Volume 47, Issue 1

The reaction of [(NEt 3 )FcBBr 2 ] (Fc:C 5 H 5 FeC 5 H 4 ) with bis(trim ethylsilyl)selenane leads to the formation of Fc 3 B 3 Se 3 (1). 1 crystallizes in the triclinic space group P1̄. The lattice constants (at 210 K) are: a = 1487.8(8) pm , b = 1563.1(8) pm, c = 1588.6(9) pm, ɑ = 107.81(4)°, β = 101.06(4)°, γ = 115.85(4) . 1 contains a nearly planar B 3 Se 3 ring with alternating B and Se atoms. The electronic structure of the model compound Ph 3 B 3 Se 3 was investigated by ab initio SCF studies.

The tellurium -nitrogen compounds Cl 3 Te(map) (1) and F 3 Te(map) (2) (map = 2-(methylamino)pyridinato), derived from N -silylated map and the corresponding tellurium (IV) halide, have been prepared and characterized. The crystal structure of 1 reveals a dimeric species with two five-coordinate Te(IV) centers that are bridged by longer Te ··· Cl contacts (356 pm average). Crystal data for 1: triclinic, a = 7.280(1), b = 9.512(1), c = 16.004(2) Å, ɑ = 96.67(1), β = 91.95(1), γ = 105.79(1)°, V = 1057(1) Å 3 , T = 293 K, space group P1̄, Z = 2. Final R and R w values for 1 are 0.026 and 0.033, respectively.

A series of manganese(II) am ides (1-4), derived from 2,6-diisopropylaniline (H 2 NAr; where Ar = 2,6-Pr i 2 C 6 H 3 ) and its N-silylated derivative H(SiMe 3 )NAr, has been prepared and characterized. The crystal structure of Mn[N(SiMe 3 )Ar] 2 [THF] (2) reveals a monomeric species with a planar three-coordinate Mn(II) center. Crystal data for 2: trigonal (hexagonal axes), a = 30.119(2) Å, c = 10.589(1) Å, V = 8319(1) Å 3 , T = 153 K, space group P3 1 (No. 144), Z = 9 (R/R w = 0.053/0.050). In contrast, Mn 3 [N(H)Ar] 4 [N (SiMe 3 ) 2 ] 2 · C 7 H 8 (4) is shown to be a novel trinuclear compound held together by nitrogen-bridges. The two terminal Mn(II) atoms have a distorted trigonal planar arrangement of nitrogen donors whereas the central Mn(II) is surrounded by a distorted tetrahedral array of nitrogen donors. Crystal data for 4: orthorhombic, a = 21.301(5) Å, b = 17.021(6) Å, c = 20.519(7) Å, V = 7439(4) Å 3 , T = 153 K, space group Pbcn (No. 60), Z = 4 (R/R w = 0.050/0.070).

As thermochromic compounds, tetraiodomercurates show phase transitions, which have been investigated by impedance spectroscopy. In the case of Ag 2 HgI 4 and Cu 2 HgI 4 we found clear changes of conductivity not present with HgI 2 . In all cases the main resistance is caused by the grain boundaries between the single crystals of the powder sample. Also diffusion in the double layer in front of the surface of the electrodes influences the spectra. Single crystal measurements of Hgl, show the different ionic mobilities along the various crystallographic directions.

The preparation of the sulfonium salts R 2 SOCH 3 + X - (R = F, Cl, CF 3 , CH 3 ; X - = AsF 6 - , SbF 6 - , Sb 2 F 11 - ) is reported. The compounds have been obtained from the sulfuranes R 2 SO with reagents CH 3 OSO + MF 6 - (M = As, Sb) in liquid SO 2 and characterized by Raman and 1 H , 13 C, and 19 F NMR spectroscopy.

Dimeric lithium-adamantylimino-di-tert-butylfluorosilane, [(Me 3 C) 2 SiF Li N Ad] 2 , adds one molecule of THF per dimer when crystallized from THF. A bicyclic compound is obtained with four- [F 2 Li(THF)N] and two-coordinated [NLiN] lithium. Lithiated di-tert-butyl-[{tert-butyldiphenylsilyl)]aminofluorosilane and di-ter-butyl-4-fluoroanilinofluorosilane both add two molecules of THF with formation of (SiFLi(THF) 2 N)-four-membered rings when crystallized from THF. THF can be replaced by TMEDA with retention of the (SiFLiN )- four-membered ring. The crystal structure of (Me 3 C)-,SiFLi(TMEDA)NC 6 H 4 F is reported.

(PPh 4 ) 2 [CuCl(NO 3 ) 3 ] · CH 2 Cl 2 is formed when ozone reacts with (PPh 4 ) 2 [Cu 2 (N 3 ) 6 ] in dichloromethane. Its crystal structure was determined by X-ray diffraction. Crystal data: a = 1113(1), b = 1156(1), c = 1965(2) pm , α = 101.02(1), β = 93.74(1), γ = 104.05(2)° at 130 K, space group P1̄, Z = 2, R = 0.057 for 3951 observed reflexions. The structure contains CH 2 Cl 2 molecules and PPh 4 + and [CuCl(NO 3 ) 3 ] 2- ions, with copper having coordination number 5. One nitrate ligand acts as a bidentate chelating unit, and the other two as monodentate ligands.

(3) Hydrocobaltation reactions of 1,3-dibora-4,5-benzofulvene (2) and 1,3-dibora[5]radialene with HCo(CO) 4 lead to the complexes tricarbonyl-(η 5 -4,5-benzo-2-isopropyl-1,3-dimethyl- 2,3-dihydro-1,3-diborolyl)cobalt (4) and tricarbonyl-(η 5 -isopropenyl-2,5-diisopropyl-1,3-dimethyl-1,3-dihydro-1,3-diborolyl)cobalt (5) in 24% and 5% yield, respectively. The constitution of 4 and 5 follows from the spectroscopic data, and is proven by an X-ray structure analysis of 4. The formation of 5 is accompanied by a 1,5-hydrogen shift in the 1.3-dibora[5]radialene (3).

(2)) CpRu(PPh 3 )(L)(SH) (L = PPh 3 (1), CO compounds react with N-(benzylsulphinyl) phthalim ides to give the chiral complexes CpRu(PPh3)(L)[S-S(O)-CH2-Ph] (4, 5). For 5, a diastereoselectivity of 10:3 is observed. The compounds 4, 5 have been characterized by their spectroscopic data. The X-ray structure d etermination of 4 shows sulphur-sulphur bond lengths of 204,4(4), 205,5(4) and 205,3(4) pm for three independent molecules.

New sesquisulfides of the lanthanides with the U 2 S 3 -type structure (M 2 S 3 , M = Tb and Dy) were prepared through the oxidation of TbClH 0,67 and DyCl 2 , respectively, with appropriate amounts of sulfur in the presence of NaCl fluxes in silica protected sealed tantalum containers at 850 °C for at least seven days. The preparation from the elements (2M + 3S; M = Tb and Dy) under otherwise analogous reaction conditions and temperatures was also successful when equimolar fluxes of NaCl were applied. The crystal structure was determined from single crystal data for Tb 2 S 3 and Dy 2 S 3 , both crystallizing with the U 2 S 3 -type structure (orthorhombic, Pnma, Z = 4; Tb 2 S 3 : a = 1067.87(8), b = 388.06(4), c = 1049.07(7) pm ; Dy 2 S 3 : a = 1062.45(7), b = 386.59(4), c = 1044.36(8) pm) when prepared under the above-mentioned conditions.

In order to elucidate specific properties of nickel sulfur complexes, reactions of recently synthesized [Ni('S 5 ')], [Ni('OS 4 ')] 2 , [Ni('N H S 4 ')] 2 , [Ni('S 4 -C 5 ')] 2 and [Ni('S 4 -C 3 ')] were investigated ('OS 4 ' 2- = 2,2'-bis(2-mercaptophenylthio)diethylether(2-), 'N H S 4 ' 2- = 2,2'-bis(2-mercaptophenylthio)diethylamine(2-), 'S 5 ' 2- = 2,2'-bis(2-mercaptophenylthio)diethylsulfide(2-), 'S 4 -C 5 ' 2- = 1,5-bis(2-mercaptophenylthio)pentane(2-), 'S 4 -C 3 ' 2- = 1,3-bis(2-mercaptophenylthio)propane(2-)). Reactions with proton acids, CH 3 COCl and cyanide led to de-coordination of the sulfur ligands, thus providing a convenient synthesis of multidentate thioether-thiolate ligands. The reactions of these Ni complexes with metal salts or metal complexes led to ligand transfer from nickel to Pd(II), Mo(IV ) and Hg(II), [Pd('S 4 -C 3 ')], [Hg('S 5 ')], [Hg('S 4 -C 3 ')]. [Hg('S 4 -C 5 ')], [Mo(O)('S 5 ')], [Mo(O)('N H S 4 ')] and [Mo(O)('OS 4 ')] were synthesized by this method. X-ray structure analysis proved that [Mo(O)('OS 4 ')] and [Mo(O)('N H S 4 ')] have a pseudooctahedral Mo coordination with cis-thiolate atoms and trans-ether or amine and oxogroup donors. Template alkylation of [Fe(CO) 2 (S 2 C 6 H 4 ) 2 ] 2- by 3-(N, N-bis-(2-bromoethyl)-amino)-propionic acid methyl ester leads to a multidentate ligand that contains functional groups in the side chain.

In order to obtain soluble molybdenum sulfur oxo complexes, [Mo(O) 2 (' bu S 4 ')] (1) (' bu S 4 ' 2- = 1,2-bis(2-mercapto-3,5-di-t-butylphenylthio)ethane(2-)) was synthesized by reaction of [Mo(O) 2 (acac) 2 ] (acac - = acetylacetonate(1-) ) with ' bu S 4 '-Li 2 . Treatment of 1 with PPh 3 yielded [μ-O{Mo(O)(' bu S 4 ')} 2 ] (2) and OPPh 3 in an oxo transfer reaction. [Mo(PMe 3 ) 2 (' bu S 2 ') 2 ] (3) (' bu S 2 ' 2- = 3,5-di-t-butyl-1,2 -benzenedithiolate(2-)) was obtained by twofold desoxygenation of 1 with excess PMe 3 via a redox coupled addition elimination reaction. 2 reacts with the oxo group donor DMSO to yield 1 and Me 2 S. The system 1/2 then catalyses the oxo transfer reaction from DMSO to PPh 3 and, therefore, shows properties modelling the co-factor in oxotransferases. In contrast to the parent compound [Mo(O) 2 ('S 4 ')] ('S 4 ' 2- = 1,2-bis(2-mercaptophenylthio)ethane(2-)), 1 is reactive towards hydrazine and its derivatives. Reactions with hydrazine and alkylhydrazines yield mixtures of products not containing nitrogen. By treatment of 1 with phenylhydrazine, the phenyldiazenido(1-) complex [Mo(NNPh) 2 (' bu S 4 ')] (4) was formed in a redox coupled condensation. According to the X-ray structure analyses of 1, 2 and 4, the molybdenum centres in these complexes are coordinated pseudo-octahedrally by the four S-donors of the ' bu S 4 ' 2- ligands, the oxo- and the N -donors.

In order to investigate the potential conversion of coordinated NO into N 2 ligands at Ru sulfur centers, the cationic Ru nitrosyl complex meso-[Ru(NO)('S 5 ')]Br (1)** was synthesized by template alkylation of [NBu 4 ][Ru(NO)('S 2 ') 2 ]** with (BrC 2 H 4 ) 2 S. 1 is reactive towards nucleophiles. Reaction with azide yields N 2 O, N 2 and [Ru('S 5 ')] 2 (2), reaction with LiNH 2 , NH 3 and NEt 3 leads to C-S bond cleavage in the 'S 5 ' ligand of 1 and to the formation of a Ru nitrosyl vinylthioetherthiolate complex.

Homoleptic complexes of palladium and platinum containing carbenoid imidazole ligands (1, 12-19 ) have been synthesized either directly from C2-lithiated N-methyl-imidazole and Pdl 2 or, indirectly (and more efficiently), from isocyanides and 2-am inoacetaldehyde diethylacetale in the presence of Pdl 2 , Ptl 2 or K 2 PtCl 4 via the respective “ open chain” diaminocarbenes 2-11. Selected IR , NMR ( 1 H , 13 C), and pos-FAB mass spectrometric data of the new compounds are reported. The X-ray structure analysis of tetrakis(N -methylimidazolin-2-ylidene)palladium-diiodide (lb ) reveals a geometry of the heterocyclic ligands which deviates considerably from the one expected for extensive 6π-electron delocalization across the ring.

The compound CH 3 -CO-NH-C(C 2 H 5 ) 2 -COOH was synthesized from the corresponding free amino acid. N-Acetyl-C α,α -diethylglycine crystallizes in the monoclinic space group P2 1 /c with a = 13.551(2)Å, b = 11.110(3)Å, c = 13.569(3)Å, β = 111.54(2)°, Z = 8 , D = 1.21 g/cm 3 . This structure was solved by direct methods and refined to R = 0.084. N-Acetyl-C α,α -diethylglycine shows a fully extended conformation in its -N H-C(C 2 H 5 ) 2 -CO- part.

Light yellow needles of crystalline nonachloroditellurous acid with the formal composition HTe 2 Cl 9 · 4H 2 O (1) (space group C2/c, a = 11.642(6), b = 13.012(4), c = 12.663(5) Å, β = 119.64(3)° at 140 K) were isolated from a saturated solution of TeCl 4 in conc. HCl. From a solution of more diluted HCl the acid HTeCl 4 OH · 5H 2 O (2) could be prepared (space group P2 1 2 1 2 1 , a = 7.065(3), b = 8.551(2), c = 18.192(6)Å at 140 K). 1 is the first acid isolated from the system TeCl 4 /HCl/H 2 O with a polymeric anion. The novel polynuclear [Te 2 Cl 9 ] n n- chains are built from alternately corner-sharing and edge-sharing distorted octahedral TeCl 6 units. The mean bond distances are 2.356 Å for terminal Te-Cl and 2.805 Å for Te-μ 2 Cl. 2 contains square-pyramidal [TeCl 4 OH] - anions with oxygen in the apical position (Te-Cl: 2.447-2.552 Å; Te-O: 1.926 Å). The cations in both structures are [H 9 O 4 ] + hydroxonium ions (O···O (1): 2.47(3), 2.55(2) and 2.57(1) Å; O···O (2): 2.550(4), 2.584(4) and 2.588(5) Å). Thus the formulae of the acids have to be written as [H 9 O 4 ] n [Te 2 Cl 9 ] n and [H 9 O 4 ][TeCl 4 OH] · H 2 O. Raman spectra of both compounds are reported.

Dipod ligands R 2 M'(OCH 2 PMe 2 ) x (CH 2 CH 2 PMe 2 ) 2-x (R = Me, Ph; M' = Si, Ge; x = 0 - 2) have been prepared by reacting R 2 M'Cl 2 and R 2 M'Cl x Vi 2-x (x = 0, 1), respectively, with Me 2 PCH 2 OH in the presence of trimethylamine, in case of the resulting vinyl-M' derivatives R 2 M'(OCH 2 PMe 2 ) x Vi 2-x (x = 0, 1) followed by the photochemical addition of Me 2 PH to the vinyl groups. Analytical (C, H) and spectroscopic (NMR, MS) investigations prove the purity and identity of the new donor/acceptor ligands.

The cyclic voltammograms of some binuclear copper(II) compounds with binucleating ligands where two molecules of tridentate ligand, N, N -bis(benzimidazol-2-ylmethyl)amine are linked by several alkyl chains, were measured under both argon and dioxygen. The results demonstrate that the binuclear copper(I) species produced by electrochemical reduction exhibit high reactivity towards dioxygen, while the reaction of the corresponding mononuclear species with oxygen is very slow. Thin-layer coulometry ([binuclear copper(I)]/[O 2 ] = 0.47 - 10.6) and thin-layer cyclic voltammetry ([binuclear copper(I)]/[O 2 ] = 4.3 - 10.6 ) revealed that two molecules of the binuclear copper(I) species react with one molecule of dioxygen.

The complex derived from Fe(NO 3 ) 3 · 9H 2 O and perchlorate salt of N,N,N',N'-tetrakis- (2-pyridylmethyl)-2-hydroxy-1,3-diaminopropane (abbreviated as H(HPTP)) is formulated as a binuclear species with μ-alkoxo and μ-hydroxo bridges, [Fe 2 (HPTP)(OH)(NO 3 ) 2 ](ClO 4 ) 2 , on the basis of analytical data, magnetic properties, and conductivity data. This complex reacts with hydrogen peroxide in water to form a violet adduct with new charge transfer bands in the range 520-600 nm. This adduct is very unstable at room temperature, indicating the high catalase-like function of this complex. The complex exhibits a high ability to degradate DNA in the presence of H 2 O 2 . The observed high catalase-like and bleomycin-like functions of the complex are discussed in terms of the activation of the peroxide ion by the binuclear iron(III) compound.

Reactions of aquacobalamine with dimethyl and diphenyl phenylphosphonite and with methyl diphenylphosphinite lead to neutral complexes in which the partially hydrolyzed an ionic ligands [PPh(OR)(O)] - (R = Me, Ph) and [PPh 2 (O)] - are P-bonded to the cobalt(III) ion of the cobalamine moiety. Hydrolysis of the prochiral phosphonite already coordinated to the chiral cobalamine leads to two diastereomers which are formed in different yields. This optical induction is seen in the 1 H and 31 P{ 1 H} N M R spectra.

Halogenation by the appropriate amounts of bromine or N-bromosuccinimide converts spirodiisophora-3',6-dione successively into the 4'-ax-mono- and 2',4'-diax-dibromo-3',6-dione. The latter is reduced by lithium aluminium hydride to the corresponding 6,3'-ketol. with retention of one or both bromo-substituents, depending on conditions. The bromoketones undergo the Favorski ring-contraction under the influence of alkalis to compounds of the bicyclo[2.2.2]octane-2-spirocyclopentane ring-system . The 13 C NMR spectra of the individual products are assigned and correlated with their structures.

The structures of mer-Cr(py) 3 (N 3 ) 3 (1) and polymeric NaCr(py) 4 (N 3 ) 4 (2) were determined by X-ray crystallography. Crystal data; 1, C 15 H 15 N 12 Cr, triclinic, space group P1̄, a = 895.3(2), b = 999.1(3), c = 1269.9(5) pm , α = 106.76(3), β = 96.69(3), γ = 116.30(2)°, V = 943.8(6) · 10 6 pm 3 , Z = 2 and R w = 0.038 for 1736 observed MoKα diffractometer data; 2, C 20 H 20 N 16 CrNa, monoclinic, space group C2/c, a = 1561.2(3), b = 1028.8(2), c = 1573.6(4) pm, β = 90.70(2)°, V = 2 527.3(9) · 10 6 pm 3 , Z = 4 and = 0.033 for 1272 MoKα diffractometer data. The coordination around the chromium (III) ion in the discrete molecules of 1 is six-coordinate with mean distances Cr-N(py) of 210.2(4) pm and Cr-N(N 3 ) of 200.8(4) pm. The terminal azido ligands are almost linear and asymmetric, the N-N bonds nearer to the metal (118.8(6) to 120.5(7) pm) being significantly longer than the terminal ones (114.7(7) to 115.5(7) pm). In compound 2, each chromium or sodium cation is six-coordinated by four azido groups and two pyridine molecules. The azido groups act as μ(1,3) bridging ligands between chromium and sodium octahedra to form a three-dimensional network structure. The chromium atoms are trans-coordinated by the pyridine ligands whereas the sodium cations are cis-coordinated.

Two novel hepta-oxygenated flavonols have been isolated from the aerial parts of Premna oligotricha and identified, primarily on the basis of N M R spectroscopy, as 3,5,5'-trihydroxy- 6,7,3',4'-tetram ethoxyflavone (2) and 3,5,7,5'-tetrahydroxy-6,3',4'-trim ethoxyflavone (3). Known flavonoids, with lower levels of oxygenation were obtained from two other Premna species, P. schimperi and P. recinosa.

The cycloaddition reaction of trifluoromethyl isocyanide to diphenylethyne yields 1,2 -diphenyl- 3,4-bis(trifluoromethyl imino)cyclobutene. 1,2-diphenyl- 3-oxo-4-trifluoromethyl iminocyclobutene is obtained as a by-product resulting from hydrolysis. The structure of 1,2-diphenyl-3,4-bis(trifluoromethyl imino)cyclobutene has been elucidated by X-ray crystal structure analysis.

Methanolothermal reaction of Rb 2 CO 3 with SnSe 2 in the presence of BaSe at 160 °C and 13 bar yields Rb 2 Sn 2 Se 5 , the structure of which was established by X-ray analysis. The crystal structure contains polyanions [Sn 2 Se 5 2- ] ∞ , which display a framework structure. The anion structure is built up from trigonal SnSe 5 bipyramids, linked together via one corner and two edges. This leads to the formation of channels parallel to the b-axis, which contain the rubidium cations. The crystal structure is isostructural to that of Tl 2 Sn 2 S 5 .