HgCl(L) complexes have been screened for antibacterial activity.

The title compound (1) is obtained as brownish crystals by reaction of HOCl 3 with NaC 5 Me 5 in tetrahydrofuran. The structure of 1, which has two slightly different independent molecules per asymmetric unit, has been elucidated by X-ray analysis. The crystals are triclinic with a = 1686.2(8) pm, b = 1816(1) pm, c = 846.5(4) pm, α = 92.02(7)°, β = 92.47(9)°, γ = 63.21(5)°, space group P1̄, D(calcd) = 1.560 g/cm 3 , and R = 0.0286, for 6219 observed reflections with I > 3σ(I).

NCAuCNH reacts with expoxides to give oxazolidine-2-ylidene (2) and 2-hydroxyalkyl complexes (3), respectively. Complexes with cyclic carbene ligands [XXX] (5) and [XXX] (7) are formed from the corresponding isocyanic metal compounds and oxiranes. 5b has been characterized by crystal structure determination. Ring opening of phenyloxirane occurs at the phenyl substituted carbon atom. (NC) 2 M(CNH) 4 (M = Fe, Ru, Os) and oxirane yield mixtures of [XXX] and [XXX].

By gas chromatography mass spectrometry and synthesis of authentic standard, trans-4-phenyl-3- buten-2-one for the first time as well as known hydrocarbons have been identified in the Dufour′s gland secretion of the African harvester ant Messor galla (Mayr).

Nitration of khellinone leads to the formation of a small amount of 3-nitrokhellinone and 5-acetyl-6-hydroxybenzofuran-4.7-dione (khellinonequinone) as a main product. The latter compound reacts with primary amines to give the corresponding imino compounds. Reaction of khellinone with o-phenylenediamine involves condensation followed by cyclisation. While on the other hand treating with phenyl hydrazines gives the phenyl hydrazone. The pyrazolobenzofuran derivative was obtained by the action of hydrazine hydrate on khellinonequinone. Finally the reaction with malononitrile leads to the formation of the ylidene derivative. Two quinone derivatives showed a weak effect on mycelial growth and aflatoxin formation.

5-(4-Methylphenyl)-2,7-diphenyl-4-phenylcarbamoylimidazolo[1,2-c]thiazol (9) reacts with tetrachloro-o-benzoquinone to give a [π4+π4]cycloadduct (17); in an obviously analogous manner 5-(4-methylphenyl)-2.7-diphenylimidazolo[1,2-c]thiazol (8) with N, N′-benzenesulfonyl-obenzoquinonediimine (14) yields compound 16 and benzenesulfinic acid. The [π4+π4]adduct 17 solvolyzes with alcohols in a stereoselective SN2″ reaction giving 24a, b. The stereochemical outcome of this reaction has been determined by an X-ray analysis of 24a.

Podands, coronands and cryptands containing 2,2′-bipyridine-units were synthesized. These Compounds can be used as ligands in Ru(II)-polypyridinecomplexes. This new route principally allows the preparation of tris-heteroleptic complexes using the appropriate cryptands. Ru(II)- polypyridines RuL 3 2+ (e.g. Ru(bpy) 3 2+ ) are interesting as sensitizers in photochemical water cleavage. Compared to Ru(bpy) 3 2+ , the photoanationrate should be reduced in the Ru(cryp) 2+ complex.

Reaction of [Rh(NBD)(P∼O) 2 ][SbF 6 ] (1) (NBD = norbornadiene) with hydrogen results in the formation of the stable dihydrido rhodium complex [cis- (2). Rh - O bond cleavage in 2 by carbon monoxide or NaBH 4 affords the products [trans-(P∼O) 2 Rh(CO) 3 ][SbF 6 ] (3) and [trans-H 2 Rh((P∼O) 2 (η 2 -H 2 BH 2 )] (5), respectively. Upon treating a THF solution of 3 with argon, 3 eliminates CO to give the complex (4) with a mono- and bidentate (ether-phosphane) ligand.