Volume 44, Issue 12

The crystal structure of Na 10 Ga 6 Sn 3 (a = 1457.6(3), c = 897.6(2) pm, P4 2 /mnm, Z = 4) contains Ga 12 icosahedra, which are connected by four of their eight exo-bound Sn atoms to form anionic chains 1 ∞ [Ga 12 Sn 4 Sn 4/2 ] 20- . The structure is discussed on the basis of the Zintl concept and Wade’s rules.

(S 4 N 3 ) 2 Se 2 Cl 10 , (S 4 N 3 ) 2 Se 2 Cl 6 and [(S 4 N 3 )SeCl 5 ] n are formed by the reaction of S 4 N 4 , Se 2 Cl 2 , and SOCl 2 . The structures of the three compounds where determined by X-ray diffraction. The yellow crystals of (S 4 N 3 ) 2 Se 2 Cl, 10 are monoclinic, space group P2 1 /a, a = 817.5(2) pm, b = 1790.4(5) pm, c = 843.1(6) pm, β = 104.31(4)°, Z = 2. The Se 2 Cl, 10 2- anion consists of 2 Cl-bridged distorted octahedra. (S 4 N 3 ) 2 Se 2 Cl 6 forms red monoclinic crystals, space group P2 1 /c, a = 1036.5(3) pm, b = 1376.5(5) pm, c = 1400.4(4) pm, β = 100.65(2)°, Ζ = 4. In the Se 2 Cl 6 2- anion the Se atoms have a square planar environment. The yellow crystals of (S 4 N 3 )SeCl 5 are orthorhombic, space group P2 1 2 1 2 1 , a = 734.2(3) pm, b = 989.4(4) pm, c = 1627.4(6) pm, Z = 4. In the SeCl 5 - anion the Se atom has an octahedral environment of chlorine atoms, thus forming a polymeric structure.

The complexes of some quinolinol sulfonamides with Cu(II), Zn(II), and Cd(II) have been synthesized and formulated as [Cu(L) 2 (H 2 O) 2 ] and [M(L) 2 ]nH 2 O, M = Zn(II), or Cd(II), n = 0—3 and L = anion of the corresponding ligand. Their structures have been suggested by elemental analysis, electronic and IR spectroscopy, and conductivity measurements. It was found that the sulfonamide ligands are monobasic bidentate ON donors of the quinolinol group. Consequently, the Zn(II) and Cd(II) complexes are formulated as tetrahedral, whereas in Cu(II) complexes a distorted octahedral environment of the metal ion is proposed. It was proven that the metal chelates inhibit and actively affect the germination of wheat seed.

[(COD)Rh(Cl)(P 1 ∼O)] (3) is obtained from [µ-ClRh(COD)] 2 (1) and the (ether-phosphane) ligand P 1 ∼O (2) [P1∼O = Ph 2 PCH 2 CH 2 OCH 3 ]. 3 reacts with AgSbF 6 to form the cationic η 2 -P l ͡ O rhodium complex [(COD)Rh(P 1 ͡ O)][SbF 6 ] (4). Addition of another ligand P 2 ∼O (5) [P 2 ∼O = Pr 2 PCH 2 C 4 H 7 O] to 4 affords the bis(ether-phosphane)rhodium complex [(COD)Rh(P 1 ∼O)(P 2 ∼O)][SbF 6 ] (6) with two different ether-phosphanes. In 6 COD is displaced by CO to give [trans-(P 1 ∼O)(P 2 ∼O)Rh(CO) 3 ][SbF 6 ] (7). The 31 Ρ{ 1 H} NMR spectrum of 7 shows a temperature dependence. When a THF solution of compound 7 is flushed with argon it undergoes elimination of carbon monoxide to form [trans-(P 1 ∼O)(P 2 ͡ O)Rh(CO)][SbF 6 ] (10), containing a bidentate coordinated P 2 ∼O ligand (5). The reaction is reversible. Oxidative addition of CH 3 I to 10 results in the formation of a 1:1 mixture of the acyl complexes [cis-(P 1 ͡ O)(P 2 ͡ O)Rh(I)(C(0)CH 3 )][SbF 6 ] (8) and [cis-(P 1 ͡ O)(P 2 ͡ O)Rh(I)(C(O)CH 3 )][SbF 6 ] (9), the reactive intermediate [trans-(P 1 ∼O)(P 2 ͡ O)Rh(I)(CH 3 )(CO)][SbF 6 ] (11) not being observed. Formation of either 8 or 9 depends on the S or R configuration of the asymmetric C-atom in 5. On cleaving one or two Rh–O bonds the back reaction to 7 occurs.

Reaction of ammonium thiosulphate with concentrated sulphuric acid in anhydrous methanol at —80°C affords [NH 4 ][HS 2 O 3 ] the anion of which was shown by Raman spectroscopy to have the structure HSSO 3 - (stretching vibrational wavenumbers: SS = 403, SH = 2486, SO = 1027, 1183, and 1219 cm -1 ; SSH bending mode = 873 cm -1 at —80°C). This salt decomposes at —20°C to give, inter alia, elemental sulfur. The Raman spectra of ND 4 DS 2 O 3 and (NH 4 ) 2 S 2 O 3 are also reported.

Gold(I) complexes with secondary phosphines R 2 PH (la—d) of the type R 2 PH · AuCl (2a—d) have been obtained in good yield from reactions of (carbonyl)chlorogold(I) and the corresponding ligand in diethylether. Both compounds 2a, b bearing aromatic substituents with R = 2,4,6-trimethylphenyl (mesityl) and 2-methylphenyl (o-tolyl), and compounds 2c, d with the bulky alkyl substituents R = t-butyl and R = cyclohexyl, resp., are air-stable crystalline solids. — The coordination compounds have been characterized by NMR and IR data, and — in the cases of 2b and 2c — by single crystal X-ray diffraction studies. Crystals of these two compounds are both monoclinic, space group P2 1 /c with four formula units (Z = 4). The analysis shows independent monomers for compound 2c with no intermolecular Au···Au contacts. Molecules of 2b are arranged in centrosymmetrical dimers (head to tail) with an Au···Au distance of 3.56 Å and a dihedral angle P—Au—Au′—P′ of 180°. (This structural study is as yet incomplete and suffers from an unsatisfactory data set for 2b.) It appears that intermolecular contacts are largely controlled by steric effects.

PPh 4 [ReF 2 Cl 2 (N 2 S 2 )] has been prepared by the reaction of PPh 4 [ReCl 4 (NSCl) 2 ] · CH 2 Cl 2 with sodium fluoride in acetonitrile suspension. The compound forms black crystals, which were characterized by IR spectroscopy as well as by an X-ray structure determination. Space group P2 1 /c, Z = 4, 2525 observed unique reflexions, R = 0.053. Lattice dimensions at 20°C: a = 1277.4(3), b = 713.2(3), c = 2860.8(4) pm. β = 97.20(3)°. The compound consists of PPh 4 + and [ReF 2 Cl 2 (N 2 S 2 )] - ions, in which the rhenium atom is surrounded octahedrally by two fluorine atoms, two chlorine atoms, and by the nitrogen atoms of a ReN 2 S 2 five-membered ring, the fluorine ligands being in trans position to the N atoms. The bond lengths ReN (172; 177 pm) and NS (155; 160 pm) are in the range of double bonds, the S—S bond is relatively long (243 pm).

Cationic halfsandwich-type complexes of sulfur dioxide, [C 5 R 5 M(PR 3 )2(SO 2 )] + (R = H, Me, M = Fe, Ru, (PR 3 ) 2 = mono- or bidentate phosphorus ligands) and [C 5 Me 5 Fe(CO)(PR 3 )(SO 2 )] + , are obtained by ligand exchange from labile cationic (M = Fe) or neutral (M = Ru) precursors. The new compounds are characterized by IR, 1 H 13 1 H, 13 C and 31 P NMR spectroscopy. Their stability increases with increasing electron density at the metal.

A series of potassium alkanecarboselenoates (2) were isolated as crystals from the reaction of the corresponding bis(acyl) selenides with potassium methanolate. The salts 2 readily react with alkyl iodides at 0°C to afford the corresponding alkyl alkanecarboselenoates (3) in quantitative yields.

Single crystals of (18-crown-6) · 2 CH 3 CN were obtained by cooling a solution of 18-crown-6 in acetonitrile to 4 °C. Space group P2 1 /n, Z = 2, 629 observed independent reflexions, R = 0.062. Lattice dimensions at 19°C: a = 911.7(1), b = 852.0(1), c = 1370.0(2) pm; β = 104.61(1)°. The compound forms a molecular structure with approximate D 3d symmetry of the crown ether molecule, and C—H ··· O interactions of the acetonitrile molecules with the crown ether, the Η···Ο distances being 243, 253, and 267 pm, respectively. [Na-15-crown-5][ReO 4 ] · CH 3 CN is formed as a by-product of the reaction of ReNCl 4 with sodium fluoride in acetonitrile in the presence of 15-crown-5 and traces of water. Space group Ρ 1̄ , Ζ = 2, 3107 observed independent reflexions, R = 0.045. Lattice dimensions at 19°C: a = 823.4(1), b = 1078.8(1), c = 1204.0(1) pm; α = 112.40(1)°, β = 94.35(1)°, γ = 104.63(1)°. The compound forms ion pairs, in which the sodium atom is sixfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by one oxygen atom of the ReO 4- ion, which is only slightly distorted. The bond length Na—OReO 3 is 237.8(8) pm, the bond angle NaORe is 164.3(5)°. [Na-15-crown-5]PF 6 is formed in the reaction of [ReCl 3 (NSCl) 2 · POC1 3 ] with sodium fluoride in acetonitrile solution in the presence of 15-crown-5. Space group Pna2 1 , Ζ = 4, 1130 observed independent reflexions, R = 0.123. The high R value is due to disorder of the skeletal atoms of the crown ether molecule. The compound forms ion pairs, in which the sodium atom is sevenfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by two fluorine atoms of the PF 6 - ion with Na—F bond lengths of 240(2), and 246(2) pm, respectively.

The crystal structures of Pb[S(CN)C=C(CN)S] and (AsPh 4 ) 2 {Pb[S(CN)C=C(CN)S] 2 } have been determined by X-ray diffraction. PbS 2 C 4 N 2 , crystallizes in the non-centrosymmetric space group P2 1 with a = 7.292(3), b = 7.420(3), c = 5.789(2) Å, β = 95.47(5)° and Ζ = 2. The lead atom is coordinated by three S atoms of dithioligands. The coordination sphere around Pb includes a stereochemically active lone-pair and is described as a distorted tetrahedron. (AsPh 4 )2[Pb(S 2 C 4 N 2 ) 2 ] crystallizes in the triclinic space group P1 with a = 17.205(3), b = 13.342(3), c = 12.059(2) Å, α = 106.15(7), β = 102.92(6), γ = 79.50(3)° and Z = 2. In the complex anion {Pb[S(CN)C=C(CN)S] 2 } 2- the Pb-atom is located at a centre of a distorted trigonal bipyramid with a stereochemically active lone-pair in an equatorial position.

The reaction of Cp 2 ZrCl 2 with [Li(THF) 2 PHMes] n (1) Mes = 2,4,6-Me 3 –C 6 H 2 ) at –78°C yields Cp 2 Zr(PHMes)(X), with X = Cl (2) (1:1 reaction), X = PHMes (3) (1:2 reaction). Although 2 and 3 could not be obtained in a pure state, NMR spectroscopic investigations confirm the proposed formulae. 2 reacts with diphenyldiazomethane at ambient temperature with insertion of the N 2 CPh 2 molecule into the Zr–P bond and formation of [xxx] (4). An X-ray structure determination of 4 shows the η 2 -bonding mode of the phosphinohydrazonido(1–) ligand to the Zr atom (Zr–N(1) 2.181(6) A; Zr–N(2) 2.205(6) A). Crystal data: space group P2 1 /n, Z = 4, (2581 observed independent reflexions, R = 0.063). Cell dimensions (19°C): a = 11.820(2), b = 18.361(2), c = 13.758(2) Å, β = 103.86(2)°.

(Cl—CH 2 CH 2 ) 2 N—P(=X)Cl 2 , X = O, reacts with 1,2-dimethylhydrazine in the presence of triethylamine to give the dihydrazide. Hexahydropyridazine as “cyclic hydrazine” leads to a tetracyclic side product formed by HCl elimination from the reactive 2-chloroethyl groups and active β-NH protons of the hexahydropyridazinyl substituents. The corresponding thio-compound, X = S. yields the monosubstitution product (Cl—CH 2 CH 2 ) 2 N—P(=S)(N(CH 3 )—N(CH 3 )H)Cl. O-Benzylhydroxyamine hydrochloride substitutes both Cl-atoms at P to ioni (Cl—CH 2 CH 2 ) 2 N—P(=S)(NH—O—CH 2 —C 6 H 5 ) 2 . The corresponding phenylesters C 6 H 5 O—P(=X)(NH—O–CH 2 —C 6 H 5 ) 2 , X = O, S, are prepared in a similar reaction.

1,2-Dioxyphenylene silicondichloride is formed as a dimer from SiCl 4 and catechol C 6 H 4 (OH) 2 as the first reaction product. The compound melts at 413 K, yielding a viscous liquid which recrystallizes very slowly presumable under the formation of the monomer. 1,2-Dioxyphenylene silicondichloride crystallizes as a dimer in the space group P2 1 /a (No. 14) with a = 1308.5(8) pm, b = 735.8(5) pm, c = 889.6(5) pm, β = 110.02(5)°, Z = 4 formula units. Silicon is tetrahedrally coordinated by two oxygen and two chlorine atoms with the mean bond lengths d̄(Si—O) = 160.7 pm and d̄(Si—Cl) = 200.7 pm. The bond angles at the Si atom range from 104.4 to 112.6° (endocyclic O—Si—O = 110.3°) and the bond angles ∢ (Si—O—C) are 131.4 and 135.9°, respectively. The results are discussed together with data of related compounds.

The stability constants of the binary Cu(AA) + and Cu(AA) 2 complexes, where AA⁻ = L-phenyl-alaninate (Phe⁻) or L-tryptophanate (Trp⁻), have been determined by potentiometric pH titrations in water, and in 30, 50, 70 and 80% (v/v) dioxane—water mixtures (I = 0.1 M, NaNO 3 ; 25 °C); the corresponding data for the complexes with L-alaninate (Ala⁻), L-valinate (Val⁻), L-norvalinate (Nva⁻), and L-leucinate (Leu⁻) are taken from our recent work (G. Liang, R. Tribolet, and H. Sigel, inorg. Chim. Acta 155, 273 (1989)). The overall stability of Cu(AA) + and Cu(AA), is governed for all amino acetates (AA⁻) by the polarity of the solvent, while the extent of the intramolecular stack formation between the aromatic side chains in Cu(AA) 2 is influenced by the hydrophobic solvation properties of the organic solvent molecules (i.e., the ethylene units of dioxane). Based on the stability difference Δ log K* AA = log K Cu(AA) Cu(AA) 2 -log K Cu(AA) Cu it is shown that Cu(Phe) 2 and Cu(Trp) 2 are more stable than Cu(Ala) 2 , and this increased stability is used for evaluating the extent of the stack formation (= closed form) in Cu(Phe) 2 and Cu(Trp) 2 : the percentages of the closed forms vary between about 25 and 80% (based on Cu(AA),2/ tot ,), and those for Cu(Val) 2 , Cu(Leu) 2 and Cu(Nva) 2 between about 10 and 30%. The formation degree of the intramolecular side-chain adduct in Cu(AA) 2 decreases (in most solvents), as one might expect, within the series: Cu(Trp) 2 > Cu(Phe) 2 > Cu(Val) 2 ≳ Cu(Leu) 2 ≳ Cu(Nva) 2 . The corresponding observations are made with M(AA) 2 complexes of Co 2+ , Ni 2+ , and Zn 2+ . The influence of the organic solvent on the intramolecular hydrophobic and stacking adducts differs somewhat: (i) Stack formation in Cu(Phe) 2 and Cu(Trp) 2 is slightly inhibited by the presence of dioxane, but even in 50% (v/v) dioxane—water the formation degree of the aromatic-ring stacks is still more than 50%. (ii) Addition of some dioxane to an aqueous solution containing Cu(Val) 2 , Cu(Leu) 2 or Cu(Nva) 2 favors the formation of the aliphatic side-chain adducts; the largest formation degree being reached close to a content of 70% dioxane. Both observations contrast with the general experience made at unbridged hydrophobic or stacking adducts: these are considerably destabilized already by the addition of relatively small amounts of an organic solvent to an aqueous solution. Such a destabilization of the closed Cu(AA) 2 species occurs only at high concentrations of the organic solvent (usually more than 70%). It should be added that the organic solvent most probably influences the structure of the intramolecular ligand-ligand adducts giving rise to a whole series of “closed” species; a resolution is presently not possible and therefore the whole stability increase is attributed to a (single) so-called “closed” species to allow a quantification of the effect. The relevance of amino acid side-chain interactions regarding cooperativity, selectivity, evolutionary aspects, and low polarity regions, as in active-site cavities of proteins, are shortly indicated.

Addition of [Re(CO) 5 ] + (as (OC) 5 ReFBF 3 ) to compounds of the type Cp(OC) 2 Fe—C(S)SR (R = CH 3 , Fe(CO) 2 Cp) gives the products [Cp(OC) 2 Fe—C(SCH 3 )S—Re(CO) 5 ] + BF 4 - (1) and {Cp(OC) 2 Fe—C[SFe(CO) 2 Cp]—S—Re(CO)5} + BF 4 - (2), respectively. Complex 2 has been characterized by an x-ray structure analysis. From (OC) 5 ReFBF 3 and (Ph 4 P) 2 (OC) 2 Fe(η 2 —CS 2 ), the complex [(Ph 3 P) 2 (OC) 2 Fe[μ 2 -η 2 (C,S):η 1 (S′)]Re(CO) 5 ] + BF 4 - (3) has been obtained.

We have developed a new, large scale, high yield synthesis of cyclopentadienyl-substituted tungsten diethylaminocarbyne complexes. In the first step an almost quantitative conversion of (η 5 -C 5 H 5 )W(CO) 3 I (1) and (η 5 -C 5 Me 5 )W(CO) 3 I (2) using EtNC and Me 3 NO occurs to give an isomeric mixture of cis and trans (η 5 -C 5 H 5 )W(CO) 2 (EtNC)I (3 a, 3b) and cis and trans (η 5 -C 5 Me 5 )W(CO) 2 (EtNC)I (4a, 4b), respectively. The isomeric mixtures of 3a and 3b and 4a and 4b are then quantitatively transformed with sodium powder in THF into the highly reactive, anionic isocyanide complexes Na[η (5 -C 5 H 5 )W(CO) 2 (EtNC)] (5) and Na[(η 5 -C 5 Me 5 )W(CO) 2 (EtNC)] (6). Finally, alkylation of the strong nucleophiles 5 and 6 with Et 3 OBF 4 occurs on the isocyanide nitrogen and yields the low-valent tungsten diethylaminocarbyne complexes (η 5 -C 5 H 5 )(CO) 2 W≡CNEt 2 (7) and (η 5 -C 5 Me 5 )(CO) 2 W≡CNEt 2 (8). Oxidative decarbonylation of 7 and 8 with iodine in CH 2 C1 2 gives the high-valent tungsten compounds (η 5 -C 5 H 5 )(I) 2 (CO)W≡CNEt 2 (9) and (η 5 -C 5 Me 5 )(I) 2 (CO)W≡CNEt 2 (10). 9 and 10 are subsequently converted with one equivalent of EtNC and TlPF 6 into the cationic carbyne complexes [(η 5 -C 5 H 5 )(I)(EtNC)(CO)W≡CNEt 2 ]PF 6 (11) and [(η 5 -C 5 Me 5 )(I)(EtNC)(CO)W≡CNEt 2 ]PF 6 (12). Advantages of this route to low- and high-valent tungsten diethylaminocarbyne complexes are discussed in comparison to the classical Fischer procedure using the carbyne complex trans-I(CO) 4 W≡CNEt 2 as precursor.

The crystal structure of SbF 5 · SO 2 is reported. SbF 5 · SO 2 crystallizes in the monoclinic space group P2 1 /n with a = 580.4(4) pm, b = 1047.7(5) pm, c = 1013.3(6) pm, β = 102.92(5)°, V = 600.57 · 10 6 (6) pm 3 , and Z = 4. It shows five intermolecular S ··· F contacts.

A reinvestigation of C. aegyptiaca L. gave in addition to phytol a new triterpene. Its structure was determined by IR, 1 H NMR and mass spectral data.

Interactions were studied of aniline, 4-methoxyaniline and 4-ethoxyaniline with tetrachloromethane, chloroform and dichloromethane in their ground and first excited singlet states. Stability constants of the complexes of these amines with the chloromethanes in cyclohexane were determined as well as their quantum yields of fluorescence in this solvent. The quenching of fluorescence of aniline and its derivatives by the chloromethanes was ascertained and characterized. Quantum yields of the formation of hydrogen chloride, ψ ΗCl , were measured during photochemically induced reaction of the amines in tetrachloromethane, chloroform and dichloromethane.

Major products of photochemical reactions of aniline in tetrachloromethane, chloroform and dichloromethane have been isolated and identified. The mechanisms of partial reactions have been discussed.

Thermolysis of Bis(η-methylcyclopentadienyl)diphenyltitanium (6) at 80°C yields benzene and (η 6 -fulvene)(η-methylcyclopentadienyl)phenyltitanium (8). Complex 8 reacts with various aldehydes and ketones by insertion into the Ti—CH 2 C 5 H 4 σ-bond to stereoselectively form the metallacyclic chiral metallocene complexes [xxx] 10a—d. Difference NOE 1 H NMR spectra of the acetaldehyde insertion product 10c (R 1 = H, R 2 = CH 3 ) have revealed a cis-arrangement of the methyl substituent and the titanium bound σ-phenyl ligand at the central metallacyclic ring system.

X-ray analysis of the intramolecular condensation product of methylene-bis-[bis-(2-oxopropyl)-phosphane oxide] (3) shows heteroadamantane structure. One of the C—P—C-angle seems to be very unusual. A value of only 95.5° was measured.

The dark grey compounds NaLiTe, KLiTe and KNaTe have been prepared and characterized by X-ray powder diffraction. NaLiTe and KNaTe are isotypic and crystallize in the orthorhombic space group Pnma with Z = 4 formula units in the unit cell. The lattice constants are a = 774.0(1), b = 462.4(2) and c = 840.6(1) pm for NaLiTe and a = 852.1(1), b = 513.4(2) and c = 926.5(1) pm for KNaTe. KLiTe crystallizes in the tetragonal space group P4/nmm with a = 483.9(2) and c = 771.7(1) pm and Z = 2.

Oxidation of 1,5-cyclooctadiene by SeO 2 /acetic anhydride (or SeO 2 /dioxane) yields the title compound 2a (or 2b, respectively). The type of reaction is not totally without precedent although the detailed mechanism is still unknown.

The colourless compounds KLiSe and KNaSe have been prepared and characterized by powder measurements. KLiSe crystallizes in a tetragonal lattice with a — 451.7(1), c = 7274 1(2) pm, Z. = 2 (P4/nmm). KNaSe crystallizes in the orthorhombic space group Pnma with a = 806.3(2), b = 481.7(1) and c = 865.1(2) pm, Z = 4.