scholarly journals New thallium(III) chloride complexes with pyridine carboxylic acids: from molecular compounds to supramolecular associations

2003 ◽  
Vol 1 (4) ◽  
pp. 441-464 ◽  
Author(s):  
Monica Toma ◽  
Agustín Sánchez ◽  
José Casas ◽  
José Sordo ◽  
María García-Tasende ◽  
...  

AbstractReactions of TlCl3 with picolinic acid (Hpic), nicotinic acid (Hnic), isonicotinic acid (Hinic) and 3-hydroxy-picolinic acid (H3hpic) afford the isolation of new chlorothallium(III) complexes. The compounds are characterized by IR, Raman and multinuclear NMR (1H,13C,205Tl). The molecular structures of [TlCl2(pic)(Hpic)]·0.5H2O (1), [TlCl2(nic)(Hnic)] (2), [TlCl(inic)2]·0.6C2H5OH (3) and [TlCl(3hpic)2(h3hpic)] (4) are determined by single-crystal X-ray diffraction. A distorted octahedral TlCl2N2O2 core containing the O,N-chelating ligands is achieved in the monomeric complex 1. The coordination polyhedron in compounds 2–4 is pentagonal bipyramidal, i.e. TlCl2NO4 in 2, and TlClN2O4 in 3 and 4, respectively. O,O′,N-Bridging ligands result in a polymer chain for 2 and a three-dimensional polymeric association in 3, while compound 4 is monomeric (O, N-and O,O-chelating ligands).


2015 ◽  
Vol 68 (6) ◽  
pp. 956 ◽  
Author(s):  
Ming-An Dang ◽  
Zi-Feng Li ◽  
Ying Liu ◽  
Gang Li

Three coordination polymers [Sr(p-H2MOPhIDC)2]n (1) (p-H3MOPhIDC = 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylic acid), {[Cd2(p-HMOPhIDC)2(4,4′-bipy)]⋅H2O}n (4,4′-bipy = 4,4′-bipyridine) (2), and [Zn(p-HMOPhIDC)(4,4′-bipy)]n (3) have been solvothermally synthesized, and structurally characterized by single-crystal X-ray diffraction. Polymer 1 indicates a three-dimensional framework, which can be simplified as a 6-connected lattice. Polymer 2 is also a three-dimensional framework, and contains mixed bridging ligands HMOPhIDC2– and 4,4′-bipy. Polymer 3 exhibits a sheet structure bearing infinite rectangles. The coordination modes of the p-H3MOPhIDC ligand, and the thermal and solid-state photoluminescence properties of the polymers have been investigated as well.



2001 ◽  
Vol 56 (11) ◽  
pp. 1188-1195 ◽  
Author(s):  
Jörg Dalluhn ◽  
Hans-Heinrich Pröhl ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones

The moisture-sensitive title compounds were obtained in good yields by treating the corresponding silver salts AgN(SO2R)2 with the thiocarbamoyl chloride Me2NC(S)Cl in acetonitrile. In the NMR solution spectra of the novel thioureas, as recorded at room temperature for 13C and up to 120 °C for 1H, the Me2N group invariably gives rise to two distinct resonances, reflecting unusually high barriers to rotation about the C(S)-NMe2 bond. The crystal structure of the ditosyl compound (triclinic, space group P1̅, X-ray diffraction at -130 °C) contains two independent molecules A and B, in which the bond lengths and angles are nearly identical, whereas the conformations exhibit pronounced discrepancies. The amide N and thiocarbonyl C atoms have trigonal-planar environments, but the S -N -S planes are strikingly rotated into approximately perpendicular orientations relative to the planar C2N-C(S)-N moieties. Other remarkable features of the molecular structures are the exceedingly long C(S)-NS2 bonds [mean: 145.4(3) pm] and the concomitantly short C -S and C(S)-NC2 bonds [mean values: 164.8(2), 132.6(3) pm]. The packing is governed by a three-dimensional system of weak hydrogen bonds and may be viewed as a self-clathrate, in which (B)2 dimers constructed from C-H···S=C interactions are inserted as guest species into parallel tunnels between (A)∞ tapes based upon short C-H···O=S contacts.



2004 ◽  
Vol 2 (3) ◽  
pp. 534-552 ◽  
Author(s):  
Monica Toma ◽  
Agustín Sánchez ◽  
María García-Tasende ◽  
José Casas ◽  
José Sordo ◽  
...  

AbstractSynthesis, spectral properties and crystal structure of dimethylthallium(III) complexes with 2-mercaptonicotinic acid (2mna), 2-mercapto-methyl-nicotinate (2mmn), 2-mercapto-ethyl-nicotinate (2men) and 2-mercapto-isopropyl-nicotinate (2min) are reported. The compounds were characterized using IR, multinuclear NMR (1H,13C,205Tl) and mass spectrometry (electrospray, ES-API). The molecular structures of [TlMe2(2mna)]·H2O, (1), [TlMe2(2mmn)], (2), [TlMe2(2men)], (3) and [TlMe2(2min)], (4) were determined by the single-crystal X-ray diffraction. In 1, the monodeprotonate O,S-bidentate ligand chelates one dimethylthallium (III) unit and simultaneously bridges (O and S) between two of these organometallic units. The Tl-O1′ and Tl-S″ interactions are leading to polymeric chain linked in a three-dimensional network by the hydrogen bonds formed between the water molecule and the oxygen O (2) atom of the acid. The thallium atom is in a distorted octahedral environment with a [TlC2O2S2] kernel. Compounds 2, 3 and 4 are similar, in all the cases already mentioned the ligand is NH deprotonated and is strongly coordinated to two dimethylthallium (III) units through the N and S atoms. Two additional weak interactions with the O and S atoms lead to a [TlC2NOS2] kernel for the metal atom, in which the coordination polyhedron is a very distorted octahedron with the methyl groups occupying the apical positions.



1984 ◽  
Vol 37 (10) ◽  
pp. 1991 ◽  
Author(s):  
SW Cowan ◽  
BF Hoskins ◽  
ERT Tiekink

The crystal and molecular structures of the title compounds, (C6H11)2PC(S)N(H)C6H5(1) and (C6H5)2PC(S)N(H)C6H5(2) have been determined by single-crystal three-dimensional X-ray diffraction techniques. Crystals of (1) are monoclinic, space group P21/c, with eight molecules in the unit cell of dimensions a 20.541(4), b 17.784(2), c 10.2564(9) � and β 94.54(1)�; (2) crystallizes in the triclinic space group P1 with two molecules in the unit cell which has the dimensions a 9.242(2), b 9.994(3), c 10.373(3) �, α 68.56(2), β 71.21(2) and γ 86.00(2)�. Both structures were refined by a least-squares procedure, applying anisotropic thermal parameters to all non-hydrogen atoms, with the use of 3119 and 2971 statistically significant reflections for (1) and (2) respectively; final R 0.055 for (1) and R 0.061 (Rw 0.062) for (2). The N, C(l), S moieties of both (1) and (2) display features consistent with the delocalization of π-electrons. There are notable differences in some of the bond angles between (I) and (2) which have been attributed to conformational effects arising from variations in steric pressures; this may account for the observed differences in reactivity between the two compounds.



1982 ◽  
Vol 35 (7) ◽  
pp. 1311 ◽  
Author(s):  
MA Bennett ◽  
K Ho ◽  
JC Jeffery ◽  
GM Mclaughlin ◽  
GB Robertson

Crystal and molecular structures of the title compounds have been determined from three dimensional X-ray diffraction data recorded on a four-circle diffractometer. Crystals of the acetyl complex, trans-PtCl(COMe)(PMePh2)2,(1), are monoclinic, space group P2,1/c, with a 12.9709(5), b 11.1024(5), c 277535(9) Ǻ, β 94.75(1)° and Z 6. Crystals of the trifluoroacetyl complex, trans-PtCl(COCF3)- (PMePh2)2, (2), are monoclinic, space group P21/n (non-standard setting of P21c), with a 11.4246(7), b 15.5750(7), c 15.4200(8) Ǻ, β 90.54(1)° and Z 4. For (I), with Z 6, the unit cell contains one set of four equivalent molecules in the general equipoint and one set of two equivalent (disordered) molecules located at inversion centres. The four molecules in (2) comprise a single equivalent set in the general equipoint. Least-squares analyses converge with R 0.042 for (1) (5696 unique data) and R 0.025 for (2) (3933 unique data). Molecules of both complexes exhibit small deformations from planar towards tetrahedral platinum geometry; the acyl and coordination planes are approximately orthogonal. The phosphine substituents in (2) and in the 'general' molecules in (1) are approximately eclipsed, and approximately eclipse the Pt-C (acetyl) bonds. In the 'special' molecules in (1) the phosphines are constrained to adopt the mutually staggered conformation found in the alkyl analogues trans-PtClR(PMePhM2)2 (R = Me, CF3, C2F2). Important comparative lengths in (1) (general molecule) and in (2) (in square brackets) are: Pt-C 2.028(6) [1.960(4)] A, Pt-Cl 2.430(2) [2.390(1)] Ǻ, Pt-P 2.301(2), 2.297(2) [2.316(1), 2.321(1)] A, C-O 1.182(8) [1.210(5)] 8, and C C (acetyl) 1.488(10) [1.547(6)] A. The trifluoroacetyl ligand forms a shorter and presumably stronger bond with platinum, and exerts a larger cis- and a smaller trans-influence than the acyl ligand. The smaller trans-influence of the trifluoroacetyl ligand is consistent with the expectation from platinum-chlorine stretching frequencies (v(Pt-Cl)).



1984 ◽  
Vol 37 (1) ◽  
pp. 197 ◽  
Author(s):  
D Dakternieks ◽  
BF Hoskins ◽  
ERT Tiekink

The crystal and molecular structures of bis (dicyclohexylphosphinodithioformato-S,P)M, M[S2CP-(C6Hl1)2]2 where M = Pt (1) and Pd (2), have been determined by single-crystal three-dimensional X-ray diffraction methods. The isomorphous crystals are monoclinic, of space group P21/c with four molecules per unit cell which has dimensions for (1) a 14.732(4), b 15.11 8(4), c 16.000(3) � and β 120.90(2)� and for (2) a 14.721(2), b 15.142(2), c 15.986(2) � and β 120.80(1)�. The structures were solved by normal Fourier methods and were refined with anisotropic thermal parameters. A full-matrix least-squares method was used, involving 3454 and 5052 statistically significant reflections for (1) and (2) respectively with final R and Rw values of 0.058 and 0.055 for (1) and 0.038 and 0.039 for (2). The complexes are isostructural. The ligand coordinates in a bidentate manner to the central atom through the phosphorus atom and one of the sulfur atoms with the metal atom in a cis-planar environment.



2013 ◽  
Vol 19 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Sasa Drmanic ◽  
Jasmina Nikolic ◽  
Aleksandar Marinkovic ◽  
Gavrilo Sekularac ◽  
Bratislav Jovanovic

The ultraviolet absorption spectra of the carboxyl group of three isomeric pyridine carboxylic acids N-oxides (picolinic acid N-oxide, nicotinic acid N-oxide and isonicotinic acid N-oxide) were determined in fourteen solvents in the wavelength range from 200 to 400 nm. The position of the absorption maxima (?max) of the examined acids showed that the ultraviolet absorption maximum wavelengths of picolinic acid N-oxide are the shortest, and those of isonicotinic acid N-oxide acid are the longest. In order to analyze the solvent effect on the obtained absorption spectra, the ultraviolet absorption frequencies of the electronic transitions in the carboxylic group of the examined acids were correlated using a total solvatochromic equation of the form max = v0 + s? + a?+ b?, where ?max is the absorption frequency (1/?max), p is a measure of the solvent polarity, ? represents the scale of solvent hydrogen bond acceptor basicities and ? represent the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The solvent effects on the ultraviolet absorption maximums of the examined acids were discussed.



2003 ◽  
Vol 81 (6) ◽  
pp. 468-475 ◽  
Author(s):  
Lijuan Li ◽  
Nada Reginato ◽  
Michael Urschey ◽  
Mark Stradiotto ◽  
John D Liarakos

Reactions involving Fe(NO)2(CO)2 and the bis(phosphine) ligands bis(diphenylphosphino)methane (DPPM), bis(diphenylphosphino)acetylene (DPPA), 1,6-bis(diphenylphosphino)hexane (DPPH), and 1,4-bis(diphenyl phosphino)benzene (DPPB) have been examined. From these reactions, the mononuclear complex, Fe(κ1-DPPM)(NO)2(CO) 3, linear dinuclear species of the type Fe2(µ-L)(NO)4(CO)2 (L = Ph2PCH2PPh2 4, Ph2PC[Formula: see text]CPPh2 5, Ph2PCH2(CH3)4CH2PPh2 6, and Ph2P(p-C6H4)PPh2 7), and macrocyclic dinuclear species of the type Fe2(µ-L)2(NO)4 (L = Ph2PCH2PPh2 8 and Ph2PC[Formula: see text]CPPh2 9) were isolated and spectroscopically characterized. For 4, 5, 8, and 9, the solid-state molecular structures of the products were determined by use of single-crystal X-ray diffraction techniques. Key words: dinitrosyliron, iron nitrosyls, dinuclear macrocycles, bis(phosphine) complexes.



2020 ◽  
pp. 174751982094836
Author(s):  
Hui Luo ◽  
Wen-Tong Chen

Two novel RE–Hg (RE = rare earth) complexes [RE(IA)3(H3O)2]2 n·2 n(HgCl4)· n(HgCl5)· nH2O·3 nH3O (RE = Y, 1; Lu, 2; IA = isonicotinic acid anion) were synthesized through hydrothermal reactions and are structurally characterized by single-crystal X-ray diffraction. The two complexes are isostructures and are characteristic of a one-dimensional chain-like structure. Both complexes are characterized by a three-dimensional supramolecular network. Photoluminescence experiments using solid-state samples show that they possess emission bands in the blue or red region. They have remarkable CIE chromaticity coordinates of (0.1172, 0.182) and (0.623, 0.3765), respectively. As a result, they are potential candidates for light-emitting materials for light-emitting diodes. They show wide optical band gaps of 3.29 eV and 2.89 eV, as revealed by the solid-state UV/Vis diffuse reflectance spectra.



Author(s):  
James A. Lake

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.



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