Volume 50, Issue 1

The title compounds have been prepared by reactions of MoCl 2 (NO) 2 with PPh 3 , OPPh 3 , or Me 3 SiNPR 3 (R = Et, Ph) in dichloromethane and acetonitrile suspension, respectively. All complexes were characterized by IR spectroscopy and by crystal structure determinations. [MoCl 2 (NO) 2 (OPEt 3 )] 2 : Space group C2/c, Z = 4, 2950 observed unique reflections, R = 0.029. Lattice dimensions at —70 °C: a = 2390.5(11), b = 875.5(5), c = 1399.1(6) pm, β = 113.18(2)°. The complex forms a centrosymmetric dimer with MoCl 2 Mo bridges, the nitrosyl groups being in a cis-arrangement. The OPEt 3 ligand is coordinated in trans position to one of the nitrosyl ligands. [MoCl 3 (NO)(OPPh 3 ) 2 • MoCl 4 (OPPh 3 ) 2 ]: Space group P2 1 /c, Z = 4, 10243 observed unique reflections, R = 0.060. Lattice dimensions at —60 °C: a = 1900.4(3), b = 1689.1(5), c = 2209.3(7) pm, β = 95.92(2)°. The structure consists of the two independent complexes [MoCl 3 (NO)(OPPh 3 ) 2 ] and [MoCl 4 (OPPh 3 ) 2 ]. In both complexes the OPPh 3 groups are in a cis-arrangement at the octahedrally coordinated Mo atoms; in the nitrosyl complex one of the OPPh 3 molecules is in trans-position to the nitrosyl ligand. [MoCl 2 (NO)(PPh 3 ) 2 (CH 3 CN)]: Space group P2 1 /n, Z = 4, 5107 observed unique reflections, R = 0.028. Lattice dimensions at 20 °C: a = 1006.5(2), b = 1527.2(2), c = 2342.3(2) pm, β = 90.97(1)°. The PPh 3 molecules are in trans-positions to one another at the octahedrally coordinated Mo atom, whereas the acetonitrile molecule is in trans-position to the nitrosyl ligand. [MoCl 4 (NPPh 3 )(OPPhi)]: Space group P2 1 , Z = 2, 3323 observed unique reflections, R = 0.057. Lattice dimensions at —70 °C: a = 985.7(8), b = 1471.2(9), c = 1215.9(11) pm, β = 100.50(3)°. The OPPh 3 molecule coordinates in trans-position to the phosphorane iminato ligand at the octahedrally coordinated Mo atom.

Aminohexahydro-closo-hexaborate(1–), Crystal Structure, 11 B NMR Spectra, Vibrational Spectra By reduction of [B 6 H 5 (NO 2 )] 2- with Fe 2+ in aqueous alkaline solution [B 6 H 6 (NH 2 )]- is formed. The compound has been separated by extraction with dichloromethane in the presence of tetrabutylammoniumbromid and precipitated from the organic phase by adding CsCH 3 COO/C 2 H 5 OH. The Crystal structure of Cs[B 6 H 6 (NH 2 )] · H 2 O has been determined by single crystal X-ray diffraction analysis; monoclinic space group C2 with a = 22.1075(14), b = 6.491(2), c = 5.9570(4) A, β = 100.168(6)°. The 11 B NMR spectrum is consistent with a mono-hetero-substituted octahedral B 6 cage with local C 4v symmetry. The IR and Raman spectra exhibit characteristic N–H, B–H and B 6 vibrations.

Crystal structure analyses of the title complexes have been carried out in order to establish their molecular configurations. The tris(chelate) complex dication in (1)(PF 6 ) 2 exhibits a mer configuration of pyridine and azo nitrogen atoms in an approximately octahedral arrangement at the metal. The dichlororuthenium bis(chelate) compound 2 has the halide ligands and the coordinated azo nitrogen centers in an equatorial cis arrangement whereas two pyridyl groups (one of each abpy ligand) occupy the axial positions. The bond distances from the metal to the nitrogen donor centers are systematically smaller for the stronger π accepting azo functions than for the more basic but less π acidic pyridyl groups, a result which differs from that obtained for Mo(0) and Cu(I) complexes of abpy. All Ru—N distances are shorter in the neutral dichloro complex 2. The non-coordinated pyridyl rings of the potentially tetradentate abpy ligands are tilted into approximate s-cis/(NN-trans)/s-trans positions (dihedral angle ω ≈ 145°) as to minimize steric repulsion, however, they do not coordinate to the metal (d Ru-N > 327 pm). While there are no significant intermolecular interactions, the observed conformation implies that considerable structural reorganization is necessary for the formation of oligonuclear complexes.

In the crystal structure of K 34 [Zn 20 In 85 ] (a = 1827.7(5) pm, c = 3980.5(8) pm, R3̅m, Nr. 166, Z = 3, R1 = 0.056, wR2 = 0.124) the In and Zn atoms form the β-rhombohedral boron structure. The structure contains In 84 Samson polyhedra, and clusters of 18 In and 10 Zn atoms, forming three In 12 icosahedra sharing two common triangular faces. The potassium atoms occupy the centres of truncated tetrahedra – forming the Samson polyhedra – and Kasper polyhedra.

The calcium and barium complexes with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone have been synthesized and characterized by X-ray structural analysis. Besides two molecules of the ligand, the calcium atom binds two molecules of ethanol in an octahedral coordination. The barium atom attains the coordination number 8 by coordinating 4 molecules of the pyrazolone ligand.

Acid constants and stability constants of nickel and zinc chelates with 2-thenoyltrifluoroacetone, dibenzoylmethane, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and 3-phenyl-4-benzoyl-5-isoxazolone were compared. The extraction of copper was studied. Thermoanalytic measurements were made using the ligands and their copper compounds in the solid state. The molecular structure of 3-phenyl-4-benzoyl-5-isoxazolone was determined by X-ray analysis. Crystal data: a = 874,7(2), b = 1959,2(7), c = 897,38(7) pm; β = 101,030(7)°; space group P 12 1 /c 1; Z = 4; R = 0,043; 1920 observed, unique reflexions.

Single crystals of Sr 2 (VO)V 2 O 8 have been prepared by quenching melts from higher temperatures. This compound represents a new structure type and crystallizes with monoclinic symmetry, space group C 6 2h –I2/a, a = 6.929, b = 16.246, c = 7.260 Å, β = 115.82°, Z = 4. The point positions occupied by V 5+ show tetrahedral coordination. The refinement of the V 4+ position led to split positions with acentric orientations of V 4+ in the octahedral O 2- surrounding. It results in a square pyramidal coordination with one short V–O distance typically for vanadyl groups.

Single crystals of Hg 3 CrO 6 have been prepared by high pressure techniques (3600 bar oxygen, 600 °C). Hg 3 CrO 6 crystallizes with trigonal symmetry, space group D 6 3 —P3 2 12, a = 7.137(1), c = 10.017(2) Å, Z = 3. Nearly linear O—Hg—O dumb-bells are connected in planes, forming strongly puckered nets of six-membered rings. Each Hg 6 O 6 ring is centered by a CrO 4 tetrahedron; the CrO 4 tetrahedra are arranged in two equally occupied split positions.

Single crystals of NaFe 3 V 3 O 12 have been prepared by solid state reaction below the melting point of the reaction mixture. This compound is isotypic to the mineral Howardevansite but shows lower triclinic symmetry, space group C 1 1 –P1, a = 6.757(2), b = 8.155(2), c = 9.816(3) Å, α = 106.05(2), β = 104.401(9), γ = 102.09(2)°, Z = 2. The acentric space group is caused by the sodium positions, all other atoms comply with the space group P̄ of Howardevansite. The different ions are coordinated by O 2- forming VO 4 tetrahedra, FeO 6 octahedra, trigonal FeO 5 bipyramids and irregular NaO 5 and NaO 7 polyhedra, respectively. The crystal chemistry is discussed with respect to Howardevansite.

Single crystals of Ba 4 LiCuO 4 (CO 3 ) 2 have been prepared by CO 2 —LASER technique and investigated by single crystal X-ray diffraction. The compound crystallizes in the tetragonal space group D 11 2d —I4̄2m (No. 121), a = 5.767(1), c = 15.2614(7) Å, Z = 2. It is isotypic with Ba 4 NaCuO 4 (CO 3 ) 2 and shows Li + with octahedral and Cu 3+ with square planar coordination by O 2- . The crystal structure are discussed with respect to the related compounds Ba 4 NaAuO 4 (O 2 ) 2 and Ba 4 KAuO 4 (C 2 ) 2 .

Single crystals of Nd 4 Mn(SiO 4 ) 3 O have been prepared by a Bi 2 O 3 flux in closed copper tubes. The colourless crystals show hexagonal symmetry, space group C 6h 2 —P6 3 /m, a = 9,4986(9), c = 6,944(2) Å, Z = 2. Nd 4 Mn(SiO 4 ) 3 O crystallizes in the Apatite structure and shows Nd 3+ and Mn 2+ with partly statistical distribution. As a consequence of this, O(2) and O(4) are occupying split positions.

The title compound has been prepared in two different ways: First, by boiling single crystals of [(C 2 H 5 ) 4 N]HgCl 3 in a mixture of n-hexane/n-octane [4:1] at T = 350 K, and second, in a synthesis from stoichiometric quantities of the components. X-ray structure analysis gave the stoichiometry [(C 2 H 5 ) 4 N] 2 Hg 3 Cl 8 , monoclinic, space group P2 1 , a = 7.538(3), b = 19.909(6), c = 10.274(3) Å, β = 95.13(1)°, V = 1535.7(9) A 3 , Z = 2. The basic [Hg 3 Cl 8 ] 2- -units form broken zig-zag chains along [100]. The Hg–Cl distances within the [Hg 3 Cl 8 ] 2- clusters range from 2.315(3) to 2.755(4) Å. This is a new coordination type for halomercurates.

(DME) 2 ] 1 (R = C 6 H 4 -4-CH 3 ; DME = dimethoxyethane) was prepared by reaction of calcium with NR=CPh-CPh=NR in DME solution. The compound forms orange, moisture sensitive crystals, which were characterized by an X-ray structure determination [space group orthorhombic, P2 1 2 1 2 1 , Z = 4, 4634 observed unique reflections, R = 0.046; lattice dimensions at –70 °C: a = 1340.2(3), b = 1528.1(3), c = 1609.1(3) pm]. The calcium atom is coordinated by the four oxygen atoms of two chelating DME molecules and two nitrogen atoms of the diazadiene ligand, bonded in its enediamide form. [Ba 2 (DME) 3 (NPh–CPh=CPh–NPh) 2 · DME] 3 was obtained from barium metal and NPh=CPh-CPh=NPh in DME solution as red crystals [space group monoclinic, P2 l /c, Z = 4, 4000 observed unique reflections, R = 0.166; lattice dimensions at -70 °C: a = 1704.5(3), b = 1786.1(4), c = 2177.4(4) pm, β = 105.98(3)°]. The two barium atoms are bridged by two differently bonded diazadiene ligands (μ 2 -Ν,Ν′;μ-Ν, σ-Ν′). Additionally, one of the barium atoms is coordinated to two DME molecules and the other one to only one of the ether molecules. A further DME molecule is a constituent of the crystal lattice.

Di-tert-butyldifluorosilane reacts with N-lithium-N′,N′-dimethylhydrazine in a molar ratio 1:1 to yield the N-di-tert-butylfluorosilyl-N′,N′-dimethylhydrazine 1. The lithium derivative of 1 (2) forms a dimer with the nitrogen atoms coordinated “side-on” to the lithium atoms. The silylation with Me 3 SiCl gives product 3. Heating 2 in a vacuum leads to the cyclodisilazane derivative 4. A bis(hydrazino)fluoroborane (5) is obtained in the reaction of 2 with trifluoroborane-etherate.

The title compound, formed by the reaction of acetophenone with 3-diethylamino-1-propylamine and sulfur, crystallizes in the orthorhombic space group P2 1 2 1 2 1 (Z = 4) with lattice constants a = 818.1(2) pm, b = 1225.1(2) pm and c = 1622.4(4) pm. The characterization of the molecule as a zwitterion is established by the observed bond parameters. Both spectroscopic investigations and the results of the X-ray structure determination show that a hydrogen atom is bonded to the amino nitrogen rather than to the imino nitrogen.

The crystal structures of (ClCN) 2 (Cl 2 PN) (1) and (ClCN)(Cl 2 PN) 2 (2) are reported. A general bonding model for heterotriazines (XCN) n (XAN) 3-n (X = 2, 1) is discussed.

The crystal structure of the potassium hexatellurate(VI) K 8 Te 6 O 17 (OH) 10 · l/2 KOH · 16 H 2 O features a cyclic polyoxotellurate anion with six octahedral TeO 6 units condensed through alternate sharing of edges and vertices.

The reaction of bis(trifluoromethyl)arsane 2 with secondary amines R 2 NH in a molar ratio of 1:3 at -60 °C allows the preparation of trifluoromethyl arsaalkenes of the type F 3 CAs=C(F)NR 2 in moderate yields (15-35%) [NR 2 = NMe 2 (3a), NMeEt (3b), NEt 2 (3c)]. The main product of the reaction of 2 with Me 2 NH is the 1,1-diamino compound F 3 CAs=C(NMe 2 ) 2 (4a). With ethyl(isopropyl)- or di(isopropyl)amine the corresponding derivatives F 3 CAs=C(F)NEt(iPr) (3d) and F 3 CAs=C(F)N(iPr) 2 (3e), respectively, are formed only in traces (3d), or not at all (3 e). However, 3d and 3e can be prepared by reacting perfluoro-2-arsapropene with the corresponding secondary amines. The new compounds 3 a to 3 e can be stored at 20 °C in chloroform solution for hours without decomposition and show Z configuration without exception. The molecular structure of 1-(diethylamino)-1,3,3,3-tetrafluoro-2-arsapropene 3c, determined by an X-ray diffraction study on single crystals, indicates a strong electronic interaction of the lone pair on nitrogen with the AsC double bond. This results in a trigonal planar arrangement at the nitrogen atom, a strongly shortened sp 2 -CN-bond (1.312 Å), an elongated AsC distance (1.867 Å), and an almost planar skeleton of the molecule.

Low-melting trihydrates of triethylamine (Et 3 N) and 4-methylpyridine (4-MePy) have been confirmed and detected by phase analysis and the crystal structures determined. Both are monoclinic with space group P2 1 /c and Z = 4 formula units per unit cell. The lattice parameters are a = 13.606, b = 6.291, c = 12.412 Å, and β = 99.47° at -100 °C for Et 3 N · 3 H 2 O, and a = 9.982, b = 6.877, c = 12.958 Å, and β = 103.50° at -90 °C for 4-MePy · 3 H 2 O. The water molecules in the two structures are hydrogen-bonded in condensed four-, five-, and six-membered rings with 1:2:1 ratio, thus forming characteristic layers parallel (100) of identical topology and tautomeric to each other. The amine molecules are linked to both sides of the layers by O-Η ··· N bonds from different O atoms.

Calcium- and strontium bis[bis(trimethylsilyl)amide] react with bis(trimethylsilyl)arsane in tetrahydrofuran to give the corresponding tetrakis(tetrahydrofuran-O) metal bis[bis(trimethylsilyl)arsanides]. The calcium derivative crystallizes in the triclinic space group P1̄ with a = 1191.7(2), b = 1232.0(2), c = 1655.0(2) pm, α = 102.46(1)°, β = 107.92(1)°, γ = 104.66(1)° and Ζ = 2, the strontium derivative in the orthorhombic space group Pbca with a = 2153.4(3), b = 1852.2(3), c = 2182.4(3) pm and Z = 8. Both molecules exist as trans-isomers with a nearly linear As-M-As moiety; however, the strontium analogue contains two remarkably different configurations for the arsenic atoms. One As atom is surrounded nearly trigonally planar with a Sr-As bond length of 310 pm, whereas the other pnictogen atom has an angle sum of 338° with a Sr-As distance of 315 pm.

The molecular and crystal structure of the dicopper(I) complex (dmp) 2 (μ-o-CH 3 C 6 H 4 S) 2 Cu 2 (1), dmp = 2,9-dimethyl-1,10-phenanthroline, has been determined. With Cu/S/Cu and S/Cu/S bond angles between 80 and 100°, the planar structure of the central CuSCuS four-membered ring is much more symmetric for 1 as compared to the analogous complex 2 of unsubstituted 1,10-phenanthroline which has a folded Cu 2 S 2 core with bond angles between 67 and 108°. This result illustrates a considerable structural flexibility of the LCu(μ-SR) 2 CuL entity which is being discussed as a possible model for Cu A centers of cytochrome c oxidase or nitrous oxide reductase. Oxidation of both complexes 1 and 2 remains irreversible even at cyclovoltammetric scan rates of 1 V/s. However, the methyl substitution in complex 1 causes increased reversibility of the electronically coupled dmpbased reduction processes. Accordingly, the EPR spectrum of 1 - · is characterized by hyperfine splitting from dmp - · and a relatively small 63,65 Cu coupling of 0.53 mT. The stabilization of 2,9-disubstituted 1,10-phenanthroline radical anions by coordination to Cu(I) is also demonstrated by detection of a single broad EPR line at g 2.0028 for the formal “Cu(0)” complex Cu(dpp) 2 = CuI(dpp - ·)(dpp), dpp = 2,9-diphenyl-1,10-phenanthroline. While the EPR signal of Cu(dpp) 2 loses intensity on cooling, possibly due to dimerization and spin-pairing, the distorted tetrahedral configuration with essential orthogonal arrangement of dpp π systems seems to disfavour an intramolecular electron hopping.

Synthesis, physical properties and the coordination with two [Ru(bpy) 2 ] 2+ complex fragments are described for 3,6-bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz), the first compact ligand which offers four equivalent α-diimine chelate sites. Spectroelectrochemistry of intensely blue {(μ-bmtz)[Ru(bpy) 2 ] 2 } n+ , n = 4, reveals a very facile reduction (n = 3) at -0.40 V vs. FeCp 2 +/o and a metal oxidation (n = 5) at + 1.18 V to a diruthenium(II/III) mixed-valent form which exhibits an intervalence transfer absorption at 1490 nm. The corresponding complex {(μ-H 2 bmtz)[Ru(bpy) 2 ] 2 } 4+ with the 1,4-dihydro form H 2 bmtz of the tetrafunctional ligand is oxidized in two steps at 0.58 and 1.07 V vs. FeCp 2 +/o .

Complexes of Uncharged Molecules, Crystal Structure The thermally labile ternary complexes 18C6 · 2MeOH · 2 HN(SO 2 Ph) 2 (2a), 18C6 · 2MeOH · 2HN(SO 2 –C 6 H 4 -4-Cl) 2 (2b) and 18C6 · 3 MeOH · HN(SO 2 Me)(SO 2 Ph) (3) were obtained by co-crystallization of 18-crown-6 (18C6) and the appropriate di(organosulfonyl)amine from methanolic solutions and characterized by low-temperature X-ray diffraction. The crystal structures of 2a (monoclinic, space group P2 1 /n) and 2b (triclinic, space group P1̄) consist of monomeric, centrosymmetric formula units. Each di(arenesulfonyl)-amine molecule is connected to a methanol molecule by an N-Η ··· O hydrogen bond (H ··· O 203 pm in 2a, 190 pm in 2b). The methanol molecules are linked to three alternate crown oxygen atoms via one O-Η ··· O(crown) hydrogen-bond and two weaker C-Η ··· O(crown) interactions (OH ··· O 201 pm in 2a, 186 pm in 2b; CH ··· O 236 and 247 pm in 2a, 240 and 254 pm in 2b); two symmetry-related oxygen atoms of the crown are involved in O-Η ··· O and the other four in C-Η ··· O interactions. The structure of complex 3 (monoclinic, space group P2 1 ) is built of infinite chains parallel to [101]. The methyl group of the di(organosulfonyl)amine is bonded by C-Η ··· O(crown) interactions to a set of three alternate oxygen atoms of the cyclic polyether (H ··· O 228, 245 and 247 pm). Starting from the acidic NH function, a sequence of three methanol molecules catenated by hydrogen bonds curves around the bulky phenyl group and links with its terminal MeOH through one O-H ··· O(crown) and two C-Η ··· O(crown) bonds to the second set of alternate oxygen atoms in the adjacent symmetry-equivalent crown (OH ··· O 193 pm, CH ··· O 248 and 250 pm). Within the chain sequence N-H ··· O′(Me)H′ ··· O″(Me)H″ ··· O‴(Me)H, the H ··· O distances are H ··· O′ 184, H′ ··· O″ 189 and H″··· O‴ 183 pm. In the structures of 2a, 2b and 3, the crown rings adopt the frequently observed D 3d pseudosymmetry.

The crystal and molecular structure of chloro(methyl phytochlorinato)iron(III), 4, have been determined by single crystal X-ray crystallography to obtain further information on the conformation of metallochlorins related to chlorophyll. The compound crystallized with two independent molecules mainly distinguished by the orientation of the axial ligand. The macrocycles show significant deviations from planarity larger than those observed in corresponding magnesium(II) complexes. The overall type of distortion is similar to those found in chlorophyllides. Compound 4 crystallized in the monoclinic space group P2 1 (MoKa,λ = 0.71063 A) with unit cell dimensions a = 12.035(6) Å, b = 13.396(8) Å, c = 19.04(2), b = 97.51(2) Å, Z = 4, V = 3043(4) Å 3 . The structure was refined to an R-value of 0.075 on the basis of 3974 reflections with I > 3.0σ(Ι) (130 Κ).

Computer modeling was used to find an effective substituent for position 5 in antagonists of the luteinizing hormone-releasing hormone (LHRH). In particular, it was desired to replace cis-3-(4-pyrazinylcarbonylaminocyclohexyl)alanine in position 5 because this substituent is laborious to synthesize. Calculations revealed that N 5 -pyrazinylcarbonylornithine (PzOrn) should be a suitable substitute for cPzACAla, with N 6 -pyrazinylcarbonyllysine (PzLys) being a second choice. Twelve analogs were synthesized in four series with DNal or DQal in position 1 and ILys or Arg in position 8. Biological assays validated the calculations and show that antagonists with PzOrn are more potent in antiovulatory assay than antagonists with PzLys. The antagonists with PzOrn were comparable in AOA with antagonists with cPzACAla. What is also important, antagonists with PzOrn released significantly less histamine than those with cPzACAla.

Diazomethane adds to plumbagin (la) yielding the indazolequinone 7 which, in the presence of sodium hydroxide, reacts to form nitrogen and the anion 4a. The latter reacts with excess juglone (lb) or juglone methyl ether (lc) forming isozeylanone (6a) and neozeylanone (6c) or their corresponding monomethyl ethers 6b and 6d, rsp. In a similar manner, the quinones 11a, 11c, and 15 originate by reaction of two molecules diazomethane with la via the indazoles 9 and 13, rsp.