Syntheses, structure, and a Mössbauer and magnetic study of Ba(4)Fe(2)I(5)S(4)

The compound Ba4Fe2I5S4 has been prepared at 1223-1123 K by the "U-assisted" reaction of FeS, BaS, S, and U with BaI2 as a flux. A more rational synthesis was also found; however, the presence of U appears to be essential for the formation of single crystals suitable for X-ray diffraction studies. Ba4Fe2I5S4 crystallizes in a new structure type with two formula units in space group I4/m of the tetragonal system. The structure consists of a Ba-I network penetrated by (1)infinity[Fe2S4] chains. Each Fe atom, which is located on a site with 4 symmetry, is tetrahedrally coordinated to four S atoms. The FeS4 tetrahedra edge-share to form linear (1)infinity[Fe2S4] chains in the [001] direction. The Fe-Fe interatomic distance in these chains is 2.5630(4) A, only about 3% longer than the shortest Fe-Fe distance in -Fe metal. Charge balance dictates that the average formal oxidation state of Fe in these chains is +2.5. The M?ssbauer spectra obtained at 85 and 270 K comprise a single quadrupole doublet that has hyperfine parameters consistent with an average Fe oxidation state of +2.5. The M?ssbauer spectrum obtained at 4.2 K consists of a single magnetic sextet with a small hyperfine field of -15.5 T. This spectrum is also consistent with rapid electron delocalization and an average Fe oxidation state of +2.5. The molar magnetic susceptibility of Ba4Fe2I5S4, obtained between 3.4 and 300 K, qualitatively indicates the presence of weak pseudo-one-dimensional ferromagnetic exchange within a linear chain above 100 K and weak three-dimensional ordering between the chains at lower temperatures.     

Synthesis,characterization and reactivity of a neutral antimony(Ⅲ) complex

Pincer complexes are widely used in organometallic and coordination chemistry.The role of antimony as a central donor atom in pincer ligands has been extensively explored in recent years.Although phenylenediamine derived PXP(X=B,Al,C,Si,Ge,Sn,N) type ligands exhibit diverse reactivity,analogues species based on antimony have been reported less frequently.Herein,we report a new PSbP complex and evaluate its reactivity.These species will broaden the family of phenylenediamine derived pincer complexes.     

Synthesis,Structure and Photochromism of a New Diarylethene and Its Ag(Ⅰ) Complex

A new symmetric diarylethene containing cyano group was synthesized and structurally characterized by elemental analysis,IR,1 H NMR and X-ray single-crystal diffraction.It belongs to the monoclinic system,space group C2/c with a = 18.848(6),b = 8.561(2),c = 16.875(5) ?,β = 100.398(6)o,V = 1344.6(11) ?~3,Z = 4,μ = 0.262 mm~(-1),Dc = 1.415 g/cm~3,M_r = 570.56,F(000) = 1160,the final R = 0.0808 and wR = 0.2107 with I 2σ(I).The two thienyls adopt reactive anti-parallel conformation and the carbon distance of photocyclization is 3.57 ?.The neighboring molecules are stacked closely with C–H…F hydrogen bonding.In addition,the photochromism of the new compound was investigated in solvents with different polarity and PMMA film.The alternative photo-irradiation of 254 nm light and ≥550 visible light can induce the reversible photo-cyclization and photo-reversion with the color interconversion between colorlessness and blue.In THF solution,the λ_(max) of diarylethene in PSS in visible band is 585 nm.The diarylethene further reacted with AgBF_4 in benzene to give rise to complex 1,which was structurally characterized by elemental analysis,IR,ESI-MS and TG.1 demonstrated reversible photochromism in both solution and PMMA film.The complexation of metal ions with diarylethene leads to a minor red-shift of the λ_(max) of 1 in THF in PSS to 590 nm.     

Synthesis, Properties and Structureof a Novel Unsymmetrical Bis (phenoxo) BridgedBinuclear Copper (Ⅱ) Complex

IntroductionIn the past decade, several binuclear metal complexes have been synthesized to model theactive sites of some biologically imPOrtant metalloenzymes such as urease[lJ, haemocyanin[2"J,and bovine erythrocyte superoxide dismutase[4~9J. However, most of the model complexes aresymmetrical binuclear metal complexes in which the two metal centers have the same coordi-nation environments, the studies of unsymmetrical binuclear metal complexes aresparseL"--14J. The present paper covers th…     

Synthesis,Crystal Structure,and Photo-and Electro-luminescence of a TADF Cu(Ⅰ) Complex

A four-coordinate mononuclear cuprous complex [Cu(ac1m)POP]BF_4·0.5(C_6H_(14))· 0.5(C_2H_5OH)(1, ac1 m = 2-(2-ethoxyphenyl)-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, POP = bis[2-(dipenylphosphino)phenyl]ether) was synthesized and characterized by elemental analysis, NMR, UV-vis, cyclic voltammetry and X-ray single-crystal structure analysis. It crystallizes in monoclinic space group P2_1/c with a = 17.0546(19), b = 15.4650(17), c = 23.685(2) ?, β = 104.007(11)°, V = 6061.1(12) ?~3, Z = 4, M_r = 1171.46, D_c = 1.284 g/cm~3, F(000) = 2432, μ = 1.50 mm~(–1), GOOF = 1.070, the final R = 0.059 and wR = 0.1640 for 8952 observed reflections with I 2σ(Ⅰ). Compound 1 is composed of a BF4-anion and a [Cu(ac1m)POP]~+ cation. The Cu(Ⅰ) ion adopts a tetrahedral coordination geometry defined by two nitrogen and two phosphorous atoms. The complex exhibits yellow luminescence with maximum emission peaks at 546 nm, lifetimes 15.1 μs and quantum yields(ф = 0.130) at room temperature. The complex displays thermally activated delayed fluorescence(TADF) at room temperature, which is proved experimentally and theoretically. And the organic light-emitting diode(OLED) with 1 as the light emitting material has the maximum current efficiency of 5.86 cd/A and the highest brightness of 3215 cd/m~2.     

Like (CO)4, Do (CS)4 and (CSe)4 Have a Triplet Ground State?

Cyclobutane‐1,2,3,4‐tetraone, (CO)₄, was computationally predicted and, subsequently, experimentally confirmed to have a triplet ground state, in which a b_2g σ MO and an a_2u π MO were each singly occupied. In contrast, the (U)CCSD(T) calculations reported herein found that cyclobutane‐1,2,3,4‐tetrathione, (CS)₄, and cyclobutane‐1,2,3,4‐tetraselenone, (CSe)₄, both had singlet ground states, in which the b_2g σ MO was doubly occupied and the a_2u π MO was empty. Our calculations showed that both the longer C?X distances and smaller coefficients on the carbon atoms in the b_2g and a_2u MOs of (CS)₄ and (CSe)₄ contributed to the difference between the ground states of these two molecules and the ground state of (CO)₄. An experimental test of the prediction of a singlet ground state for (CS)₄ is proposed.     

Synthesis,Structure and Magnetic Property of a Binuclear Nickel(Ⅱ) Complex

A new binuclear complex [Ni2(2,2'-bpy)2(C8H3NO6)2(H2O)4] 1 (2,2'-bpy = 2,2'- bipyridine, C8H3NO6 = 4-nitrophthalate) has been synthesized by a hydrothermal reaction and characterized by X-ray single-crystal diffraction analysis. The complex crystallizes in triclinic, space group P1 with a = 7.206(2), b = 10.337(4), c = 12.480(4) , α = 89.887(11), β = 77.033(9), γ = 78.349(6)o, V = 886.3(5) 3, Z = 1, C36H30Ni2N6O16, Mr = 920.08, Dc = 1.724 g cm-3, F(000) = 472, μ = 1.152 mm-1, the final R = 0.0458 and wR = 0.1163 for 3372 observed reflections with I 2σ(Ⅰ). The two Ni(Ⅱ) ions are bridged by two 4-nitrophthalates both in a bis-monodentate mode. Magnetic measurements reveal that the intramolecular exchange couplings in the dimer are ferromagnetic with 2J/k = 2.32 K, D =-1.44 K and g = 2.18.     

Synthesis,Crystal Structure and Photoluminescence of a Three-coordinate Ag(Ⅰ) Complex

A three-coordinate Ag(I) complex, [Ag(Mepzpy)(PAr3)]BF4·H2O(1, Mepzpy = 3-methyl-1-(2-pyridyl)pyrazole, PAr3 = tri(o-tolyl)phosphine), was synthesized from the reaction of Ag(CH3CN)4BF4, PAr3 and Mepzpy in CH3 CN at room temperature. The compound was characterized by UV-vis, NMR and X-ray single-crystal structure analysis. It crystallizes in triclinic space group P1 with a = 10.2251(5), b = 10.6014(5), c = 15.7012(5) , α = 92.963(3), β = 92.641(3), γ = 114.647(4)o, V = 1540.6(1) 3, Z = 2, Mr = 676.24, Dc = 1.458 g/cm3, F(000) = 688, μ = 6.187 mm-1, GOOF = 1.038, the final R = 0.0530 and w R = 0.1493 for 6371 observed reflections with I 2σ(I). Compound 1 is ionic. It is composed of a BF4- anion and a [Ag(Mepzpy)(PAr3)]+ cation. The Ag(I) ion adopts a distorted trigonal pyramidal coordination geometry defined by two nitrogen atoms and a phosphorous atom. The complex emits blue luminescence with maximum peaks at 470 nm in solid state at room temperature.     

Synthesis, Crystal Structure and Characterization of a New Manganese(Ⅱ)Tetracarboxylate

By hydrothermal synthesis,a manganese(Ⅱ)tetracarboxylate [Mn(2,2'-bipyridi-ne)btec)o.5(H2O)]2n(H4btec=1,2,4,5-benzenetetracarboxylic acid)was obtained and characteri-zed by single-crystal X-ray diffraction,IR,elemental analysis and thermogravimetrie analysis.It crystallizes in triclinic,space group P(1),with a=7.721(4),b=8.905(5),c=10.712(6)(A),α=80.899(8),β=70.371(8),γ=78.201(8)°,z=2,V=675.8(7)(A)3,Mr=354.20,Dc=1.741 g/cm3,μ=1.007mm-1,F(000)=360,S=0.956,(△/σ)max=0.000,the final R=0.0490 and wR=0.1262.This compound presents an infinite 1D polymer featuring a double-chain structure.The Mn(Ⅱ)ion is five-coordinated.The four carboxylate groups of btec4- are all deprotonated and coordinated to four Mn atoms in a monodentate fashion,forming a 1D double chain structure with a cavity.Such chains are interconnected by π-π stacking interactions into 2D layers which are further interlinked into a supramolecular structure by hydrogen bonds.     

Facile Syntheses of (±)-Curcuphenol, (±)-Curcudiol, (±)-Curcuhydroquinone,and (±)-Curcuquinone

The syntheses of (±)-curcuphenol 1, (±)-curcudiol 2, (±)-curcuhydroquinone 3, and (±)-curcuquinone 4 have been achieved. The key steps involved in the syntheses were the Reformatsky reaction and hydrogenation reaction.     

Crystal Structure,Spectroscopic Characterization,and Electrochemical and Thermal Stability Properties of a Dinuclear Nickel(Ⅱ) Complex

A new nickel(Ⅱ) complex Ni_2(L)_2(2,2?-bipy)2·5.5H_2 O with methy-bicycle[2.2.1]hept-5-ene-2,3-dicarboxylic acid(H2L) and 2,2?-bipyridine(2,2?-bipy) as ligands has been synthesized in the mixed solvent DMF and water(v:v = 5:2). It crystallizes in the triclinic space group P1 with a = 10.414(2), b = 12.884(3), c = 16.176(4) ?, α = 70.715(5), β = 80.599(5), γ = 77.383(6)o, V = 1989.4(8) ?3, Dc = 1.531 g/cm3, Z = 2, F(000) = 958, GOOF = 1.028, the final R = 0.0808 and w R = 0.2036. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two nickel ions are bridged by two μ2-η1:η0 3-carboxylate groups of L2- anions. The coordination environment of Ni(Ⅱ) ion is Ni N_2O_3, giving a distorted square pyramidal geometry. The thermal stability and electrochemical properties of the complex were investigated.     

Synthesis and characterization of a 2, 5-Bis(trimethylsilyl)-substituted Bis(1, 1′-silolide) dianion

A novel silyl-substituted bis(1, 1′-silolide) dianion has been isolated and characterized by single-crystal X-ray analysis for the first time. The ¹H, ²⁹Si, and ¹³C NMR spectra show significant delocalization of the negative charges to the silole ring. X-ray crystallography revealed equalized C?C distances and DFT calculation also indicates for significant aromaticity. Reaction with trimethylchlorosilane gave the expected bis(1, 2, 5-tris(trimethylsilyl)-3, 4-diphenyl-silacyclopentadienyl).     

Syntheses and Crystal Structures of a Cadmium(Ⅱ) and a Zinc(Ⅱ) Complexes with the Flexible Ligand 1-Acetic Acid-2, 2'-biimidazole

Reactions of NaAcebiim(NaAcebiim = 1-acetic acid-2, 2′-biimidazole monosodium salt) and cadmium or zinc nitrate produce two supramolecular architectures, namely, 1D [Cd(Acebiim)(NO3)(H2O)]n(1) and 0D [Zn(Acebiim)2(H2O)2]·2H2O(2) in acidic aqueous solutions. Single-crystal X-ray diffraction analysis reveals that complex 1 crystallizes in the triclinic system, space group P1, and 2 is of monoclinic system, space group P21/n. In 1, two nitrate groups link two Cd(Ⅱ) ions forming [Cd2(NO3)2(H2O)2] as secondary building units that are interconnected by the Acebiim- ligand into an infinite ladder. In 2, the hydrogen-bonded synthon R22(16) between the N–H moieties and carboxylic acid link [Zn(Acebiim)2(H2O)2], generating a 1D-extended ribbon. Moreover, hydrogen bonds and π-π interactions further stabilize the 3D supramolecular architecture.     

Molecular and supramolecular properties of a Hg(II) complex with (E)-N,N′-bis(2-pyridyl)iminoisoindoline: synthesis,spectroscopy, X-ray structure and Hirshfeld surface analyses,and DFT calculations

A scarcity of metal complexes containing (E)-N,N′-bis(heteroaryl)iminoisoindolines has prompted us to investigate the coordinating ability and supramolecular behavior of (E)-N,N′-bis(2-pyridyl)iminoisoindoline (2-pyimiso), a versatile iminobis(pyridyl) ligand. The 1:1 reaction of HgCl₂ with 2-pyimiso in MeOH afforded a dinuclear complex, [{HgCl(2-pyimiso)}₂(μ-Cl)₂] (1). The complex has been characterized by elemental microanalysis, vibrational spectroscopy (FTIR and FT-Raman) and ¹H NMR spectroscopy. DFT calculations at the B3LYP-D3/LACV3P** level have been used in support of our vibrational analysis. Single-crystal X-ray diffraction data have shown that the coordination geometry of 1 is intermediate between the trigonal pyramidal and seesaw shapes insofar as each Hg(II) is four-coordinate and 2-pyimiso is a monodentate ligand. X-ray structure and Hirshfeld surface analyses have revealed that the supramolecular arrangement of 1 comprises perpendicular 1-D chains along the [011] direction assembled by nonclassical C–H?Cl–Hg and C–H?π hydrogen bonds. Moreover, adjacent sheets parallel to the bc-plane are interconnected by C–H?N_py, π–π_py stacking, and Hg?π_py interactions.     

Synthesis, Crystal Structure and Quantum Chemistry Calculation of a Bis(dafone) Di(dmf) Copper(Ⅱ) Complex

The title compound [Cu(dafone)2(DMF)2](2ClO4 1 (dafone = 4,5-diazafluoren- 9-one, dmf = N,N(A)-dimethyl formamide) was synthesized by the reaction of Cu(ClO4 )2 and dafone in DMF solution at room temperature with pH = 3.0.The single-crystal X-ray analysis has revealed that 1 crystallizes in monoclinic, space group P21/n with a = 8.4853(8), b = 13.1520 (14), c = 14.3866(12) (A), β = 102.629(3)o, V = 1566.7(3) (A)3, C28H26Cl2CuN6O12, Mr = 773.00, Z = 2, Dc = 1.639 g/cm3 , F(000) = 790, μ = 0.942 mm-1, the final R = 0.0438 and wR = 0.1214 for 3165 obser- ved reflections with I > 2σ(I).X-ray analysis shows that compound 1 has unsymmetric chelation of dafone with one Cu-N bond being much longer than the other.Coordination geometry of Cu is a highly distorted octahedron and the whole structure is stabilized by π-π stacking and static attractive forces from [ClO4]- anions.Based on the crystal data, quantum chemistry calculation at the DFT/ B3LPY level was used to reveal the electronic structure of 1.     

Synthesis,characterization, and DNA interaction of mononuclear copper(II) and zinc(II) complexes having a hard–soft NS donor ligand

Knoevenagel condensate-based Schiff base ligands (L) containing N and S donor sites have been designed and synthesized [L = 3-cinnamalideneacetylacetonethiosemicarbazone (CAT)/3-cinnamalideneacetylacetoneethylthiosemicarbazone (CAET)/3-cinnamalideneacetylacetonephenylthiosemicarbazone (CAPT)]. They afford complexes of the type [ML] [M = Cu(II) and Zn(II)]. Both the ligands and their complexes were characterized by analytical and spectral data. Intercalative binding of these complexes with DNA has been investigated by electronic absorption spectroscopy, viscosity measurements, cyclic voltammetry, and differential pulse voltammetry. Electrophoretic study of the complexes indicates that they efficiently cleave supercoiled pUC19 DNA in the presence of hydrogen peroxide.     

Hydrothermal Synthesis,Crystal Structure and Properties of a Lanthanum(Ⅲ) Complex Based on a N,O-Donor Ligand

A novel metal-organic complex [La(o-NCP)3]n(o-HNCP = 2-(2-carboxyphenyl)imidazo(4,5- f)(1,10)-phenanthroline) has been hydrothermally synthesized and characterized by elemental analysis, infrared analysis and X-ray single-crystal diffraction. The complex crystallizes in triclinic, space group P1 with a = 9.898(2), b = 16.193(3), c = 16.909(3) , α = 67.68(3), β = 80.85(3), γ = 78.78(3)o, V = 2448.2(8) A3, Z = 2, Mr = 1156.9, Dc = 1.569 g/cm3, μ = 0.71073 A, F(000) = 1164, GOOF = 1.065, the final R = 0.051 and wR = 0.123 for 8539 observed reflections with I 2A(I). The complex exhibits a one-dimensional double chain structure. The adjacent chains are further connected by N–H...N hydrogen bonds which help to form a two-dimensional supramolecular architecture. Furthermore, the complex exhibits excellent thermal stability and luminescent property.     

π-Extended and six-coordinate iron(II) complexes: structures, magnetic properties, and the electrochemical synthesis of a conducting iron(II) metallopolymer

Herein, we describe the preparation of three new bidentate π-extended derivatives of the ligand N-phenyl-2-pyridinalimine (ppi) containing a 3-thienyl (4) substituent at position 4 of the aniline ring or 2-thienyl (6) or phenyl (2) substituents at each of the 2,5 positions of the aniline rings. Three iron(2+) complexes (7-9) containing these ligands were prepared by combining two equivalents each of 2, 4, or 6 with Fe(NCS)(2), and the resulting neutral, six-coordinate complexes were fully characterized, including with single crystal X-ray diffraction experiments in the case of complexes 7 and 9. Variable temperature magnetic susceptibility and Mo?ssbauer experiments confirm the presence of spin-crossover in complexes 7 and 8, and the unusual solid state variable temperature magnetic properties of complex 9 likely result from crystal packing forces. Electropolymerization of the 2,5-dithienyl-substituted complex (9) produces a conducting and electrochromic metallopolymer film (poly-9).     

Total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine

A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo[1,2-a]azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12.