Ternary Indides Eu2Pd2In and Eu2Pt2In

The indides Eu₂Pd₂In and Eu₂Pt₂In were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were characterized by powder X‐ray diffraction. The structures were refined on the basis of single‐crystal X‐ray diffractometer data: HT‐Pr₂Co₂Al type, C2/c, a = 1035.7(2), b = 592.9(1), c = 823.6(2) pm, β = 104.26(1) °, wR2 = 0.026, 1075 F² values, 25 variables for Eu₂Pd₂In and a = 1017.2(2), b = 588.7(1), c = 826.5(1) pm, β = 103.76(1) °, wR2 = 0.062, 706 F² values, 25 variables for Eu₂Pt₂In. The indium atoms have four platinum (palladium) neighbors in strongly distorted tetrahedral coordination at Pt–In and Pd–In distances ranging from 273 to 275 pm. These InPd_4/2 and InPt_4/2 units are condensed via common edges to infinite InPd₂ and InPt₂ chains, which are surrounded by the europium atoms. The chains form the motif of hexagonal rod packing.     

Die isotypen Verbindungen BaRh2Si2, BaIr2Si2 und BaPt2Ga2 – eine monokline Verzerrungsvariante der CaRh2B2-Struktur

The Isotypic Compounds BaRh₂Si₂, BaIr₂Si₂, and BaPt₂Ga₂ – a Monoclinic Distortion Variant of the CaRh₂B₂ Structure The new compounds BaRh₂Si₂ (monoclinic, P2₁/c, a = 792.6(1) pm, b = 664.5(7) pm, c = 767.9(4) pm, β = 91.2(1)°, Z = 4, 2867 reflexions, 47 parameters, R = 0.024), BaIr₂Si₂ (monoclinic, P2₁/c, a = 792.47(6) pm, b = 664.28(6) pm, c = 772.22(6) pm, β = 92.181(7)°, Z = 4, 1939 reflexions, 47 parameters, R = 0.037) and BaPt₂Ga₂ (monoclinic, P2₁/c, a = 850.4(1) pm, b = 647.3(1) pm, c = 819.8(1) pm, β = 95.97(1)°, Z = 4, 1506 reflexions, 47 parameters, R = 0.038) were prepared by reaction of the elements. Their structures were determined from single crystal data. The compounds crystallize isotypically with a distortion variant of the CaRh₂B₂ type of structure.     

Relativistic calculation of autoionization widths of 1s2s2pjJ, 1s2s2 2S1/2, and 1s2pJ 2pj′J levels

The autoionization widths of levels 1s 2s 2p_jJ, 1s2s^{2 2}S_1/2, and 1s2p_j2p_j′ J have been calculated for ions with Z = 6–30. The calculation has been carried out in intermediate coupling. The decay amplitudes have been calculated in a relativistic approximation.     

Some highly fluorinated acyclic,cyclic, and polycyclic derivatives of Cl2NCF2CF2NCl2 and Cl2CNCCl2CCl2NCCl2

When Cl₂NCF₂CF₂NCl₂ is heated with CF₂CFX (X = Cl, F) ClXCFCF₂N(Cl)CF₂CF₂N(Cl)CF₂CXClF (X = Cl, 2 ; F, 3 ) is formed. Mercury extracts chlorine fluoride from 2 and 3 to form new polyfluorobisazomethines, ClXCFCF₂NCFCFNCF₂CXClF (X = Cl, 4 ; F, 5 ). Photolysis of the product obtained from CCl₂NCCl₂CCl₂NCCl₂ with ClF, CF₂ClN(Cl)CF ClCFClN(Cl)CF₂Cl ( 6 ) gives another bisazomethine, CF₂ClNCFCFNCF₂Cl ( 7 ) with concomitant loss of Cl₂. At 25°C, in the presence of CsF, 4 and 5 are cyclized to give (X = Cl, 8 ; F, 9 ), and 7 forms a bicyclic derivative at 100°C, ( 1 ). Addition of chlorine fluoride to 8 and to 1 produces ( 10 ) and ( 14 ), respectively. Photolysis of 10 results in the loss of CFCl₃ to form ( 11 ), and 14 loses Cl₂ and dimerizes to the hydrazine ( 15 ). The further addition of ClF to 11 gives rise to ( 12 ) which when photolyzed at 3000 Å forms a second cyclic hydrazine, ( 13 ).     

LaPt2Ge2 und EuPt2Ge2 – Neubestimmung der Kristallstrukturen

LaPt₂Ge₂ and EuPt₂Ge₂ – Revision of the Crystal Structures LaPt₂Ge₂ was rechecked by single crystal X‐ray methods resulting in space group P2₁/c (in place of P2₁) and the lattice constants a = 9.953(3), b = 4.439(1), c = 8.879Å, β = 90.62(4)°, and Z = 4. In contrast to previous reports the cell volume had to be doubled. The same is true for EuPt₂Ge₂ (a = 9.731(1), b = 4.446(1), c = 8.823(1) Å, β = 91.26(1)°). The crystal structures correspond to a monoclinic variant of the tetragonal CaBe₂Ge₂ type, whereas the distortion can be described as different rotations of the coordination polyhedra around the La and Eu atoms, respectively. It is most likely that the compounds APt₂Ge₂ with A = Ca, Y, La‐Dy undergo phase transitions at higher temperatures forming then the undistorted CaBe₂Ge₂ type, space group P4/nmm. This was confirmed for SmPt₂Ge₂ (a = 4.292(1), c = 9.980(1) Å; Z = 2) and might also be the case for APt₂Ge₂ with A = Ca, Nd, Sm, Eu, and Gd.     

Preparation of bisdiazoalkane and related complexes from the reactions of diazo compounds with the dinitrogen complexestrans-[M(N2)2(Ph 2PCH2CH2PPh 2)2] (M=Mo or W)

Summary Reactions oftrans-[M(N₂)₂(dppe)₂] (A;M=Mo, W;dppe=Ph ₂PCH₂CH₂PPh ₂) with ethyldiazoacetate, N₂CHCOOEt, yield the bisdiazoalkane speciestrans-[M(N₂CHCOOEt)₂(dppe)₂], upon simple replacement of the dinitrogen ligand by ethyldiazoacetate. However, diazomethane, N₂CH₂, reacts withA with loss of N₂ to give products which we tentatively formulate as containing methylene ligands,trans-[M(CH₂)₂(dppe)₂].

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Herstellung von Bisdiazoalkan- und ähnlichen Komplexen aus den Reaktionen von Diazoverbindungen mit Distickstoffkomplexen des Typstrans-[M(N₂)₂(Ph ₂PCH₂CH₂PPh ₂)₂] mitM=Mo oder W

Zusammenfassung Die Reaktion vontrans-[M(N₂)₂(dppe)₂] (A:dppe=Ph ₂PCH₂CH₂PPh ₂ undM=Mo oder W) mit Ethyldiazoacetat, N₂CHCOOEt, ergab nach einfachem Austausch des Distickstoffliganden mit Ethyldiazoacetat die Bisdiazoalkanetrans-[M(N₂CHCOOEt)₂(dppe)₂]. Diazomethan (N₂CH₂) hingegen reagierte mitA unter Verlust von N₂ zu Produkten, die tentativ alstrans-[M(CH₂)₂(dppe)₂] mit Methylenliganden formuliert wurden.

     

Nouvelle Synthese Des 2-Thioxoethylphosphonates, 2- mercaptovinylphosphonates, 2-Phosphoryl-3-thioxopropanoates, 2-Thiomethylvinylphosphonates, 2-Thioethoxycarbonylmethylvinylphosphonates

The cyanomethylphosphonates 1 and the ethyl phosphoacetates 2 were reacted with some fluorophenylisothiocyanates to give the 2-thioxoethylphosphonates 3 in tautomeric equilibrium with the corresponding 2-mercaptovinylphosphonates 3 ′ and the 2-phosphoryl-3-thioxopropanoates 4 , respectively. Reaction of the cyanomethylphosphonates 1 with fluorophenylisothiocyanates in presence of methyliodide furnished the 2- thiometylvinylphosphonates 5 . The 2-mercaptovinylphosphonates 3 ′ reacted with ethyl chloroacetate in refluxing ethanol in the presence of triethylamine to give S-substitued derivatives 6 .     

Ca2Pd2In and Ca2Pt2In with Monoclinic HT‐Pr2Co2Al Type Structure

The metal‐rich indides Ca₂Pd₂In and Ca₂Pt₂In were synthesised from the elements in sealed tantalum ampoules in an induction furnace. Both samples were investigated by X‐ray powder and single crystal diffraction: HT‐Pr₂Co₂Al type, C2/c, a = 1017.6(5), b = 574.1(3), c = 812.7(3) pm, β = 104.54(2)°, wR2 = 0.0344, 590 F² values for Ca₂Pd₂In and a = 1004.3(3), b = 568.9(1), c = 813.1(2) pm, β = 104.25(2)°, wR2 = 0.0435, 654 F² values for Ca₂Pt₂In with 25 variables per refinement. The structure contain Pd₂ (272 pm) and Pt₂ (264 pm) dumb‐bells with a trigonal prismatic coordination for each transition metal atom. These AlB₂ related slabs are condensed via common edges. Together the palladium and indium atoms build up three‐dimensional [Pd₂In] and [Pt₂In] polyanionic networks in which the calcium atoms fill larger channels. The bonding of calcium to the network proceeds via shorter Ca–Pd and Ca–Pt contacts. Ca₂Pd₂In and Ca₂Pt₂In are Pauli paramagnets.     

Kinetics and products of chlorine atom initiated oxidation of HCF2OCF2OCF2CF2OCF2H and HCF2O(CF2O)n‐(CF2CF2O)mCF2H

Smog chamber/FTIR techniques were used to measure k(Cl + HCF₂OCF₂OCF₂‐CF₂OCF₂H) = k(Cl + HCF₂O(CF₂O)_n(CF₂CF₂O)_mCF₂H) = (5.0 ± 1.4) × 10^?17 cm³ molecule^?1 s^?1 in 700 Torr of N₂/O₂ diluent at 296 ± 1 K. The Cl‐initiated atmospheric oxidation of HCF₂OCF₂OCF₂CF₂OCF₂H and the sample of HCF₂O(CF₂O)_n(CF₂CF₂O)_mCF₂H used in this work gave COF₂ in molar yields of (476 ± 36)% and (859 ± 63)%, respectively, with no other observable carbon containing products (i.e., essentially complete conversion of both hydrofluoropolyethers into COF₂). The results are discussed with respect to the atmospheric chemistry and environmental impact of hydrofluoropolyethers of the general formula HCF₂O(CF₂O)_n(CF₂CF₂O)_mCF₂H. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 819–825, 2008     

BaAg2S2, ein Thioargentat im CaAl2Si2-Strukturtyp

BaAg₂S₂, a Thioargentate with the CaAl₂Si₂-Type Structure BaAg₂S₂ could be obtained as crystalline powder by the reaction of barium-bis[dicyanoargentate(I)] in a stream of hydrogensulfid at 500°C. Single crystals grew at 480°C in an evacuated glass ampoule filled with a flux of potassium thiocyanate and powdery BaAg₂S₂ as solid. BaAg₂S₂ crystallises in the trigonal CaAl₂Si₂-typ structure, a = 4.386(1) Å, c = 7.194(2) Å, space group P3 m1, Z = 1. The structure was determined from four-circle diffractometer data. The silver-sulphur distances are discussed with respect to the corresponding distances of the hitherto known alkaline earth-transition metal pnictides, also crystallizing in the CaAl₂Si₂-typ structure.     

Synthesis and characterization of arsacycloalkanes and their palladium and platinum complexes,and X‐ray structure of [PdCl2(PhAsCH2CH2CH2CH2CH2)2]

Reactions of PhAsCl₂ with BrMg(CH₂)_nMgBr (n = 4 or 5) in THF gave phenylarsacycloalkanes as colourless oily liquids which could be distilled under vacuum. Treatment of PhAs(CH₂)_n­with MCl₂(RCN)₂ (M = Pd or Pt; R = Ph­or Me) afforded mononuclear complexes, [MCl₂{PhAs(CH₂)_n}₂]. Reactions with [Pt₂Cl₂(μ‐Cl)₂(PEt₃)₂] gave mixed‐ligand complexes, [PtCl₂(PEt₃){PhAs(CH₂)_n]. The palladium complexes adopt a trans geometry whereas the platinum complexes exist in a cis configuration. The crystal and molecular structure of [PdCl₂(PhAsCH₂CH₂CH₂CH₂CH₂)₂] was determined by X‐ray diffraction methods. The molecule consists of a square‐planar palladium atom with trans chlorides and trans arsa ligands. The six‐membered ‘AsC₅′ ring adopts a chair conformation. Copyright © 1999 John Wiley & Sons, Ltd.     

Study on the reactions of the dinitrogen complexestrans-[M(N2)2(Ph 2PCH2CH2PPh 2)2] (M=Mo or W) with ethyldiazoacetate: Formation of an Azo compound and of a phosphazene species

Complextrans-[Mo(N₂)₂(dppe)₂] (dppe=Ph ₂PCH₂CH₂PPh ₂) reacts with NN=CHCOOEt in benzene solution to afford benzene-azomethane,Ph-N=N-CH₃, as the main organic product. However, the phosphazene speciesPh ₂P(N₂CHCOOEt)(CH₂CH₂)P(N₂CHCOOEt)Ph ₂ is formed by irradiating aTHF solution oftrans-[W(N₂)₂(dppe)₂] in the presence of ethyldiazoacetate; in moist solution, the phosphazene bonds undergo a partial hydrolysis, and the phosphonium species [Ph ₂P(NHNCHCOOEt)(CH₂CH₂)P(NHNCHCOOEt)Ph ₂]²⁺ appears to be formed.

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Untersuchungen zu den Reaktionen der Distickstoff-Komplexetrans-[M(N₂)₂(Ph ₂PCH₂CH₂PPh ₂)₂] (M=Mo oder W) mit Ethyldiazoacetat: Die Bildung einer Azoverbindung und eines Phosphazens

Zusammenfassung Die Komplexetrans-[Mo(N₂)₂(dppe)₂] (dppe=Ph ₂PCH₂CH₂PPh ₂) reagieren mit NN=CHCOOEt in benzolischer Lösung zuPh-N=N-CH₃ als organischem Hauptprodukt. Andererseits wird bei der Bestrahlung vontrans-[W(N₂)₂(dppe)₂] inTHF-Lösung in der Gegenwart von Ethyldiazoacetat das PhosphazenPh ₂P(N₂CHCOOEt)(CH₂CH₂)P(N₂CHCOOEt)Ph ₂ gebildet; in feuchter Lösung erleidet die Phosphazen-Bindung eine teilweise Hydrolyse und die Phosphonium-Spezies [Ph ₂P(NHNCHCOOEt)(CH₂CH₂)P(NHNCHCOOEt)Ph ₂]²⁺ scheint gebildet zu werden.

     

CHARACTERIZATION OF GALLIUM-NITROGEN ADDUCTS BY X-RAY STRUCTURAL AND NMR SPECTRAL STUDIES. CRYSTAL STRUCTURE OF [(PhMe2CCH2)2GaCI]2 AND OF ITS MONOMERIC t-BUTYLAMINE ADDUCT, (PhMe2CCH2)2GaCI[NH2(t-Bu)]

Abstract

The nature of [(PhMe₂CCH₂)₂GaCl]₂ and its adducts with NH₂(t-Bu) and NH₂(n-Pr) have been investigated. [(PhMe₂CCH₂)₂GaCl]₂ crystallizes in the monoclinic space group P2₁/c with a=11.2495(16)Å, b = 21.4977(32)A, c = 7.8337(15)Å, β = 93.489(14)°, V= 1891.0(5)ų and D(calcd.)= 1.305 Mg/m³ for Z = 2. The structure was refined to R(F) = 4.2% for 1672 reflections above 6[sgrave](F). The molecule has perfect C_i symmetry, a planar Ga(μ-Cl)₂Ga core and an expanded C(α)-Ga-C(α) angle of 137.9(3)° between the neophyl ligands. (PhMe₂CCH₂)₂-GaCl[NH₂(t-Bu)] crystallizes in the monoclinic space group P2₁/n with a = 6.4023(10) A, b= 17.4274(25) A, c = 22.2389(38) Å, β = 94.939(13)°, V= 2472.2(7)ų and D(calcd.) = 1.225 Mg/m³ for Z = 4. This structure was refined to R(F) = 3.9% for 1700 reflections above 6[sgrave](F). The crystal structure is stabilized by intermolecular Cl … H-N hydrogen bonds and the central Ga(III) atom has a distorted tetrahedral geometry. A benzene solution of (PhMe₂-CCH₂)₂GaCl[NH₂(t-Bu)] is in equilibrium with [(PhMe₂CCH₂)₂GaCl]₂[NH₂(t-Bu)] and free amine according to ¹HNMR studies. In contrast to this, a solution of (PhMe₂CCH₂)-GaCl₂[NH₂(t-Bu)] is in equilibrium with [(PhMe₂CCH₂)GaCl₂]₂[NH₂(t-Bu)], free [(PhMe₂-CCH₂)-GaCl₂]₂ and free amine. Solutions of (PhMe₂CCH₂)₂GaCI[NH₂(n-Pr)] and (PhMe₂CCH₂)GaCl₂[NH₂(n-Pr)] show no evidence for similar equilibria.     

Synthese von einigen 2H-Pyran-2-on-Derivaten

The Synthesis of Some 2H-Pyran-2-one Derivatives Derivatives of 6-unsubstituted 2H-pyran-2-one have been synthesized by several different methods. The 4-chloro-2H-pyran-2-one ( 9 ) is the most important, since it serves as starting material for the synthesis of different 4-substituted 2H-pyran-2-ones (Scheme 2). Also described are simple transformations of cumalic-acid derivatives producing 5-(2,2-dichlorovinyl)-2H-pyran-2-one ( 23 ), 2-oxo-2H-pyran-2-carbonitrile ( 26 ), and 4,5-bis(trifluoromethyl)-2H-pyran-2-one ( 32 ) (Scheme 3 and 4).     

Synthesis,Spectroscopic Studies and Crystal Structures of [Et2Sn(O2AsMe2)2] and [Ph2Sn(O2AsMe2)(μ‐OMe)]2

[Et₂Sn(O₂AsMe₂)₂] ( 1 ) and [Ph₂Sn(O₂AsMe₂)(μ‐OMe)]₂ ( 2 ) were synthesized by treatment of Et₂SnO and Ph₂SnS with HO₂AsMe₂ in Methanol, respectively. The compounds were characterized by elemental analyses, vibrational spectroscopy and mass spectrometry. According to X‐ray diffraction measurements compound 1 crystallizes monoclinic in space group P2₁/n with cell parameters a = 804.89(3), b = 987.11(5), c = 966.42(4) pm, β = 113.354(3)°. The unit cell parameters of 2 , which crystallizes in the same space group, are a = 974.4(1), b = 1463.3(1), c = 1228.9(1) pm, β = 111.324(3)°. The (SnOAsO)₄ rings of 1 are linked and form a two‐dimensional network with the SnEt groups pointing into the holes of the next layer. Compound 2 occurs as a dimer with internal Sn(OMe)₂Sn bridges in the (SnOAsO)₂ rings. The vibrational and mass spectra are given and discussed.     

Cd2Cu(PO4)2

During an investigation of the insufficiently known system M1O–M2O–X₂O₅–H₂O (M1 = Cd²⁺, Sr²⁺ and Ba²⁺; M2 = Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺ and Mg²⁺; X = P⁵⁺, As⁵⁺ and V⁵⁺), single crystals of the novel compound dicadmium copper(II) bis[phosphate(V)], Cd₂Cu(PO₄)₂, were obtained. This compound belongs to a small group of compounds adopting a Cu₃(PO₄)₂‐type structure and having the general formula M1₂M2(XO₄)₂ (M1/M2 = Cd²⁺, Cu²⁺, Mg²⁺ and Zn²⁺; X = As⁵⁺, P⁵⁺ and V⁵⁺). The crystal structure is characterized by the interconnection of infinite [Cu(PO₄)₂]_n chains and [Cd₂O₁₀]_n double chains, both extending along the a axis. Exceptional characteristics of this structure are its novel chemical composition and the occurrence of double chains of CdO₆ polyhedra that were not found in related structures. In contrast to the isomorphous compounds, where the M1 cations are coordinated by five O atoms, the Cd atom is coordinated by six. The dissimilarity in the geometry of M1 coordination between Cd₂Cu(PO₄)₂ and the isomorphous compounds is mostly due to the larger ionic radius of the Cd cation in comparison with the Cu, Mg and Zn cations. Sharing a common edge, two CdO₆ polyhedra form Cd₂O₁₀ dimers. Each such dimer is bonded to another dimer sharing common vertices, forming [Cd₂O₁₀]_n double chains in the [100] direction. The Cu atoms, located on an inversion centre (site symmetry ), form isolated CuO₄ squares interconnected by PO₄ tetrahedra, forming [Cu(PO₄)₂]_n chains similar to those found in related structures. Conversely, the [Cd₂O₁₀]_n double chains, which were not found in related structures, are an exclusive feature of this structure.     

Synthesis and crystal structure of [V_2(μ-S_2)_2(S_2CNEt_2)_4]·2CH_3Cl

[V_2(μ-S_2)_2(S_2CNEt_2)_4].2CH_3Cl was synthesized by the reaction of NaS_2CNEt_2,Li_2S andVOCl_3 at room temperature.Crystal data:M=1061.3,space group Pbca,with the orthorhombicparameters:a=20.123(3),b=20.485(4),c=10.911(3),V=4497.7,Z=4,D_c=1.57g/cm~3,Mo Kσradiation(λ=0.71069()?),μ=13.2 cm~(-1),F(000)=2168.Final R=0.041 and R_w=0.047 for 2288 ob-served reflections with I>3σ(1).The coordination sphere of each V atom in title compound is a dis-torted tetragonal prism composed of two bidentate dithiocarbamate and two S_(2~((2-)) ligands.The V—Vdistance is 2.890 while the V—S distances fall in the range of 2.422—2.505.     

Phosphaniminato-Komplexe von Bor. Synthese und Kristallstrukturen von [BBr2(NPMe3)]2, [B2Br3(NPiPr3)2]Br, [B2(NPEt3)4]Br2, [B2Br2(NPPh3)3]BBr4 und [{B2(NMe2)2}2(NPEt3)2]Cl2

Phosphoraneiminato Complexes of Boron. Syntheses and Crystal Structures of [BBr₂(NPMe₃)]₂, [B₂Br₃(NPⁱPr₃)₂]Br, [B₂(NPEt₃)₄]Br₂, [B₂Br₂(NPPh₃)₃]BBr₄ and [{B₂(NMe₂)₂}₂(NPEt₃)₂]Cl The bromoderivatives of the title compounds are prepared from the corresponding silylated phosphoraneimines Me₃SiNPR₃ and boron tribromide. The boron subcompound [{B₂(NMe₂)₂}₂(NPEt₃)₂]Cl₂ derives from Me₃SiNPEt₃ and B₂Cl₂(NMe₂)₂. All complexes are characterized by NMR and IR spectroscopy as well as by crystal structure determinations. [BBr₂(NPMe₃)]₂ (1): Space group P2₁/n, Z = 2, R = 0.031. Lattice dimensions at ?50°C: a = 723.8, b = 894.2, c = 1305.4 pm, β = 92.35°. 1 forms centrosymmetric molecules in which the boron atoms are linked via μ₂-N bridges of the NPMe₃^? groups of from B₂N₂ four-membered rings with B? N distances of 149.9 and 150.9 pm. B₂Br₃(NPⁱPr₃)₂]Br (2): Space group P2₁, Z = 2, R = 0.059. Lattice dimensions at ?80°C: a = 817.6, b = 2198.7, c = 851.5 pm, β = 115.09°. In the cations of 2 the boron atoms are lined via the μ₂-N atoms of the NPⁱPr₃^? groups to form planar, asymmetric B₂N₂ four-membered rings with B? N distances of 143 and 156 pm. [B₂(NPEt₃)₄[Br₂·4CH₂Cl₂ (3): Space group C2/c, Z = 4, R = 0.042. Lattice dimensions at ?50°C: a = 1946.1, b = 1180.3, c = 2311.3 pm, β = 101.02°. The structure contains centrosymmetric dications in which both the boron atoms are lined by the N atoms of two of the NPEt₃^? groups to form a B₂N₂ four-membered ring with B? N distances of 149.6 pm. The remaining two NPEt₃^? groups are terminally bonded with very short B? N distances of 133.5 pm. B₂Br₂(NPPh₃)₃]BBr₄ (4): Space group P1 , Z = 2, R = 0.065. Lattice dimension at ?50°C: a = 1025.7, b = 1496.1, c = 1807.0 pm, α = 85.09°, β = 82.90°, γ = 82.72°. In the cation the boron atoms are lined via the μ₂-N atoms of two of the NPPh₃^? groups to form a nearly planer B₂N₂ four-membered ring with B? N distances of 149.3-153.1 pm. The third NPPh₃³ group is terminally connected with teh sp² hybridized boron atom and with a B? N distance of 134.1 pm along with an almost linear BNP bond angle of 173.6°. [{B₂(NMe₂)₂}₂(NPEt₂)₂]Cl₂ · 3CH₂Cl₂ (5): Space group C2/c, Z = 4, R = 0.098. Lattice dimensions at ?70°C: a = 1557.9, b = 1294.7, c = 2122.9 pm, β = 96.08°. The structure of 4 contains centrosymmetric dications in which two by two B-B dumb-bells are linked via the μ₂-N atoms of the two NEPt₃^? groups to form B₄N₂ six-membered rings with B? N distances of 150 and 156 pm and B-B distances of 173 pm. The B? N distances of the terminally bonded NMe₂^? groups correspond to 138 pm double bonds.     

K2[Mo2O4(C2O4)2(H2O)2]·3H2O

The crystal and molecular structure of dipotassium di‐μ‐oxo‐bis[aqua(oxalato‐O¹,O²)oxomolybdenum(III)] trihydrate, K₂­[Mo₂O₄(C₂O₄)₂(H₂O)₂]·3H₂O, has been determined from X‐ray diffraction data. In the dimeric anion, which has approximate twofold symmetry, each Mo atom is in a distorted octahedral coordination, being bonded to one terminal oxo‐O atom, two bridging O atoms, two O atoms from the oxalato ligand and one from the water mol­ecule. Bond lengths trans to the multiple‐bonded terminal oxo ligand are larger than those in the cis position, confirming the trans influence as a generally valid rule.     

Copper(II) Halide Complexes of 2-Aminopyrimidines: Crystal Structures of [(2-aminopyrimidine) n CuCl2] (n=1,2) and (2-amino-5-bromopyrimidine)2CuBr2

The reaction of CuX₂(X=Cl, Br) with 2-aminopyrimidine in aqueous solution, or 2-amino-5-bromopyrimidine in aqueous acid yields compounds of the forms [LCuCl₂] _n (1), [L₂CuCl₂] (2) and [L'₂CuBr₂] (3) [L=2-aminopyrimidine; L'=2-amino-5-bromo-pyrimidine]. The three compounds all form layered structures in which each copper ion is coordinated to two 2-aminopyrimidine molecules and two halide ions. Common structural threads involve bridging ligation [either by monomeric (1) or hydrogen bonded ligand dimers (2 and 3)], N-H···X and N-H···N hydrogen bonding and π-π stacking interactions as well as semi-coordinate Cu···X bond formation (1 and 2) or Br···Br interactions (3). Compounds 1 and 2 crystallize as two-dimensional coordination polymers with asymmetrically bihalide bridged (CuX₂) _n chains cross-linked into sheets by the 2-aminopyrimidine molecules (1) or by hydrogen bonded L₂ dimers (2). The halide bibridged chains expand their primary copper coordination spheres to give 4 + 2 coordination spheres in 1 and 2. In 3, the layer structure involves coordination of the hydrogen bonded L'₂ dimers and C-Br···Br- interactions. Crystal data: (1): monoclinic, P2₁/m, a=3.929(1), b=12.373(2), c=7.050(1)å, β=91.206(4)°, V=342.7(1)&Aringsup3;, Z=2, D _calc= 2.225Mg/m³, μ=3.878 mm^-1, R=0.0269 for [|I|≥3σ(I)]. For (2): triclinic, P-1, a=4.095(4), b=7.309(5), c=10.123(6) å, α=86.28(6), β=78.44(6), γ=74.55(8)°, V=286.1(4) ų, Z=1, D _calc=1.884 Mg/m³, μ=2.360 mm^-1, R=0.0506 for [|I|≥2σ(I)]. For (3): triclinic, P-1, a=6.074(4), b=7.673(3), c=8.887(3) å, α=108.43(3) β=100.86(5), γ=106.96(4)°, V=357.0(3) ų, Z=1, D _calc=2.657 Mg/m³, μ=12.714mm^-1, R=0.0409 for [|I|≥2σ(I)].