Crystal structure – reactivity correlations in the solid state photochemistry of N-(tert-butyl)succinimide

1994 ◽  
Vol 72 (9) ◽  
pp. 1952-1960 ◽  
Author(s):  
Tai Y. Fu ◽  
John R. Scheffer ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Crystalline State ◽  
Crystal And Molecular Structure ◽  
Carbonyl Oxygen ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Tert Butyl ◽  
Close Contacts

In order to provide experimental evidence on the stereoelectronic requirements for intramolecular hydrogen atom abstraction by carbonyl oxygen, N-(tert-butyl)succinimide, 1, was investigated by the crystal structure – reactivity correlation method. In this method, the success or failure of a given reaction in the crystalline state is correlated with the geometric parameters associated with the process as determined by X-ray crystallography. In the case of N-(tert-butyl)succinimide, the crystal and molecular structure shows that the molecule adopts a conformation in which there are very close contacts (d = 2.17–2.24 Å) between the carbonyl oxygen atoms and certain γ-hydrogen atoms on the tert-butyl group. In accord with these close contacts, ultraviolet irradiation of N-(tert-butyl)succinimide in the crystalline state leads to transfer of one of the γ-hydrogen atoms from carbon to oxygen. This produces a 1,4-biradical which closes to form a cyclobutanol, and the cyclobutanol undergoes ring opening to afford the final stable product, tetrahydro-1H-azepine-2,5-dione, 2. The crystal and molecular structure of photoproduct 2 is also reported. In contrast to many solid state transformations, there was no discernable melting of the crystals during reaction, and complete conversions of 1 into 2 could be achieved. The isolated chemical yield of photoproduct 2 from the solid state reaction (79%) is in fact considerably higher than that reported by Kanaoka and Hatanaka for the corresponding solution phase process (49%). This permitted the solid state reaction to be followed to 100% conversion by X-ray powder diffractometry, which showed that the process is a single crystal-to-polycrystalline transformation involving a regular and progressive conversion of 1 into 2 with no obvious diffraction peaks that might be attributable to the intermediate cyclobutanol.

The crystal and molecular structure of syn-2,11-diselena[3,3]metacyclophane and comparison with the dithia-analogue

1982 ◽  
Vol 60 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Reginald H. Mitchell
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Crystal And Molecular Structure ◽  
State Structure ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Anti Conformer ◽  
R Value

The crystal structure of syn-2,11-diselena[3,3]metacyclophane, 1a, has been determined by single crystal X-ray diffraction and refined to an R-value of 0.039. The crystal structure is monoclinic with a = 1926(1), b = 801.4(3), c = 924(1) pm, β = 98.9(1)°, and is isomorphous with that of the analogous sulphur compound. The space group is P21/n with 4 molecules per cell, D(meas) = 1.733 g cm−3, D(calcd) = 1.726 g cm−3. The molecule has the syn-conformation with the largest possible Se—Se distance of 721.8 pm. The benzenoid rings form a dihedral angle of 19.1°. The distance between the internal aryl hydrogen atoms on rings 1 and 2 is 285.1 pm. The internal aryl C atoms are 314.6 pm apart. The 1Hmr solution spectra of 1a are consistent with the solid state structure, and can be explained without involving equilibration with an anti-conformer.

Crystal and Molecular Structure of 3-(N-Methoxy-N-methylcarbamoyl)- 2,2,5,5-tetramethyl-1-oxy-pyrroline

2010 ◽  
Vol 65 (4) ◽  
pp. 475-478
Author(s):  
Guido D. Frey ◽  
Eberhardt Herdtweck
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Crystal And Molecular Structure ◽  
Layer Structure ◽  
Nitroxide Radical ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Stable Nitroxide

The crystal structure of the stable nitroxide radical 3-(N-methoxy-N-methylcarbamoyl)-2,2,5,5- tetramethyl-1-oxy-pyrroline was determined from single-crystal X-ray data: orthorhombic, space group Pbca (no. 61), a = 9.0213(1), b = 12.8625(1), c = 21.2406(2) Å, V = 2464.68(4) Å3 and Z = 8. The adjacent molecules assemble to a supramolecular layer structure in the solid state, linked by two intermolecular C-H...O hydrogen bonds.

The crystal structure of C.I. Pigment Red 2, 1′-(2,5-dichlorophenyl)azo-2′hydroxy-3′-phenylamidonaphthalene

1977 ◽  
Vol 146 (4-6) ◽  
Author(s):  
A. Whitaker
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Intramolecular Hydrogen

AbstractThe crystal and molecular structure of C.I. Pigment Red 2, l′-(2,5-dichlorophenyl)azo-2′-hydroxy-3′-phenylamidonaphthalene has been determined by x-ray diffraction techniques. It crystallizes in the monoclinic system with cell parametersThe hydrogen atoms have been found and included but not refined. The final residual is 15.3%. The molecule is probably in the form of the hydrazone tautomer. The intramolecular hydrogen bonds keep most of the molecule approximately planar while it appears that the remainder is held in the same plane due to steric hinderence between the molecules. The molecules are packed in columns with alternate molecules antiparallel and are linked by van der Waals forces.

The Meisenheimer rearrangement in heterocyclic synthesis. II. Synthesis and X-ray crystal structure of a tetrahydro-1H-2,3-benzoxazocine and preparation of a hexahydro-2,3-benzoxazonine

1980 ◽  
Vol 33 (6) ◽  
pp. 1323 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
PE Davies ◽  
CLWAH Raston
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Acetic Acid ◽  
Crystal And Molecular Structure ◽  
Phosphorus Oxychloride ◽  
Crystallographic Analysis ◽  
Heterocyclic Synthesis ◽  
Reaction Conditions ◽  
X Ray ◽  
Heterocyclic Derivatives

The heterocyclic derivatives, 8,9-dimethoxy-3-methyl-1-phenyl-3,4,5,6- tetrahydro-1H-2,3-benzoxazocine(3a) and 9,10-dimethoxy-3-methyl-1- phenyl-1,3,4,5,6,7-hexahydro-2,3-benzoxazonine (3b),examples of two new ring systems, have been prepared by Meisenheimer rearrangement of the corresponding 2-benzazepine and 2-benzazocine N-oxide derivatives (2a) and (2b). The Bischler-Napieralski-type cyclization reaction was used in the preparation of the tertiary amine precursors of these N-oxides reaction conditions for the cyclization were critical and phosphorus oxychloride in refluxing butanenitrile was found to give the best yields of the seven- or eight-membered cyclic imine intermediates. Reductive cleavage of the benzoxazocine derivative (3a) with zinc in acetic acid followed by N-methylation gave the expected product, [2-{3- (dimethylamino)propyl}-4,5-di-methoxyphenyl]phenylmethanol (12). The crystal and molecular structure of (3a) has been determined by X-ray crystallographic analysis.

Crystal Structure of (NH4)2[Mo3S(S2)6] Containing the Novel Isolated Cluster [MO3S13]2-

1979 ◽  
Vol 34 (3) ◽  
pp. 434-436 ◽  
Author(s):  
A. Müller ◽  
S. Pohl ◽  
M. Dartmann ◽  
J. P. Cohen ◽  
J. M. Bennett ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Aqueous Solutions ◽  
Single Crystal ◽  
Ammonium Salt ◽  
Crystal And Molecular Structure ◽  
Monoclinic Space Group ◽  
The Novel ◽  
Mean Values ◽  
X Ray

Abstract The novel tri-nuclear metal-sulfur cluster [Mo3S(S2)6]2- can be obtained as its ammonium salt by the reaction of a Moiv containing aqueous solutions with polysulfide. Its crystal and molecular structure has been determined by a single crystal X-ray study. The crystals are monoclinic (space group Cm, with a = 11.577(6) Å, b = 16.448(7) Å, c = 5.716(2) Å, β = 117.30(3)°, V = 967.2 Å3 , Z = 2, dexptl. = 2.54(2) g/cm3 , dcal = 2.54 g/cm3). The structure consists of isolated [Mo3S(S2)6]2- units, with three Mo atoms at the vertices of a triangle. There are bridging as well as terminal S22--ligands lying above and below the Mo3-plane (bond distances: Mo-Mo = 2.722 Å, Mo-S(terminal) = 2.435, Mo-S(bridging) = 2.452, Mo3-S = 2.353(4) Å and S-S = 2.04 Å (mean values)).

The Meisenheimer Rearrangement in Heterocyclic Synthesis. IV. Derivatives of the 2H,6H-1,5,4-Benzodioxazocine and 7H-1,6,5-Benzodioxazonine Ring Systems: X-Ray Crystal Structure of 10-Methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7H-1,6,5-benzodioxazonine

1988 ◽  
Vol 41 (3) ◽  
pp. 293 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
LM Engelhardt ◽  
IWK Gunawardana ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Ring System ◽  
Heterocyclic Synthesis ◽  
Rearrangement Product ◽  
Ring Systems ◽  
X Ray ◽  
Derivatives Of ◽  
Moderate Yield

Meisenheimer rearrangement of the N-oxides (4) derived from a series of 5-aryl-4-methyl-2,3,4,5-tetrahydro-1,4-benzoxazepines (3) gave rise to eight derivatives (5) of the new 2H,6H-1,5,4-benzodioxazocine ring system. Reaction of 9-methoxy-5-methyl-6-phenyl-3,4,5,6- tetrahydro-2H-1,5-benzoxazocine (6) with 3-chloroperoxybenzoic acid gave an unstable N-oxide (7). A Meisenheimer rearrangement product from (7), 10-methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7 H-1,6,5- benzodioxazonine (8), the first example of this ring system, was isolated directly in moderate yield on oxidation of (6) with cooling. The crystal and molecular structure of (8) has been determined by X-ray crystallographic methods.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

Crystal and Molecular Structure of 3-Iodo-2-propynyl-N-butylcarbamate

1997 ◽  
Vol 52 (2) ◽  
pp. 256-258 ◽  
Author(s):  
Evgeni V. Avtomonov ◽  
Rainer Grüning ◽  
Jörg Lorberth
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Carbamate Group ◽  
Oxygen Atoms

Abstract The crystal structure of the title compound has been determined by X-ray diffraction methods. Due to the Lewis acidic character of the iodine substituent a “zig-zag” chain is formed via intermolecular interactions (2.933(4) A) between iodine and oxygen atoms of theocarbamate moiety. A three-dimensional network is formed through hydrogen-bridging (2.04 A) between NH-groups and the oxygen atoms of the neighbouring carbamate group of the next molecule.

The Crystal Structure of the Tetrameric Adduct of Antimony Trichloride and Phosphoryl Isothiocyanate, [SbCl3·OP(NCS)3]4

1994 ◽  
Vol 49 (4) ◽  
pp. 441-444 ◽  
Author(s):  
Alexander V. Sienkiewicz ◽  
Anatoliy A. Kapshuk
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Antimony Trichloride ◽  
Cage Structure ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cubic System ◽  
Tetrameric Complex

The crystal and molecular structure of the tetrameric complex of the composition [SbCl3·OP(NCS)3]4 synthesized from SbCl3 and OP(NCS)3 in CCl4 waso determined by X-ray crystallography [143 m space group, cubic system with a = 13.927(4) Å]. The complex exhibits a tetranuclear "cage" structure with a [Sb4O4] core which consists of μ3-bridging oxygen and six coordinate antimony(III) atoms; the Sb-O distance, 3.060 Å, is exceptionally long.

Lanthanide Complexes with Carbacylamidophosphates: The First Registration of Chelate Coordination of the Neutral Ligand Form in the Structure of Di-(N,Nf-tetramethyl-NM -benzoylphosphoryl- triamide)cerium(III) Nitrate

2000 ◽  
Vol 55 (7) ◽  
pp. 576-582 ◽  
Author(s):  
Katerina E. Gubina ◽  
Vladimir A. Ovchynnikov ◽  
Vladimir M. Amirkhanov ◽  
Helmut Fischer ◽  
Rüdiger Stumpf ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Coordination Compounds ◽  
Metal Ion ◽  
Lanthanide Complexes ◽  
Carbonyl Oxygen ◽  
Neutral Ligand ◽  
Crystal Data ◽  
X Ray

Abstract The coordination compounds of the general formula Ln(HL)2(NO3)3, (where Ln = La - Eu (without Pm), HL = C6H5C(O)NHP(O)[N(CH3)2]2, N,Nʹ-tetramethyl-Nʺ-benzovlphosphoryl-triamide) have been synthesized and characterized by means of IR, UV-VIS, 1H, 31P NMR spectroscopy, and X-ray analysis. The complexes are isostructural according to X-ray powder diffraction studies. The crystal structure of the cerium(lll) complex has been determined. Crystal data: monoclinic, P21/c, with a = 10.503(9), b = 15.62(2), c = 21.91(2) Å, β = 99.56(8)°, Z = 4, V = 3546(6) Å3, R1= 0.0550, wR2 = 0.1383 for 6970 unique reflections used. The complex has a molecular structure. Neutral phosphoryltriamide ligands are coordinated to the metal ion in a bidentate manner via phosphoryl and carbonyl oxygen atoms with formation of six membered chelate rings. The coordination polyhedron of the Ce atom is a sphenocorona; C.N. = 10 (4 O[HL] + 6 O [NO3-]).

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