Electronic and Structural Properties of Iron(II) and Nickel(II) Cationic Complexes of 2-(Pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole

1997 ◽  
Vol 50 (2) ◽  
pp. 129 ◽  
Author(s):  
Bradley J. Childs ◽  
John M. Cadogan ◽  
Donald C. Craig ◽  
Marcia L. Scudder ◽  
Harold A. Goodwin
Keyword(s):  
Room Temperature ◽  
Singlet State ◽  
Monoclinic Space Group ◽  
Counter Anion ◽  
Triclinic Space Group ◽  
Space Group ◽  
A Value ◽  
Complex Salts ◽  
Electronic And Structural Properties ◽  
Continuous Temperature

Complex salts containing the [FeIIN6]2+ derivative of 2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole (pzaptH) undergo continuous, temperature-induced singlet (1A1) quintet (5T2) transitions with the transition temperature being dependent on the nature of the counter anion and the presence of solvate water, the latter tending to stabilize the singlet state. A transition is also observed for the fluoroborate salt in methanol solution. The extent of stabilization of the singlet state for iron(II) in these complexes is somewhat greater than in those derived from the previously studied 2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole. The crystal structures of [Fe(pzaptH)2] [CF3SO3]2 and [Ni(pzaptH)2] [BF4]2.2H2O have been determined. The average Fe-N distance is 1·985 Å, a value consistent with the essentially low-spin nature of the complex at room temperature, and the average Ni-N distance is 2·089 Å. In both complexes the bridging >NH group is involved in hydrogen bonding to the anions and, in the nickel complex, also to the solvate water. The uncoordinated nitrogen of the pyrazine ring is not hydrogen-bonded. Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]iron(II) triflate: triclinic, space group P -1, a 8·794(5), b 11·082(6), c 17·49(1) Å, α 77·59(4), β 86·80(4), γ 84·21(4)°, Z 2. Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]nickel(II) tetrafluoroborate dihydrate: monoclinic, space group P 21/c, a 8·784(3), b 8·795(2), c 41·16(1) Å, β 94·58(2)°, Z 4.

Electronic and Structural Properties of the Spin Crossover Systems Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) Thiocyanate and Selenocyanate

2000 ◽  
Vol 53 (9) ◽  
pp. 755 ◽  
Author(s):  
Kristian H. Sugiyarto ◽  
Marcia L. Scudder ◽  
Donald C. Craig ◽  
Harold A. Goodwin
Keyword(s):  
Hydrogen Bonding ◽  
High Spin ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Face To Face ◽  
Bright Yellow ◽  
Electronic And Structural Properties

Essentially high-spin [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) were isolated from an aqueous reaction mixture. Both salts undergo an abrupt transition to low spin below room temperature, that for the thiocyanate occurring in two steps and the high-spin Æ low-spin Æ high-spin cycle being accompanied by hysteresis in both steps. Recrystallization of the salts from nitromethane yielded a mixture from which bright yellow crystals were separated for structure determination. In addition, from the recrystallized selenocyanate, deep red-brown crystals of composition [Fe(bpp)2][NCSe]2·H2O·0.25 CH3NO2 were obtained. Recrystallized [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 were identified as high spin with average Fe–N distances of 2.16 and 2.17 Å, respectively. In the unit cell of [Fe(bpp)2][NCSe]2·H2O·0.25 CH3NO2, there are four independent iron atoms, three identified as low spin and the fourth as high spin. All salts crystallize in a layer-type array involving edge-to-face and face-to-face aryl–aryl-type interactions. Hydrogen bonding between pyrazole >NH groups, anions and solvate molecules is observed. The structure of the uncoordinated ligand was also determined, the molecule being found in a planar arrangement with thecis–cis configuration for the pyrazolyl groups relative to the central pyridyl and the >NH group being at the N 2 atom. Hydrogen bonding involving the >NH groups leads to stepped stacks of molecules. The principal difference in the geometry of coordinated and free bpp molecules is a contraction in the angles about the interannular bridges in the chelate rings. [Fe(bpp)2][NCS]2·2H2O: triclinic, space group P1–, a 8.302(6), b 8.446(6), c 21.531(13) Å, a 78.78(5), b 82.80(5), g 89.85(4)˚, Z 2. [Fe(bpp)2][NCSe]2: triclinic, space group P1–, a 8.354(4), b 8.409(4), c 19.918(9) Å, a 87.02(3), b 83.15(3), g 88.86(3)˚, Z 2. [Fe(bpp)2][NCSe]2·H2O·0.25 CH3NO2: monoclinic, space group Pn, a 16.425(12), b 20.774(9), c 16.933(14) Å, b 90.91(4)˚, Z 8. Uncoordinated bpp: orthorhombic, space group Pna21, a 8.075(3), b 22.479(9), c 5.525(1) Å, b Z 4.

Structural, Magnetic and Mössbauer Spectral Studies of Salts of Bis[2,6-bis(pyrazol-3-yl)pyridine]iron(II)—a Spin Crossover System

1994 ◽  
Vol 47 (5) ◽  
pp. 869 ◽  
Author(s):  
KH Sugiyarto ◽  
DC Craig ◽  
AD Rae ◽  
HA Goodwin
Keyword(s):  
Thermal Hysteresis ◽  
Complex Cation ◽  
Residual Fraction ◽  
Spectral Studies ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Degree Of Hydration ◽  
Complex Salts ◽  
Species Being

The magnetic and Mossbauer spectral properties of hydrated and anhydrous complex salts [Fe( bpp )2] X2, where bpp = [2,6-bis(pyrazol-3-yl)pyridine] and X = PF6, BF4, Br, I, NO3, are indicative of a temperature-induced singlet (1A1) ↔ quintet (5T2) transition in the complex cation. The nature of the transition depends on the anion and the degree of hydration. The transition is displaced to lower temperatures in the anhydrous species and for the hydrated is only partial above room temperature. The transition in the hydrated hexafluorophosphate salt occurs in two steps, and that in the anhydrous hexafluorophosphate is incomplete, a high residual fraction of quintet state species being retained below the transition temperature. For the anhydrous complexes the transition is discontinuous and that in the complex iodide is associated with a narrow thermal hysteresis with transition temperatures Tc ↓ = 203 K and Tc ↑ = 205 K. The structures of [Fe( bpp )2]I2.4H2O and [Fe( bpp )2][BF4]2.3H2O have been determined at 298 K. Both complex salts are essentially low spin at this temperature and have an average Fe-N distance of 1.95 Ǻ. The structures reveal in both instances an extended hydrogen-bonded network involving the uncoordinated >NH groups of the ligands, the anions and lattice water. It is suggested that it is this bonding which is responsible for the favouring of the singlet state in the hydrated salts. Bis [2,6-bis(pyrazol-3-yl)pyridine]iron(II) diiodide tetrahydrate : triclinic, space group Pī , a 8.276(8), b 8.305(7), c 21.941(27) Ǻ, α 98.11(5), β 90.08(6), γ 90.82(6)°, Z 2. Bis [2,6-bis(pyrazol-3-yl)pyridine]iron(II) bis ( tetrafluoroborate ) trihydrate : monoclinic, space group C2/c, a 31.222(15), b 14.456(3), c 12.907(5) Ǻ, β 99.40(2)°, Z 8.

Kristallstrukturen, Schwingungsspektren und Normalkoordinaten- analysen von trans-[OsO2(ox)2]2– und trans-[OsO2(mal)2]2–/ Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of trans-[OsO2(ox)2]2– and trans -[OsO2(mal)2]2–

1998 ◽  
Vol 53 (8) ◽  
pp. 823-828 ◽  
Author(s):  
A. Strueß ◽  
W. Preetz
Keyword(s):  
Crystal Structures ◽  
Vibrational Spectra ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Ir And Raman

Abstract The crystal structures of trans-(Ph4P)2[OsO2(ox)2] (monoclinic, space group P21/n, a = 12.281(2), b = 14.5440(13), c = 13.9810(12) Å, β = 100.000(8)°, Z = 2) and trans- (n-Bu4N)2[OsO2(mal)2] (triclinic, space group P1̄, a = 10.365(4),b = 10.707(3), c - 11.473(5) A, a = 73.00(2), β = 64.44(3), 7 = 82.55(3)°, Z = 1) have been determined by single crystal X-ray diffraction analysis. The IR and Raman spectra of these complexes were measured at room temperature. Based on the molecular parameters of the X-ray determinations normal coordinate analyses have been performed and the vibrations assigned. The valence force constants of [OsO2(ox)2]2- are fd(Os=O) = 6.7, fd(Os-O) = 2.9, fd(C-O) = 5.05, fd(C=O) = 11.2 and fd(C-C) = 4.7 mdyn/Å and of [OsO2(mal)2]2- fd(Os=O) = 6.7, fd(Os-O) = 2.9, fd(C-O) = 4.86, fd(C=O) =11.1 and fd(C-C) = 4.07 mdyn/Å.

Addition der schweren Chalkogen-Atome und Halogenonium-Ionen an Carbodiphosphorane / Addition of the Heavy Chalkogen Atoms and Halogenonium Ions to Carbodiphosphoranes

1985 ◽  
Vol 40 (10) ◽  
pp. 1293-1300 ◽  
Author(s):  
H. Schmidbaur ◽  
Chr. Zybill ◽  
D. Neugebauer ◽  
G. Müller
Keyword(s):  
Room Temperature ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Molar Ratios ◽  
Structure Factors ◽  
Elemental Iodine

Hexaphenylcarbodiphosphorane Ph3P=C=PPh3 (1) forms deeply coloured, crystalline 1:1 ad- ducts with elemental sulfur, selenium and tellurium (2, 3 and 7, respectively). A superior method of synthesis for 7 is the reaction of Na2Te with (Ph3P)2CCl⊕Cl⊖. All three compounds are thermally unstable and decompose at or below room temperature. A selenium adduct 5 was also obtained with Me3P = C = PPh, (4). The compounds 2 and 3 can be alkylated at the chalkogen atoms using MeOSO2F or PhCH2Cl. Oxydation of 3 leads to Se - Se coupling.Addition of elemental iodine to 1 in molar ratios 1:1. 2:3 and 1:2 affords salt-like products composed of the (Ph2P)2Cl⊕ cation associated with I⊖ and/or I3⊖ anions (8a-c).The crystal and molecular structures of 3 and 8b have been determined by single crystal X-ray diffraction. 3′, containing one half equivalent of disordered tetrahydrofuran, crystallizes in the monoclinic space group P21/n (a = 10.848(6), b = 17.433(8). c = 16.848(9) Å, β = 91.51(5)°. V = 3185.07 Å3, ϱx = 1359 gcm-3, Z = 4). Based on 3488 structure factors, the final R value was 0.103. The selenium is attached to the ylidic carbon atom without major changes of the Ph3P=C=PPh3 skeleton (C - Se = 1.99 Å). 8b crystallizes in the triclinic space group P1̄ (a = 9.935(2). b = 11.507(2), c = 16.646(3) Å, α = 90.91(1), β = 112.00(1), γ = 96.60(1)°, V = 1749.15 A3, ϱx = 1.741 gcm-3, Z = 2). Refinement of 382 parameters on 5096 structure factors converged at R = 0.043. The molecular structure shows close similarities to the selenium adduct 3 (C-I = 2.12 Å).

scholarly journals Synthesis and molecular structure of biologically significant bis(1,3-dimesityl-4,5-naphthoquinoimidazol-2-ylidene)gold(I) complexes with chloride and dichloridoaurate counter-ions

2019 ◽  
Vol 75 (4) ◽  
pp. 462-468 ◽  
Author(s):  
Jayaraman Selvakumar ◽  
Meredith H. Miles ◽  
David A. Grossie ◽  
Kuppuswamy Arumugam
Keyword(s):  
Crystal Lattice ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Counter Anion ◽  
Triclinic Space Group ◽  
Space Group ◽  
One Dimensional ◽  
Average Value ◽  
Counter Ions

Diffraction-quality single crystals of two gold(I) complexes, namely bis(1,3-dimesityl-4,5-naphthoquinoimidazol-2-ylidene)gold(I) chloride benzene monosolvate, [Au(C29H26N2O2)2]Cl·C6H6or [(NQMes)2Au]Cl·C6H6,2, and bis(1,3-dimesityl-4,5-naphthoquinoimidazol-2-ylidene)gold(I) dichloridoaurate(I) dichloromethane disolvate, [Au(C29H26N2O2)2][AuCl2]·2CH2Cl2or [(NQMes)2Au][AuCl2]·2CH2Cl2,4, were isolated and studied with the aid of single-crystal X-ray diffraction analysis. Compound2crystallizes in a monoclinic space groupC2/cwith eight molecules in the unit cell, while compound4crystallizes in the triclinic space groupP\overline{1} with two molecules in the unit cell. The crystal lattice of compound2reveals C—H...Cl−interactions that are present throughout the entire structure representing head-to-tail contacts between the aromatic (C—H) hydrogens of naphthoquinone and Cl−counter-ions. Compound4stacks with the aid of short interactions between a naphthoquinone O atom of one molecule and the mesityl methyl group of another molecule along theaaxis, leading to a one-dimensional strand that is held together by strong π–η2interactions between the imidazolium backbone and the [AuCl2]−counter-ion. The bond angles defined by the AuIatom and two carbene C atoms [C(carbene)—Au—C(carbene)] in compounds2and4are nearly rectilinear, with an average value of ∼174.1 [2]°. Though2and4share the same cation, they differ in their counter-anion, which alters the crystal lattice of the two compounds. The knowledge gleaned from these studies is expected to be useful in understanding the molecular interactions of2and4under physiological conditions.

Structures and phase transition of three isomers of 1-phenylindolin-2-one derivatives: 6-chloro-1-phenylindolin-2-one, 4-chloro-1-phenylindolin-2-one and 1-(3-chlorophenyl)indolin-2-one

2018 ◽  
Vol 74 (12) ◽  
pp. 1750-1758
Author(s):  
Bing Wang ◽  
Qi Fang
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Phenyl Ring ◽  
Density Functional ◽  
Room Temperature ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Functional Theory ◽  
Triclinic Space Group ◽  
Space Group

Three 1-phenylindolin-2-one derivatives, namely 6-chloro-1-phenylindolin-2-one (A), 4-chloro-1-phenylindolin-2-one (B) and 1-(3-chlorophenyl)indolin-2-one (C), all C14H10ClNO, have been synthesized and the structures of these compounds at room temperature (A RT, B RT and C RT) and low temperature (A LT, B LT and C LT) have been determined. Crystal A at 295 K (A RT) crystallized in the monoclinic space group P21/c and the phenyl ring of the unique molecule exhibits disorder over two positions. At low temperature, the disorder disappeared and crystal A at 90 K (A LT) crystallized in the triclinic space group P\overline{1} with a doubled unit-cell volume and four molecules in the asymmetric unit. Density functional theory (DFT) calculations revealed a low oscillation barrier (0.24 kcal mol−1) of the phenyl ring of molecule A and the phase transition from the P21/c structure to the P\overline{1} structure can be interpreted in terms of the freezing out of the two conformations at low temperature. Crystal B retains space group P21/c in the temperature range from 100 to 297 K. A kind of obtuse-cell to acute-cell change can be recognized; if the unit cell of B LT at 100 K is set to be a standard obtuse cell [β = 90.341 (2)°] and the cell is kept untransformed in the course of temperature changing, the cell of B RT at 297 K was found to be acute [β = 89.288 (2)°]. The molecules in structure C are packed in layers, with C—H...O hydrogen bonds between neighbouring layers.

scholarly journals Crystal structures ofN-(pyridin-2-ylmethyl)pyrazine-2-carboxamide (monoclinic polymorph) andN-(pyridin-4-ylmethyl)pyrazine-2-carboxamide

2014 ◽  
Vol 70 (7) ◽  
pp. 18-22 ◽  
Author(s):  
Dilovan S. Cati ◽  
Helen Stoeckli-Evans
Keyword(s):  
Hydrogen Bonds ◽  
Room Temperature ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Three Dimensional Structure ◽  
Π Interactions ◽  
Centroid Distance

The title compounds, C11H10N4O (HL1) and C11H10N4O (HL2), are pyridine 2-ylmethyl and 4-ylmethyl derivatives, respectively, of pyrazine-2-carboxamide. HL1 was measured at 153 K and crystallized in the monoclinic space groupP21/cwithZ= 4. There has been a report of the same structure measured at room temperature but assumed to crystallize in the triclinic space groupP-1 withZ= 4 [Sasanet al.(2008).Monatsh. Chem.139, 773–780]. In HL1, the pyridine ring is inclined to the pyrazine ring by 61.34 (6)°, while in HL2 this dihedral angle is 84.33 (12)°. In both molecules, there is a short N—H...N interaction involving the pyrazine carboxamide unit. In the crystal of HL1, molecules are linked by N—H...N hydrogen bonds, forming inversion dimers with anR22(10) ring motif. The dimers are linkedviabifurcated-acceptor C—H...O hydrogen bonds, forming sheets lying parallel to (102). The sheets are linkedviaC—H...N hydrogen bonds, forming a three-dimensional structure. In the crystal of HL2, molecules are linked by N—H...N and C—H...N hydrogen bonds to form chains propagating along [010]. The chains are linkedviaC—H...O hydrogen bonds, forming sheets lying parallel to (100). Within the sheets there are π–π interactions involving neighbouring pyrazine rings [inter-centroid distance = 3.711 (15) Å]. Adjacent sheets are linkedviaparallel slipped π–π interactions involving inversion-related pyridine rings [inter-centroid distance = 3.6395 (17) Å], forming a three-dimensional structure.

Structural and Electronic Properties of Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazolato]iron(II) and Its Solvated Derivatives

1994 ◽  
Vol 47 (5) ◽  
pp. 891 ◽  
Author(s):  
BJ Childs ◽  
DC Craig ◽  
KA Ross ◽  
ML Scudder ◽  
HA Goodwin
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Singlet State ◽  
Methanol Solution ◽  
Monoclinic Space Group ◽  
Deprotonated Form ◽  
Complex Molecules ◽  
Quintet State ◽  
Structural And Electronic Properties ◽  
Continuous Temperature

The uncharged complex [Fe( pzapt )2] [ pzapt is the deprotonated form of 2-(pyrazin-2-ylamino)-4-(pyridin-2-yl) thiazole ] crystallizes with varying degrees of solvation , depending on the solvent. The electronic properties of the solvates differ. For all of them temperature dependence of the magnetic moment is observed, associated with a continuous temperature-induced singlet (1A1) ↔ quintet (5T2) transition. The transition is centred below room temperature for the benzene solvates but the unsolvated and chloroform solvate complexes exist predominantly in a singlet low-spin state. Overall the stabilization of the singlet state is greater in this system than in the previously studied [Fe( papt )2] [ paptH = 2-(pyridin-2-ylamino)-4-(pyridin-2-yl) thiazole ]. A spin equilibrium has been characterized for both [Fe( pzapt )2] and [Fe( papt )2] in methanol solution. The crystal structure of [Fe( pzapt )2].3/2C6H6 reveals Fe-N bond lengths consistent with both singlet and quintet state iron(II) being present. The benzene molecules are incorporated into the lattice as groups of three by occupying channels created by the packing of the complex molecules. Bis [2-(pyrazin-2-ylamino)-4-(pyridin-2-yl) thiazole ]iron(II) sesquibenzene solvate: monoclinic, space group P 21/c, a 14.894(7), b 12.601(2), c 16.777(8) Ǻ, β 94.57(2)°, Z 4.

Structural Characterization of Two Crystalline Forms of Bis[2-(1,5-dimethyltrazol-3-yl)-1,10-phenanthroline]-iron(II) Perchlorate—a Spin Crossover System

1996 ◽  
Vol 49 (4) ◽  
pp. 497 ◽  
Author(s):  
KH Sugiyarto ◽  
DC Craig ◽  
HA Goodwin
Keyword(s):  
Room Temperature ◽  
Singlet State ◽  
Crystal Packing ◽  
Bulk Sample ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Quintet State ◽  
Crystalline Forms

At room temperature bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate has magnetic and Mossbauer spectral properties which indicate that it contains both singlet and quintet state iron(II) in a ratio of approximately 1:2. Two polymorphs were identified in a small batch of crystals grown from acetone/ethanol for crystal structure determination. In polymorph 1 the average iron-nitrogen distance (1.97 Ǻ) is close to the value usually obtained for purely singlet state iron(II) in an [FeN6]2+ system, whereas that for polymorph 2 (2.09 Ǻ) is consistent with the 1:2 ratio of singlet-to-quintet state species. The Mossbauer spectrum of the crystallographic sample is virtually identical to that of the bulk sample. There are small differences in the coordination sphere which could account for the different extent of stabilization of the singlet state in the two polymorphs. The crystal packing differs markedly for the two polymorphs but reveals no obvious rationalization for the spin-state differences. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate , two-thirds water (polymorph 1): monoclinic, space group P 21/c, a 10.766(3), b 25.806(3), c 12.491(4) Ǻ, β 91.17(1)°, Z 4. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate monohydrate (polymorph 2): orthorhombic, space group Pbca, a 16.687(4), b 12.272(2), c 34.305(8) Ǻ, Z 8.

Supramoleküle aus Kronenethern und geminalen Sulfonen: Synthese von vier binären Komplexen und Kristallstruktur von (CH2CH2O)4·2H 2C(SO2C2H5)2/Supramolecules of Crown Ethers with Geminal Sulfones: Synthesis of Four Binary Complexes and Crystal Structure of (CH2CH2O )4·2H2C(SO2C2H5)2

1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Binary Complexes ◽  
Cyclic Polyethers ◽  
Adjacent Unit ◽  
Methylene Group

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.

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