'Soft' Calixarenes–Structural Aspects of Calixarene Allyl Ethers and of Thiacalixarene Synthesis

1998 ◽  
Vol 51 (2) ◽  
pp. 111 ◽  
Author(s):  
Xavier Delaigue ◽  
Jack M. Harrowfield ◽  
M. Wais Hosseini ◽  
Mauro Mocerino ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Room Temperature ◽  
Asymmetric Unit ◽  
X Ray ◽  
Allyl Ethers ◽  
Alternate Form ◽  
Phenolic Oxygen ◽  
Complexation Studies ◽  
Structure Determinations ◽  
Centrosymmetric Dimers ◽  
Structural Aspects

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for an array of p-t-butylcalix[n]arenes, n = 4 or 6, diversely functionalized at the phenolic oxygen atoms: the 1,3-diallyl 2,4-dimethyl ether for n = 4 (1), the hexaallyl ether for n = 6 (2), and the 1,3-dibenzyl 2,4-bis(dimethylthiocarbamoyl) derivative for n = 4 (3), with a view to establishing ligand baseline conformations for subsequent metal complexation studies, and for exploring any inclusion properties. Compound (1) is monoclinic, P21/c, a 16·751(9), b 20·772(7), c 27·91(1) Å, β 99·39(4)°, Z = 8, conventional R on |F| being 0·060 for No 4396 'observed' (I > 3σ(I )) reflections. Compound (2) is triclinic, P-1, a 19·63(2), b 14·57(2), c 14·188(9) Å, α 107·84(8), β 93·26(7), γ 99·48(10)°, Z = 2, R 0·067 for No 7315. Compound (3), as its methanol monosolvate, is triclinic, P-1, a 15·592(4), b 15·17(3), c 14·31(2) Å, α 88·8(1), β 64·3(1), γ 75·7(1)°, Z = 2, R 0·076 for No 3802. The conformation of (1) is similar to that previously established for an analogue in which two of the t-butyl groups were absent; the conformation of (2) is that of a flattened 1,2,3-alternate form, the asymmetric unit being a pair of half (centrosymmetric) dimers; the conformation of (3) is 1,3-alternate.

Lewis-Base Adducts of Lead(II) Compounds. XVI. Synthetic and Structural Studies of Some Adducts of 2-Aminomethylpyridine With Lead(II) Compounds

1996 ◽  
Vol 49 (10) ◽  
pp. 1127 ◽  
Author(s):  
JM Harrowfield ◽  
H Miyamae ◽  
BW Skelton ◽  
AA Soudi ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Lewis Base ◽  
Structural Studies ◽  
Problem Structure ◽  
Coordination Environment ◽  
X Ray ◽  
The Third ◽  
Structure Determinations ◽  
Centrosymmetric Dimers

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 2:1 adducts of 2-aminomethylpyridine ('amp') with lead(II) nitrate and thiocyanate . [(amp)2Pb(NO3)2]2 is triclinic, Pī, a 11.616(4), b 11.145(6), c 7.341(3) Ǻ, α 83.87(4), β 89.17(3), γ 64.12(3)°, Z = 1 dimer ; R was 0.043 for No 3529 independent 'observed' (I > 3σ(I)) reflections. [(amp)2Pb(SCN)2]2 is also triclinic, Pī , a 12.121(9), b 9.301(14), c 8.615(8) Ǻ, α 70.11(10), β 84.00(7), γ 79.38(10)°, Z = 1 dimer (R 0.033 for No 3467). Both complexes are centrosymmetric dimers ; the coordination environment is made up in each case of a pair of N,N°-bidentate bases, one terminally bound anion (O,O°-chelating nitrate or S-bonded thiocyanate ) and bridging anions. In the case of the thiocyanates, these bridge end-on, so that the lead(II) environment is seven-coordinate PbN5S2; in the nitrate, the anion chelates through two of its oxygen atoms, bridging via the third, so that the lead(II) environment is nine-coordinate PbN4O5. A 'problem structure', [(amp)2Pb(ClO4)2], monoclinic, C2/c (?), a 14.528(3), b 8.203(3), c 15.495(6) Ǻ, β 91.14(3)°, Z = 4 f.u ., R 0.044 for No 1775, is also recorded, the crystal seemingly a disordered aggregate of [(N, N′-amp)2Pb(OClO3)2] moieties.

Crystal Structure of Two Different Hydrate Phases of Bis[2,4,6-tri(2-pyridyl)-1,3,5-triazine]cobalt(II) Diiodide

1990 ◽  
Vol 43 (7) ◽  
pp. 1269 ◽  
Author(s):  
BN Figgis ◽  
ES Kucharski ◽  
S Mitra ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Ground State ◽  
Room Temperature ◽  
Spin Component ◽  
Asymmetric Unit ◽  
Tridentate Ligands ◽  
X Ray ◽  
Structure Determinations ◽  
Electronic Ground

The title compound crystallizes at room temperature from aqueous solution as two distinct hydrated phases, both monoclinic and characterized by single-crystal X-ray structure determinations. The dihydrate ('blocks') is C2/c, a 42.58(2), b 9.099(8), c 21.14(1)Ǻ, β 112.12(4)°, Z= 8; R was 0.048 for 3784 'observed' reflections. The c. 3.75 hydrate ('Tetrahydrate'?) ('needles') is P21/c, a 9.348(2), b 36.663(8), c 23.071(8)Ǻ, β 93.51(2)°, Z 8; R was 0.050 for 6042 'observed' reflections. There are one and two independent cations in the asymmetric unit of each structure; all cations have the metal atom 'mer' coordinated by a pair of tridentate ligands. In the C2/c phase, Co-N (central) are 2.057(4) and 2.063(4)Ǻ with N-Co-N 175.8(2)°; Co-N (distal) are 2.163(6)-2.187(6)Ǻ. In the P21/c phase, in the first cation, Co-N are 2.045(8) and 2.050(7)Ǻ (central) [with N-Co-N, 167.0(3)°] and 2.193(8)-2.216(8)Ǻ (distal), while, in the second, Co-N (central) are 2.030(8) and 2.042(8)Ǻ with N-Co-N, 168.3(3)°; Co-N (distal) are 2.164(8)-2.227(8)Ǻ. These Co-N distances are longer than those observed in the [Co( tpy )2]2+ cations hitherto studied ( tpy = 2,2′:6′,2′-terpyridine), in which the electronic ground state has an appreciable low-spin component.

A 35-year-old mystery solved: a facile synthetic route and structural confirmation of tetrachlorobis(diethyl ether)tungsten(IV)

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Thomas E. Shaw ◽  
Alfred P. Sattelberger ◽  
Titel Jurca
Keyword(s):  
Crystal Structure ◽  
Diethyl Ether ◽  
Thermal Instability ◽  
Room Temperature ◽  
Surface Characteristics ◽  
Hirshfeld Surface ◽  
Asymmetric Unit ◽  
Synthetic Route ◽  
X Ray ◽  
Elemental Analyses

The true identity of the diethyl ether adduct of tungsten(IV) chloride, WCl4(Et2O) x , has been in doubt since 1985. Initially postulated as the bis-adduct, WCl4(Et2O)2, questions arose when elemental analyses were more in line with a mono-ether adduct, viz. WCl4(Et2O). It was proposed that this was due to the thermal instability of the bis-adduct. Here, we report the room-temperature X-ray crystal structure and Hirshfeld surface characteristics of trans-tetrachloridobis(diethyl ether)tungsten(IV), trans-WCl4(Et2O)2 or trans-[WCl4(C4H10O)2]. The compound crystallizes, with half of the molecule in the asymmetric unit, in the centrosymmetric space group P21/n. The W—O distance is 2.070 (2) Å, while the W—Cl distances are 2.3586 (10) and 2.3554 (10) Å.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

Structural Systematics of 2/4-Nitrophenoxide Complexes of Closed-Shell Metal Ions. VII Acid Salts of the 4-Nitrophenoxides of Group 2

1998 ◽  
Vol 51 (8) ◽  
pp. 785 ◽  
Author(s):  
Jack M. Harrowfield ◽  
Raj Pal Sharma ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Calcium Salt ◽  
Three Dimensional ◽  
Closed Shell ◽  
The Other ◽  
X Ray ◽  
C 23 ◽  
Structure Determinations ◽  
Group 2 ◽  
Acid Salts

Room-temperature single-crystal X-ray structure determinations are recorded for a number of Group 2 4-nitrophenoxide acid salts, variously hydrated M(4-np)2.x(4-npH).yH2O. Ca(4-np)2.2(4-npH).8H2O is monoclinic, P 21/n, a 30·52(1), b 10·027(1), c 23·65(2) Å, β 116·3(5)°, Z = 8, conventional R on |F| being 0·058 for No 5092 independent ‘observed’ (I > 3s(I)) reflections. Sr(4-np)2.2(4-npH).8H2O, based on a subcell of the former, is monoclinic, P 21/c, a 15·576(5), b10·081(6), c 24·20(2) Å, β 117·99(5)° , Z = 4, R 0·054 for No 2908. Ba(4-np)2.2(4-npH).4H2O is orthorhombic, Fdd2, a 28·01(1), b 19·90(1), c 10·692(7)Å, Z = 8, R 0·028 for No 1967. The strontium array (and that of the calcium salt developed from it) may be represented as [(H2O)6Sr(4-npH.4-np)] (4-npH.4-np), a neutral ligand being unsymmetrically chelated to the strontium through the nitro group, with a quasi-parallel counter ion hydrogen-bonded to it by phenoxide confrontation. The other two 4-np residues make up a similar phenoxide-confronting pair (4-npH.4-np), the hydrogen being more intimately associated with one moiety. The barium salt is also an interesting array: the 10-coordinate barium lies on a crystallographic 2 axis, in an environment of two pairs of symmetry-related nitro-chelating ligand anions, and a pair of nitro-O coordinating neutral 4-npH ligands; the whole [(H2O)4Ba(4-np)2(4-npH)2] array may be envisaged as a single neutral (super)molecule. Hydrogen bonds between confronting phenoxides of the neutral 4-npH components of the parent and the 4-np- components of neighbouring molecules link the whole into a three-dimensional array.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXIV Syntheses, Spectroscopy and Structures of Some 1 : 4 Adducts of Copper(I) and Silver(I) Perchlorates with Triphenylarsine and Triphenylstibine

1997 ◽  
Vol 50 (6) ◽  
pp. 539 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
Robert D. Hart ◽  
John D. Kildea ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
X Ray ◽  
Cation Disorder ◽  
Structure Determinations ◽  
Consistent Picture ◽  
Far Infrared Spectra

Syntheses and room-temperature single crystal X-ray structure determinations are recorded for adducts [M(EPh3)4] (ClO4), M = Cu, E = As (1), Sb (2); M = Ag, E = As (3), Sb (4), enabling comparison with analogous, previously studied MP4 and MN4 environments. The four complexes so characterized all crystallize in the familiar rhombohedral R-3 array (a ≈ 14·4, c ≈ 52 Å, hexagonal setting) with the metal and chlorine atoms located on crystallographic threefold axes. In these arrays Cu–E (axial, off axis) are 2·493(2), 2·533(1) for (1), and 2·572(1), 2·577(1) Å for (2), the disparity in the two independent M-E distances being diminished relative to those of previously studied phosphorus analogues, perhaps in consequence of increasing E size. In (3) and (4), some cation disorder is evident in respect of the ligand pnictide atom (E); for the major components Ag-E are 2·652(3), 2·680(2) in (3); 2·732(2), 2·7295(8) Å in (4). Problems associated in defining the metal atom environment geometries in the latter are, nevertheless, more satisfactorily overcome in two further determinations of nitrate salts: [Ag(SbPh3)4] (NO3) (5) is of the rhombohedral family with no cation core disorder, Ag–E (axial, off axis) being 2·720(4), 2·725(2) Å, while the structural characterization of a 1 : 4 triphenylarsine adduct of silver nitrate is recorded as its tetraethanol solvate, namely [Ag(AsPh3)4] (NO3).~ 4C2H5OH(6), monoclinic, C2/c, a 18·373(4), b 20·786(5), c 21·070(8) Å, β 108·18(3)°, Z = 4 f.u. The silver atom of the [Ag(AsPh3)4]+cation unusually lies on a crystallographic 2 (rather than a 3 ) axis of the incipiently23 (T) array, with Ag-As 2·649(2), 2·650(2) Å and As-Ag-As ranging from 108·22(4) to 111·41(6)°. The structure determination of a chloroform solvate of (2), denoted (2a), of low precision, is noted, together with the structure of an interesting artefact, isomorphous with the rhombohedral oxoanion array, modelled as [Ag(PPh3)4]2 (SiF6).py (7). Bands in the far-infrared spectra of [M(AsPh3)4] (ClO4) are assigned to v(MAs) vibrations at 119 (M = Cu) and 103 cm¯1 (M = Ag); this produces a more consistent picture of the variation in the wavenumbers of the v(ME) modes in [M(EPh3)4]+ compounds than was available previously.

scholarly journals Powder X-ray diffraction of trimethoprim Form I, C14H18N4O3

2020 ◽  
Vol 35 (1) ◽  
pp. 69-70
Author(s):  
Jerry Hong ◽  
Joseph T. Golab ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
The United States ◽  
Unit Cell ◽  
Cell Length ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Determinations ◽  
Unit Cell Length

Trimethoprim crystallizes in the triclinic space group P-1 (#2) with a = 10.5085(3), b = 10.5417(2), c = 8.05869(13) Å, α = 101.23371(21), β = 112.1787(3), γ = 112.6321(4)°, V = 743.729 Å3, and Z = 2. A reduced cell search in the Cambridge Structural Database yielded three previous structure determinations, using data collected at 100 K, 173 K, and room temperature. In this work, the sample was ordered from the United States Pharmacopeial Convention (USP) and analyzed as-received. The room temperature (295 K) crystal structure was refined using synchrotron (λ = 0.412826 Å) powder diffraction data and optimized using density functional theory techniques. We found similar hydrogen bonding patterns with the previous determinations. In addition, we identified two C–H⋯O hydrogen bonds, which also contribute to the crystal energy. When comparing the previously reported trimethoprim structure determinations, the unit cell length lattice parameters were found to contract at lower temperatures, particularly 100 K. All structures show reasonable agreement, with unit cell length differences ranging between 0.05 and 0.15 Å. The diffraction data for this study were collected on beamline 11-BM at the Advanced Photon Source, and the powder X-ray diffraction pattern of the compound has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Synthesis and Structure of the Binuclear 1 : 1 Silver(I) 2-Hydroxy-3,5-dinitrobenzoate/Triphenylphosphine Complex

2003 ◽  
Vol 56 (7) ◽  
pp. 718
Author(s):  
A. Hamid bin Othman ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Structure Determination ◽  
Room Temperature ◽  
The Other ◽  
Triphenyl Phosphine ◽  
X Ray ◽  
Carboxylate Oxygen ◽  
Phenolic Oxygen ◽  
Triphenylphosphine Complex ◽  
Silver Atoms

A room-temperature single-crystal X-ray structure determination of the 1 : 1 adduct of silver(I) 2-hydroxy-3,5-dinitrobenzoate/triphenyl-phosphine (AgL/PPh3) was recorded, showing it to be a binuclear centrosymmetric system with the silver atoms bridged by one of the carboxy oxygen atoms of each ligand, [(PPh3)Ag(μ-O)2Ag(PPh3)] as in the parent acetate; the phenolic oxygen, retaining its protonation, is hydrogen bonded within the ligand to the other feebly chelating carboxylate oxygen.

Lewis-Base Adducts of Lead(II) Compounds. XVII. Synthetic and Structural Studies of Some 1:1 Adducts of 2,2':6,2'-Terpyridine With Lead(II) Salts

1996 ◽  
Vol 49 (10) ◽  
pp. 1135 ◽  
Author(s):  
LM Engelhardt ◽  
JM Harrowfield ◽  
H Miyamae ◽  
JM Patrick ◽  
BW Skelton ◽  
...  
Keyword(s):  
Water Molecule ◽  
Single Crystal ◽  
Room Temperature ◽  
Lewis Base ◽  
Polymeric Chain ◽  
Lead Atom ◽  
X Ray ◽  
Structure Determinations ◽  
Pass Through ◽  
Nitrate And Nitrite

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1:1 adducts of 2,2':6',2"-terpyridine (' tpy ') with the lead(II) oxoanion salts perchlorate, nitrate and nitrite, ( tpy ) Pb ( oxoanion )2. All structures are monoclinic, C2/c, Z = 4, with approximate ranges a from 9 to 11 Ǻ, b from 16 to 20 Ǻ, c from 9.8 to 13.8 Ǻ, β from 113 to 130° and V from 1650 to 1850 Ǻ3. In all cases the lead(II) atoms are disposed on crystallographic 2 axes which also pass through the axis of the central tpy ring; a pair of symmetry related oxoanions link successive lead atoms in a one-dimensional polymeric chain parallel to the ac cell diagonal, one pair of oxygen atoms functioning as an O,O'-bidentate with another oxygen (replaced by the nitrogen in the nitrite) bridging to the adjacent lead atom; the third anionic oxygen atom in the nitrate is replaced by a water molecule in the nitrite, which thus becomes a monohydrate. Residuals were 0.030, 0.034 and 0.040 for 2122, 1564 and 2059 independent 'observed' (I > 3σ(I)) reflections respectively. Also recorded are the syntheses and room-temperature single-crystal X-ray structure determinations for 1:1 aducts of 2,2':6',2"-terpyridine with lead(II) chloride, bromide and iodide, the chloride and bromide being hydrated. ( tpy )PbCl2.H2O is monoclinic, P 21/c, a 8.938(1), b 15,210(7), c 13.414(3) Ǻ, β 115.17(1)°, Z = 4 f.u .; R was 0.036 for No = 3346 independent, 'observed' reflections. The complex is centrosymmetric, binuclear [( tpy ) (H2O)( Cl ) Pb (μ- Cl )2Pb( Cl )(OH2)( tpy )], with the two lead atoms linked by bridging chlorine atoms; the lead atoms are seven-coordinate N3,O,ClPb(μ- Cl )2. The bromide ( tpy )PbBr2.2/3H2O, triclinic, Pī, a 12.360(6), b 12.452(4), c 18.372(6) Ǻ, α 108.31(3), β 109.44(3), γ 90.56(3)°, Z = 6 f.u ., R being 0.046 for No 7282, is in fact trinuclear [Pb3Br6( tpy )6].2H2O, a novel and elegant oligomer with quasi-2 symmetry in which a central lead atom (on the quasi-2 axis) is seven-coordinated [( tpy ) Pb (μ-Br)4] with the associated bromides bridging to a pair of peripheral lead atoms, also seven coordinated, [( tpy )(Br) Pb (μ-Br)3]. Unsolvated ( tpy )PbI2, triclinic, Pī , a 10.834(3), b 9.023(3), c 8.906(2) Ǻ, α 80.34(2), β 89.40(2), γ 79.78(2)°, Z = 2 f.u ., R 0.031 for No 2347 is, like the chloride, centrosymmetric binuclear, [( tpy )(I) Pb (μ-I)2Pb(I)( tpy )], but with the lead(II) now six-coordinate N3(I) Pb (μ-I)2. In both chloride and iodide, the tpy plane is approximately normal to the Pb ... Pb line with the water molecule of the chloride approximately trans to the central tpy nitrogen; in the iodide that site is occupied by the terminal halide.

Structural Systematics of Rare Earth Complexes. XXII. ('Maximally') Hydrated Rare Earth Iodides

2000 ◽  
Vol 53 (10) ◽  
pp. 867 ◽  
Author(s):  
Kevin C. Lim ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Low Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Second Phase ◽  
X Ray ◽  
Structure Determinations ◽  
Trivalent Rare Earth ◽  
Trigonal Prismatic

Low-temperature (c. 153 K) single-crystal X-ray structure determinations, carried out on trivalent rare earth iodides crystallized from aqueous solution at room temperature, have defined two series of hydrates, LnI3.nH2O. For Ln = La–Ho, a nonahydrate phase (n = 9) is defined, orthorhombic Pmmn, a ~ 11.5, b ~ 8.0, c ~ 8.8 Å, Z = 2, the second phase (n = 10), monoclinic P21/c, Z = 4 being defined for Ln = Er–Lu, a ~ 8.2, b ~ 12.8, c ~ 17.1 Å, β ~ 103.7˚. Neither of these phases is isomorphous with any of those pertinent to the previously studied chloride or bromide (hydrated) arrays, nor, unlike those, does the halide (iodide) in any case enter the coordination sphere of the lanthanoid. The n = 9 phase takes the form [Ln(OH2)9]I3, the nine-coordinate lanthanoid environment stereochemistry being tricapped trigonal-prismatic, while the n = 10 phase is [Ln(OH2)8]I3.2H2O, the eight-coordinate lanthanoid environment being square-antiprismatic.

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