Band 63, Heft 5

Several new copper(II) complexes with guaiacyl lignin models vanillin (HL1) [Cu(L1) 2 (nia) 2 ] (1) (nia = nicotinamide) or vanillic acid (HL 2 ) [Cu(L2) 2 (nia) 2 ] (2) [Cu 2 (μ-L2) 4 (nia) 2 ] (3), and [Cu(L2) 2 (Hetam) 2 ] (4) (Hetam = ethanolamine) were isolated and characterized. The molecular structure of complex 1 reveals bidentate vanillin (HL1) coordination via the methoxy and the deprotonated hydroxy groups. On the other hand, the vanillic acid (HL2) complexes 2 - 4 show a deprotonated carboxylate group with chelating coordination mode in 2, bridging in 3 and monodentate coordination in 4. The mononuclear complexes 1, 2 and 4 show a distorted trans octahedral coordination sphere with pairs of monodentate and chelating ligands. A replacement of the monodentate nicotinamide ligand in 2 with the bidentate ethanolamine ligand in 4 changes the coordination mode of the vanillic acid anion from bidentate (complex 2) to monodentate (complex 4). This shift inside the coordination sphere reveals different O-Cu-O Jahn-Teller axes by the vanillic acid anion in 2 and ethanolamine in 4. Empty channels are present in the crystal structure of the dinuclear complex 3, stabilized by hydrogen bonds and π-π stacking.

A new polyoxometalate(POM)-templated inorganic-organic hybrid compound, [Ag 6 (trz) 6 ]- [PMo 12 O 40 ] 2 ・ 6H 2 O (1) (trz = 1,2,4-triazole) has been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, thermogravimetric analysis and cyclic voltammetry. In compound 1, six Ag + ions are linked by six trz molecules to give a hexanuclear [Ag 6 (trz) 6 ] 6+ cycle. The six trz molecules are not co-planar, but adopt a crown-like shape. Cavities, with sizes of about 7.706×7.706 Å 2 , are found with the hexanuclear cycles packed along the c axis. The Keggin anions, as templates, are inserted in the 3D supramolecular framework. The electrochemical and electrocatalytic behavior of 1 has been studied in detail. The results exhibit that the redox ability of the Keggin anions can be maintained in the hybrid solid which has good electrocatalytic activity toward the reduction of bromate, hydrogen peroxide and nitrite.

The dinuclear nickel(II) complex [Ni 2 LCl] + (1), where (L) 2− represents a 24-membered macrocyclic hexamine-dithiophenolate ligand, reacts readily with 5-R-tetrazolate ligands to give the complexes [Ni 2 L(RCN 4 )] + , where R = H (2), Me (3), Ph (4). The new complexes were either isolated as perchlorate or tetraphenylborate salts and fully characterized by elemental analysis, UV/Vis, and IR spectroscopy. The structures of 2[BPh 4 ] · MeCN, 3[BPh 4 ] · 2MeCN, and 4[BPh 4 ] ·MeCN were determined by X-ray crystallography, showing that all tetrazolate units are in a 2,3-bridging mode to generate dioctahedral N 3 Ni(μ-S) 2 (μ-N 4 CR)NiN 3 core structures. The RCN 4 − groups interact less strongly with the [Ni 2 L] 2+ fragment than pyrazolate ligands (CH) 3 N 2 − as reflected in the longer Ni-N distances.

A new binuclear complex, [Cd(ClCH 2 CH 2 CO 2 ) 2 (phen)] 2 (1), has been synthesized and structurally characterized by single crystal X-ray diffraction methods. The Cd atoms are linked by carboxylate oxygen atoms into a four-membered Cd 2 O 2 rhombic ring with a Cd···Cd separation of 3.824 Å . Two carboxylate groups act as bidentate, and two as both bidentate bridging and bidentate chelating ligands. The hydrogen bonding and π-π stacking interactions are responsible for the supramolecular assembly and stabilization of the crystal structure. The complex has been characterized by elemental analysis, IR and UV/Vis spectra, and thermogravimetric and differential thermal analysis (TG/DTA). The complex exhibits blue fluorescence in the solid at room temperature.

Rb[(Zr 6 C)Cl 15 ] was prepared by heating ZrCl 4 , Zr powder, RbCl and Al 4 C 3 at 850 °C for 21 days. The crystal structure was determined by single crystal X-ray diffraction (space group Pmma, a = 18.484(3), b = 18.962(2), c = 9.708(1) Å, V = 2505.4(6) Å 3 , and Z = 4). Rb[(Zr 6 C)Cl 15 ] crystallises in the Cs[Nb 6 Cl 15 ]-type structure. It is built up from two interconnected types of cluster chains, one with linear Zr−Cl a−a -Zr bridges, the other one with bent bridges. The rubidium cations are spread over three different sites within the cluster network which differs significantly from the cation distribution in the comparable potassium and caesium phases. The cation distribution can be rationalised considering the size of the cavities and the Coulombic interactions.

Dichroic, pink to blue single crystals of Sr 7 H 12 Cl 2 and Sr 7 H 12 Br 2 were obtained by reacting Sr with SrX 2 or NaX and NaNH 2 or NH 4 X (X = Cl, Br) as hydrogen sources in a Na melt at 900 °C for 12 h in silica-jacketed stainless-steel or Ta ampoules. The crystal structures of the new compounds were determined by means of single crystal X-ray diffraction. Both title compounds crystallize isotypically to Ba 7 Cl 2 F 12 in the hexagonal space group P6̅ (no. 174) with the lattice parameters a = 998.06(3), c = 392.84(3) pm for Sr 7 H 12 Cl 2 and a = 1004.62(3), c = 399.68(3) pm for Sr 7 H 12 Br 2 . The hydride positions taken from the difference Fourier map agree with those of the fluorides of the isotypic compound Ba 7 F 12 Cl 12 . The validity of our structural results is corroborated by EUTAX calculations and the comparison to SrH 2 , SrX 2 and SrHX.

Single crystals of the compounds Ca 4 OCl 6 , Sr 4 OBr 6 , Ba 4 OBr 6 , and Ba 2 OI 2 were obtained by solid-state reactions. The crystals of Ba 2 OI 2 are transparent and colorless and isopointal to K 2 ZnO 2 adopting the orthorhombic space group Ibam (no. 72, Z = 4) with the cell parameters a = 747.20(9), b = 1392.02(18), and c = 678.12(9) pm. Sr 4 OBr 6 and Ba 4 OBr 6 are isotypic to Ba 4 OCl 6 (or isopointal to K 6 ZnO 4 ) and crystallize in the hexagonal space group P6 3 mc (no. 186, Z = 2) exhibiting the cell parameters a = 982.20(4) and c = 750.41(7) pm for Sr 4 OBr 6 and a = 1030.10(2) and c = 785.92(4) pm for Ba 4 OBr 6 . In the ternary systems Ca-O-X (X = Cl, Br or I) the only compound found other than the starting materials was the already known Ca 4 OCl 6 which is also isotypic to Ba 4 OCl 6 crystallizing in the hexagonal space group P6 3 mc (no. 186, Z = 2) with the cell parameters a = 903.30(6) and c = 683.27(8) pm.

Pale grey-blue, transparent single crystals of Ba 2 [BN 2 ]Cl (I4 1 32 (no. 214), a = 1462.88(1) pm, Z = 24) are obtained by the reaction of Ba, BaCl 2 , BN and NaN 3 in arc-welded Ta ampoules at 1200 K. The crystal structure was determined by single crystal X-ray structure analysis. The Raman and IR spectra of the title compound show the expected fundamental frequencies (νs = 1038; νas = 1969 and 2087; δ = 616 / 636 cm −1 ) for a nitridoborate unit with D ∞h symmetry. The [N-B-N] structure obtained by X-ray single crystal structure determination corroborates this finding within the standard deviations of the measurement with d(B-N) = 132.3(8) pm and ∡ (N-B-N) = 178.5(13)°. Our results compare well to the data reported for cubic and orthorhombic Ba3[BN2]2 as well as to the isotypic compound Ba 2 [BN 2 ]Br.

Single crystals of Ca 11 N 6 [CN 2 ] 2 (dark red needles, tetragonal, P4 2 /mnm (no. 136), a = 1456.22(5), and c = 361.86(2) pm, Z = 2), Ca 4 N 2 [CN 2 ] (transparent yellow needles, orthorhombic, Pnma (no. 62), a = 1146.51(11), b = 358.33(4), and c = 1385.77(13) pm, Z = 4) and Ca[CN 2 ] (transparent, colorless, triangular plates, rhombohedral, R3̅m (no. 166), a = 369.00(3), and c = 1477.5(3) pm, Z = 3) were obtained by the reaction of Na 2 [CN 2 ], CaCl 2 and Ca 3 N 2 (if demanded by stoichiometry) in arc-welded Ta ampoules at temperatures between 1200 - 1400 K. Their crystal structures were re-determined by means of single crystal X-ray structure analyses. Additionally, the Raman spectra were recorded on these same single crystals, whereas the IR spectra were obtained with the KBr pellet technique. The title compounds exhibit characteristic features for carbodiimide units with D∞h symmetry (d(C-N) = 121.7 - 123.8 pm and ∡ (N-C-N) = 180°). The vibrational frequencies of these units are in the expected range (Ca 11 N 6 [CN 2 ] 2 : νs = 1230, νs = 2008; δ = 673/645/624 cm −1 ; Ca 4 N 2 [CN 2 ]: νs = 1230, νs = 1986; δ = 672/647 cm −1 ; Ca[CN 2 ]: νs = 1274, νs = 2031, δ = 668 cm −1 ). The structural results are more precise than the previously reported data, and with the newly attained Raman spectrum of Ca 11 N 6 [CN 2 ] 2 we correct data reported earlier.

Well crystallized samples of the intermetallic zinc compounds CeNiZn and CeAuZn were synthesized from the elements in sealed tantalum ampoules. They were investigated by X-ray diffraction on powders and single crystals. CeNiZn: ZrNiAl type, space group P6̅2m, Z = 3, a = 713.3(3), c = 388.7(1) pm, wR2 = 0.0422 for 14 refined variables and 286 F 2 values; CeAuZn: TiNiSi type, space group Pnma, Z = 4, a = 719.2(2), b = 462.7(1), c = 796.5(2) pm, wR2 = 0.0403 for 20 refined variables and 467 F 2 values. Magnetic susceptibility data reveal that CeNiZn is an intermediate-valent cerium compound with essentially tetravalent cerium. CeAuZn shows Curie-Weiss paramagnetism with an experimental magnetic moment of 2.51(1) μB per Ce atom and θP = −70(1) K. No magnetic ordering is observed down to 2.1 K.

This work reports the synthesis and characterization of a new copper complex with nadolol, a betablocker aminoalcohol. The stoichiometry found was Na[Cu(nadololate)(CO 3 )] · H 2 O. Electronic and vibrational spectroscopy analysis was performed, and the crystal structure of Na[Cu(nadololate)-(CO 3 )] · H 2 O was determined by X-ray diffraction.

A series of new 3-(4-chlorophenyl)-5-(pyridin-4-yl)-4-(arylmethyleneamino)-4H-1,2,4-triazole derivatives 3 were prepared in good yields by treatment of 4-amino-3-(4-chlorophenyl)-5-(pyridine- 4-yl)-4H-1,2,4-triazole (2) with selected aldehydes. Compounds 3 were reduced with NaBH 4 to afford the corresponding 3-(4-chlorophenyl)-5-(pyridin-4-yl)-4-(arylmethylamino)-4H-1,2,4-triazole derivatives 4. Eighteen new compounds were synthesized and characterized by elemental analyses, IR, 1 H NMR and 13 C NMR spectral data. The compounds were screened for their antioxidant and antiradical activities.

Cyclocondensation reaction of ethyl 7,8-diamino-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline- 3-carboxylate (2) or the -3-carboxylic acid 3 with sym-1,2- diketones produced the corresponding ethyl 2,3-disubstituted pyrido[2,3- f ]quinoxaline-8-carboxylates (4a - h) or the -8-carboxylic acids 5a - h, respectively. The structures for these new heterocycles are supported by analytical and spectral (IR, MS, NMR) data. Compounds 5a - c, g, h exhibit moderate activity against an assortment of bacterial species.

Several new 3-aminopyrrole derivatives have been synthesized from 3-substituted amino-2-phenylacrylonitriles using Thorpe-Ziegler cyclization. These substituted pyrroles are readily converted into 5H-pyrrolo[3,2-d]pyrimidines (9-deazapurines).

Azobenzene-based monomers and their polymers containing donor or acceptor groups at terminal positions have been synthesized. The liquid crystalline (LC) mesophase stability of one type of polymer and mixtures of donor or acceptor substituted polymers have been investigated. Mesophase formation and stability of the mixtures were studied using differential scanning calorimetry (DSC) and a hot-stage optical polarizing microscope (HOPM). The mesophase stability of the mixtures was better than those of the individual components. Binary mixture studies of acceptor monomers (a) and donor monomers (d) show that the pure low molecular weight compounds did not form any molecular aggregates and failed to show LC properties, whereas the mixture of donor substituted azobenzene and acceptor substituted azobenzene exhibits LC property. In the case of polymers, the individual acceptors (A) or donors (D) exhibit LC property, and their mixture stabilizes the crystallinity of the mesophase. The results of correlation studies of various proportions of mixtures of a/d and A/D with regard to LC properties and their mesophase stabilities are presented

The bis-ketonic Mannich base, N,N-bis(β -benzoylethyl)methylamine hydrochloride (1) reacts with primary arylamines and diamines to give ketonic sec-arylamines 3a - e and 4. The piperidines 7a - c were obtained from 1 and primary alkylamines, whereas the 1,4-diazepine derivative 10 was obtained from 1 and ethylenediamine. Treatment of the bis-base 1,4-di[β -(N-morpholino)propionyl]benzene bis(hydrochloride) (11) with primary arylamines gave the corresponding bis-(sec-arylamines) 12a - b, whereas its reaction with ophenylenediamine afforded the bis[1,5-benzodiazepine] ring system 14. The synthesis of the diazacyclophane ring system 15 has been achieved by treating 11 with piperazine. Attempted synthesis of 4- aza-[7]-paracyclophane (16) from 11 and benzylamine led to 17. The reaction of 1 or 11 with phenylhydrazine gave the 2-pyrazolines 18 and 19. Treatment of 3 or 4 with phenylhydrazine and formaldehyde afforded the 2H-1,2,4-triazepines 20a - c and the bis[2H-1,2,4-triazepine] ring system 21.

A series of new 3,5,6-thiadiaza-4-hexenoates (4a - k) were synthesized from the reaction of the corresponding hydrazonoyl halides 1 with ethyl mercaptoacetate (3). These compounds underwent intramolecular cyclization to 1,3,4-thiadiazin-5-one derivatives (5a - k) in the presence of MeONa or LiH. The structures of the synthesized compounds were confirmed by their elemental analyses and spectral data.

A new tricyclic clerodane-type diterpene, nepetolide (1), has been isolated from Nepeta suavis along with three known compounds namely β -sitosterol, stigmasterol, and ursolic acid. The structure elucidation of the isolated compounds was based primarily on two-dimensional (2D)-NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond correlation (HMBC) experiments.

A phytochemical study of Sideritis infernalis led to the isolation of the new nor-diterpene adejone (17-nor-7α,18-dihydroxy-ent-kaur-16-one). The biosynthesis of this compound implies the decarboxylation of an epoxy-acid as the last step. In addition, three diterpenes with an ent-kaurene skeleton, episideridiol, candicandiol 7α-monoacetate and candidiol 15α-monoacetate, have been isolated from S. candicans for the first time in nature.

The rare earth-rich intermetallic magnesium compounds RE 4 PdMg (RE =Y, Sm,Gd) and RE 4 PtMg (RE =Y,Nd, Sm, Gd) were prepared by melting of the elements in sealed tantalum tubes in an induction furnace. These new Gd 4 RhIn-type compounds were characterized by X-ray powder diffraction. The structures of the gadolinium compounds were refined from single crystal X-ray diffractometer data: space group F4̅3m, Z = 16, a = 1388.1(2) pm, wR2 = 0.0392, 381 F 2 values and 20 variables for Gd 4 Pd 1.14 Mg 0.86 and a = 1387.6(2) pm, wR2 = 0.0519, 409 F 2 values, BASF = 0.47(4) and 21 variables for Gd 4 Pt 1.07 Mg 0.93 . The gadolinium atoms build up palladium (platinum) centered trigonal prisms which are condensed via common corners and edges, leading to three-dimensional networks. The magnesium atoms form Mg 4 tetrahedra which show slight mixing with the platinum metal.