Volume 35, Issue 1

The new compound CaMnBi 2 has been analytically and structurally characterized. CaMnBi 2 crystallizes in the tetragonal system (a = 450 ± 1 pm, c = 1108 ± 2 pm, space group P4/nmm). Mn and Bi atoms form fourfold pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Ca atoms between which further Bi atoms are located forming squarenets. The structure is strongly related to that of SrZnSb 2 which can be interpreted as a distorted variant of the new CaMnBi 2 type.

Single crystals of Sr 2 Ti 6 O 13 were prepared by heating a mixture of SrO·Ti 2 O 3 ·2TiO 2 in a vacuum furnace to 1800 °C for 6 hours. X-ray investigations show monoclinic symmetry (a = 1525,0, b = 376,9, c = 916,4 pm; β = 99,15°, space group C 3 2h -C2/m). Sr 2 Ti 6 O 13 is isotypic with Ba 2 Ti 6 O 13 .

BaHgSnS 4 was prepared for the first time and the crystal structure determined by using single crystal X-ray methods, a = 1080,4, b = 1084,o, c = 661,3 pm. Space group: C 10 2V -Pnn2 (No. 34) orthorhombic. There are pairs of edge-sharing tetrahedra linked together to form two-dimensional net works. The crystal structure is similar to that of BaCdSnS 4 [1].

Triclinic niobium(V) iodide was prepared from the elements at an iodine pressure of 3-4 bar in a temperature gradient from 400 to 230 °C. It crystallizes in the space group P1̄ with a = 7.591(3), b = 10,322(3), c = 6.977(3) Å, α = 90.93(3), β = 116.17(3), γ = 109.07(3)°, Z = 2 Nbls. The single-crystal X-ray structure analysis shows the compound to contain dimeric Nb 2 I 10 molecules with Nb-I bond lengths of 2.933 and 2.939(1) A for the bridge bonds and of 2.639···2.720(1) Å for the terminal bonds. The structure is isotypic with triclinic β-UCl 5 . The infrared spectrum indicates stretching vibrations at 148, 202, 214 and 242 cm-1 .

Antimony(V) Chloride, Acetoacetanilide At room temperature acetoacetanilide and antimony(V) chloride form a 1:1-(1) and a 1:2-adduct (2). These adducts react to the heterocycles C 10 H 10 Cl 4 NO 2 Sb (3) and C 10 H 9 Cl 5 NO 2 Sb (4). 3 exists in solution in two stereoisomers. The Free Energy of Activation for the transformation of the isomers is estimated.

The crystal and molecular structure of the compound Sn 3 (NC(CH 3 ) 3 ) 4 H 2 has been determined from X-ray data (R=0.044). The crystals are cubic, space group Pa3, with cell dimension a - 1713.6(8) pm and Z = 8. The molecules, which have a seco-norcubane like Sn 3 N 4 framework, are statistically disordered, thus forming closed packed pairs of molecules. The Sn 3 N 4 cage deviates strongly from a cube, the bond angles at Sn approaching 80°, and at N 100°. The averaged Sn-N bond distance is 223(1) pm.

Kautsky’s siloxene was prepared in a topochemical reaction from large crystals of CaSi 2 . The structure model was revised. Siloxene is a subsiliceous acid [Si 6 ]H 3 (OH) 3 and consists of two-dimensional corrugated Si-layers with three Si-Si bonds per silicon and an OH-or H-ligand, respectively. Ordering of adjacent layers is turbostratic. The layer lattice is capable of forming intercalation complexes. On intercalation only the layer distance is changed. The alkoxylated derivatives Si 6 H 3 (OCH 3 ) 3n and Si 6 H 3 (OC 2 H 5 ) 3n are also able to intercalate polar molecules.

The overcrowded molecules 1,1,3,3-tetra-tert-butyldisiloxane-1,3-diol (2) and penta-tertbutyldisiloxanol (4) have been obtained during the attempted synthesis of tri-tert-butylsilanol and di-tert-butylsilanediol by reaction of tri-tert-butylsilane and di-tert-butylchlorosilane, resp., with silver nitrate. Compounds 2 and 4 were also formed either by condensation of two molecules of di-tert-butylsilanediol or by co-condensation of the silanediol with tri-tert-butylsilanol in the presence of jo-toluenesulfonic acid. Reactions of tri-tert-butylsilanol with silicon tetrachloride yielded 1,1,1,5,5,5-hexa-tert-butyl-3,3-dichlorotrisiloxane.

Several oligomeric perchloro silanes of the type Cl 2n + 2 Si n (n= 1 to 6) were studied by 29 Si NMR. n-Cl 12 Si 5 was synthesized for the first time. Structures of isomeric silanes could be determined by substituent effects.

[(t-C 4 H 9 ) 3 PH] 2 [{Ru(μI)I 2 (CO)[P(t-C 4 H 9 ) 2 H]} 2 ] is prepared by the reaction of RUC 13 · (H 2 O) x with CO, NaI, and P(t-C 4 H 9 ) 3 in 2-methoxyethanol. Its IR, Raman, and NMR spectra are reported and discussed. [Ru(μ-I)(CO) 2 P(t-C 4 H 9 ) 2 H) 2 is obtained by the reaction of [Ru(μ-I)I(CO) 3 ] 2 with P(t-C 4 H 9 ) 3 in 2-methoxyethanol. The X 18 MAA′M′X′ 18 spin system of its 1 H NMR spectrum is analysed.

The system H + /MoO 4 2- was investigated by Raman spectroscopy in the range Z = 0 to 1.14 at initial concentrations C MoO₄ 2 - = 0.02 to 2M and concentrations of the ionic medium C Me+ = 2C MoO₄ 2- to 3M Me(Cl,NO 3 ) (Me=Li, Na, K,NH 4 , Mg/2). The mole-ratio method and intensity difference diagrams do not indicate any species between MoO 4 2- and Mo 7 O 24 6- contrary to propositions in recent papers. A detailed evaluation of the extensive data shows the possible portion of such species to be < 3 % , this value having a statistical certainty of 95%. Comparing the solutions having Z = 1.1 by fingerprint procedures, in all cases Mo 7 O 24 6- is the first main product (detectable by static methods) irrespective of the nature and concentration of the ionic medium. Thus, Mg 2+ ions do not influence the course of aggregation of molybdate ions as has been proposed in the literature. This is in accordance with theoretical investigations since the Mo 7 O 24 6- ion has the distinction of a number of favourable structural parameters in the system that become operative in case of scarcity of H + ions.

In the reaction of dimethyl- and diethylantimony iodide with magnesium, trimethylchlorosilane and tetrahydrofurane the new compounds 1-dimethyl- and diethylstibino- 4-trimethylsiloxibutane 1, 2 are produced. The reactions of dimethyl- and diethylantimony bromides with magnesium in THF in the presence of trimethylchlorosilane only yield the corresponding distibanes.

TiCl 4 reacts with trimethylsilyl difluorophosphate (Me 3 SiPO 2 F 2 ) and with trimethylsilyl dimethylphosphinate (Me 3 SiPO 2 Me 2 ) at room temperature under cleavage of the Si-O bond to give the principal products Cl 2 Ti(PO 2 F 2 ) 2 and Cl 2 Ti(PO 2 Me 2 ) 2 , respectively. The former product has also been obtained from the reaction of P 2 O 3 F 4 with TiCl 4 -SbCl 5 is capable of cleaving the P-O bond in P 2 O 3 F 4 to give Cl 4 SbPO 2 F 2 , but forms addition compounds with Me 3 SiPO 2 F 2 and Me 3 SiPO 2 Me 2 in which the terminal oxygen atoms of the esters are bound to antimony. IR spectra have been used to elucidate the structures of the prepared compounds.

Bis(diphenylphosphino)amine, [(C 6 H 5 )P 2 NH (1), can be metallated with n-butyl-lithium to hthium-bis(diphenylphosphino)amid, [(C 6 H 5 )P 2 NLi (2), It reacts with CH 3 OD to give N-Deutero-bis(diphenylphosphino)amine, [(C 6 H 5 )P 2 ND (3). The compounds were characterized by infrared, Raman, 1 H and 31 P NMR spectroscopy.

The stable free radicals 4-carboxy-2,2,6,6-tetramethylpiperidinooxyl, 4-carboxy-methylene-2,2,6,6-tetramethylpiperidinooxyl, 4-carboxymethyl-2,2,6,6-tetramethylpipe-ridinooxyl and 3′-carboxy-2,2,6,6-tetramethylpiperidine-4-spiro-2′-oxirane-l-yloxyl have been prepared and used as ligands in copper(II) complexes. The magnetic moments and the EPR spectra of the complexes and the free radicals have been investigated and compared with complexes containing diamagnetic cyclohexanecarboxylic acid or cyclo -hexaneacetic acid ligands. One of the copper(II) complexes shows a considerable inter-action between the nitroxyl radicals of the ligands.

The reaction of fac-K 2 [OsX 3 l 3 ] (X = Cl, Br) with pyridine and glycerin gives dark red crystals of trans-[OsClI(py) 4 ] or trans-[OsBrI(py) 4 ], soluble in organic solvents, and sublimable in vacuum at 300 or 320 °C. The structure is established by vibrational and mass spectra. With HX adducts of type trans-[OsXI(py) 4 ]·2 HX are formed, soluble in water with violet colour.

The lithiumphosphido complex cis-Mo(CO) 4 (Me 2 PLi) 2 reacts with dichlorophosphines RPCl 2 (R = Ph, Bu t ) to give coordination compounds of tetraphosphines Me 2 P-PR-PR-PMe 2 , whereas the complex of the triphosphine cis-Mo(CO) 4 (Ph 2 P-PMe-PPh 2 ) is obtained starting with the lithiumphosphido complex cis-Mo(CO) 4 (Ph 2 PLi) 2 . Phenyldilithiumphosphine and the chlorophosphine complexes cis-Mo(CO) 4 (R 2 PCl) 2 (R = Me, Ph) give in low yield cis-Mo(CO) 4 (R 2 P-PPh-PPh-PR 2 ) and cis-Mo(CO) 4 (R 2 P-PPh-PR 2 ). The mechanisms of these reactions are discussed. The { 31 P} 1 H- and { 1 H} 31 P-NMR spectra are analysed and correlated with the structures of these complexes.

By reaction of [(π-H 5 H 5 )(CO) 2 Mn≡C-C 6 H 5 ]BCl 4 with NaRe(CO) 5 a new type of complex is obtained. It crystallizes in the monoclinic space group P2 1 /c, Z = 4, a - 1115(1), b= 1464(1), c= 1657(2) pm, β= 136.79(8)°. Structure determination reveals a binuclear complex, the Mn-Re bond (281.7(3) pm) of which is bridged by the a-carbon atom of a phenylketenyl group (Mn-C 221(3), Re-C 224(3) pm) and semi-bridged by a CO group (Mn-C 187(4), Re-C 254(4), Mn-C-0 160(3)°).

Reaction of dicarbonyl(η-cyclopentadienyl)(methylpropiolate)manganese(I) with various stoichiometric quantities of tert-butyl lithium and subsequent addition of HCl or CH 3 OSO 2 F allows the isolation of vinylidene complexes of the general type CpMn(CO) 2 =C=CR 1 R 2 R 1 =H, CH 3 ; R 2 = COOCH 3 , COt-Bu, COH(t-Bu) 2 ). The compound with R 1 =H, R 2= COOCH 3 adds another CpMn(CO) 2 fragment, with formation of a bridged vinylidene species with a Cp 2 Mn 2 (CO) 4 unit. The reaction with amide or methoxide leads to the formation of carbene complexes CpMn(CO) 2 = C(R 1 )CH 2 -COOCH 3 (Rx = NH 2 , OCH 3 ).

The N-methylarylhydrazones of mesoxalodinitrile (3) and of ethyl cyanoglyoxalate (7) could be prepared via methylation of the corresponding phenylhydrazones 4 and 6 respectively. The hydrazones 3 and 8 reacted with hydrazine hydrate to yield the amidra-zone 1 and the hydrazide 2 b. The behavior of compounds 1 and 2 a, b towards a variety of reagents is reported. A variety of new α-arylhydrazononitriles were synthesised.

Betaine, Arsonium Ylides A systematic study on the nature of decomposition of betaine formed by nucleophilic attack of semistabilized arsonium ylides on thiocarbonyl substrates has been carried out. A series of substituted benzylidenetriphenylarsenanes have been generated from their corresponding salts and condensed with few cyclic thioketones to yield exocyclic olefins as exclusive products. The non-availability of thioepoxides indicates that the mode of decomposition of such type of betaines is quite analogous to the betaine formed by phosphonium ylides. The structure of the products have been assigned by IR and NMR spectral studies.

Some substituted benzylidenetriphenylarsenanes have been generated from their precursors and treated with acid chlorides or acid anhydrides to afford intermediate arsonium salts which in the presence of starting ylides undergo transylidation to give carbonyl stabilized arsonium ylides in fair to good yields. The structures of these stabilized ylides were confirmed on the basis of their spectral data.

The reaction of N-bromosuccinimide with ⊿ 5 -steroids such as, diosgenin, cholesterol, stigmasterol and dehydroisoandrosterone were studied. It was found that NBS in a solvent mixture of acetone, water and acetic acid (8:1:0.1) oxidises the olefinic bond of all the previous steroidal compounds to the corresponding transglycollic, 5α,6β-di-hydroxylic products in about 60% yield at room temperature.

The 1,3-diphenylisobenzofuran oxidation was investigated in methanolic and dodecyl-ammonium propionate reversed micellar solutions using fluorescein sodium as photosensitizer. The furan oxidation was caused by the singlet oxygen mechanism (Type II). Aniline enhanced remarkably the furan oxidation in methanolic solutions, but inhibited highly this oxidation in the reversed micellar solutions. This enhancement of the furan oxidation was considered to be brought about by the occurrence of a radical mechanism (Type I) besides Type II mechanism. No Type I reaction occurred in the micellar solutions. The rate constants concerning with both reaction processes were evaluated by kinetic analysis, employing various aryl-and alkyl-amines. The reaction mechanism of Type I and the quenching mechanism of singlet oxygen by amines were discussed from the relationship between the rate constants, and the ionization potential of amines and the solvent polarity.

New mixed-valence compounds of the type K 2 [Pt(NH 3 )X 3 ]-[Pt(NH 3 )X 5 ] (where X - Cl or Br) were prepared by partial oxidation-addition of K[Pt(NH 3 )X 3 ] with Cl 2 and Br 2 . The absorption and polarized reflectance spectra of these compounds show a semiconductor behaviour in one dimension and the resonance Raman spectra indicate the ···Pt(II) ···X -Pt(IV)-X chain.

The compounds KHgAs, KHgSb and KZnAs were prepared and their structures determined by powder and single crystal data. The compounds crystallize in a modified Ni 2 In-type structure, space group P6 3 /mmc-D 4 6h . The cell parameters are: KHgAs a = 450.6pm, c = 997.6pm, c/a = 2.21; KHgSb a = 478.4pm, c = 1022.5pm, c/a = 2.14; KZnAs a = 423.0pm, c = 1023.4pm, c/a = 2.42.

Tetrachloroaluminates, -ferrates and -gallates of formulae A I M III CL 4 with A 1 = Cs, Rb, In, Tl, NH 4 as well as the high temperature forms of the potassium compounds (KM III Cl 4 -III) crystallize with the baryte type structure. LiM III CL 4 , NaM III Cl 4 , and KM III Cl 4 -II (M III = AI, Fe, Ga), isotypic among themselves, belong -dependent on the size of the A + ion -to three different structure types.