Showing papers in "Zeitschrift für Naturforschung. B, A journal of chemical sciences in 2002"
TL;DR: In this paper, the preparation, crystal structure and optical absorption spectra of [CH 3 SC(NH 2 ] 3 SnI 5 (1), [HSC(NH2 ) 2 ] SnBr 4 (2), [C 6 H 5 CH 2 SC-(NH 2 )2 ] 4 Pb 3 I 1 0 (4) are reported.
Abstract: The preparation, crystal structure and optical absorption spectra of [CH 3 SC(NH 2 ) 2 ] 3 SnI 5 (1), [CH 3 SC(NH 2 ) 2 ][HSC(NH 2 ) 2 ]SnBr 4 (2), (CH 3 C 5 H 4 NCH 3 )PbBr 3 (3), and [C 6 H 5 CH 2 SC-(NH 2 ) 2 ] 4 Pb 3 I 1 0 (4) are reported. The compounds 1, 2, 3 consist of MX 6 -octahedra (M = Sn, Pb, X = I, Br) forming one-dimensional single chains (compounds 1, 3) or double chains (compound 2). The compound 4 forms a two-dimensional inorganic network via comer sharing of three face sharing octahedral units. Because of their low-dimensional character, a blue shift of the excitonic absorption bands, in comparison to those of higher dimensionality systems, is observed.
28 citations
Journal Article•
TL;DR: In this paper, the authors synthesize three membered rings As 3 - 3 with As-As distances of 243.0 to 247.5 pm, and characterize them via single crystal x-ray studies and Raman spectroscopy.
Abstract: The title compounds were synthesized from the elements and characterized via single crystal x-ray studies and Raman spectroscopy. In the Zint1 phases A 3 As 7 (A = K, Rb, Cs) the As atoms form nortricyclene-analogous anions As 3 - 7 with As-As distances ranging from 230 to 254 pm. The three compounds crystallize with different new structure types containing different packings of the As7 anions: K 3 As 7 (orthorhombic, Pbca; a = 1291.9(8), b = 2544.1(9), c = 1537.7(16) pm) shows a double hexagonal close packing (ABAC stacking of planes of hexagonal close packed anions), Rb 3 As 7 (monoclinic, P2 1 /c, a = 757.3(5), b = 1310.2(8), c = 2692.7(18) pm , β = 91.972(12)°) shows a hexagonal close packing (AB) and the Cs compound (orthorhombic, Pbca, a = 1022.8(5), b = 1317.6(7), c = 2195.2(11) pm) a cubic close packing (ABC) (also present in the HT-forms of the three compounds) respectively. The alkaline metal monoarsenides AAs (A = K, Rb) crystallize with the NaP structure type (A = K/Rb: orthorhombic, P2 1 2 1 2 1 ; a = 661.7(5) / 658.1(8), b = 688.8(6) / 691.6(8), c = 1197.3(10) / 1204.7(10) pm, Z = 8) with approximate fourfold screw axes 4 1 of As - chains, whereas the crystal structure of CsAs (hexagonal, P62m, a = 1219.7(3), c = 1046.3(2) pm, Z= 18) contains three crystallographically independent three membered rings As 3 - 3 with As-As distances of 243.0 to 247.5 pm.
24 citations
TL;DR: In this article, the ternary antimonides YbTSb (T= Ni, Pd, Pt, Cu, Ag, Au) were synthesized by reaction of the elements in sealed tantalum tubes in a high-frequency furnace.
Abstract: The ternary antimonides YbTSb (T= Ni, Pd, Pt, Cu, Ag, Au) were synthesized by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. The structures of YbCuSb (NdPtSb type), YbAgSb (TiNiSi type), and YbAuSb (NdPtSb type) were confirmed on the basis of X-ray powder diffraction data. Those of the nickel, palladium, and platinum based antimonides (cubic MgAgAs type) were refined from single crystal X-ray data. The nickel based antimonide has a pronounced homogeneity range YbNi x Sb. The structures of five crystals have been investigated. The cubic lattice parameter increases with increasing nickel content from 613.13(6) pm (x = 0.17) to 621.25(5) pm (x = 0.63). Full occupancy of the palladium and antimony sites was observed for YbPdSb while the platinum compound shows some platinum vacancies leading to the composition YbPt 0 . 9 6 9 ( 7 ) Sb for the investigated crystal. A new, high-temperature modification of YbPdSb was obtained by rapidly quenching an arc-melted sample: TiNiSi type, Pnma, a = 725.6(2), b = 458.3(1), c = 785.4(2) pm, wR2 = 0.1255, 421 F 2 values, 20 variables. The antimonides YbTSb (T= Ni, Pd, Pt, Cu, Ag, Au) show single 1 2 1 Sb Mossbauer signals at isomer shifts ranging from -7.34 to -7.82 mm/s. The crystal chemistry and chemical bonding of these antimonides is discussed.
24 citations
TL;DR: In this paper, the crystal structure of the iodide complex was determined by X-ray diffraction methods and shown to feature only monomers with extremely large intermolecular Au-Au contacts of 4.162 A.
Abstract: The complexes ( t BuNC)AuCl and ( t BUNC)AuI 1 3 C-labeled at the isocyanide group were prepared and investigated by concentration- and temperature-dependent IR and NMR spectroscopy in dichloromethane solution. No indication for association of the molecules was obtained. The crystal structure of the iodide complex was determined by X-ray diffraction methods and shown to feature only monomers with extremely large intermolecular Au-Au contacts of 4.162 A, well beyond the sum of the van der Waals radii. It therefore appears that ( t BuNC)AuI is a rare example of a sterically non-hindered L-Au-X complex which shows no aurophilic interactions whatsoever. In a quantum-chemical analysis (at the local MP2 level) of the dimerization of the model compounds (MeNC)AuCl and (MeNC)AuI in various dimer geometries it was demonstrated that the energy-balance of the dimerization is very delicate and not dominated solely by contributions from correlation / relativistic (aurophilic) effects.
22 citations
TL;DR: A new strontium lithium titanate with composition SrLi 2 Ti 6 O 1 4 has been discovered in the ternary system SrO - Li 2 O - TiO 2.
Abstract: A new strontium lithium titanate with composition SrLi 2 Ti 6 O 1 4 has been discovered in the ternary system SrO - Li 2 O - TiO 2 . Single crystals of this compound have been grown by the flux method. The structure of SrLi 2 Ti 6 O 1 4 has been solved using X-ray data (Mo-K α radiation, orthorhombic, space group Cmca, Z = 8, with a = 16.570(5), b = 11.150(2), c = 11.458(2) A, R 1 = 0.039 (wR 2 = 0.087)). The crystal structure is built by edge and corner sharing TiO 6 octahedra which form layers parallel to the (100) plane. Consecutive layers [deduced from a mirror plane parallel to (100)] are linked by common corners in the a direction. Lithium atoms in tetrahedral coordination occupy vacancies of the framework of titanium octahedra, while strontium atoms lie in 1,1-coordinated sites between two successive layers.
20 citations
TL;DR: In this article, 5-(dimethylamino)methylidene substituted hydantoin and thiohydantoin derivatives with carbocyclic C-nucleophiles were determined by NMR, using NOESY and 2D HMBC techniques.
Abstract: 3-Substituted 5-[(Z)-heteroarylmethylidene]imidazolidine-2,4-dione and 5-[(Z)-heteroarylmethylidene]-2-thiooxoimidazolidin-4-one derivatives were prepared stereoselectively by coupling of 5-(dimethylamino)methylidene substituted hydantoin and thiohydantoin derivatives with carbocyclic and heterocyclic C-nucleophiles. Configuration around the exocyclic C=C double bond was determined by NMR, using NOESY and 2D HMBC techniques.
17 citations
Journal Article•
TL;DR: In this article, the NiO 6 octahedron is built by two water molecules and four oxygen atoms of the dicarboxylate ligands, which connect the Ni octahedral to a three-dimensional network.
Abstract: From a solution of Ni(CH 3 COO) 2 . 4 H 2 O and acetylenedicarboxylic acid in deionized water single crystals of Ni(C 2 (COO) 2 )(H 2 O) 4 . 2 H 2 O (P2 1 /a, Z= 2, isotypic to Co(C 2 (COO) 2 )(H 2 O) 4 . 2 H 2 O) were obtained by slow evaporation of the solvent. In the solid state structure nickel is octahedrally surrounded by four water molecules and two oxygen atoms of the carboxylate anions. These octahedra are connected to chains by the dicarboxylates. Heating the hexahydrate to 100 °C in a stream of argon leads to Ni(C 2 (COO) 2 )(H 2 O) 2 (C2/c, Z = 4, isotypic to Mn[C 2 (COO) 2 ] . 2 H 2 O). Here, the NiO 6 octahedron is built by two water molecules and four oxygen atoms of the dicarboxylate ligands, which connect the Ni octahedra to a three-dimensional network. Thermoanalytical investigations show another mass loss at about 200 °C, which leads to non-crystalline products. Finally, at about 400 °C NiO is formed. Measurements of the magnetic susceptibilities result in the expected behaviour for Ni 2 + in an octahedral co-ordination ( 3 A 2 ground state). The effective magnetic moment at room temperature is μ e f f = 3.20 μ B .
17 citations
TL;DR: Two series of the title compounds were prepared by reaction of 1,2-bis(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)ethane with N-aryl-2-oxopropane-hydrazonoyl chlorides as discussed by the authors.
Abstract: Two series of the title compounds were prepared by reaction of 1,2-bis(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)ethane with N-aryl-2-oxopropane-hydrazonoyl chlorides. The spectral data of such compounds indicated that they exist predominantly in the bis-hydrazone tautomeric form.
16 citations
TL;DR: N-(5-Chlorosalicylidene)-2-hydroxy-5-chloroaniline was synthesized and its crystal structure determined by semi-empirical quantum mechanical AMI calculations as mentioned in this paper.
Abstract: N-(5-Chlorosalicylidene)-2-hydroxy-5-chloroaniline was synthesized and its crystal structure determined. It crystallizes in the orthorhombic space group Pna2 1 with a = 14.668(4), b = 6.084(3), c = 27.980(4) A, R = 0.051 for 4788 independent reflections). There are two independent nearly planar molecules in the asymmetric unit. The intramolecular hydrogen bonds occur between the pairs of atoms N1 and O1 [2.553(6) A], N1 and 02 [2.585(5) A], N2 and 03 [2.567(6) A], N2 and 04 [2.620(5) A], the hydrogen atoms essentially being bonded to the nitrogen atoms. The neighboring molecules are linked via an intermolecular O-H...O hydrogen bond [2.557(5) A]. Conformations of the title compound were investigated by semi-empirical quantum mechanical AMI calculations. The optimized geometry of the molecular structure corresponding to the nearly planar conformation is the most stable conformation in the calculations. The results strongly indicate that the minimum energy conformation is primarily determined by non-bonded steric interactions.
16 citations
TL;DR: In this article, the compounds Ln 3 Cu 4 P 4 O 2 -x (Ln = Pr, Sm) were prepared by annealing the elemental components in a NaCl/KCl flux.
Abstract: The compounds Ln 3 Cu 4 P 4 O 2 - x (Ln = Pr, Sm) were prepared by annealing the elemental components in a NaCl/KCl flux. They crystallize with an ordered Zr 3 Cu 4 Si 6 -type structure (space group I4/mmm, Z = 2), which was refined from single-crystal X-ray data for both compounds; Pr 3 Cu 4 P 4 O 2 - x : a = 397.8(1), c = 2658.7(3) pm, R = 0.046 for 235 structure factors and 19 variable parameters; Sm 3 Cu 4 P 4 O 2 - x : a = 392.8(1), c = 2643.6(3) pm, R = 0.057 for 145 F values and 19 variables. The refinements showed partial occupancy for the oxygen positions resulting in approximately 1.5 oxygen atoms per formula unit. Half of the phosphorus atoms form pairs with typical two-electron bond distances of 222.8(4) and 221.7(8) pm, respectively. Using oxidation numbers chemical bonding in these phosphide oxides can be rationalized with the formula (Ln+3)3(Cu + 1 ) 4 (P-P) - 4 (P - 3 )) 2 (O - 2 ) 1 . 5 . Hence, the empirical formula may also be doubled (Ln 6 Cu 8 P 8 O 3 ), and the compounds are expected to be semiconducting.
16 citations
TL;DR: In this article, pseudobinary cyanides of monovalent and divalent metals were synthesized, and X-ray and Raman data of the cyanides were measured, and single crystal Xray structure analyses were performed on Zn(CN) 2 (Pn3m (No. 224), a = 591.28(11) pm, Hg(CN 2 (I42d (No).
Abstract: Pseudobinary cyanides of monovalent and divalent metals were synthesized, and X-ray and Raman data of the cyanides were measured. Single crystal X-ray structure analyses were performed on Zn(CN) 2 (Pn3m (No. 224), a = 591.32(7) pm), Hg(CN) 2 (I42d (No. 122), a = 969.22(14) and c = 890,15(18) pm) and for the first time on AgCN (142d (No. 166), a = 600.58(8) and c = 526.28(11) pm). The data are compared with literature data. The reaction of TlF and NaCN in 25% aqueous ammonia solution in air led to Tl 5 (CO 3 ) 2 (CN) which was characterized by X-ray (Cmca (No. 64), 1468.1(3), 1171.6(2) and 1266.0(3) pm) and Raman spectroscopy.
TL;DR: The crystal packing in the structures of various solvent-free halinilinium halides involves with one exception the formation of approximately planar hydrophilic regions that contain classical hydrogen bonds N-H...X - (X = halogen).
Abstract: The crystal packing in the structures of various solvent-free (mono)haloanilinium halides involves with one exception the formation of approximately planar hydrophilic regions that contain classical hydrogen bonds N-H...X - (X = halogen). Common to the substructures of all layers are rings of general graph set R n 2 n (4n), involving equal numbers of chloride acceptors and NH 2 moieties (two hydrogen atoms of the positively charged NH 3 groups). The 2-substituted derivatives contain the shortest X...X - contacts, and these are within the layers; it could be argued that the contacts are forced upon the system by the 2-substitution pattern. In 3-chloro-anilinium chloride and its bromine analogue, the layers consist of ribbons connected by short C-H...X - interactions. In all these compounds, the aromatic groups project from the layers and form hydrophobic regions; the layers are linked by weak interactions of the form X...X or C-H...X. There is appreciable interdigitation of hydrophobic groups from adjacent layers except for the ribbon structures. 3-Iodoanilinium iodide displays a completely different structure, in which all the atoms except some hydrogen atoms of the NH 3 groups lie in a crystallographic mirror plane, but without forming separate hydrophilic and hydrophobic regions. The salt 4-bromoanilinium bromide could only be obtained as a hemihydrate; it too forms hydrophilic layers, but these are highly puckered.
TL;DR: A series of amino-(type 3) as well as hydrazino-substituted quinoxalines (type 8) have been synthesized in order to study their ability to complex with iron(III) and zinc(II) ions as mentioned in this paper.
Abstract: A series of amino-(type 3) as well as hydrazino-substituted quinoxalines (type 8) have been synthesized in order to study their ability to complex with iron(III) and zinc(II) ions. Cyclization of 2,3-dichloroquinoxaline (1) with a bis-amidine 9 leads to ring-fused quinoxalines of type 10. One of these compounds (10a) forms a unique macrocyclic hexameric complex 14 with zinc ions in the presence of 2,6-diisopropyl phenolate. In an analogous manner, the monomeric complexes 12 and 13 could be synthesized. All of these new zinc complexes catalyze the copolymerization of cyclohexene oxide and carbon dioxide with a high degree of selectivity in the resulting polymers.
TL;DR: In this article, Azides, Azidoborates, Tetraazidoborate, tetraphenylphosphonium tetraazide, and [P(C 6 H 5 ) 4 ][B(N 3 ) 4 ], was obtained from BH 3 O(C 2H 5 ) 2 and HN 3.
Abstract: Azides, Azidoborates, Tetraazidoborate Tetraphenylphosphonium tetraazidoborate, [P(C 6 H 5 ) 4 ][B(N 3 ) 4 ], was obtained from B(N 3 ) 3 - in situ prepared from BH 3 O(C 2 H 5 ) 2 and HN 3 - and [P(C 6 H 5 ) 4 ][N 3 ]. Recrystallization from an acetonitrile / hexane mixture yielded colorless crystals in 60% yield. The molecular structure was determined by single crystal X-ray diffraction and the [B(N 3 ) 4 ] - anion was shown to possess S 4 symmetry.
Journal Article•
TL;DR: In this article, the structures of supersilyl triflate, tBu 3 SiO 3 SCF 3, and bissupersilyl hydrazine were determined by X-ray structure analysis.
Abstract: An excellent supersilylation agent, supersilyl triflate, tBu 3 SiO 3 SCF 3 , is easily obtained from tBu 3 SiH and CF 3 SO 3 H. Supersilyl triflate, tBu 3 SiO 3 SCF 3 , reacts with lithium amide or lithium hydrazide to form the supersilyl amine, tBu 3 SiNH 2 , or the supersilyl hydrazines, tBu 3 SiNH-NH 2 and tBu 3 SiNH-HNSitBu 3 , respectively. The structures of supersilyl triflate, tBu 3 SiO 3 SCF 3 , and bissupersilyl hydrazine, tBu 3 SiNH-HNSitBu 3 , have been determined by X-ray structure analysis.
TL;DR: In this article, it was shown that tristriphenylphosphine and gold(I) chloride can form a crystalline phase with two molecules of dichloromethane, and that the gold atom shows only a minor displacement from the plane of the phosphorus atoms.
Abstract: Tris(triphenylphosphine)gold(I) chloride was found to form a crystalline phase with two molecules of dichloromethane. In the crystal the chlorine atom is almost fully dissociated from the [(Ph 3 P) 3 Au] + cation. The gold atom shows only a minor displacement from the plane of the phosphorus atoms (sum of the angles P-Au-P 355.35°; d(Au-Cl) 2.7962(6) A), very similar to the geometry of the solvent-free crystalline phase. The results are discussed in the context of all known structures for compounds [(Ph 3 P) 3 MCl], M = Cu, Ag, Au. The variations in structure appear to be dominated by electronic (relativistic) rather than steric effects.
TL;DR: The structure of 1,1,4,4-tetrakis(2-hydroxyethyl)-2-tetrrazene (4) was determined by X-ray diffraction analysis as discussed by the authors.
Abstract: Five hydroxyethyl-2-tetrazenes (1 - 5) and their methyl ethers (6 - 10) have been synthesized and hydrogen bonding in these compounds has been investigated by theoretical and spectroscopic (IR, 'H NMR, 1 5 N NMR) methods.The structure of 1,1,4,4-tetrakis(2-hydroxyethyl)-2-tetrazene (4) was determined by X-ray diffraction analysis. Several conformations with intramolecular hydrogen bonds were investigated by ab initio B3LYP as well as semiempirical SCF calculations. In all cases, conformers with OH---N hydrogen bonds with azo nitrogen atoms as acceptors (conformers A, B, C) are found as most stable. In compounds with small or flexible N 1 - and N 4 -substituents R besides the hydroxyethyl group (3, 4), hydrogen bonds forming six-membered rings, with the R groups taking syn positions at the N 1 -N 2 and N 3 -N 4 bonds (conformer A), are preferred over those with seven-membered rings and R taking anti positions (conformer B). Steric interaction in the other compounds (1, 2, 5) leads to destabilization of conformers A and conformers B become more stable. A special case is presented by compound 4 which has only hydroxyethyl substituents on the 2-tetrazene unit. In the most stable conformer (4C) there are two OH- - -O and one OH- - -N hydrogen bonds. By IR solution measurements intra- and intermolecular hydrogen bonds could be distinguished. Association shifts Δδ measured by 1 H NMR spectroscopy, indicate that the investigated compounds exhibit comparable association properties with intermolecular association clearly prevailing. 1 5 N NMR spectra of compounds 1 -10 in two solvents have been measured if solubility was sufficient. The data indicate that all nitrogen atoms of 1 - 5 participate in H bonding. In the crystalline state, molecules 4 adopt a conformation without intramolecular H bonds (4D) and are associated by intermolecular OH- - -O hydrogen bonds that form a three-dimensional network. An untypical decomposition pattern was discovered for benzyl derivatives 5 and 10.
TL;DR: In this paper, a xanthone dixylopyranoside has been isolated from Swertia thomsonii C. B. Clarke and its structure established as 1,7-dihydroxy-3,8-dimethoxyxanthone 1-O-[β-D-xylopranosyl-(1→4)-β -D-Xyloparanoside on the basis of spectral evidence.
Abstract: A xanthone dixylopyranoside has been isolated from Swertia thomsonii C. B. Clarke and its structure established as 1,7-dihydroxy-3,8-dimethoxyxanthone 1-O-[β-D-xylopyranosyl-(1→4)-β-D-xylopyranoside on the basis of spectral evidence, particularly 2D NMR studies. Three known compounds, 1,7-dihydroxy-3,8-dimethoxyxanthone, swertianin (1,7,8-trihydroxy-3-methoxy-xanthone) and ursolic acid were also isolated from this species.
TL;DR: In this article, the structures of 6-(4-methylphenyl)-6,7-dihydro-5H-dibenz[c,e]azepine-5-carbonitrile have been unambiguously confirmed by single-crystal X-ray crystallography.
Abstract: Ethenetetracarbonitrile (2, in benzene solution) and 1,3-dioxoindan-2-ylidene propanedinitrile (4, in ethanol or acetonitrile solution) act on N-aryl-2,3-dihydro-lH-benz[d,e]isoquinolines 6a-d and N-aryl-6,7-dihydro-5H-dibenz[c,e]azepines 11a-d via hydride abstraction followed by addition of cyanide to the iminium carbon atom forming the corresponding 1- and 5-carbonitriles 9a-d and 13a-d, respectively, in moderate to medium yields. Additionally, the known 1,3-dihydroxy-2H-inden-2-ylidenepropanedinitrile 15 and a novel dispirocyclopropane (17) are formed from 4 in the reaction with 6 in acetonitrile and ethanol, respectively. The structures of 17 and 6-(4-methylphenyl)-6,7-dihydro-5H-dibenz[c,e]azepine-5-carbonitrile have been unambiguously confirmed by single-crystal X-ray crystallography.
TL;DR: In this article, the authors presented six structures of 2, 4, 5, 6 and 3, 5-dichloroanilinium chlorides with annelated R 2 4 (8) rings with NH 2 donors (two hydrogen atoms from the positively charged NH 3 groups) and chloride acceptors.
Abstract: Of the six structures presented here, five involve clearly defined hydrophilic layers built up from classical hydrogen bonding systems. Of three solvent-free structures, 2,4- and 3,5-dichloroanilinium chlorides both form ribbon structures involving annelated R 2 4 (8) rings with NH 2 donors (two hydrogen atoms from the positively charged NH 3 groups) and chloride acceptors. The ribbons are linked by weaker interactions to form layers. 2,5-Dichloroanilinium chloride forms a layer structure directly, with rings R 3 6 (12) exactly analogous to those previously observed in 2-chloroanilinium chloride. 2,6-Dichloroanilinium chloride methanol solvate forms a different type of ribbon structure, with alternating R 2 4 (8) and R 4 6 (12) rings; the latter involve two chlorides, two NH 2 groups and two methanols. These ribbons too are linked to form layers. 2,3-Dichloroanilinium chloride hydrate forms layers with two types of ring R 3 5 (10); one involves two NH 2 , two chlorides and the OH part of a water, whereas in the other, an NH 2 is replaced by OH 2 . In all these structures the aromatic groups project approximately perpendicular to the layers to form hydrophobic regions; for all except 3,5-dichloroanilinium chloride, neighbouring layers are linked by weaker interactions such as C-H...Cl hydrogen bonds or Cl...Cl contacts. The final structure, 3,5-dichloroanilinium chloride 1/4-hydrate, is completely different; it involves two types of columns, one built up from quadrilaterals of Cl...Cl contacts between cations and the other consisting of "nanotubes' of NH 3 groups and chloride anions linked by two- and three-centre hydrogen bonds. The columns are in turn linked by cation-anion Cl...Cl interactions.
TL;DR: In this paper, a complex of N-methylisatin and N(4)-dimethylthiosemicarbazide (MIs4DM) was obtained in the orthorhombic space group Pbcn.
Abstract: N-Methylisatin N(4)-dimethylthiosemicarbazone, HMIs4DM, prepared by condensation of N-methylisatin and N(4)-dimethylthiosemicarbazide crystallizes in the orthorhombic space group Pbc2 1 , with a = 7.539(1), b = 11.566(4), c = 29.320(1) A, V = 2556.6(9) A 3 and Z = 8. Cadmium metal was oxidized in the presence of HMIs4DM in an acetonitrile solution, which produced a complex of the formula [Cd(MIs4DM) 2 ]. [Cd(MIs4DM) 2 ] crystallizes in the orthorhombic space group Pbcn with a = 15.529(5), b = 10.672(4), c = 16.247(3) A, V = 2692.7(14) A 3 and Z = 8. [Cd(MIs4DM) 2 ] is symmetrical with two identical MIs4DM ligands that are at an angle of about 80°.
TL;DR: Piperazinium tetraiodocadmate(II)-monohydrate, [C 4 H 1 2 N 2 ]CdBr 4 H 2 O (1) crystallizes with isolated [CdI 4 ] 2 - anions, piperzinium cations, and water molecules (monoclinic, P2 1 /c, Z = 4, a = 698.7(1), b = 1348.6(3), and c = 1432.97(3)° at 293 K) as discussed by the authors ).
Abstract: Piperazinium tetrabromocadmate(II)-monohydrate, [C 4 H 1 2 N 2 ]CdBr 4 H 2 O (1) crystallizes with isolated [CdBr 4 ] 2 - anions, piperazinium cations, and water molecules (monoclinic, P2 1 /c, Z = 4, a = 698.7(1), b = 1348.6(3), and c = 1432.4(3) pm, β = 92.97(3)° at 293 K). The crystal structure of 1 is almost the same as that reported in Inorg. Chim. Acta 187, 141 (1991). The crystal of piperazinium tetraiodocadmate(II), [C 4 H 1 2 N 2 ]CdI 4 (2) consists of isolated [CdI 4 ] 2 - anions and piperazinium cations (orthorhombic, P2 1 2 1 2 1 , Z = 4, a = 903.2(5), b = 1226.3(6), and c = 1307.9(7) pm at 293 K). The room temperature phase of bis(trimethylsulphonium) tetrabromocadmate(II), [(CH 3 ) 3 S] 2 CdBr 4 (3) has isolated [CdBr 4 ] 2 - anions and trimethylsulphonium cations (orthorhombic, P2 1 2 1 2 1 , Z = 4, a = 911.3(1), b = 1329.2(2), and c = 1454.7(2) pm at 293 K).
TL;DR: In this paper, the molecular structures of 2,2,N-Trimethyl-N-phenyl-2H-azirin-3-amine were established by X-ray crystal structure determination.
Abstract: 2,2,N-Trimethyl-N-phenyl-2H-azirin-3-amine (1a) was prepared by successive treatment of 2,N-dimethyl-N-phenylpropanamide (18) with phosgene, triethylamine, and sodium azide. Reaction of 1a in THF solution with boron trifluoride gave 2-amino-1,3,3-trimethyl-3H-indolium tetrafluoroborate (19) in high yield.The latter reacted with acetic anhydride in pyridine to give a mixture of N-(2,3-dihydro-1,3,3-trimethylindol-2-yliden)acetamide (22) and 2,3-di- hydro-1,3,3-trimethylindol-2-one (21). On hydrolysis with aqueous HCl, 22 was converted to 21.The molecular structures of 19 and 22 were established by X-ray crystal structure determination.
TL;DR: In this article, the reactivity of di-borane(4)yl complexes with respect to substitution of X and CO was investigated, and all the derivatives were fully characterised in solution by NMR spectroscopy and by elemental analysis.
Abstract: Reaction of various 1,2-dihalodiboranes(4) with Na[(η 5 -C 5 H 4 R)M(CO) 3 ] yielded the di-borane(4)yl complexes [X(Me2N)B-B(NMe 2 ){η 5 -(C 5 H 4 R))M(CO) 3 }] (5, X = Cl, R = H, M = Mo; 6, X = Br, R = me, M = Mo; 7, X = Br, R =H, M = W; 8, X = Br, R = Me, M = W) and [Cl(C 4 H 8 N))B-B(NC 4 H 8 ){η 5 -(C 5 H 5 )W(CO) 3 }] (9). The reactivity of di-borane(4)yl complexes of the type [X(Me2N)B-B(NMe 2 ){η 5 -(C 5 H 5 )M(CO) n }] (X = Cl, Br; M(CO) n = Fe(CO) 2 , Mo(CO) 3 ) with respect to substitution of X and CO, respectively, was investigated. The novel derivatives [MeO(Me2N)B-B(NMe 2 ){η 5 -(C 5 H 5 )Mo(CO) 3 }] (10), [MeO(Me 2 N)B-B(NMe 2 ){η 5 -(C 5 H 5 )Fe(CO) 2 }] (11), and [Br(Me 2 N)B-B(NMe 2 ){η 5 -(C 5 H 5 )-Mo(CO) 2 (PMe 3 )}] (12) were obtained. All compounds were fully characterised in solution by NMR spectroscopy and by elemental analysis.
TL;DR: The tetrapodal pentadentate tetratosylate 2,6-C 5 H 3 N[CMe(CH 2 OTs) 2 ] 2 (2) with thiourea or diphenylphosphide, but found them not to proceed cleanly and to give mixtures of products as discussed by the authors.
Abstract: With the intention of preparing tetrapodal pentadentate ligands having NS 4 or NP 4 donor sets, we investigated reactions of the previously reported tetratosylate 2,6-C 5 H 3 N[CMe(CH 2 OTs) 2 ] 2 (2) with thiourea or diphenylphosphide, but found them not to proceed cleanly, and to give mixtures of products. A derivative of 2 better suited to nucleophilic substitution is the corresponding tetrabromide 2,6-C 5 H 3 N[CMe(CH 2 Br) 2 ] 2 (2,6-bis-(2-bromo-1-bromomethyl-1-methyl-ethyl)-pyridine, 3), which is obtained in excellent yield from 2 by treatment with LiBr in dimethylsulfoxide. The reaction of 3 with 4 eq of thiourea in refluxing ethanol gives a single product. Substitution is not quantitative, however, and the product likely is a bis(thiouronium) bis(bromide) salt. Similarly, the reaction of 3 with 4 eq of potassium O-ethyl xanthogenate displaces only two out of the four bromo substituents under the chosen conditions; workup then leads to what is formulated as a bis(thietane) derivative formed by intramolecular cyclisation. By contrast, nucleophilic substitution with NaSEt in ethanol is quantitative, and the thioether 2,6-C 5 H 3 N[CMe(CH 2 SEt) 2 ] 2 (2,6-bis-(2-ethylsulfanyl-1-ethyl-sulfanylmethyl-1-methyl-ethyl)-pyridine, 4) has been isolated in close to 60% yield. Likewise, and in spite of the considerable steric bulk amassed in the molecule, the reaction of 3 with an excess of KPPh 2 in THF proceeds smoothly (even at -50 °C), to give the tetraphosphane 2,6-C 5 H 3 N[CMe(CH 2 PPh 2 ) 2 ] 2 (2,6-bis-{2-(diphenyl-phosphanyl)-1-[(diphenyl-phosphanyl)-methyl]-1-methyl-ethyl}-pyridine, 5) in 65% yield. In order to assess possible pathways of oxidative degradation relevant to the coordination chemistry of this ligand, 5 was treated with NO in CH 2 Cl 2 or ether at different temperatures. In two cases, reaction was observed to produce the oxide 2,6-C 5 H 3 N[CMe(CH 2 P(=O)Ph 2 ) 2 ] 2 (6) as a colourless solid in near quantitative yield, with concomitant formation of N 2 O. All compounds have been characterised by 1 H, 1 3 C and 3 1 P NMR spectroscopy (as applicable); IR spectroscopic and elemental analysis data are reported, and the crystal structure of 6 has been determined.
Journal Article•
TL;DR: In this paper, low-temperature X-ray structures are reported for three onium salts of general formula BH + (MeSO 2 ) 2 N -, where BH+ is Me 3 N + CH 2 CH 2 OH (1; orthorhombic, space group P2 1 2 1 2 2 1, Z' = 1), Me 3 n+ CH 2 C(O)OH (2); orthor-hemogeneous, P2 2 1/c, Z'= 1).
Abstract: In order to study weak hydrogen bonds originating from inductively activated C(sp 3 )-H donor groups, low-temperature X-ray structures are reported for three onium salts of general formula BH + (MeSO 2 ) 2 N - , where BH + is Me 3 N + CH 2 CH 2 OH (1; orthorhombic, space group P2 1 2 1 2 1 , Z' = 1), Me 3 N + CH 2 C(O)OH (2; orthorhombic, P2 1 2 1 2 1 , Z' = 1), or Me 2 HN + CH 2 CH 2 NMe 2 (3; monoclinic, P2 1 /c, Z' = 1). The asymmetric units consist of cation-anion pairs assembled by an O-H...O=S hydrogen bond in 1, an O-H...N- bond in 2, and an N + -H...N - bond in 3. The packings display a plethora of short interionic C(sp 3 )-H...O/N contacts that are geometrically consistent with weak hydrogen bonding; those taken into consideration have normalized parameters d(H...O) ≤ 269 pm, d(H...N) ≤ 257 pm and θ(C-H...O/N) ≥ 127°. The roles of the weak hydrogen bonds are as follows: In structures 1 and 3, the anions are associated into corrugated layers, which intercalate catemers of cations (1) or stacks of discrete cations (3), whereas structure 2 involves cation catemers surrounded by four anion catemers and vice versa; moreover, all cations are linked to adjacent anions by several weak hydrogen bonds (and to one anion in particular by the strong H bond). Among the cation-anion interactions, the N + (CH 2 -H...) 3 O tripod pattern arising in 1 and 2 is of special interest.
TL;DR: In this paper, single crystals of K 1.1 0 Zr 2 Se 6, Rb 0. 8 6 Zr2 Se 6 and Cs 0.8 0 ZR 2 Se6 were obtained by reacting powdered mixtures of A 2 Se (A = K, Rb, Cs), Zr and Se at 850 °C.
Abstract: Single crystals of K 1 . 1 0 Zr 2 Se 6 , Rb 0 . 8 6 Zr 2 Se 6 and Cs 0 . 8 0 Zr 2 Se 6 were obtained by reacting powdered mixtures of A 2 Se (A = K, Rb, Cs), Zr and Se at 850 °C. K 1 . 1 0 Zr 2 Se 6 and Rb 0 . 8 6 Zr 2 Se 6 crystallize in space group Immm (Z = 2), with a = 3.746(3), b = 5.354(8), c = 21.929(3) A and a = 3.756(1), b = 5.354(8), c = 22.81(1) A, respectively. Cs 0 . 8 0 Zr 2 Se 6 crystallizes in space group Cmc2 1 (Z = 2), with a = 3.747(1), b = 24.102(5), c = 5.332(2) A. The compounds are characterized by complex anionic layers 2 ∞ [Zr 2 Se 6 ] x - with intercalated alkali cations. As in ZrSe 3 , the layers are built from columns of trigonal prisms 1 ∞ [ZrSe 3 ], connected by additional waist contacts, yielding an eightfold coordination for the Zr atoms. The mean Zr-Se bond lengths correspond to those found in the binary compound. The Se-Se bond lengths are significantly altered, however, indicating a reduction of the Se-Se bond order due to the electron transfer from the alkali metal.
TL;DR: The first transition metal complex of methanesulfonylhydrazine was reported in this article, where the coordination geometry is pseudo-tetrahedral and the ligand MSH adopts a conformation that was found by previous ab initio calculations to be a transition state and not a stationary point for the free ligand.
Abstract: The article reports the first transition metal complex of methanesulfonylhydrazine, a molecule known for important pharmacological and chemical applications. The complex [ZnCl 2 (MSH) 2 ], MSH = CH 3 SO 2 NHNH 2 , has been synthesized and its structure characterized by means of X-ray analysis. The coordination geometry is pseudo-tetrahedral and the ligand MSH adopts a conformation that was found by previous ab initio calculations to be a transition state and not a stationary point for the free ligand.
TL;DR: The reaction of 6-hydrazinopyrimidine-2,4-dione derivative 1 with alkyl or aryl isocyanates 2a-d resulted in a novel and facile synthesis of pyrazolo[3,4d]pyrimidine derivative 5a-D in good yield as mentioned in this paper.
Abstract: The reaction of 6-hydrazinopyrimidine-2,4-dione derivative 1 with alkyl or aryl isocyanates 2a-d resulted in a novel and facile synthesis of pyrazolo[3,4-d]pyrimidine derivative 5a-d in good yield.
Journal Article•
TL;DR: In this article, the structure of (dimethyl-tert-butylsilyl)-substituted silatetrazoline has been determined by X-ray structure analysis.
Abstract: The silanimine tBu 2 Si=N-SitBu 3 reacts with the silyl azides tBuMe 2 SiN 3 or tBu 2 SiXN 3 (X = H, Me, F, Cl, Br) to form the corresponding tert-butyl-substituted 1-tri-tert-butylsilyl-4-triorganosilyl-5,5-di-tert-butylsilatetrazolines. The silatetrazolines with chloro-di-tert-butylsilyl and bromo-di-tert-butylsilyl substituents can also be synthesized by treating two equivalents of tBu 2 SiXN 3 (X = Cl, Br) with the silanide tBu 3 SiNa. In the thermolysis of the silaterazolines the silanimines tBu 2 Si=N-SiXtBu 2 (X = F, Cl, Br, tBu) and silyl azides are formed in a first-order process. The silanimines tBu 2 Si=N-SiXtBu 2 (X = F, Cl, Br, tBu) have been trapped with acetone by en-reaction. The structure of (dimethyl-tert-butylsilyl)-substituted silatetrazoline has been determined by X-ray structure analysis.