Volume 70, Issue 4

Orthorhombic dysprosium orthogallate DyGaO 3 and trigonal gallium orthoborate GaBO 3 were synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 8.5 GPa/1350 °C and 8 GPa/700 °C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data collected at room temperature. The orthorhombic dysprosium orthogallate crystallizes in the space group Pnma ( Z = 4) with the parameters a = 552.6(2), b = 754.5(2), c = 527.7(2) pm, V = 0.22002(8) nm 3 , R 1 = 0.0309, and wR 2 = 0.0662 (all data) and the trigonal compound GaBO 3 in the space group R 3̅ c (Z = 6) with the parameters a = 457.10(6), c = 1419.2(3) pm, V = 0.25681(7) nm 3 , R 1 = 0.0147, and wR 2 = 0.0356 (all data).

A new copper(II) coordination polymer [Cu 2 (C 5 H 4 NCOO) 2 (C 7 H 5 N 4 ) 2 ] n ( 1 ) has been synthesized with 4-pyridinecarboxylate and 3-(pyridin-2-yl)-1,2,4-triazolyl ligands. The crystal structure shows that two neighboring copper(II) ions are coordinated with two deprotonated (anionic) 3-(pyridin-2-yl)-1,2,4-triazole ligands to form a binuclear structure. Adjacent binuclear units are linked by 4-pyridinecarboxylate anions to form a three-dimensional network structure. The magnetic, fluorescent, and electrochemical properties and thermal stability of 1 were studied. The results show that 1 exhibits antiferromagnetic interaction, and upon excitation at 318 nm, it has an intense fluorescent emission at approximately 430 nm. The electron transfer of 1 is irreversible in electrode reactions. The thermogravimetric analysis shows that 1 is stable below 240 °C.

The title compound ( 5 ) was prepared by a reaction sequence starting from 2,3,4,5-tetramethoxytoluene ( 1 ) via the Blanc reaction, oxidation and alkylation. The described method provides a good yield of the C-6 heterocyclic-substituted benzoquinone derivative and is suitable for the synthesis of other benzoquinone derivatives.

The acetylene-bis(carboxamidinium) salt 4 dehydrates carboxylic acids to the corresponding anhydrides, as the byproduct 2-oxo-but-2-en-amidinium salt 6b was isolated. Aromatic hydroxy compounds and 2-furyl-methylmercaptan add to the triple bond of the salt 4 to give 2-aryloxy- and 2-alkylmercapto-but-2-ene-bis(amidinium) salts 7 – 9 . According to this reaction principle, 2-organoamino-buten-2-ene-bis(amidinium) salts 10 and 11 were prepared from 4 and primary and secondary amines, whereas 4-chlorobenzhydrazide reacted with 4 to give the imidazole-3-carboxamidinium salt 13 . The reaction of CH 2 -acidic compounds as malononitrile or ethyl cyanoacetate with the bis(amidinium) salt 4 affords 2-cyanomethylene-but-3-enamidinium salts 15 . With the CH-acidic diethyl 2-bromomalonate, compound 4 undergoes a Michael-initiated ring closure cyclopropenation reaction with further ring opening by the released Br – to the corresponding 2-diethoxycarbonylmethylene-3-bromo-but-3-enamidinium salt 18 . Unlike cyclopentadiene and furane, the reaction of N -methylpyrrole and bis(amidinium) salt 4 does not lead to Diels–Alder [4 + 2] cycloadduct but to the Michael-type 1:1 adduct 20 . Pyrrole- and thiophene-2-carboxamidinium salts 23 – 25 can be prepared from compound 4 and esters of glycine, N -methylglycine (sarcosine), and mercaptoacetic acid, respectively. The derivatives of quinoxaline-2-carboxamidinium salts 29 are accessible from aromatic 1,2-diamines and compound 4 . The reaction of the CH 2 /NH-acidic cyanoacetamide with the bis(amidinium) salt 4 produced the 3-pyrroline-2-on derivatives 33 .

A new series of (2 Z ,2′ E )-dimethyl 2,2′-[(2 Z ,2′ Z )-3,3′-(alkanediyl)bis(4-oxo-2-iminothiozolidin-3-yl-5-ylidene)]acetates has been synthesized by the reaction of N , N ″-(1, ω -alkanediyl)bis( N ′-organylthiourea) derivatives with dimethyl acetylenedicarboxylate. The structures were established by spectroscopic data, elemental analyses, and single crystal X-ray crystallography. A rationale for the formation of the products is presented.

The title compound was prepared by reaction, in aqueous solution, of Tl 2 CO 3 and H 2 C 2 O 4 ·2H 2 O in a molar ratio of 1:2. Its crystal structure was solved by X-ray diffraction methods. It crystallizes in the monoclinic space group P 2 1 /a with Z = 2 molecules per unit cell. The oxalic acid molecule and the oxalate anion are planar, residing on crystallographic inversion centers, and linked to each other by strong O–H···O hydrogen bonds giving rise to a polymeric structure. The Tl(I) ion is in a distorted polyhedral coordination with nine neighboring O atoms, five of oxalate anions and four others of oxalic acid molecules. The FTIR and FT-Raman spectra of the compound were also recorded and are briefly discussed.

Several samples of the solid solutions CeRu 1– x Pd x Sn and CeRh 1– x Pd x Sn have been synthesized by arc-melting and characterized by X-ray powder diffraction. Guinier powder patterns prove that the ZrNiAl-type structure is the dominating one, besides the CeRuSn and TiNiSi type structures. The structures of CeRu 0.28 Pd 0.72 Sn (ZrNiAl type, P 6̅2 m , a = 751.95(3), c = 418.70(2) pm, wR 2 = 0.0274, 332 F 2 values, 14 variables) and CeRh 0.66 Pd 0.34 Sn (ZrNiAl type, P 6̅2 m , a = 750.26(3), c = 411.59(2) pm, wR 2 = 0.0533, 358 F 2 values, 14 variables) were refined from single crystal diffractometer data. Magnetic measurements in combination with XANES (X-Ray Absorption Near Edge Structure) clearly proved intermediate cerium valencies for most compounds and revealed the best fitting parameters for those with the ICF model (Interconfiguration fluctuation). The electrical resistivity is also influenced by the substitutions. At low and high valence electron counts (VECs) metallic character is present, while around the VEC of CeRhSn the typical resistivity behavior for valence fluctuating compounds is observed.

Starting from the new compound SrHg 2 Sn 2 , which is isoelectronic and also isotypic to the indide SrIn 4 , the successive substitution of Sn against the electron poor Hg has been investigated in a combined synthetic, crystallographic, and bond-theoretical study. Along the 1:4 section Sr(Hg 1– x Sn x ) 4 a series of compounds with Sn contents x between 0.5 and 0.2 were synthesized from stoichiometric ratios of the elements. Their crystal structures, which represent three different variants of the EuIn 4 -type structure, have been determined using single crystal X-ray data. The most electron rich compound SrHg 2 Sn 2 crystallizes in the original EuIn 4 -type [monoclinic, C 2 /m , a = 1257.9(14), b = 490.1(4), c = 997.8(12) pm, β = 117.60(6)°, Z = 4, R 1 = 0.0838], with a fully ordered Hg and Sn distribution. The four atom sites form two different folded ladders with an alternating Hg/Sn distribution. Like in the KHg 2 -type, the ladders are connected via six-membered rings. In between, double tubes with an internal Sn–Sn bond are connected via further Sn–Sn bonds to form sheets similar to those observed in SiAs. The most electron-poor phase SrHg 3.2 Sn 0.8 crystallizes in a strongly distorted variant of this structure [ a = 1172.8(4), b = 497.9(2), c = 1010.0(4) pm, β = 118.860(7)°, Z = 4, R 1 = 0.0549]. Herein, additional Hg–Hg bonds are formed, and the open tubes are distorted into rods of edge-sharing rhombohedra resembling the structure motifs of elemental Hg. At an intermediate valence electron (v.e.) number, i.e., in SrHg 2.5 Sn 1.5 , an isomorphous tripled superstructure ( a = 2704.4(5), b = 493.87(7), c = 1197.1(2) pm, β = 90.838(14)°, Z = 12, R 1 = 0.0475) occurs, where the building blocks of the two variants of the EuIn 4 -type structure alternate in a 1:2 ratio. The bonding situation and the “coloring,” i.e., the Hg/Sn distribution in the polyanionic network, are discussed considering the different sizes of the atoms and the charge distribution (Bader AIM charges), which has been calculated within the framework of the FP-LAPW density functional theory for SrHg 2 Sn 2 and the model compounds “SrHg 3 Sn” and “SrHg 4 .”

A mixed lithium/beryllium diethylhydroxylaminate compound containing n butyl beryllium units of total molecular composition n Be(ONEt 2 ) 2 [(LiONEt 2 ) 2 n BuBeONEt 2 ] 2 ( 1 ) was isolated from a reaction mixture of n butyl lithium, N,N -diethylhydroxylamine and BeCl 2 in diethylether/thf. The crystal structure of 1 has been determined by X-ray diffraction. The aggregate is composed of two ladder-type subunits connected in a beryllium-centered distorted tetrahedron of four oxygen atoms. Only the lithium atoms are engaged in coordination with the nitrogen donor atoms. The DFT calculations support the positional occupation determined for Li and Be in the crystal structure. The DFT and the solid-state structure are in excellent agreement, indicating only weak intermolecular interactions in the solid state. Structural details of metal atom coordination are discussed.

The new intermetallic compound Sc 5 Co 2 In 4 was synthesized by arc melting of the pure metals. Its crystal structure was investigated from single-crystal X-ray data: Pbam, a = 17.3400(7), b = 7.5940(5), c = 3.3128(2) Å, R 1 = 0.0337, wR 2 = 0.0620 for 1502 independent reflections with [ I >2 σ( I )]. It is the first representative of the Lu 5 Ni 2 In 4 type with cobalt.