Volume 47, Issue 4

The reaction of calcium-bis[bis(trimethylsilyl)amide]-THF (1/2) with benzonitrile in THF nearly quantitatively yields the title compound calcium-bis[N,N'-bis(trimethylsilyl)- benzamidinate]-THF (1/2). Under similar conditions pivalonitrile substitutes an ether ligand of calcium-bis[bis(trimethylsilyl)amide]-DME (1/2) without the formation of the corresponding amidinate derivative. The calcium-di(benzamidinate) [H 5 C 6 -C(NSiMe 3 ) 2 ] 2 Ca · 2THF crystallizes in the space group Pbcn with {a = 188.8(6); b = 1286.0(3); c = 1802.5(5) pm; Z = 4}. The calcium atom is hexa-coordinate with a distorted octahedral trans-configuration and with Ca - O and Ca - N bond distances of 238 and 243 pm, respectively. The bond lengths within the NCN moiety with values of 132 pm are characteristic of a diazaallylic system. The short N - Si bond lengths of about 170.5 pm as well as the high field shift of the 29 Si{ 1 H} NMR signal are evidence for an effective backdonation of the anionic charge from the nitrogen to the silicon atoms.

The structure of bis(m-aminobenzonitrile)dimercury(I) dinitrate, [Hg 2 (m -NH 2 C 6 H 4 CN) 2 ](NO 3 ) 2 has been determined by single crystal X-ray diffraction techniques and refined to an R w -value of 0.022. The crystals are triclinic, space group P1 with a = 5.4878(1) Å, b = 8.4085(1) Å, c = 9.6062(1) Å, α = 92.599(3)°, β = 94.763(3)°, γ = 89.614(3)° and Z = 1. The Hg 2 2+ -ion [Hg-Hg 2.524(1) Å] is approximately axially coordinated to amino nitrogen atoms [Hg - N 2.209(4) Å, Hg - Hg - N 169.5(3)°]. Additional amino hydrogen bonds to oxygen are building chains along the b-axis containing units of L - Hg - Hg - L groups.

The preparation of Hg(NH 3 ) 2 Cl 2 doped with a small amount of Cu 2+ is reported. The EPR and ligand field reflectance spectra indicate the presence of “CuCl 4 (NH 3 ) 2 ” polyhedra with a compressed tetragonal geometry and confirm, that the centres in Cu 2+ doped NH 4 Cl possess the same geometry - as postulated earlier. The Cu 2+ centres in Hg(NH 3 ) 2 Cl 2 are less compressed than those in NH 4 Cl, however, as could be deduced from the copper(II) hyperfine values, which are strongly influenced by the quite different admixture of the metal 4s orbital into the A lg (d z2 ) ground state in the two cases, and from the comparable energies of the d - d transitions.

The reaction of organometallic indium halides R 2 InBr and RInCl 2 (R = {Cp(CO) 2 Fe}, {Cp(CO) 3 Mo}) with silylated chalcogens E(SiMe 3 ) 2 (E = S, Se, Te) leads to the formation of cage compounds which contain a central In 4 E 4 cube. The structures of [{Cp(CO) 2 Fe} 4 In 4 Se 4 ] (1), [{Cp(CO) 3 Mo} 4 In 4 S 4 ] (2), [{Cp(CO) 2 Fe} 4 In 4 S 4 ] (3) and [{Cp(CO) 3 Mo} 4 In 4 Te 4 ] (4) were determined by X-ray crystallography.

Ca 2 [FeN 2 ] (monocl., C2/m (No. 12); a = 1093.0(2) pm, b = 496.0(1) pm, c = 684.4(1) pm, β = 121.09(1)°; Z = 4) and Sr 2 [FeN 2 ] (tricl., P1̄ (No. 2); a = 653.8(1) pm, b = 869.0(2) pm, c = 893.2(2) pm, α = 90.22(2)°, β = 109.45(1)°, γ = 102.30(1)°; Z = 5) were prepared by reaction of mixtures Ca 3 N 2 /Fe (Sr 2 N/Fe) with nitrogen (1 atm) at 850 C. The crystal structure of Ca 2 [FeN 2 ] contains isolated planar anions [Fe 2 N 4 ] 8- ; in the crystal structure of Sr 2 [FeN 2 ] planar [Fe 2 N 4 ] 8- units are present as well as linear anions [FeN 2 ] 4- .

The orange-red Tc 2 (O 2 CCH 3 ) 4 Br 2 has been prepared for the first time by reaction of [Tc 2 Br 8 ] 2- with glacial acetic acid and acetic anhydride. The IR and Raman spectra have been recorded at 80 K and are compared with those of the analogous compounds Tc 2 (O 2 CCH 3 ) 4 Cl 2 , Re 2 (O 2 CCH 3 ) 4 Cl 2 and Re 2 (O 2 CCH 3 ) 4 Br 2 . The assignment according to the point group D 4h is supported by normal coordinate analysis based on a general valence force field. The quadruple M - M bond is stabilized by the bridging acetato and destabilized by the axial halogeno ligands. The valence force constants f d (MM) are determined to 3,96-4,08 mdyn/Å. The interaction constants f dd (MM/MX), f dd (MM/MO) and f dα (MM/MMO) are about three times higher for the technetates as compared with the rhenates. The stronger interaction between oppo­site bonds in the equatorial ligand sphere is revealed by the stretching interaction constants f dd' , which are about two times higher than f dd for M - O bonds at right angles. The strong coupling of the ring co-ordinates implies extensive mixing of the M - O valence and deformation modes. The electronic spectra of Tc 2 (O 2 CCH 3 ) 4 X 2 , agree with those of the corresponding Re compounds.

Na 2 HgS 2 and K 2 HgS 2 were obtained as colourless, tabular crystals by reacting the alkali sulfides Na 2 S and K 2 S with red HgS at 970 K. Both compounds are orthorhombic: Na 2 HgS 2 , oP40, s.g. Pbca with a = 18.24(2) Å, b = 7.494(5) Å, c = 7.237(5) Å, Z = 8; K 2 HgS 2 , oP20, s.g. Pbcm a = 10.697(6) Å, b = 7.958(8) Å, c = 7.272(9) Å, Z = 4. Their crystal structures were determined from four circle diffractometer data and refined anisotropically to conventional R-factors of 0.056 (Na 2 HgS 2 ) and 0.062 (K 2 HgS 2 ) for 945 and 485 reflections with F 0 2 > 3σ(F 0 2 ), resp. The crystal structures represent new structure types. They are closely related with each other and can be derived from hcp-arrays of the chalcogen-atoms. Characteristic feature is the formation of discrete, almost linear [S - Hs - S] 2- dithiomercurate anions with average HgS-bond lengths of 2.31 Å.

Treatment of the bifunctional chlorophosphine R 2 P-CH 2 -PRCl (R = tBu) with diironenneacarbonyl affords the binuclear complex Fe 2 (CO) 6 [μ 2 ,η 3 -P (tBu )-CH 2 -P(tBu)-CMe 2 -CH 2 ] (2) by oxidative addition reaction and metallation of one of the tBu groups within the tBu 2 P - CH 2 unit. At elevated temperatures 2 eliminates isobutene, the phosphido complex Fe 2 (CO) 6 [(μ 2 -P(tBu)) 2 CH 2 ] (3) being formed. The crystal structure of 2 (space group P1̄ with a = 8.663(3), b = 10.849(4), c = 14.618(6) Å, α = 103.02(2), β = 96.32(3), γ = 112.77(2)°, Z = 2) reveals a binuclear complex with a P(tBu) - CH 2 - P(tBu) - CMe 2 - CH 2 ligand backbone spanning the Fe - Fe bond via a phosphido (μ 2 -P(tBu)(CH 2 )) and a phosphinoalkyl (μ 2 -P(tBu)-CMe 2 -CH 2 ) bridge. A strained, four-membered P 2 CFe ring is formed through coordination of the P - C - P donor set to Fe(2).

The crystal structure of tetramesityldistibane consists of isolated Mes 4 Sb 2 molecules in the trans conformation (average distance Sb -C 219 pm, distance Sb -Sb 284.9(1) pm, angles SbC 2 97°-100°, Sb 2 C 92°-109°). In the structure of trimesitylstibane there are stacks of isolated trigonal pyramidal Mes 3 Sb molecules (average distance Sb -C 218 pm, angles SbC 2 , 104 -106°).

The addition of pentacarbonylrhenate to [(OC) 3 Mn(thiophene)] + , [(OC) 3 M(η 6 -C 6 H 4 R 2 )] + (M = Mn, Re; R = H, Me, Cl) yields the σ,π-hydrocarbon bridged complexes (OC) 3 Mn(μ-η 4 :η 1 -C 4 H 4 S)Re(CO) 5 and (OC) 3 M(μ-η 6 :η 1 -C 6 H 4 R 2 )Re(CO) 5 , respectively. The latter complexes have also been obtained from (OC) 5 MFBF 3 (M = Mn, Re) and C 6 H 5 Re(CO) 5 . The fluxional behaviour of the cyclohexadienyl bridged complexes is probably due to a 1,2-shift of the Re(CO) 5 group. The reaction of [Re(CO) 5 ] - with [(η 5 -C 5 H 5 )Fe(η 6 -p-C 6 H 4 (R)Cl)] + (R = H, Me, Cl) proceeds with substitution of chlorine to give the heterobimetallic compounds [(η 5 -C 5 H 5 )Fe[μ-η 6 :η 1 -C 6 H 4 (R)]Re(CO) 5 ] + .

A new synthesis for 2-chloro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ 3 -triazaphosphinane (1) is described. Chlorine-fluorine exchange in 1 by means of sodium fluoride in acetonitrile in the presence of catalytic amounts of a crown ether furnished 2-fluoro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ 3 -triazaphosphinane (2). The synthesis of the bromine and iodine analogues, 3 and 4, by metathesis of 1 with the appropriate trimethylsilyl halides, Me 3 SiBr and Me 3 SiI, respectively, is also described. The syntheses of an iron(0)tetracarbonyl complex (5) and of a dichloroplatinum( II) complex (6) are reported. A single crystal X-ray diffraction study was conducted on 6. [P2 1 /c, a = 1161.3(3), b = 1423.2(3), c = 1247.7(3) pm, β = 109.42(2)°, R = 0.028], There are deviations from ideal square planar geometry at platinum. The heterocycles display a flattened boat conformation. A Staudinger reaction of 1 with Me 3 SiN 3 led to the formation of a substituted cyclotriphosphazene.

The reaction of phthaloyl chloride 2 with 1,3-dimethylurea 1 in dichloromethane at room temperature leads to the formation of N ,N -1,1'-phthaloyl-bis(1,3-dimethylurea) 3 whereas in refluxing solvent N-methyl-phthalimide 4 is the principal product. The reaction of 1,3- bis(trimethylsilyl)-1,3-dimethylurea 5 separately with phthaloyl- 2, 4-nitrobenzoyl- 6, and 5-chlorothiophene-2-carbonyl chloride 9 results in the formation of 1,3-phthaloyl-1,3-dimethylurea 7, 1,3-bis(4-nitrobenzoyl)- 1,3-dimethylurea 8, and N,N-bis(5-chlorothiophene- 2-carbonyl)-N-methylamine 12, respectively. The reaction of N,N-bis- (trimethylsilyl)acetamide 11 with 9 furnished N,N-bis(5-chlorothiophene-2-carbonyl)-acetamide 13, while the reaction of 13 with 1,3-dimethylthiourea 10 afforded 1.3-dimethyl-1,3- bis(5-chlorothiophene-2-carbonyl)thiourea 14. The structures of 3 and 12 were confirmed by low temperature X-ray crystallography. Both display crystallographic twofold symmetry.

Reduction of naturally occurring para-and ortho-benzoquinone derivatives M to their respective radical anions M ·⊖ can be accomplished under largely aprotic conditions either by cautious low-temperature reaction in THF containing an excess of (2.2.2) cryptand at a potassium mirror or by using the "mild" single electron transfer reagent tetrabutylammonium boranate R 4 N ⊕ BH 4 ⊖ in DMF. On addition of soluble alkali tetraphenylborates Me ⊕ [B(C 6 H 5 ) 4 ] ⊖ , their hitherto unknown radical ion pairs [M ·⊖ Me ⊕ ] · and/or triple ion radical cations [Me ⊕ M ·⊖ Me ⊕ ] ·⊕ form, which might be of biological relevance in molecular carrier and "turn off -turn on" switch processes. On addition of metal perchlorates Me ⊕n (ClO 4 ⊖ ) n with multiply charged counter cations Me ⊕n the respective paramagnetic species [M ·⊖ Me ⊕n ] ·(n-1)⊕ result. Assuming exclusive one-electron transfer reductions without any redox fragmentation reac­tions, ESR, ENDOR and GENERAL TRIPLE spectra are presented and discussed for the following radical anions and radical ion pairs: mitomycin C (M ·⊖ and [M ·⊖ Me x ⊕ ] ·(x-1)⊕ with Me ⊕ = Li ⊕ , Na ⊕ ), streptonigrine (M ·⊖ and [M ·⊖ Li x ⊕ ] ·(x-1)⊕ ), Entobex® (M ·⊖ and [M ·⊖ Me ⊕n ] ·(n-1)⊕ with Me ⊕n = Li ⊕ , Na ⊕ , Cd ⊕⊕ , (H 5 C 6 ) 2 Tl ⊕ ) as well as brucinequinone ([M ·⊖ Me ⊕n ] ·(n-1)⊕ with Me ⊕n = Li ⊕ , Cd ⊕⊕ , Pb ⊕⊕ , La ⊕⊕⊕ ).

A number of macrocyclic (1b-3b) and linear oligoether compounds (4b-8b) with 2,2'- methylenebis(4-aminophenol) or 2-aminophenol characteristic building blocks have been synthesized by reduction of the corresponding nitro derivatives with Pd -C/hydrazine hydrate. The pKa' values of the new compounds have been determined by potentiometric titration. These and the observed spectroscopic data are discussed and compared with related compounds. A crystalline 1:1 complex of the diamino crown 3b with NaSCN has also been prepared and characterized.

Triphenyltin dichloro- and dibromo-phosphate have been prepared from the reactions of (Ph 3 Sn) 2 O with POCl 3 and with POBr 3 , respectively. The reactions of POCl 3 with R 2 SnO (R = Me, Et) lead to R 2 Sn (O 2 PCl 2 ) 2 and R 2 SnCl 2 . Diethyltin bis(dichlorophosphate) has been also prepared by the treatment of (Et 2 ClSn) 2 O with POCl 3 . The infrared spectra of Ph 3 SnO 2 PX 2 (X = Cl, Br) and Et 2 Sn(O 2 PCl 2 ) 2 are found to be consistent with polymeric structures with pentacoordinated tin atoms in Ph 3 SnO 2 PX 2 and hexacoordinated tin atoms in Et 2 Sn(O 2 PCl 2 ) 2 . The El mass spectra of R 3 SnO 2 PCl 2 (R = Me, Ph) and R 2 Sn(O 2 PCl 2 ) 2 (R = Me, Et) are given and discussed.

A series of triphenylgermanium selenocarboxylates 3 were synthesized and characterized. The esters 3 are thermally stable, but labile towards moisture and oxygen. They react with arenesulfenyl chlorides and areneselenenyl bromides at room temperature to afford the corresponding acyl arenesulfenyl selenides and acyl aryl diselenides in moderate yields.

The isomeric thiacyclooctanones 1b-d are transformed via the semicarbazones Z-2b,c, E-2b,c and 2d to the bicyclic 1,2,3-selenadiazoles 3b,c, 3b´,c´ and 3d. The ring closure reaction with SeO 2 is highly regioselective and doesn’t depend on the Z /E -ratio of the semicarbazones. A detailed 1 H and 13 C NMR study was made for 1, 2 and 3.

The synthesis and characterization of polysiloxanes containing styrylthiophene units as side groups are described. Polysiloxanes containing spacers with six or eleven methylene units exhibit smectic phases. If the spacer contains only three methylene units, the polysiloxanes exhibit no liquid crystalline behaviour.

A variety of new polyfunctionally substituted pyridines, naphthopyrans and pyrazolopyrimidines were prepared via reacting ylidenemalononitriles with thiophenol, thionaphthol, naphthols and or aminopyrazoles.

Birch reduction of spirodiisophorones by sodium in liquid ammonia - t-butanol reduces their normally inert 6-keto-group, producing the corresponding secondary alcohols, the 6-hydroxygroup of which assumes the endo- or exo-configuration. 3´-Oximinospirodiisophor-6-one is converted predominantly into the 6-endo-hydroxy-compound , from which the 3´,6-endo-ketol is obtainable by the action of sodium bisulphite. 3´-eq(and ax)-Hydroxyspirodiisophor-6-one each yield a pair of stereoisomeric 3´,6-diols, distinguished by their spectral characteristics and derivatives. Spirodiisophora-3´,6-dione yields a mixture of the same four diols, three of which are isolable in low yield. The structure of selected compounds is correlated with their assigned 13 C NMR spectra.

Benzyl 2,3-anhydro-4-0-triflyl-β-L-ribopyranoside (1) and benzyl 2,3-anhydro-4-O-triflyl-α-D-lyxopyranoside (3) react with pyridine to give benzyl 2,3-anhydro-4-deoxy-4-[N]-pyridinium - α-D-lyxopyranoside triflate (2) and benzyl 2,3-anhydro-4-deoxy-4-[N]-pyridinium -β-L-ribopyranoside triflate (4). Similar reactions with thiourea and dimethylsulfoxide are mentioned. Compound 2 is stable at room temperature, whereas compound 4 decomposes in a few hours (neighbouring group effect). The 13 C NMR assignments of 2 are proved by 13 C { 1 H} single frequency decoupling experiments.

(PF 3 )AuCl was prepared from PF 3 and Au 2 Cl 6 in SOCl 2 as a solvent. It is more stable than the analogous CO complex. It has a vapor pressure of about 10 -4 mbar at room temperature. Its IR , NMR and mass spectra are reported.

Chlorosulfonium hexachloroantimonate crystallizes in the monoclinic space group C 2/m with a = 1405.5(3) pm, b = 1055.1(2) pm , c = 882.2(2) pm, β = 110.05(3)° at 169 K with 4 formula units per unit cell. A distorted octahedral coordination around sulphur is formed by three S - C l bonds and three interionic sulphur chlorine contacts. The interionic interactions in SCl 3 + salts of known crystal structures are discussed.

The enantiomers of the fungicidal and bactericidal (3-chloro-1,2,4-thiadiazol-5-yl)-(3´-chloro-1´,2´,4´-thiadiazoyl-5´-ylthiomethyl)-sulfoxide (2) have been separated by liquid chromatography on triacetylcellulose. Tested in a photometer assay on Torulopsis H 24 and Erwinia carotovorum (+)-2 and (-)-2 show practically the same activity and do not differ from the racemic mixture.

The binuclear complex [(Ph 3 PAu) 2 Se(p-C 6 F 4 Cl)] + SbF 6 - was prepared from Ph 3 PAuCl and (p-C 6 F 4 Cl) 2 Se 2 in the presence of AgSbF 6 . The crystal structure shows a short intramolecular gold-gold interaction, which leads to an extreme distortion in the coordination geometry at selenium.