[Co(HOC10H6COO)2(H2O)4]配合物的合成、晶体结构和性质研究

Complex [Co(HOC₁₀H₆COO)₂(H₂O)₄] was synthesized by reaction of hydroxy-2-naphthoic acid with CoCl₂·6H₂O. The compound was characterized by elemental analysis, IR and the structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P2₁/n with a=0.675 8(2) nm, b=0.518 15(14) nm, c=2.962 9(9) nm, β=94.925(8)°. V=1.033 6(5) nm³, Z=2, D=1.624 Mg·m^-3, F(000)=522. The Co atom has an octahedron coordination geometry and was six-coordinated with two oxygen atoms from two carboxylate ligands and four oxygen atoms from four water molecules. The complex molecules were linked by different hydrogen bonds to form a 2D network. The complex has thermal stability and shows a strong fluorescent emission at 421 nm (λ_ex=342 nm). CCDC: 250903.     

配位聚合物{[Co(4,4′-bpy)(H2O)4](Fum)·4H2O}n的合成和晶体结构

The complex {[Co(4,4′-bpy)(H₂O)₄](Fum)·4H₂O}_n(where 4,4′-bpy = 4,4′-bipyridine and Fum = fumarate) was synthesized and characterized by X-ray diffraction. The complex consists of one-dimensional chains containing cobalt(Ⅱ) ions bridged by 4,4′-bpy molecules. The six-coordination of Co²⁺ is achieved by means of four water molecules. The fumarate is not coordinated to cobalt ion while it forms hydrogen bonds with coordinated and non-coordinated water molecules and extends the structure into three-dimensional hydrogen bonding network. CCDC: 190488.     

双核配合物[Cu2(TS)(H2O)]·CH3OH的自组装制备和晶体结构

The binuclear complex [Cu₂(TS)(H₂O)]·CH₃OH, where TS denotes the binucleating ligand derived from the schiff base N,N′-bis(3-carboxylsalidene)trimethylenediamine, was obtained from the self-decomposition of mononuclear complex Na₂CuTS·H₂O. It crystallizes in the monoclinic system, space group P2₁/c. The lattice parameters are a=11.935(2)?,b=15.667(3)?,c=11.621(2)?,β=111.60(3)°,V=2020.2(7)?³, Z=4 with R=0.0467. The structure is made of binuclear units, in which two copper atoms are bridged by two phenolic oxygen atoms. The “inside”copper atom is coordinated by two nitrogens, two phenolic oxygens in a planar coordi-nation site, the copper atom deviates from the mean plane by 0.47?. The “outside” copper atom is five coordinated by two phenolic oxygen atoms、two equatorial carboxyl oxygen atoms and one axial water oxygen atom in a distorted tetragonal cone site, the copper atom is pulled out of the equatorial plane by 0.46?.     

{[Co(4，4′-bipy)(H2O)4]·(α-Furacrylic acid)2·(H2O)}n的水热合成、晶体结构及电化学分析

A complex {[Co(4,4′-bipy)(H₂O)₄]·(α-Furacrylic acid)₂·(H₂O)}_n with α-furacrylic acid, 4,4′-bipy and cobaltous chloride hexahydrate has been synthesized by means of hydrothermal way and characterized. Crystal data for this complex: monoclinic, space group P2₁/c, a=1.147 0(2) nm, b=1.099 9(2) nm, c=1.111 1(2) nm, β=97.829(3)°, V=1.388 7(5) nm³, D_c=1.429 g·cm^-3, Z=2, μ(Mo Kα)=0.682 mm^-1, F(000)=622, S=1.025, R₁=0.035 8, wR₂=0.086 1. The crystal structure shows that the cobalt(Ⅱ) ion is coordinated with two nitrogen atoms of two 4,4′-bipy molecules and four oxygen atoms from four water molecules, respectively, giving a distorted octahedral coordination geometry. Adjacent cobalt(Ⅱ) ions are bridged by 4,4′-bipy groups, resulting in a 1D chain structure. The adjacent Co(Ⅱ)-Co(Ⅱ) distance is 1.147 0 nm. The cobalt(Ⅱ) ion isn′ t coordinated with α-Furacrylic acid. The complex molecules form 2D structure through hydrogen bonds. The cyclic voltametric behavior of the complex was also investigated. CCDC: 648243.     

一维链状钴配位聚合物{[Co(C4H4O5)(H2O)2]·H2O}n的合成与晶体结构

One dimensional chain cobalt coordination polymer has been synthesized with malic acid and cobalt(Ⅱ) chloride anhydrous, and characterized by the element analysis, IR, TGA and single crystal X-ray diffraction structure analysis. The title complex crystallizes in monoclinic system with space group P2₁, a=0.575 61(9) nm, b=0.905 86(14) nm, c=0.841 02(13) nm, β=105.350(2)°; V=0.422 88(11) nm³, Z=2, D_c=1.924 Mg·m^-3, μ=2.044 mm^-1, F(000)=250, and final R₁=0.029 3, wR₂=0.074 2. The crystal structure shows that the cobalt ion is coordinated with four oxygen atoms from two different malate molecules and two oxygen atoms from two water molecules respectively, forming a distorted octahedral coordination geometry. Two adjacent cobalt(Ⅱ) atoms are bridged by one malate groups in bis-monodentate mode, constructing a one dimensional chain structure along b axis, with the adjacent Co…Co distance being 0.530 9 nm. Moreover, the molecules are packed in three-dimensional supramolecular network though the intermolecular hydrogen bonds. CCDC: 704441.     

含有双螺旋链的配位聚合物[Co(dpa)prz0.5]n的合成、晶体结构及磁性质

A coordination polymer [Co(dpa)prz_0.5]_n(1) with double-helix chains has been constructed hydrothermally using H₂dpa (H₂dpa=diphenic acid), prz (prz=piperazine) and Co(NO₃)₂·6H₂O. The structure and magnetic properties of the complex were investigated. The complex crystallizes in triclinic system and P1 space group. Each Co atom is five-coordinated and takes a distorted tetragonal pyramid geometry. Two carboxylates of the H₂dpa ligands bridge four Co(Ⅱ) ions to form infinite right-handed or left-handed helical -C-O-Co- chains. The two types of helical chains are interconnected to each other through the Co(Ⅱ) centers to produce double-helix chains. The chains form a 2D sheet through the coordination interaction of prz molecules between adjacent chains. The sheets are further interlinked by hydrogen bond interactions to generate 3D coordination frameworks. Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Co(Ⅱ) ions. CCDC: 709275.     

一种新型羧酸-磺酸双功能配体的钴配合物的合成与三维氢键网络结构

Using the ligand 4-sulfonyl-2,6-naphthalenedicarboxylate (SNDC), a coordination compound [Co(H₂O)₆]₂[Co(SNDC)₂(H₂O)₄]·4H₂O(1) was synthesized and characterized by elemental analysis, thermal analysis, IR and single crystal X-ray diffraction structure analysis. The complex crystallizes in the triclinic P1 space group. The crystallographic data are: a=0.722 4(3) nm, b=1.181 2(4) nm, c=1.353 4(5) nm, V=1.039 47(7) nm³, Z=1, D_c=1.795 g·cm^-3, R₁=0.055 8, wR₂=0.148 7. In the complex, the cobalt(Ⅱ) mononuclear anion ([Co(SNDC)₂(H₂O)₄]^4-) adopts the six-coordinated octahedral geometry furnished by two carboxylate oxygen atoms from the SNDC ligands and four water oxygen atoms. The cobalt(Ⅱ) mononuclear anions are self-assembled into two-dimensional sheets through hydrogen bonding between coordinated water molecules and carboxylate oxygens and π-π stacking of the aromatic naphthalene moieties. The [Co(H₂O)₆]²⁺ cations are intercalated between the layers through additional hydrogen bonds involving coordinated water molecules and sulfonate/carboxylate oxygen atoms. CCDC: 694556.     

异双核配合物[CuCo(TS)(H2O)]·H2O的晶体结构和热分析性质研究

The single-crystal of [CuCo(TS)(H₂O)·H₂O],where TS is the schiff base N,N＇-bis(3-carboxylsalidene)trimethylenediamine, was obtained and its crystal structure was determined by the single-crystal X-ray diffraction method at room temperature. It crystallizes in the monoclinic system, space group P2₁/c. The lattice parameters are a=11.855(2)?, b=14.722(3)?, c=12.080(2)?, β=117.32(3)°, V=1879.4(7)?³ , Z=4 with R₁=0.0330. The structure is made of heterobinuclear units . The copper atom is coordinated by two nitrogens, two phenolic oxygens, in a square-planar manner. And the cobalt atom is coordinated by two phenolic oxygen atoms, two equatorial carboxyl oxygen atoms and one axial water oxygen atom, in a distorted square pyramid. Two metal atoms are bridged by two phenolic oxygens. In the crystal packing, the neutral molecules built layers. Within these layers the molecules are connected through hydrogen bonds. And the thermal property of the complex according to crystal structure is also investigated.     

配合物[Co(phen)2(m-chlorobenzoic acid)2·(H2O)]·(H2O)2的水热合成、晶体结构电化学分析

The title complex has been synthesized with m-chlorobenzoic acid, 1,10-phenanthroline and cobalt perchlorate anhydrous in the solvent mixture of water and methanol. Crystal data for this complex: triclinic, space group P1, a=0.870 7(3) nm, b=1.284 4(4) nm, c=1.692 9(5) nm; α=75.430(5)°, β=77.562(5)°, γ=86.346(5)°, V=1.789 4(9) nm³, D_c=1.456 g·cm^-3, Z=2, F(000)=806. Final GooF=1.065, R₁=0.068 4, wR₂=0.127 5. The crystal stru-cture shows that the Cobaly ion is coordinated with four nitrogen atoms from two 1,10-phenanthroline molecules and two oxygen atoms from one m-chlorobenzoic acid molecule and one water molecule respectively, forming a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex is also reported. CCDC: 619087.     

一维链状4-羧基苯氧乙酸桥联钴配位聚合物[Co(p-CPOA)(2，2′-bipy)(H2O)]n的合成与晶体结构

A novel coordination polymer of [Co(p-CPOA)(2，2′-bipy)(H₂O)]_n (p-CPOA^2-=4-carboxylphenoxyacetate dianion, 2,2′-bipy=2,2′-bipyridine) was synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. The title complex crystallizes in monoclinic space group C2/c, with a=1.424 4(3) nm, b=1.316 6(3) nm, c=1.947 7(4) nm, β=104.56(3)°. V=3.535 3(14) nm³, Z=8, R=0.028 5, wR=0.089 1. The cobalt(Ⅱ) ion displays a distorted octahedral coordination geometry, defined by three carboxyl oxygen atoms from different p-CPOA^2- groups, two nitrogen atoms from 2,2′-bipyridine ligand and one water molecule. The cobalt atoms are bridged by p-CPOA^2- groups, forming a one-dimensional chain structure along a axis. The adjacent Co…Co atoms distance is 0.996 8 nm. A layer supramolecular network is contrsucted by the hydrogen bonds and π-π stacking interactions. CCDC: 220039.     

Co[(C6H11O)2PS2]2·2Py的合成和晶体结构

Oxidation process of Co[(C₆H₁₁O)₂PS₂]₂ and substitute-reduction reaction of Co[(C₆H₁₁O)₂PS₂]₃ with pyridine have been studied by spectrophotometric methods, respectively. The equilibrium constant was found to be K=0.63±0.02(mol·dm^-3)^-3. The crystal structure of Co[(C₆H₁₁O)₂PS₂]₂·2Py has been determined by X-ray diff- raction method. The crystal belongs to triclinic system, space group P1, with cell parameters: a=6.944(2)?,b=9.277(3)?,c=15.981(6)?,α=91.79(3)°,β=99.55(3)°,γ=94.44(3)°,V=1011.2(6)?³,Z=2,M_r=803.94,D_c=1.320Mg·m^-3,F(000)=425,μ=0.747mm^-1,final R=0.0700 and wR=0.1988 for 3626 re-flections with I≥2σ(I). The cobalt atom in the title complex has a octahedral geometry with four Co-S bonds and two Co-N bonds. The central atom P is tetrahedrally surrounded by two sulphur atoms and two oxygen atoms in the dicyclohexyldithiophosphate ligand. The six carbon atoms of cyclohexyl take the chair conformation.     

过渡金属-碱土金属铜钙四核配合物Cu2Ca2L2(H2O)6·2H2O的合成和晶体结构

The transition metal and alkaline earth metal tetranuclear complex Cu₂Ca₂L₂(H₂O)₆·2H₂O where H₄L represents the Schiff base N-3-carboxylsalicylideneglycylglycine was prepared and its crystal structure was determined by the single-crystal X-ray diffraction method at room temperature. It crystallizes in the monoclinic system, space group C2/c. The lattice parameters are a=2.128 2(2) nm, b=1.231 73(14) nm, c=1.32342(15) nm, β=93.619(2)°, M_r=939.81, D_c=1.803Mg·m^-3, F(000)=1 928, Z=4 with R₁=0.046 6. Each copper atom is coordinated by two nitrogen atoms, one carboxylate oxygen atom and one phenolic oxygen atom, in a square-planner manner. And each calcium atom is coordinated by three water oxygen atoms, three carboxylate oxygen atoms and one phenolic oxygen atom in a distorted pentagonal bipyramid. Two pentagonal bipyramids are connected by two carboxyl groups. CCDC: 239969.     

有机锡配合物{[(n-C8H17)2Sn(O2CCH2CS2NC4H8O)]2O}2的合成，表征及晶体结构

The title complex {[(n-C₈H₁₇)₂Sn(O₂CCH₂CS₂NC₄H₈O)]₂O}₂ has been synthesized by the reaction of (morpholinylthiocarbamoylthio)acetic acid with the di-n-octyltin oxide in 1∶1 molar ratio. The complex was characterized by elemental analysis, IR and ¹H NMR. The crystal and molecular structure of complex was determined by X-ray single crystal diffraction. The crystal belongs to triclinic system with space group P1 and unit cell dimensions: a=1.201 5(9) nm, b=1.481 8(11) nm, c=1.894 1(14) nm, α=72.485(10)°, β=88.586(10)°, γ=66.893(9)°, and Z=1, μ=1.034 mm^-1, V=2.941(4) nm³, D_c=1.295 g·cm^-3, F(000)=1 196, R₁=0.058 8, wR₂=0.155 8. The complex is a centrosymmetric structure with a four-membered central endo-cyclic Sn₂O₂ unit in which two bridged oxygen atoms both connect with an exo-cyclic tin atom. The endo-cyclic tin atoms and the exo-cyclic tin atom are all five-coordinate and have coordination geometry of distorted trigonal bipyramid with an additional weak coordination carboxylate oxygen. Four carboxylate ligands are divided into two types. And two of them are monodentate and connecting to each of exo-cyclic tin atoms by using one oxygen atom, whereas the others bridge to each pair of exo-and endo-cyclic tin atoms utilizing one oxygen atom. CCDC: 277048.     

杂-双核配合物[CaCu(C3H2O4)2(H2O)4]n的合成、晶体结构及热稳定性

The title complex， [CaCu(C₃H₂O₄)₂(H₂O)₄]_n， with a formula of C₆H₁₂CaCuO₁₂ and M_r=379.78 has been sy-nthesized and characterized by single crystal X-ray diffraction structure analysis， elemental analysis， IR spectra and TG-DTG techniques. The results show that the crystal is Orthorhombic， space group Pbcn with a=0.669 21(5) nm， b=1.370 23(5) nm， c=1.322 39(10) nm， V=1.212 59(16) nm³， D_c=2.080 g·cm^-3， μ=2.288 mm^-1， F(000)=772 and Z=4. The final R=0.054 0 and wR=0.112 8 for 1 189 observed reflections with I>2σ(I). The structure of the title complex consists of CaO₈ polyhedra and CuO₆ elongated octahedra linked together by malonate ligands. The Ca(Ⅱ) cation， on a twofold axis， is coordinated by two water molecules and six malonate O atoms. The Cu(Ⅱ) cation， which lies in a centre of symmetry in an octahedral arrangement， is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane， with the shortest Cu…Cu distance of 0.762 46(6) nm. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds. Its thermo gravimetric analysis was determined by TG-DTG techniques. CCDC: 663184.     

一维链钴配位聚合物{[Co(H2O)4(3,3′-azpy)](3,3′-azpy)3(PF6)2}n的结构和性质的研究

The complex {[Co(H₂O)₄(3,3′-azpy)](3,3′-azpy)₃(PF₆)₂}_n(3,3′-azpy=3,3′-azobispyridine) has been synthesized and characterized. The crystal (C₄₀H₄₀F₁₂CoN₁₆O₄P₂, M_r=1157.75) belongs to the triclinic system, space group P1 with the following crystallographic parameters: a=10.759(2),b=11.012(2), c=23.207(4)?; α=85.330(10), β=83.470(10),γ=69.770(10)°;V=2560.6(8)?³,D_c=1.502g·cm^-3, μ(MoKα)= 0.498mm^-1,F(000)=1178,Z=2, and final R₁=0.0469, wR₂=0.1053 for observed reflections 5549 (I> 2.00σ(I)).The X-ray analysis reveals that cobalt(Ⅱ) cation coordination environment is a distorted octahedral geometry, the Co²⁺ ion is coordinated by four oxygen atoms of water in the equatorial plane, while the two nitrogen atoms of 3,3′-azpy occupy the axial positions. The complex forms a one-dimensional chain structure via 3,3′-azpy bridging ligand. The one-dimensional chain forms three-dimensional network by hydrogen bonds and π-π inter-actions.     

二聚体配合物[(n-Bu)2Sn(C10H8N2O3)(C2H5OH)]2的合成和晶体结构

The novel seven-coordinate complex [(n-Bu)₂Sn(C₁₀H₈N₂O₃)(C₂H₅OH)]₂ (C₁₀H₈N₂O₃^2- is the dinegative ion of 2-oxo-propionic acid benzoyl hydrazone) was synthesized by the reaction of (n-Bu)₂SnO with 2-oxo-propionic acid benzoyl hydrazone in 1∶1 molar ratio in benzene-ethanol (V/V, 3/1), and its structure was characterized by X-ray single crystal diffraction. The crystal belongs to a tetragonal system with space group I4₁/a, a=2.4890(2)nm, b=2.4890(2)nm, c=1.5170(3)nm, V=9.398(2)nm³, Z=8, F(000)=3968, D_c=1.366g·cm^-3, and the structure was refined to final R₁=0.0530, wR₂=0.0971. The structure of the title complex is described as a dimer through weak interactions of Sn…O bonding and hydrogen bond. The tin atoms rendered sev-en-coordination in a distorted pentagonal bipyramid geometry structure, four oxygen atoms [O1, O2, O2^#1 and O4] and one nitrogen atom N2 formed the equatorial plane and C11-Sn1-C15 is the axis. CCDC: 212696.     

二聚体有机锡配合物{[n-Bu2Sn(O2CCH2CS2NC4H8)]2O}2的合成，表征及晶体结构(英)

The title compound, {[n-Bu₂Sn(O₂CCH₂CS₂NC₄H₈)]₂O}₂, has been synthesized by the reaction of (tetrahydro-pyrrodithiolocarbamoylthio)acetic acid with the di-n-bubyltin oxide in 1∶1 molar ratio. The complex has been characterized by elemental analysis, IR and NMR. The crystal structure of it has been determined by X-ray single crystal diffraction. And the results showed that the crystal belongs to triclinic system with space group P1 and some crystal parameters: a=1.220 2(9) nm, b=1.315 8(10) nm, c=1.380 4(10) nm, α=111.215(9)°， β=99.357(9)°， γ=96.075(10)°, V=2.006(2) nm³, Z=1, F(000)=908, μ=1.489 mm^-1, D_c=1.474 g·cm^-3, R₁=0.037 5, wR₂=0.0839. The complex has a centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn₂O₂ unit in which two bridged oxygen atoms both connect with an exo-cyclic tin atom which has a distorted octahedron. Each of the endo-cyclic tin atoms exhibits a distorted trigonal bipyramid coordination geometry with an additional weak coordination carboxylate oxygen. Four carboxylate ligands are divided into two types. And two of them are bidentate and connecting to each of exo-cyclic tin atoms by using both oxygen atoms, whereas the others bridge to each pair of exo-and endo-cyclic tin atoms utilizing one oxygen atom only. CCDC: 220513.     

配合物[Cu(HPHAc)2(py)2](H2PHAc=苯羟乙酸，py=吡啶)的合成和晶体结构

The novel copper(Ⅱ) complex with α-hydroxyphenylacetic acid (H₂PHAc) and pyridine (py) ligands, [Cu(HPHAc)₂(py)₂], has been synthesized and characterized by elemental analysis and IR spectroscopy. Its crystal structure was determined by single crystal X-ray diffraction techniques. The crystal belongs to monoclinic with space group C2/c. The cell parameters are: a=1.712 5(3) nm, b=1.533 2(2) nm, c=0.963 42(14) nm, β=111.866(2)°, V=2.347 6(6) nm³, and D_c=1.483 Mg·m^-3, Z=4, F(000)=1 084. The structure was refined to final R₁=0.071 4, wR₂=0.166 1. The complex has a six-coordinated distorted octahedral geometry, in which copper(Ⅱ) ion coordinates with two carboxylic oxygen atoms and two hydroxyl oxygen atoms from the two α-hydroxyphenylacetic acid ligands, two nitrogen atoms from the two pyridine ligands. The analysis of the crystal structure indicates that the complex has a one-dimensional chain structure, which is formed by intermolecular hydrogen bonds. CCDC: 255346.     

草酸根桥联的双核铜(Ⅱ)配合物[Cu2(phen)2(H2O)2(μ2-C2O4)](NO3)2的合成及晶体结构

A new binuclear copper(Ⅱ) complex, [Cu₂(phen)₂(H₂O)₂(μ₂-C₂O₄)](NO₃)₂, has been synthesized and characterized by elemental analysis, IR and UV-Vis spectrum. Its crystal structure was determined by single crystal X-ray diffraction techniques. Crystal data: monoclinic, space group P2₁/c, a=0.712 21(8) nm, b=1.170 93(14) nm, c=1.783 7(2) nm, β=111.828(2)°, and V=1.380 8(3) nm³, D_c=1.769 Mg·m^-3, Z=2, F(000)=744, R₁=0.025 4, wR₂=0.069 5, Gof=1.077, Δρ=328～-455 e·nm^-3. The complex is packed by one centrosymmetry binuclear copper(Ⅱ) unit, oxalate dianion and NO₃^- anion. In the molecule structure of the title complex, two Cu(Ⅱ) ions are bridged by oxalate dianion and each Cu(Ⅱ) ions coordinates with two nitrogen atoms from 1,10-phenanthroline ligand and one oxygen atom from water to form a five-coordinate distorted square-pyramidal configuration. The hydrogen bonds are observed between coordinated water molecules and NO₃^- anions. The analysis of the crystal structure indicates that the complex has a two-dimensional stacking network structure, which is formed by intramolecular hydrogen bonds, intermolecular hydrogen bonds and stacking effect of aromatic ring. CCDC: 255345.     

配合物[Cu2(m-MBA)4(2，2′-bipy)2(H2O)]·H2O的水热合成、晶体结构及电化学分析

A copper(Ⅱ) complex [Cu₂(m-MBA)₄(2，2′-bipy)₂(H₂O)]·H₂O with m-methylbenzoic acid (m-MBA), 2,2′-bipyridine (2,2′-bipy) and water molecule has been synthesized by means of hydrothermal way and characterized. Crystal data for this complex: monoclinic, space group C2/c, a=2.591 8(5) nm, b=1.414 2(3) nm, c=1.790 8(4) nm, β=131.80(3)°, V=4.893 3(17) nm³, D_c=1.379 g·cm^-3, Z=4, F(000)=2 104 , Final GooF=1.034, R₁=0.065 6, wR₂=0.197 6. The crystal structure shows that two neighboring copper(Ⅱ) ions are linked together by two bridging-chelating m-methylbenzoic acid groups, one bridging water molecule, forming a cage structure and the Cu(Ⅱ)-Cu(Ⅱ) bond distance is 0.366 7 nm. Each copper(Ⅱ) ion is coordinated with two nitrogen atoms of one 2,2′-bipyridine molecule and four oxygen atoms from three m-methylbenzoic acid molecules and one water molecule, repectiveley, forming a distorted octahedral coordination geometry. The cyclic voltammetric behavior of the Complex was also investigated. CCDC: 648619.