Volume 34, Issue 6

The new compound K 5 CuSb 2 crystallizes in the space group R3̄m with the constants a = 591(2) pm, c = 2814(4) pm, c/a = 4.76. There are linear (Sb-Cu-Sb) 5- groups in the structure which are isoelectronic to the HgCl 2 molecule.

Single crystals of Cu 0,5 Nb 1,5 O 3,7 were prepared and investigated by X-ray methods (a = 376.7, b = 507.3, c = 374,9 pm; β = 101.5°; space group: P2 1 -C 2 2 ). The statistically occupied metal positions (Nb/Cu) have a trigonal prismatic O 2- surrounding.

Five new oxidpnictides have been prepared and structurally characterized. They crystallize in the tetragonal system, I4/mmm, with the following constants: Sr 2 Mn 3 As 2 O 2 : a = 416 ± 1 pm, c = 1884 ± 4 pm, c/a = 4.529, Ba 2 Mn 3 As 2 O 2 : a = 424.8 ± 0 5 pm, c = 1977 ± 3 pm, c/a = 4.654, Sr 2 Mn 3 Sb 2 O 2 : a = 426.2 ± 0.4 pm, c = 2011 ± 2 pm, c/a = 4.718, Ba 2 Mn 3 Sb 2 O 2 : a = 436.7 ± 0.5 pm, c = 2078 ± 2 pm, c/a = 4.758, Sr 2 Mn 3 Bi 2 O 2 : a = 428 ± 1 pm, c = 2055 ± 5 pm, c/a = 4.801. Mn- and As(Sb,Bi) atoms form tetragonal pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Sr atoms, in which Mn and O atoms are located forming MnO 4 square plane nets.

Na 6 Pt 8 Ge 8 was prepared from the elements; it crystallizes in a cubic structure, space group I4̄3m, a= 761.4 pm. The phase contains two structural elements: The Pt-atoms form tetrahedra, which are covered by bigger Ge-tetrahedra. The Na-atoms build a 3-D-network consisting of chains crossed under right angels.

Phosphanes P(NHX) 3 , which are usually unstable, were prepared as ligands in the complexes (CO) 5 MoP(NHX) 3 (X = H, Me, i-Pr, Ph, PhNH) (2-6) by reactions of (CO) 5 MoPCl 3 with ammonia, primary amines, and Phenylhydrazine. Attempts to prepare (CO) 5 MoP(NH-t-Bu) 3 were unsuccessful: however, (CO) 5 MoPCl 3 reacts with an excess of t-BuNH 2 under similar conditions to give (CO) 5 MoNH 2 -t-Bu (7) and (CO) 5 Mo[P(NH-t-Bu)N 2 -Bu] 2 (8). The diazadiphosphetidin complex 8, in which the metal is bound to phosphorus, can also be prepared directly by UV-irridation of a THF solution of Mo(CO) 6 and the free ligand.

The preparation of the sulfanes [(CH 3 O) 3 Si-(CH 2 ) 2 -] 2 Sn (n=1-4) 2-5 and the corresponding mercaptane 1 is communicated. The 1 H and 13 C NMR spectra of 1-5 are reported and discussed. The infrared and Raman spectra are discussed in view of C-S-and S-S-bonding.

Dialkylmonofluorophosphites react with PCI 3 or PBr 3 to yield the title compounds 6 and 7. These reactions take place only in the presence of protic catalysts. As a working hypothesis, it is assumed that phosphorus is quinquevalent in the transition state. The 31 P and 11 F NMR data are tabulated.

[Mn(CO) 3 (R 2 PCH 2 ) 3 CCH 3 ]ClO 4 (1a) (R = C 6 H 5 ) reacts with NaBH 4 on UV irradiation to yield HMn(CO) 2 (R 2 PCH 2 ) 3 CCH 3 (2a). [Mn(CO) 3 (R 2 PCH 2 ) 3 CCH 3 ]BR 4 (1b) gives only decomposition products. Boiling of 1a or b and NaOH in acetone/water does nots give 2a but the new hydride HMn(CO) 3 (R 2 PCH 2 ) 2 C(CH 3 )CH 2 PR 2 (3a). This compound cannot be prepared on ultraviolet irradiation of a solution of 1a or b and NaBH 4 in methyl alcohol or acetone. The analogous deutendes DMn(CO) 2 (R 2 )PCH 2 ) 3 CCH 3 (2b) and DMn(CO) 3 (R 2 PCH 2 ) 2 C(CH 3 )CH 2 PR 2 (3b) were also prepared. The new compounds were characterized by their IR, Raman, 1 H NMR and 31 P NMR spectra.

The antitumor activity of vanadocene dichloride is investigated against Ehrlich ascites tumor in CFi mice. The application of 80 or 90 mg/kg 24 h after transplantation achieves 100% tumor inhibition until day 30. On treatment with higher doses death of an increasing number of animals is caused by substance toxicity. The results of this study indicate that vanadocene dichloride exhibits antineoplastic properties similar to those found for titanocene dichloride and cis-dichlorodiammine-platinum(II).

An examination of the 1 H-{ 11 B}, 11 B, 11 B-{ 1 H}, and 31 P-{ 1 H} NMR behaviour of the compounds [M(B 5 H 8 )(X)(dppe)] has been made [M = Ni, Pd and Pt; X = halogen; dppe = bis(diphenylphosphino)ethane]. Some relaxation phenomena are rationalised, and it is concluded that all the compounds examined have a static metallo -nido-penta -borane structure in which the metal atom occupies a bridging position between two basal boron atoms. Some temperature and solvent effects are also presented and briefly discussed.

The title compound N,N-bis(trimethylstannyl)trifluoromethanesulfonamide (1) reacts with S 2 Cl 2 , SOCl 2 and SO 2 Cl 2 in a molar ratio 2:1 to yield the compounds S 2 Cl 2 a twelve-membered ring 6. These are the largest neutral sulfur-nitrogen rings of coordination number two at the sulfur atoms known to date. 3 reacts with SOCI2 under migration of a methyl group from the tin to a sulfur atom to yield CF 3 SO 2 (R 3 Sn)NS(CH 3 )NSO 2 CF 3 (7). 2,2,4,4-Tetramethyl-1,3-bis(trifluormethylsulfonyl)cyclodisilazan and 7 are formed by the reaction of 3 with R 2 SiCl 2 - The analogous four-membered germanium compound 8 is obtained from 1 and R 2 GeCl 2 . While the pyrolysis of 1 yields only the six-membered cyclotristannazan 9, the six-membered germanium analog is only formed in minor amounts. By treating 9 with R 3 SiCl the ring is decomposed to give 10. A six-membered ring is formed from the reaction of 1 with ClR 2 SiOSiR 2 Cl 11. The structure of 6 is discussed in detail. 6 crystallizes in the monoclinic space group C2/c with a = 24.408(5), b = 7.377(2), c = 16.715(3) Å, β = 117.16(3)° and Z = 4. It has a chair conformation which is different from the isoelectronic S 12 -structure.

The reaction behaviour of CCl 2 F 2 adsorbed on silica gel and a natural adsorbent (Mecca Sand) was investigated by means of the 14 C-labelled compound. While in the dark no conversion of the substance on silica gel was detected, a significant degradation to 14 CO 2 was observed on the dry sand. The mineralisation (up to 70%) was due to the applied amount of sand. On irradiation with UV light (λ > 290 nm) the 14 CCl 2 F 2 adsorbed on silica gel was partially degraded to 14 CO 2 . However, the mineralisation rate of about 1 % was of less importance in comparison to the rate on the dry sand. The results indicate that the mineralisation takes place at “active sites” on the surface.

4-Fluorophenylisonitrile and 4-nitrophenylisonitrile react with μ-dichloro-bis[dicarbo-nylrhodium(I)] [Rh(CO 2 )Cl] 2 yielding the blue tetrakis(4-fluorophenylisonitrile)rhodium-(I)chloride hydrate (1) and the dark green tetrakis(4-nitrophenylisonitrile)rhodium(I) chloride (2). Yellow Perchlorates 3 (of 1) and 4 (of 2) can be obtained from both compounds. 1 crystallizes in the monoclinic space group P 2 1 /c with a - 10.57(2) Å, b = 11.459(5) Å, c = 23.71(5) Å, β = 107.14(4)°, Z = 4. Compound 2 crystallizes in the triclinic space group P1̄ with a = 12.34(4) Å, b = 10.704(3) Å, c = 13.703(3) Å, α = 106.58(2)°, β = 106.07(4)°, γ = 108.29(3)°, Z = 2. 3 belongs to the rhombic space group Pnmm or Pnm2 with a = 11.523(4) Å, b= 15.48(1) Å, c= 15.915(9) Å, Z = 4 and 4 is triclinic with a = 6.987(4) Å, b = 14.300(7) Å, c == 16.983(7)1, α = 71.89(3)°, β = 89.20(4)°, γ = 79.54(4)°, Z = 2. The structures of 1 and 2 were determined by Patterson and Fourier methods from diffractometer data and refined by least squares to R - 0.062 (1) or R = 0.157 (2). Crystals of both compounds contain metal-to-metal bonded dimers with a Rh-Rh bond distance of 3.207(2) Å in 1 and 3.25(1) Å in 2. the ligands of the two adjacent complex units taking an eclipsed position. These dimers are arranged in layers. There is a second type of layer in 1 containing the water molecules which are hydrogen bonded to the chloride counterions. The blue color of 1 is caused by a strong absorption at 16700 cm -1 (597 nm). 2 has a similar absorption band at 16500 cm -1 (606 nm). Compounds 3 and 4 contain the monomeric complex units.

The hexagonal red compound K 4 Tl 2 S 3 (a - 1060, c = 711.0 pm; Z = 2) and the monoclinic red K 7 TlS 4 (a = 1225, b = 1646, c = 1408 pm, β = 103.2°; Z = 8) were found in the system K 2 S-Tl 2 S by DTA and X-ray investigation; Rb 4 Tl 2 S 3 (hexagonal with a = 1074 and c = 767.4 pm; Z = 2) is the only compound in the system Rb 2 S-Tl 2 S.

N-silylated aminoiminophosphines react with aluminium trihalides to give acyclic zwitterions having two-coordinated phosphorus. At about room temperature these adducts decompose by elimination of silylhalide and formation of 1,3,2λ 2 ,4-diazaphosphonia-aluminatacyclobutanes. Reaction of halogens and alkyl halides with the cyclic zwitterions results in formation of the corresponding 1,1-addition products. With alkyl-azides one obtains bicyclic phosphorus nitrogen heterocycles whilst in the reaction with trimethyl-silylazide the isomeric monocyclic azide derivative is formed. The IR and NMR spectra of the cyclic zwitterions are briefly discussed.

Nucleophilic Substitution, Palladium(II), Formazan, 1-(2-hydroxyphenyl)-3,5-diphenylformazan, Solvent Effects, Substitution Reactions Nucleophilic substitution in different non-aqueous solvents at square planar complexes of palladium(II) with 1-(2-hydroxyphenyl)-3,5-diphenylformazan (H 2 Fo) according to FoPdX + Y → FoPdY + X, with X = ammonia and pyridine and Y = triphenylphos-phine, thiourea and the thiocyanate ion, obeys the rate law: rate = k 1 [FoPdX] + k 2 [FoPdX][Y]. Values of k 1 and k 2 were obtained at 25.0 °C. From measured solubilities and literature values of transfer functions the transfer chemical potentials for initial and transition state were calculated. A comparison of these quantities in different solvents leads to the conclusion that non-specific solvation effects are dominant in these compounds. The mutual dependence of the effects of leaving and entering ligands and solvent on the substitution rate indicates a level of synchronicity of bond-breaking and bond-making that is unusually high for palladium(II) complexes.

Aminolysis of cis-NPCl 2 (NSOX) 2 , with X = Cl or F, by MeNH 2 and EtNH 2 proceeds via a geminal substitution pattern. Preparation of the mono-and disubstituted derivatives is described, the NMR data are discussed.

The diamagnetic complexes 1,2-C 6 H 4 (C≡CCu) 2 , 1,2-C 6 H 4 (C≡CCU) 2 ·2 Pet 3 , 1,2-C 6 H 4 (C≡CCu) 2 ·Pet 3 (et=C 2 H 5 ) and K 3 Cu(1,2-C 6 H 4 (C≡C) 2 ) 2 are prepared by reactions of Cul with the dipotassium salt of 1,2-diethynylbenzene o-C 6 H 4 (C≡CK) 2 in liquid ammonia. The IR-active νC≡C frequencies and possible structures of the polymeric solids are discussed.

The title compound, A, has been prepared from the corresponding chloro complex by reaction with potassium bromide in aqueous solution. A crystallizes in the monoclinic space group P2 1 /n with Z = 2 and lattice parameters a = 11.748(5), b = 10.419(4), c = 8.383(4) Å and β = 95.35(5)°. An X-ray analysis shows that A posseses crystallographic symmetry 1̄, that within the limits of error, the π-bonded cyclobutadiene ring is a square with an average C-C bond distance of 1.464 Å, and that the methyl groups are displaced away from the nickel atom, the average distance between the ring plane and the methyl C atoms being 0.20 Å.

1 H and 13 C NMR spectra of hexafluorophosphates of ferricinium (1) and 1,1′-dimethyl -ferricinium cations (2) and the EPR spectrum of 2 were recorded. Pseudocontact and contact contributions of isotropic shift were calculated and constants of hyperfine inter-action estimated according to Jesson. It is shown that the calculations of pseudocontact and contact shift via magnetic susceptibility components according to Kurland and McGarvey do not change the signs of HFS constants. According to the suggested mecha-nisms of spin derealization the π-contribution is the dominating one.

2-Acetyl-1,3-indandione Derivatives, Amines, Diazonium Salts 2-Acetyl-1,3-indandione (1) undergoes the Mannich reaction with piperidine or diethyl-amine hydrochloride to give compounds 2 and 3, respectively. On treatment 1 with ethylenediamine hydrochloride and formaldehyde, 2,2′-[ethylene bis[imino(1-oxotri-methylene)]]di-1,3-indandione (4) was obtained. With primary aromatic amines it yielded 2-[N-(substituted phenyl)acetimidoyl]-1,3-indandione (5a-i). The condensation of 1 with o-aminophenol yielded a mixture of 5c and the oxazepinone (6), while condensation with 2,3-diaminopyridine gave the diazepinone (7). Mannich reaction of 5a and g with piperidine hydrochloride and formaldehyde gave 8a, b. The coupling of 1 with diazonium salts was investigated.

The electronic spectra of a series of substituted 4-hydroxypyrimidines are calculated by the INDO/CI method. Best agreement with the experimental values is obtained when the geometry of the 4(3H)-pyrimidone form is used. Calculated total energies seem to be less suitable for determining tautomeric equilibria than a comparision between experimental and theoretical transition energies.

Conformational studies on synthetic segments)* of ACTH using circular dichroism (CD) are described. The segments [Val 4 ]-ACTH (1-10) = I, [Pro 1 , Ala 2 , Ala 3 , Val 4 ]-ACTH (1-10) = II and ACTH (11-23) = III have been synthesized according to the Liquid-Phase-Method with polyethylene glycol (PEG) as solubilizing C-terminal protecting group. The peptide PEG esters were studied in water and 2,2,2-trifluoroethanol (TFE) and the dependence of chain length, side chain protection and solvent upon the conformation has been evaluated. From these measurements, I shows partially helical structure in TFE and β-conformation in H 2 O. The modified 10-peptide II with strong helix formers at the N-terminus shows substantial amounts of helical structure in TFE and in water. A significant increase in helical structure is observed by adding the Pro residue to the N-terminus. The CD spectra of the 13-peptide III ist also typical for partially helical structure, however other types of ordered conformations cannot be excluded. The experimental data are compared with the results from calculations of the secondary structure deduced from the empirical prediction scheme of Chou and Fasman and the more elaborated statistical mechanical treatment of peptide conformations proposed by Tanaka and Scheraga. The agreement between experimental data and theoretical prediction is reason-able for I and II, whereas III is expected to adopt extended conformations beside unordered forms. The experimentally found unique behaviour of Prolin was rationalized by the asymmetric helix nucleation feature of this residue. A model for the most probable conformation of ACTH is proposed and a critical evaluation of the predictive schemes is given.

The preparation of two new alkaline earth metal complexes with acetylacetone, where the latter acts as a ligand in its diketoform, is described. The solid compounds are characterized by elemental analysis, IR spectra and X-ray diffraction patterns.

Diazadistibetidines of the type (XSbNCR 3 ) 2 , with X = Cl, Br and R = CH 3 , have been synthesized by reacting SbX 3 with LiN(CR 3 )SiR 3 -The initial reaction products R 3 C(R 3 Si)NSbX 2 (1) split off R 3 SiX with formation of the four-membered rings 2. The silylated bis(amino)-halostibines 3 do not eliminate R 3 SiX even at 200 °C.