CRYSTAL STRUCTURES AND TRIBOLUMINESCENT ACTIVITIES OF SAMARIUM(III) COMPLEXES

Abstract

The triboluminescence spectra and crystal structures of 1,2-dimethylpyridinium tetrakis(2-thenoyltrifluoroacetonato)samarium(III) (1) and 1,2,6-trimethylpyridinium tetrakis(2-thenoyltrifluoroacetonato)samarium(III) (2) were determined. The triboluminescent maximums are similar to those of the photoluminescence. Complex 1 is centrosymmetric and the triboluminescent emission may correlate with the disorder of all S atoms, all CF₃ groups and the cation. The triboluminescent activity of complex 2 may correlate with its noncentrosymmetric space group. Complex 1 crystallizes in the monoclinic space group P2₁/a with cell parameters a = 19.874(2) Å, b = 22.922(2)Å, c = 21.188(1)Å, β = 108.126(6)°, V = 9173(1)ų; Z = 8; R = 0.0758 and R_w = 0.1315. Complex 2 crystallizes in the monoclinic space group Pn with cell parameters a = 11.2808(6)Å, b = 11.0199(5)Å c c = 18.4336(9)Å, β = 108.126(6)° V = 2285.28(19)ų; Z = 4; R = 0.0347 and R_w = 0.0900. All the structures were refined by full-matrix least squares methods.     

The crystal structure of a Terbium(III) complex with 1,1-Cyclobutanedicarboxylic acid

A complex of 1,1-cyclobutanedicarboxylic acid with terbium was obtained as a pentahydrate. The salt crystallizes in the monoclinic system, space group P2₁/n with a = 15.885(3), b = 8.489(2), c = 19.189(4)?Å, β = 106.02(3)° and Z = 4. The structure was solved by direct methods and refined to R = 0.0537. The complex forms polymeric chains in which terbium(III) ions are linked by carboxylate bridges. Each terbium cation is surrounded by carboxylate oxygen atoms and two or three water oxygen atoms, giving coordination number 9. The structure is stabilized by a system of hydrogen bonds.     

CRYSTAL STRUCTURE OF THE ISOMORPHOUS COMPLEXES TETRAAQUABIS(2,6-DIHYDROXY-BENZOATO-O)(2,6-DIHYDROXY-BENZOATO-O,O)TERBIUM(III) AND HOLMIUM(III) DIHYDRATE

Abstract

The structures of isomorphic Tb(III) and Ho(III) complexes with 2,6-dihydroxybenzoic acid of formula [Tb(C₇H₅O₄] 2H₂O and [Ho(C₇H₅O₄)₃ 4H₂O] 2H₂O has been determined by X-ray diffraction and refined to a residual R = 0.030 for 5376 observed reflections and R = 0.0284 for 5660 observed reflections, for Tb(III) and Ho(III) complexes, respectively. Crystals are triclinic, space group P1 with a= 10.748(2), b=11.309(2), c = 12.452(2)Å, α = 82.28(3), ? = 73.05(5), γ = 68.27(3)° for Tb(III) and a= 10.731(2), b=11.269(2), c = 12.436(2)Å, α = 82.25(3), β = 72.92(3), γ = 68.46(3)° for Ho(III).

In the structure of these monomelic complexes the metal ions are coordinated by oxygen atoms of one bidentate chelating and two monodentate carboxylate groups and four molecules of water. Tb-O distances are in the range 2.323(3)-2.506(3) Å and Ho-0 2.297(3)-2.486(3) Å. The crystal structure, consisting of discrete units of neutral complexes with two molecules of water of crystallization is stabilized by intra-and intermolecular hydrogen bonds.     

THE CRYSTAL AND MOLECULAR STRUCTURE OF PRASEODYMIUM(III) 2-FURANCARBOXYLATE DIHYDRATE

Abstract

Praseodymium(III) 2-furanocarboxylate dihydrate is monoclinic, space group P2₁/c. The lattice parameters area a = 10.349(2). b = 16.727(3), c = 9.458(1) Å, β = 92.61(1)°. The crystal structure was solved and refined by a full-matrix least-squares method to R = 0.034 and R_w = 0.039 from 2333 reflections. Carboxylic ions bond in the complex as bidentates and as bi- and terdentate-bridging ligands. The water molecules bond to the metal. The coordination number of the praseodymium atom is nine. The coordination polyhedron is intermediate between a distorted tricapped trigonal prism and a distorted monocapped square antiprism.     

CRYSTAL STRUCTURE AND THERMAL ANALYSIS OF A 4,4′-BIPY-BRIDGED BINUCLEAR ZINC(II) COMPLEX, 2[R2NCS2]2 · Zn(4,4′-BIPY) (R=PIPERIDYL)

Abstract

The crystal structure of the title complex 2[R₂NCS₂]₂ · Zn(4,4′-bipy) (R = Piperidyl), 1, revealed that it consists of dimers made up from two crystallographically independent molecules. Each zinc atom in 1 forms a 5-coordinate pseudo-square-based pyramidal arrangement (with four Zn-S and one Zn-N interactions). Bondlengths to Zn with the coordinating atoms are comparable to those in other Zn(II) dithiocarbamate complexes. The piperidine ring has a chair conformation. To allow improved packing, the title complex molecules form an approximately linear arrangement extending along both a and b. TGA showed that 1 is decomposed in two close steps to produce ZnS as identified by residual weight. The complex 1 crystallizes in the monoclinic space group C2/c with cell parameters: a = 22.021(5), b = 22.215(3), c = 17.537(2) Å, β = 93.49(2)°, V = 8563(3) ų and Z = 8. The structure was refined by full-matrix least-squares methods to R = 0.067, R_w = 0.114.     

STEREOCHEMISTRY OF (R)-2-METHYLAZIRIDINE COMPLEXES OF COBALT(III) AND DIMERIZATION OF THE LIGAND

Abstract

A cobalt(III) complex containing (R)-2-methylaziridine (R-meaz), [Co(R-meaz)(NH₃)₅]³⁺, was prepared and the two diastereomers arising from the presence of the chiral nitrogen atom (N(R) and N(S)) were separated by column chromatography. Molecular mechanics calculations estimated the N(R)-isomer to be more stable. This result was supported by the x-ray structure determination of the more abundant (ca. 94%) isomer, N(R)-[Co(R-meaz)(NH₃)₅]Br₃H₂O. Crystal data: monoclinic, P2₁, a = 7.357(1), b = 9.780(1), c = 10.426(1) Å, μ = 93.58(1)°, V= 748.7(3) ų, Z= 2. Kinetic studies of isomerization (epimerization) between the two isomers revealed that inversion at the nitrogen center was very slow (5 × 10^?2 M^?1 S^?1at 25 °C). The small rate constant seems to be related to the strained three-membered structure of the meaz ligand. The reaction of Na₃[Co(N0₂)6] and R-meaz yielded a complex containing two dimerized R-meaz chelates, trans-[Co(NO₂)2(di-R-meaz)₂] (di-R-meaz =RR)-α,2-dimethyl-l-aziridineethanamine). The crystal strucrure of trans-[Co(NO₂)₂ (di-R-meaz)₂]C1O₄H₂O was established by x-ray crystallography. Crystal data: orthorhombic, P2₁2₁2₁, a = 11.784(6), b = 21.023(9), c = 8.608(7) Å, V = 2133(2) ų, Z = 4.     

X‐Ray Crystal Structures and Quantum Chemical Calculations of Tetraphenyl‐arsonium Tetraazidoaurate(III) and Azido(triphenylphosphine)Gold(I)

The single crystal X‐ray structure determinations are reported for [Ph₄As][Au(N₃)₄] ( 1 ) and Ph₃PAuN₃ ( 2 ). Compound 1 is an ionic species with a “windmill” shaped anion. It crystallizes in the monoclinic space group C2/c, a = 18.396(2), b = 6.2492(4), c = 23.555(2) Å; β = 107.98(1)°, Z = 4, R1_{(all data)} = 0.0227, wR2 = 0.0374. The lattice parameters of compound 2 , which crystallizes in the orthorhombic space group P2₁2₁2₁, are a = 10.9252(1), b = 11.5642(1), c = 13.0993(1) Å; Z = 4, R1_{(all data)} = 0.0176, wR = 0.0334. The experimentally obtained X‐ray data and vibrational frequencies of both compounds were compared with those calculated at B3LYP/LANL2DZ and B3LYP/SDD level of theory and for 1 also at the MP2/SDD level.     

SYNTHESIS,CHARACTERIZATION AND CRYSTAL STRUCTURE OF A COMPLEX OF EUROPIUM PERCHLORATE WITH METHYLENE BIS(DIPHENYLPHOSPHINE OXIDE)

Abstract

A complex of europium perchlorate with methylene bis(diphenylphosphine oxide) (HMPPO), [Eu(HMPPO)₄](ClO₄)₃·2H₂O has been synthesized and characterized by X-ray crystallography, infrared spectroscopy and thermal analysis. The X-ray structure of the complex shows Eu(III) is coordinated by eight oxygen atoms from four HMPPO ligands, forming a distorted square antiprism coordination geometry. The complex crystallizes in space group P-1 with cell parameters a = 15.807(3), b = 17.868(4), c = 20.656(4) Å, α = 86.85(3)°, β = 82.33(3)°, γ = 66.75(3)°. The final R_l and R_w are 0.0803 and 0.1994, respectively, for 9540 observed reflections [I > 2[sgrave](I)]. Its luminescent properties have also been studied.     

Syntheses,Characterization and x-ray Structures of Gold(III) Complexes Obtained by Addition of Bases to Gold(III)(2-Pyridinecarboxaldehyde)

Reaction of potassium tetrachloroaurate(III), KAuCl₄, with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic HX (X=OH, OMe, OEt, OCH₂CH₂CH₂, OCH₂CH₂CH₂CH₃, OCH₂CF₃) solvents. Compounds in which the pyridine ligand is N or N-O coordinated in a newly carbonyl hydrated or in semi- and acetal-forms, derived by addition of one or two hydroxylic molecules, have been isolated; these include dichloro[pyridine-2(α-hydroxymethanolato)]gold(III) (1), dichloro[pyridine-2(α-ethoxymethanolato)] gold(III) (2), dichloro[pyridine-2[α-(2,2,2-trifluoroethoxymethanolato)]gold(III) (3), trichloro(2-pyridinecarboxaldehyde dimethyl acetal)gold(III) (4), trichloro(2-pyridinecarboxaldehyde diethyl acetal)gold(III) (5), trichloro(2-pyridinecarboxaldehyde di-1-propyl acetal)gold(III) (6) and trichloro(2-pyridinecarboxaldehyde di-1-butyl acetal)gold(III) (7). The crystal and molecular structures of (2), (5) and (7) have been determined by X-ray methods. Compound (2) crystallizes in space group Pna2₁ with Z=4, a=7.8914(4), b=17.3660(4) and c=8.3873(5)Å; (5) crystallizes in space group P&1macr; with Z=2, a=7.7779(3), b=8.2878(2) and c=13.3202(6)Å, α=96.975(2), β=95.096(2), γ=115.027(2)°; (7) crystallizes in space group P2₁/a with Z=4, a=14.5438(12), b=8.9865(7) and c=15.0362(11)Å.     

Synthesis and characterization of a mononuclear ruthenium(III) triazole complex

A mononuclear ruthenium(III) complex containing ethylenediaminetetraacetate (edta), [Ru(Hedta)(Htrz)] · 4H₂O (1) (Htrz = 1H-1,2,4-triazole), has been synthesized and the structure was determined by single-crystal X-ray diffraction. The complex crystallizes in the triclinic space group P 1, with the unit cell parameters a = 7.212(3) Å, b = 9.873(4) Å, c = 13.806(6) Å, α = 91.945(6)°, β = 100.078(6)°, γ = 97.230(7) and Z = 2. The complex was also characterized by elemental analysis, IR, UV–Vis and ESR spectra. Cyclic voltammetry for the complex shows a ruthenium(III)/ruthenium(IV) oxidation and a ruthenium(III)/ruthenium(II) reduction within the range of ?1.5–0.5 V. Magnetic susceptibility data give an effective moment of 1.81 B.M. at room temperature.     

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF TRIS(DIMETHYLDITHIOCARBAMATE) INDIUM(III), In[S2CN(CH3)2]3

Abstract

The synthesis and structure of the indium dithiocarbamate, In[S₂CN(CH₃)₂]₃·(1/2) 4-mepy (4-mepy=4-methylpyridine), is described. Indium metal was oxidized by tetramethylthiuram disulfide in 4-methylpyridine at 25°C to form a new, homoleptic indium(III) dithiocarbamate in yields exceeding 60%. In[S₂CN(CH₃)₂]₃ exists as a discrete molecule with a distorted-octahedral geometry. The compound crystallizes in the P 1 (No. 2) space group with a=9.282(1)Å, b=10.081(1)Å, c=12.502Å, α=73.91(1)°, β=70.21(1)°, γ=85.84(1)°, Z=2, V(Å)=1057.3(3), R=0.046 and R_w =0.061.     

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF BIS (2-AMINOMETHYLAZIRIDINE)NICKEL(II) PERCHLORATE

Abstract

The structure of the big (2-aminomethylaziridine = azida)nickel(II) complex was determined by X-ray diffraction methods. The compound, [Ni(azida)₂](C1O₄)2, crystallizes in the triclinic space group P1, Z=l, with a = 7.3545(4), b = 8.5235(5), c = 6.2156(4)Å, α= 101.871(6). β = 103.217(6), γ= 111.283(4)°, and V= 335.07(5) ų. The crystal shows discrete centrosymmetncal [Ni(azida)]²⁺ units in which azida acts as bidentate chelating ligand through N aziridine and N amino atoms. Thus, Ni has a four-coordinate square-planar geometry with four nitrogens of azida. The aziridine ring is almost perpendicular to the coordination plane. The dihedral angle between the aziridine plane and the coordination plane is 75.28°.     

Nickel(II) 1,10-Phenanthroline complexes: cis-[Aqua(Bromo) bis (1,10-Phenanthroline)Nickel(II)] Bromide Trihydrate and ( tris (1,10-Phenanthroline)Nickel(II)] Bromide Octahydrate

[Ni(phen)₂(H₂O)Br]Br·3H₂O where phen is 1,10-phenanthroline, is a light-blue material which crystallizes in the monoclinic space group P2₁/c with Z = 4, a = 10.4300(4), b = 25.310(2), c = 9.7790(9)?Å and β = 102.932(6)°. The structure was determined at ambient temperature from 5161 reflections with R = 0.0643 and R _w = 0.1306. The structure consists of a complex cation, a bromide anion and three waters of hydration. The Ni atom is pseudo-octahedral with a cis arrangement of Br and H₂O. This cis geometry persists in solution, as evidenced by ¹H NMR spectroscopy, although the Br may be replaced by another H₂O. [Ni(phen)₃]Br₂·8H₂O is a light-red material which crystallizes in the monoclinic space group C2/m with Z = 8, a = 23.6320(11), b = 21.4880(13), c = 15.5470(9)?Å and β = 107.927(3)°. The structure was determined at 120?K from 6820 reflections with R = 0.0733 and R _w = 0.1022. The structure consists of a complex cation, two bromide anions and eight waters of hydration. The anions and waters are extensively disordered. The Ni atom is pseudo-octahedral.     

Synthesis and characterization of a dinuclear (Hedta)Ru(III) complex

A ruthenium(III) complex containing ethylenediaminetetraacetate (edta), [{Ru(Hedta)}₂(Pyz)]?·?8H₂O (1) (Pyz?=?pyrazine), has been synthesized by the reaction between K[Ru(Hedta)Cl]?·?1.5H₂O and pyrazine. The structure of the complex was determined by single X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1 with a?=?7.293(9)?Å, b?=?10.575(14)?Å, c?=?12.742(16)?Å, α?=?104.044(19)°, β?=?91.893(19)°, γ?=?93.35(2)°, Z?=?1. The product was also characterized by IR, UV-Vis, EPR spectrum and magnetic techniques.     

Crystal Structures of (18-Crown-6)-(2-Hydroxyethylammonium) Tetracyanonickelate(Ii) and 10-Amino-Decylammonium Tetracyanonickeltate(II)

Abstract

The crystal structures of the two title tetracyanonickelate(II) salts of organic ammonium ions, (18-crown-6)-(2-hydroxyethylammonium) tetracyanonickelate(II), I, and 10-aminodecylammonium tetracyano nick-elate(II), II, have been analyzed. I crystallizes in the monoclinic space group P2₁/n with a = 10.458(2), b = 8.267(3), c = 24.045(2) Å, β = 94.09(1)°, V = 2074(1) ų, Z = 2, R = 0.061 for 2274 reflections; II is triclinic P ₁ with a = 9.437(3), b = 10.094(3), c = 9.205(3)Å,a = 110.16(2), β = 112.72(3), γ = 69.16(2)°, V = 733.7(5) ų 2=1, R = 0.040 including all the hydrogen atoms refined for 2724 reflections. The square planar tetracyanonickelate(II) anion is in a favourable position to form hydrogen bonds via N with the hydroxyl group in I and the ammonio group in II, respectively.     

SYNTHESIS AND CHARACTERIZATION OF A LINEAR μ-OXO DIIRON(III) COMPOUND AND A COPPER(II) NITRITE COMPLEX CONTAINING,A TRIPODAL POLYBENZIMIDAZOLE LIGAND

Abstract

Iron(III) and copper(II) complexes of the polybenzimidazole ligand, tris((benzimidazol-2-yl)methyl)amine (tmba) have been synthesized and structurally characterized. The mononuclear complex [Cu(tmba)(NO₂)]⁺[CH₃OH][NO^? ₂], 1, has been isolated and characterized by X-ray crystallography. The complex crystallizes in the triclinic space group P1 with two molecules in the unit cell of dimension a = 8.891(5), b = 11.775(6), and c = 13.702(8)Å, and α = 67.76(1), β = 71.79(2) and γ = 88.96(1)°, and volume = 1253.0(12)ų. The structure was refined to a final agreement factor R = 0.0901 using 4134 observed reflections. The complex consists of cationic copper(tmba) complex covalently bonded to a nitrite, and a pair of these cations is dibridged by a pair of nitrite anions. The gap between this dimer is occupied by a methanol molecule. The coordination environment around each copper can be described as trigonal bipyramidal, with the tertiary amine, a benzimidazole nitrogen and an oxygen from the nitrite providing the ligating atoms of the trigonal plane.

The μ-oxo bridged binuclear complex [Fe₂O(tmba)₂Cl₂](H₂O)(EtOH)₂·Cl₂, 2, was also characterized by single crystal X-ray diffraction and magnetic susceptibility. The complex crystallizes in the triclinic space group P1 with one molecule in the unit cell of dimensions, a = 11.5791(7), b = 13.3369(8), and c = 13.7002(9) Å, and α = 103.904(1), β = 108.903(2) and γ = 112.845(1)°, and volume = 1674.1(2) å³. The structure was refined to a final agreement factor R = 0.073 using 5597 observed reflections. The complex is a centrosymmetric dimer, with the two iron(III) atoms bridged by an oxygen atom, with an Fe—O—Fe angle of 180°, and a Fe—Fe distance of 3.61(1)Å. The coordination around each iron(III) is best described as octahedral, with the bridging oxygen trans to one end of the benzimidazole group, and a chlorine atom trans to the tertiary amine nitrogen of the ligand.     

Synthesis,Spectroscopic and X-ray Structural Study of cis-diazidobis- (ethylenediamine)Cobalt(III) Thiocyanate

Reaction of cis-diazidobis(ethylenediamine)cobalt(III)nitrate with ammonium thiocyanate in a 1?:?2 molar ratio in aqueous medium gave the title cobalt(III) compound, cis-[Co(en)₂(N₃)₂]SCN, as reddish brown crystals in almost quantitative yield. The complex salt was characterized by elemental analysis, IR, electronic, ¹H and ¹³C NMR spectroscopic studies. An X-ray structure determination revealed an ionic structure with the monoclinic space group P2₁/c, having cell dimensions a = 12.1950(6), b = 9.0317(5), c = 12.6017(7)?Å; β = 113.419(1)°, V = 1273.63(12)?ų and Z = 4. The structure was refined by a full-matrix least-square procedures to R ₁ = 0.0297 and wR ₂ = 0.0697.     

SYNTHESIS,CRYSTAL STRUCTURE AND MAGNETIC PROPERTIES OF A MANGANESE(III) COMPLEX WITH SALICYLATE AND IMIDAZOLE LIGANDS

Abstract

A new manganese(III) complex [HimH][Mn(sal)₂(imH)₂]CH₃OH (sal = salicylate, C₇H₄O₃ ^2-; imH = imidazole, C₃H₄N₂; [HimH]⁺ = imidazole cation (C₃H₅N₂) has been prepared and characterized by X-ray analysis and magnetic measurements. The compound crystallizes in the monoclinic space group P2 ₁ with a = 9.931(2), b = 10.237(1), c = 12.926(7) Å, β = 102.740° and Z = 2. The structure has been refined to R = 0.030 and R_w = 0.031. The Mn(III) ion has elongated octahedral coordination with mutually trans imidazoles occupying axial sites. The equatorial plane is defined by four O atoms of two salicylates. Each [HimH]⁺ cation (imidazolium) is associated with two complex anions through hydrogen bonds as an imidazolium bridge. The variable temperature magnetic susceptibility for the complex in the temperature range 77-300 K has been interpreted in terms of a single-ion zero-field splitting model with a molecular field term correction. The values obtained for D, g. and zj' are -6.93 cm^?1, 2.00 and -0.90 cm^?1.     

The synthesis and structural studies of mixed ligand complex,tris(1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one)mono(1-phenyl-3-methyl-pyrazol-5-one)neodymium(III) monohydrate

A mixed ligand neodymium complex containing 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one (HPMTFP) and 1-phenyl-3-methyl-pyrazol-5-one (PMP), with molecular formula Nd (PMTFP)₃·PMP·H₂O was synthesized. Its crystal and molecular structure has been determined by single crystal X-ray diffraction method. The complex crystallizes in monoclinic system with space group C⁵₂-P2₁/n. There are four formula units in a cell of dimensions a = 12.837(3), b = 23.763(5), c = 16.810(4) Å, β = 109.58(2)°. The structure has been refined by full-matrix least-squares techniques to a final R value of 0.0487 and R_w value of 0.432. The neodymium atom is coordinated to eight oxygen atoms with the average Nd—O bond length 2.439Å. Its thermostability, and mass spectrum have been discussed.     

STRUCTURE AND PROPERTIES OF N,N-DI-n-BUTYLDITHIOCARBAMATO-1, 2-DICYANOETHENE-1, 2-DITHIOLATO-GOLD(III)

Abstract

The crystal and molecular structure and some spectral data of the compound N,N-di-n-butyldithiocarbamato-1, 2-dicyanoethene-1, 2-dithiolato-gold(III), AuS₂CN(C₄H₉)₂S₂C₂(CN)₂, are reported. The crystal structure has been determined from a three-dimensional single-crystal X-ray diffraction study. The orthorombic cell, space group Pbca, with a=14.066(3), b=28.980(2) and c=9.192(2) Å, contains eight formula units. Intensity data were collected on an automatic diffractometer. The structural parameters were refined by full-matrix least-squares methods to a conventional R-factor of 0.047 for 1587 independent non-zero reflections. The structure determination proved the compound to be a mixed dithiocarbamato-dithiolato complex, Au(dtc)(mnt), (dtc=N,N-di-n-butyl-dithiocarbamate, mnt=maleonitriledithiolate ≡ 1, 2-dicyanoethene-1, 2-dithiolate), as expected from spectral data. The gold atom is in approximately square-planar coordination, however, deviations from mm2 (C_2#) symmetry are considerable. Au-S bond distances in the dtc-moiety (2.329(5) Å and 2.324(5) Å) are significantly longer than those in the mnt-moiety (2.303(5) Å and 2.284(5) Å). The molecules are packed pairwise around inversion centres with relatively short intermolecular S-S distances.