Crystal structure and physical characterization of <Emphasis Type="Italic">N</Emphasis>-(3,3-dimethylbutyl)-<Emphasis Type="SmallCaps">l</Emphasis>-α-aspartyl-<Emphasis Type="SmallCaps">l</Emphasis>-phenylalanine,the hydrolysis product of neotame

The hydrolysis product of neotame, N-(3,3-dimethylbutyl)-l--aspartyl-l-phenylalanine (DMBAP), was crystallized from water as an anhydrate with a melting point at 197C with decomposition. Its crystal structure was determined by single crystal X-ray diffractometry. The crystal is orthorhombic with space group P2₁2_₁2₁ with Z=4 and one molecule per asymmetric unit. The cell constants are a=5.520 (2) Å, $b=10.608$ (5) Å and c= 31.92 (2) Å. The ¹³C solid-state nuclear magnetic resonance spectrum of DMBAP is compared with those of neotame monohydrate and neotame methanol solvate.     

Crystal structures of the benzene and ethanol solvates of neotame

The benzene and ethanol solvates of neotame crystallized from solutions of neotame anhydrate in benzene and ethanol, respectively. The crystal structures of the two solvates were determined by single-crystal X-ray diffraction using synchrotron radiation. The benzene solvate crystallizes in the monoclinic space group, P2₁, Z = 2, with one neotame molecule and one benzene molecule per asymmetric unit. The cell constants are a = 13.060 (6) Å, b = 5.582 (2) Å, c = 17.954 (9) Å, and = 102.079 (15)°. The ethanol solvate crystallizes in the orthorhombic space group, P2₁2₁2₁ with Z = 8 (Z = 2). The cell constants are a = 10.047 (4) Å, b = 17.001 (4) Å, and c = 28.948 (7) Å. Intermolecular hydrogen bonding among neotame molecules is evident in the two crystals. The benzene solvate has a nonpolar region containing the benzene molecules, with the benzene rings and alkyl chains of the neotame molecules.     

Synthesis and crystal structure of 4,4′-bis(4-pyridylethyl)biphenyl, noncovalently hydrogen bonded two-dimensional networks

A new pyridine containing compound, 4,4-bis(4-pyridylethyl)biphenyl 1, was synthesized and its structure was determined by X-ray crystallography. Two kinds of two-dimensional networks linked by hydrogen bonds were obtained with different crystal solvents: 1·2H₂O, monoclinic, space group P2₁/n with a = 8.3280(10), b = 5.5990(10), c = 24.054(4) Å, = 98.79(2)°, V = 1108.4(3) ų, Z = 2, Dc = 1.200 g cm^–3, R1 = 0.0558; 1·CH₃OH·2H₂O, triclinic, space group P-1 with a = 8.3310(10), b = 12.861(2), c = 13.111(2) Å, = 64.110(10), = 75.000(10), = 83.750(10)°, V = 1220.7(3) ų, Z = 2, Dc = 1.177 g cm^–3, R1 = 0.0529. It is interesting that in the hydrate the host molecule of 1 contains an essentially flat biphenyl section, while in the methanol complex the host molecule of 1 contains a substantial twist in the center of the biphenyl section. The compounds were also characterized by NMR and FTIR spectroscopies. The ¹H and ¹³C NMR assignments for 1 were carried out by 2D NMR spectral measurements in acetonitrile-d ₃.     

Crystal structures of methanol and ethanol solvates of secalonic acid D

The methanol and ethanol solvates of secalonic acid D (SAD) share the same packing pattern exhibited by the acetic acid solvate of secalonic acid A, the enantiomer of SAD. Both solvates crystallize in space group C2, with a = 17.648(2), b = 7.0897(10), c = 13.060(2) Å and = 93.482(2)° for the methanol form, and a = 18.010(4), b = 7.395(2), c = 13.053(3) Å and = 96.882(4)° for the ethanol form.     

Solid-state conformational heterogeneity of the 2,2,5,5-tetramethyl-3,4-hexandione monohydrazone: X-ray diffraction and MAS NMR experiments

The X-ray diffraction study of the 2,2,5,5-tetramethyl-3,4-hexandione mono-hydrazone 1 shows a solid solution of two screwed conformers in the crystal. In each of these conformers, the conjugated C=O and C=N double bonds have an approximately perpendicular orientation with = 101.1°(2) and –93.4°(2), respectively. AM1 theoretical calculations give the same result for the isolated molecule. The calculated rotational barrier around the central single bond of the conjugated moiety is about 45.98 kJ mol^–1 which is higher than the classical values observed for 1,3 conjugated systems (28.42 kJ mol^–1 in the 1,3-butadiene). Variable temperature ¹³C CPMAS NMR experiments show hindered rotation around the COC(CH₃)₃ tert-butyl group in the solid state. 1 crystallizes in the triclinic space group P ₁ with a = 10.106(1)Å, b = 11.698(1)Å, c = 12.313(1)Å, = 62.108(1)° = 70.517(1)° = 66.052(1), V = 1157.0(3)ų, D _calc = 1.06 with Z = 4.     

X-ray structure and 1H NMR assignment of 1-methyl-1,4-dihydro-4-oxo-4′-methylthio-3,3′-diquinolinyl sulfide

The title compound (C₂₀H₁₆N₂OS₂) is orthorhombic, with a = 9.290(2), b = 11.874(3), c = 15.971(4) Å and space group P2₁2₁2₁. Two quinoline moieties are nearly perpendicular to each other (103.5(2)°). Two pairs of heteroatoms in ortho-positions are in very close contact. The 4-oxo and 4-methylthio groups are trans-orientated to the central sulfur bridge. The sulfide preserves a skew conformation. The unusual H-2 proton upfield shift is induced by the ring current effect.     

Bis(triphenylphosphoranylidene)ammonium tetraethylborate, (Ph3P)32N+BEt34-: preparation and structure

The compound (Ph₃P)₃2N,⁺BEt₄ ^- is readily prepared from (Ph₃P)₂N⁺Cl^– and LiBHEt₃. The NMR spectrum (¹H, ¹³C. ¹¹B, ³³P) are reported. C₄₄H₅₀NBP₂ M = 665.64, Triclinic, P (#2), a = 11.530(4), b = 15.397(9), c = 11.497(9) Å, = 102.94(6), = 102.87(4), = 89.34(4)°, V = 1938(4) ų, and Z= 2.     

Crystal structure and spectroscopy of 4-N-benzylaminocoumarin

The structure of 4-N-benzylaminocoumarin (C₁₆H₁₃NO₂) has been determined by X-ray diffraction and the Ft-ir,¹H- and¹³C-nmr spectra of the compound were recorded. Crystals of the compound are monoclinic, space group P2₁/c, with cell dimensiona=8.077(2),b=14.598(4),c=10.890(3) Å, and =97.76(3)°. The Ft-ir and nmr spectra indicate that the nitrogen atom is in the amino form in solution. The crystal structure is consistent with this observation, but the C(3)–C(4) double bond is clearly delocalized to include the lone pair on the nitrogen atom.     

Crystal structure and characterization of [Co(saccharinate)2(L1)(H2O)2] n solvate: A new microporous coordination polymer generated from 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (L1) and [Co(saccharinate)2·4H2O]·2H2O

A new microporous coordination polymer, [Co(saccharinate)₂(L1)(H₂O)₂] _n solvate, has been prepared from the reaction of the N,N bidentate ligand 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (L1) with [Co(saccharinate)₂·4H₂O]·2H₂O in a methylene chloride/ethanol solvent mixture. The compound crystallizes in the triclinic system, space group P-1, with lattice parameters a = 7.6893(5) Å, b = 11.0169(7) Å, c = 11.2369(7) Å, = 66.2610(10)°, = 74.4160(10)°, = 74.6740(10)°. The structure consists of one-dimensional chains composed of octahedrally coordinated Co(II) centers linked by L1. The packing of these chains, along with intrachain and interchain hydrogen bonds, generates a 3-D framework with infinite channels that are occupied by disordered guest molecules. The compound was further characterized by IR spectroscopy and DTA/TGA.     

Identification of a new family of diphosphate compounds, AI2BII3(P2O7)2: Structures of Ag2Co3(P2O7)2, Ag2Mn3(P2O7)2, and Na2Cd3(P2O7)2

Syntheses and single-crystal X-ray structural results are reported for three new mixed diphosphates of the family A^I ₂B^II ₃(P₂O₇)₂; Ag₂Co₃(P₂O₇)₂ (I), Ag₂Mn₃(P₂O₇)₂ (II), and Na₂Cd₃(P₂O₇)₂ (III). All crystallize in the triclinic system, space group P1 bar: (I) a = 5.351(4), b = 6.375(4), c = 16.532(4) Å, = 80.83(6) = 81.45(4), = 72.87(5)°, V = 528.9(6) ų, Z = 2, D _calc = 4.649 mg/m³, R/Rw = 0.0428/0.0548 for 3949 obs. reflns; (II) a = 5.432(7), b = 6.619(6), c = 16.51(3) Å, = 80.78(8) = 82.43(9), = 72.82(7)°, V = 557.7(13) ų, Z = 2, D _calc = 4.338 mg/m³, R/Rw = 0.0679/0.1303 for 2100 obs. reflns and (III) a = 5.67(3), b = 7.08(4), c = 7.90(4) Å, = 77.0(2), = 82.5(2), = 67.8(2)°, V = 286(3) ų, Z = 2, D _calc = 4.249 mg/m³, R/Rw = 0.0307/0.0342 for 1945 obs. reflns. (I) and (II) are isostructural but (III) is of a different type. All three structures are characterized by layers of P₂O₇ groups alternating with layers of mixed metal atoms. Differences are seen in the conglomerate bonding patterns of B atoms and in the irregular geometry of Ag in (I) and (II) compared to the octahedral bonding seen for Na in (III). The differences in structure may be understood in terms of the ratios of the ionic radii of A and B atoms.     

Terbium and holmium trans-2,3-dimethylacrylic acid complexes with 1,10-phenanthroline

Novel dinuclear complexes, [REL₃(phen)]₂ (where RE = Tb, Ho; HL = trans-2,3-dimethylacrylic acid; phen = 1,10-phenantheoline), were synthesized and determined by elemental analysis, infrared absorption spectra (IR), thermogravimetric analysis (TGA), and X-ray diffraction. The Tb complex crystallizes in space group P2_1/n with the cell dimensions a = 12.939(2) Å, b = 13.018(2) Å, c = 15.400(3) Å and = 94.72(1)°. The Ho complex crystallizes in P ⁽⁹⁾ with a = 12.406(3) Å, b = 13.280(3) Å, c = 9.823(2) Å, = 110.80(2)°, = 103.42(2)°, = 63.67(1)°. The Tb atom is nine coordinate and the separation of Tb...Tb* is 3.97 Å. The Ho atom is eight coordinate and the separation of Ho...Ho* is 4.01 Å.     

X-ray structure and NMR assignment of 4-methoxy-4′-methylthio-3,3′-diquinolinyl sulfidea

The title compound (C₂₀H₁₆N₂OS₂) is monoclinic, witha=7.786(3).,b=13.252(3),c=17.162(4) Å, =99.16(3)° and space groupP2₁/n. Two quinoline moieties are nearly perpendicular to each other (112.9(2)°). Both methoxy and methylthio groups are trans-orientated with the respect to the C(3)–S(1)–C(13) plane. Two pairs of the heteroatoms in ortho-positions are in very close contact. The conformation of the molecule explains an unusual¹H NMR spectrum     

Structure of 1,2,3,4,9,9-hexachloro-6,7-tetrahydro-l,4-methano-naphthalene: a facially differentiated, annulated 1,3-cyclohexadiene

The X-ray crystal structure of the title compound is reported. Crystal data: T = 100 K, monoclinic, P2₁/n, a = 8.2990(17), b = 13.2300(26), c = 12.0350(24) Å, = 93.676(30)°, V = 1318.7 (5) ų, and R = 0.0368. The methylene carbon atoms in the cyclohexadiene ring are disordered over two positions above and below the ring plane. The chlorine substituted endocyclic double bond deviates from planarity with an angle of 8.10(13)° toward the endo-face. The facially differentiated 1,3-cyclohexadiene moiety is only slightly pyramidalized, deviating 1.75(20)° also toward the endo-face of the tricyclic system.     

Crystal structure of bis(η5-methylcyclopentadienyl)-bis(4-methylbenzenesulfonato-O)-molybdenum(IV)

The compound bis(⁵-methylcyclopentadienyl)-bis(4-methylbenzenesulfonato-O)-molybdenum (IV) crystallizes in space-group P2₁/c, a = 8.2956(5), b = 26.896(3), c = 11.4196(11) Å, = 96.101(7)°, Z = 4. The sulfonate ligands are monodentate and the molybdenum atom has pseudotetrahedral coordination geometry, with angles O–Mo–O 72.0(1)° and Cp–Mo–Cp 134.9(1)° (Cp = ring centroid).     

Helical chirality of pyrrolo[1,2-a][1,10]phenanthroline derivatives

The objective of the study was to confirm by X-ray analysis the phenomenon of helical chirality inferred from solution ¹H-NMR data for a series of derivatives based on the novel pyrrolo[1,2-a][1,10]phenanthroline system. The syntheses of the title compounds and their ¹H-NMR data are presented. Crystals of the representative compound ethyl, 1-(4-phenylbenzoyl)-pyrrolo[1,2-a][1,10]phenanthroline-3-carboxylate, with molecular formula C₃₁H₂₂N₂O₃, were found to crystallize in the triclinic system, space group P 1 with a = 7.8541(1), b = 11.2605(2), c = 13.4093(3) Å, = 92.244(1), = 90.292(1), = 106.475(1) and Z = 2. The X-ray analysis revealed the predicted helicity of the phenanthroline system as well as its origin, namely the proximity of the pyridine N atom and the carbonyl C atom of the phenylbenzoyl residue, with non-bonded distance N s C of only 2.465(2) Å. A secondary, but significant distortion, involving displacement of the carbonyl C atom by more than 0.5 Å from the pyrrole ring, was evident. The crystal structure is maintained by C–H s O hydrogen bonds and – interactions.     

Molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene(phenylsulfonylimino)-σ3λ5-phosphorane

The crystal and molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene (phenylsulfonylimino)-³⁵-phosphorane, 2,4,6-Bu^t ₃-C₆H₂-P(=CHPh)(=N--SO₂Ph), has been determined. Crystal data: triclinic, , a = 9.472(5), b = 11.427(5), c = 13.684(5) Å, = 90.61(3), = 101.21(4), = 97.02(4)°, V = 1441.1 ų, Z = 2, D _c = 1.20 g cm^–3. The observed in 1 noticeable elongation of the P=N bond 1.563(3) Å and shortening of the P=C bond 1.617(3)Å have been discussed in terms of the electron withdrawing ability of substituents on the basis of ab initio (HF/6–31+G**) calculations of the model systems.     

X-ray Crystallographic Structures of Two Lamotrigine Analogues: (I) 3,5-Diamino-6-(2-chlorophenyl)-1,2,4-triazine Water Solvate and (II) 3,5-Diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine Methanol Solvate

Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine, C₉H₈ClN₅, (465BL) as a hydrate, and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine, C₉H₇Cl₂N₅, (469BR) as a methanol solvate, have been carried out at liquid nitrogen temperature and room temperature, respectively. A detailed comparison of the two structures is given. Both are centrosymmetric with (I) in the orthorhombic space group Pbca, a = 12.2507(3), b = 15.7160(6), c = 21.71496(9) ?, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) ?, β = 111.59(1)°, Z = 8. Final R indices [I > 2sigma(I)] for (I) are R1 = 0.0670, wR2 = 0.1515 and for (II) R1 = 0.0434, wR2 = 0.1185. Structure (I) has water of crystallization in the lattice and (II) includes a solvated CH₃OH. Structure (I) is characterized by having two crystallographically independent molecules, A and B, of 465BL, per asymmetric unit. Molecule B has a very unusual feature in that the 2-chlorophenyl ring is statistically disordered, occupying site (1) in 87.5% of the structure and site (2) in 12.5% of the structure. Sites (1) and (2) are related by an exact 180° pivot of the phenyl ring about the ring linkage bond. The presence of two independent molecules per asymmetric unit provides an ideal opportunity for the conformational flexibility of the molecule 465BL to be studied. Structure (I) also includes a further unusual feature in that the lattice contains one fully occupied water molecule and an additional solvated water which is only 33% occupied. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry The crystal structures of two lamotrigine analogues: (I) 3, 5-diamino-6-(2-chlorophenyl)-1, 2, 4-triazine, water solvate and (II) 3, 5-diamino-6-(3,6-dichlorophenyl)-1, 2, 4-triazine methanol solvate are presented. Structure (I) includes two molecules per asymmetric unit labeled A and B where molecule B is unusually disordered having Cl in either position 2 (87.5% occupied) or position 6 of the phenyl ring (12.5% occupied), the two sites being related by 180deg rotation about the ring linkage bond. Molecule I(A) on the other hand shows no disorder. The relative orientations of the two rings in I(A and B) and in II is shown to be different. Lamotrigine and analogues have been investigated for some time for their effects on the central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW 1003C87) are voltage-gated sodium channel blockers as well as blocking the release of the neurotransmitter glutamate. BW 1003C87 has also been shown to reduce the release of glutamate evoked by veratrine in brain tissue, providing a therapeutic approach in both cerebral ischemia and epilepsy [B. S. Meldrum, J. H. Swan, M. J. Leach, M. H. Millan, R. Gwinn, K. Kadota, S. H Graham, J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.]. This is one of a series of papers on the structures of lamotrigine analogues.      

Crystal structure of anhydrous bismuth iodate, Bi(IO3)3

Bismuth iodate was synthesized by precipitation from bismuth nitrate and iodic acid. The powder was dissolved in dilute nitric acid and single crystals were obtained by slow evaporation at 70°C. Bi(IO₃)₃ crystallizes in the monoclinic system, space group P2₁/n (N° 14), a = 8.8882(2) Å, b = 5.9445(2) Å, c = 15.2445(5) Å, = 97.064(1) Å. BiO9 polyhedra are edge-connected forming chains parallel to the b axis; these chains are linked through (IO₃) groups forming layers parallel to (101). The 3D framework is designed by linking these layers through long I–O bonds. DSC analysis shows a remarkable thermal stability.     

Low Temperature X-ray Structures of Two Crystalline Forms (I) and (II) of the Pyrimidine Derivative and Sodium Channel Blocker BW1003C87: 5-(2,3,5-Trichlorophenyl)-2,4-diaminopyrimidine

Abstract The X-ray crystal structures of two crystalline forms of 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine, C₁₀H₇Cl₃N₄ (code name BW1003C87) (I) and (II), have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are centrosymmetric, with structure (I) in the triclinic space group P unit cell a = 6.4870(10), b = 9.216(2), c = 12.016(2) ?, α = 75.78(3)°, β = 89.95(3)°, γ = 83.45(3)°, V = 691.5(2) ?³, Z = 2 and density (calculated) = 1.544 Mg/m3; and (II) in the monoclinic space group P2₁/c, unit cell a = 12.000(2), b = 7.518(2), c = 13.450(3) ?, β = 97.87(3)°, V = 1202.0(5) ?³, Z = 4, Density (calculated) = 1.600 Mg/m3. Structure (I) includes a solvated CH₃OH in the lattice. Final R indices [I > 2sigma(I)] are R1 = 0.0427, wR2 = 0.1075 for (I) and R1 = 0.0487, wR2 = 0.1222 for (II). R indices (all data) are R1 = 0.0470, wR2 = 0.1118 for (I) and R1 = 0.0623, wR2 = 0.1299 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. Both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW1003C87), the subject of the present study, are anticonvulsant as well as neuroprotective in models of brain ischaemia and in a model of white matter ischaemia. BW1003C87 is a sodium channel blocker which also reduces the release of the neurotransmitter glutamate. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this drug family and their biological activities. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine occurs in two crystalline forms whose X-ray structures are described here. The molecular conformations in (I) and (II) are quite distinct as illustrated, the ring linkage torsion angle differing by 23.5 deg. (I) has a methanol solvate molecule in the lattice.      

Reaction of 1,2-bis(diphenylphosphino)cyclobutenedione (bpcbd) with fac-BrRe(CO)3(THF)2: X-ray diffraction structure of the dimeric complex [BrRe(CO)3]2(bpcbd) ⋅ CH2Cl2

Treatment of the diphosphine ligand 1,2-bis(diphenylphosphino)cyclobutenedione (bpcbd) with the THF adduct fac-BrRe(CO)₃(THF)₂ at room temperature furnishes the new dirhenium compound [BrRe(CO)₃]₂(bpcbd) instead of the expected mononuclear compound fac-BrRe(CO)₃(bpcbd). [BrRe(CO)₃]₂(bpcbd) was characterized in solution by IR spectroscopy, and the solid-state structure was solved by X-ray crystallography. [BrRe(CO)₃]₂(bpcbd), as the CH₂Cl₂ solvate, crystallizes in the space group P , a = 11.173(1), b = 13.362(1), c = 15.250(1) Å, = 108.973(7)°, = 99.477(8)°, = 110.466(7)°, V = 1915.0(3) ų, Z = 2, and d _calc = 2.143 g-cm^–3. The structure of [BrRe(CO)₃]₂(bpcbd) consists of two rhenium centers that are six-coordinate and possess nearly ideal octahedral geometry. The two Re(CO)₃ units are linked together by the bridging diphosphine ligand and two bridging bromide groups.