Powder X-ray crystallography of gallium 3-hydroxy-4-pyronates

1995 ◽  
Vol 10 (2) ◽  
pp. 140-142
Author(s):  
Lawrence R. Bernstein

Two complexes of gallium with 3-hydroxy-4-pyrones were synthesized as potential pharmaceutical compounds for oral administration. These compounds were analyzed by powder X-ray diffraction followed by computer indexing of the data. The first compound, tris(3-hydroxy-2-methyl-4-pyronato)gallium [Ga(C6H5O3)3], was found to be orthorhombic, a = 18.500(2), b = 16.948(2), c = 12.012(2) Å, V = 3766(1) Å3, Z = 8, Dm = 1.56(5), Dx = 1.570. The compound appears closely analogous to a similar compound containing Al instead of Ga, which crystallizes in space group Pbca. The second compound, tris(3-hydroxy-2-ethyl-4-pyronato)gallium [Ga(C7H7O3)3], was found to be monoclinic, a = 31.634(2), b = 8.7662(5), c = 7.8982(5) Å, β = 103.240(6)°, V = 2132.0(5) Å3, Z = 4, Dm = 1.50(5), Dx = 1.517, with a primitive space group.

1992 ◽  
Vol 70 (3) ◽  
pp. 792-801 ◽  
Author(s):  
Jagadese J. Vittal ◽  
Philip A. W. Dean ◽  
Nicholas C. Payne

The structures of three tetramethylammonium salts containing anions of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd) were determined by single crystal X-ray diffraction techniques. The Zn salt crystallizes in different space groups depending upon the solvent combination used in the synthesis. Thus crystals of (Me4N)2[Zn4(SePh)10], 1, grown from a mixture of methanol, acetonitrile, and acetone are triclinic, space group [Formula: see text] with cell dimensions a = 13.214(2), b = 23.859(2), c = 13.072(1) Å, α = 91.134(8), β = 113.350(8), γ = 79.865(9)°, and Z = 2. In the absence of acetone, a solvated crystal (Me4N)2[Zn4(SePh)10]•CH3CN, 2, is formed, which belongs to the monoclinic space group P21/n with a = 14.248(1), b = 39.722(2), c = 13.408(1) Å, β = 97.132(5)°, and Z = 4. The Cd salt (Me4N)2[Cd4(SePh)10], 3, crystallizes in the monoclinic space group P21/c, with a = 20.830(2), b = 14.282(1), c = 25.872(1) Å, β = 99.626(6)°, and Z = 4. These three salts are the first examples of homoleptic, tetranuclear selenolatometal(II) anions with (μ-Se)6M4 cages of adamantane-type stereochemistry. In each case the phenyl substituents of the bridging ligands adopt the configuration [aae, aae, aee, aee], which has the minimum number of two 1,3-axial–axial non-bonding substituent interactions. Keywords: selenolate complexes, synthesis, X-ray crystallography, isomerism, adamantane stereochemistry.


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.


1988 ◽  
Vol 41 (2) ◽  
pp. 195 ◽  
Author(s):  
D Dakternieks ◽  
BF Hoskins ◽  
CL Rolls

The isomer of Ph3Sn[Ph2PC(S) NPh] formed depends on the method of preparation. The crystal and molecular structure of the tin(IV) complex Ph3Sn[Ph2PC(S) NPh ] has been established by single-crystal X-ray diffraction techniques. The crystals are monolinic, space group P21/n, a 12.620(2), b 10.541(2), c 24.292(4)Ǻ, β 96.90(1) with Z 4; R and Rw were 0.031 and 0.034 respectively for 5632 unique reflections with I > 3σ(I). The crystals consist of discrete Ph3Sn[Ph2PC(S) NPh ] molecules. There is a tetrahedral environment about the tin atom formed by the three phenylic carbons and a sulfur atom of the [Ph2PC(S) NPh ]- ligand . Comparisons are made with the structurally similar compound Ph3Sn[(c-C6H11)2PC(S) NPh ]. On the basis of these comparisons and on earlier n.m.r . data, a favoured four-centered mechanism for insertion of dipolar PhNCS into the tin-phosphorus bond of Ph3SnPPh2 is inferred. Differences in reactivity of Ph2PC(S)N(H)Ph and (c-C6H11)2PC(S)N(H)Ph appear to result from electronic rather than steric effects.


2000 ◽  
Vol 78 (2) ◽  
pp. 280-290 ◽  
Author(s):  
Paul-Louis Fabre ◽  
Christophe Pena ◽  
Anne Marie Galibert ◽  
Brigitte Soula ◽  
Gérald Bernardinelli ◽  
...  

The compound (Ph4P)2(trans-cdcb)·2H2O (trans-cdcb2- = 2,4-bis(dicyanomethylene)-cyclobutane-1,3-dione dianion) has been synthesized and characterized by X-ray crystallography. Crystal data: triclinic, space group P1, a = 10.829(2) Å, b = 11.297(2) Å, c = 11.515(2) Å, α = 79.61(1)°, β = 68.54(1)°, γ = 63.49(1)°, V = 1172.9(4) Å3, Z = 1, R = 0.036, Rw = 0.047. With the dianion as a ligand, two complexes have been obtained and characterized by X-ray crystallography, UV-visible spectroscopy, and electrochemistry. The copper(II) complex [Cu(trans-cdcb)(H2O)4·2H2O]n consists of polymeric chains with copper atoms bonded to two of the nitrile groups of the ligand. Crystal data: monoclinic, space group P21/c, a = 9.6366(6) Å, b = 7.1292(3) Å, c = 10.7018(6) Å, β = 99.603(4)°, V = 724.92(7) Å3, Z = 2, R = 0.026, Rw = 0.041. The copper(I) complex[Cu2(trans-cdcb)(CH3CN)4·2CH3CN]n consists of polymeric chains with copper atoms bonded by all the four nitrile groups of the ligand. Crystal data: monoclinic, space group P21/n, a = 10.654(2) Å, b = 8.736(1) Å, c = 14.654(3) Å, β = 109.01(2)°, V = 1291.3(9) Å3, Z = 2, R = 0.037, Rw = 0.041. In CH3CN solution, the copper complexes are dissociated. Moreover, copper(II) is reduced into copper(I) by the dianion. Electrochemistry in the solid state (polymer coated electrode) showed the redox transitions of the different compounds.Key words: pseudo-oxocarbons, X-ray diffraction, copper(II) complex, copper(I) complex, electrochemical behaviour.


1994 ◽  
Vol 72 (5) ◽  
pp. 1218-1224 ◽  
Author(s):  
G. W. Buchanan ◽  
A. Rodrigue ◽  
K. Bourque ◽  
A. C. Chiverton ◽  
I. R. Castleden ◽  
...  

Solid phase 45.3 MHz 13C NMR spectra of ortho-dimethoxydiphenyl ether, 1, dibenzo[b,e]-15-crown-5- ether, 2, and tetrabenzo[b,e,q,t]-30-crown-10 ether, 3, have been obtained. Chemical shift trends are discussed in terms of the asymmetric units and structural features available from X-ray crystallographic data. Comparison with solution 13C spectra are made. The crystal structures of 1 and 3 were determined by X-ray diffraction at room temperature. 1 crystallizes in space group P21/a with a = 13.366(1), b = 8.230(1), c = 12.303(1) Å, β = 116.63(1)°, Z = 4. 3 crystallizes in space group P21/c with a = 7.903(1), b = 26.337(2), c = 7.852(1) Å, β = 97.28(1)°, Z = 2. The structures were solved by direct methods and refined by full-matrix least squares to residuals of 0.055 using 1727 reflections for 1 and of 0.042 using 2590 reflections for 3.


1996 ◽  
Vol 74 (11) ◽  
pp. 2349-2362 ◽  
Author(s):  
Peter Blenkiron ◽  
Arthur J. Carty ◽  
John F. Corrigan ◽  
Didier Pilette ◽  
Nicholas J. Taylor

The phosphino-diynes (PPh2C≡C-C≡CR) (R = But, Ph, SiMe3) are obtained in excellent yield from the corresponding diyne anions RC≡C-C≡C− by quenching with PPh2Cl. Monosubstitution on Ru3(CO)12 yields the trinuclear clusters Ru3(CO)11,(PPh2C≡C-C≡CR), which upon thermolysis afford the butadiynyl complexes Ru2(CO)6(μ-η1,η2α,β-C≡C-C≡CR)(μ-PPh2) (R = But, 7a; R = Ph, 7b;R = SiMe3, 7c) as the major products. The full characterization of the series of compounds (7a–c) Ru2(CO)6(μ-η1,η2α,β-C≡C-C≡CR)(μ-PPh2) is reported including an X-ray diffraction study of 7a. Crystals of 7a are monoclinic, a = 9.849(2), b = 9.886(2), c = 28.368(9) Å, β = 95.18(2)°, space group P21/n, and Z = 4; refinement converged to R = 0.0243 (Rw = 0.0253). The structure shows that the tetracarbon chain is bonded to the first metal atom by a simple M—C σ bond and to the second via a dative π interaction leaving an outer alkyne unit uncoordinated. In the reaction between 7a and cobalt carbonyl, a Co2(CO)6 moiety becomes attached to the -Cγ≡C8- bond in a tetrahedral arrangement to give the tetranuclear mixed-metal species Ru2(CO)6(μ-PPh2)(μ-η1,η2α,β;μ-η1,η2γ,δ-C≡C-C≡But)Co2(CO)68, as confirmed by X-ray crystallography: triclinic, a = 9.9969(9), b = 11.3018(9), c = 17.268(1) Å, α = 90.653(6)°, β = 100.911(6)°, γ = 110.465(5)°, space group [Formula: see text] and Z = 2; refinement converged to R = 0.0222 (Rw = 0.0264). Key words: diruthenium complexes, butadiynyl, synthesis, structure.


Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group


1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones

In a systematic search for supramolecular complexes involving all combinations of the cyclic polyethers 12-crown-4 (12C4), 15-crown-5 (15C 5), 18-crown-6 (18C 6) and dibenzo- 18-crown-6 (DB -18C6), and the geminal di- or trisulfones H2C(SO 2Me)2, H2C (SO2Et)2 and HC (SO2Me)3-n (SO2Et)n (n = 0 -3 ) , only the following four complexes could be isolated and unequivocally characterized by elemental analysis and 1H NMR spectroscopy: [(12C4){H2C (SO2Et)2}2] (3), [(18C6){H2C (S O2Me)2}] (4), [(DB -18C 6){H2C (SO2Et)2}] (5) and [(D B -18C 6)2{HC (SO2Me )(SO2Et)2}3] (6). The structure of 3 (triclinic, space group P1̄) consists of crystallographically centrosymmetric formula units, in which the disulfone molecules are bonded on each side of the ring by two C -H ··· O(crown) interactions originating from the central methylene group (H···O 213 pm) and from the methylene group of one EtSO2 moiety ( H ··· O 237 pm). Formula units related by translation are connected into parallel strands by a third type of reciprocal C -H ···O bond (H ···O 232 pm) between the second H atom of the central methylene group and a sulfonyl oxygen atom of the adjacent unit. The structure of 4 (monoclinic, space group C2/c) showed severe disorder of the crown ether and could not be refined satisfactorily. Compounds 5 and 6 crystallized as long and extremely thin fibres, indicative of linear-polymeric supramolecular structures; single crystals for X-ray crystallography were not available.


1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.


2020 ◽  
Vol 75 (8) ◽  
pp. 765-768
Author(s):  
Bohdana Belan ◽  
Dorota Kowalska ◽  
Mariya Dzevenko ◽  
Mykola Manyako ◽  
Roman Gladyshevskii

AbstractThe crystal structure of the phase Ce5AgxGe4−x (x = 0.1−1.08) has been determined using single-crystal X-ray diffraction data for Ce5Ag0.1Ge3.9. This phase is isotypic with Sm5Ge4: space group Pnma (No. 62), Pearson code oP36, Z = 4, a = 7.9632(2), b = 15.2693(5), c = 8.0803(2) Å; R1 = 0.0261, wR2 = 0.0460, 1428 F2 values and 48 variables. The two crystallographic positions 8d and 4c show Ge/Ag mixing, leading to a slight increase in the lattice parameters as compared to those of the pure binary compound Ce5Ge4.


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