Helical chirality of 1-phenacyl-1,10-phenanthrolinium bromides

Evidence for non-coplanarity of the pyridine and pyridinium rings in a series of 1-phenacyl-1,10-phenanthrolinium bromides was gleaned from ¹H-NMR data recorded in DMSO-d ₆ solution. The X-ray structure of 1-(4-chlorophenacyl)-1,10-phenanthrolinium bromide, as representative of this series, was determined in order to establish whether such a molecular distortion occurs in the solid state. The title compound crystallizes in the space group C2/c as a sesquihydrate of formula C₂₀H₁₄BrClN₂O·1.5H₂O with a = 35.7348(3) Å, b = 5.3468(1) Å, c = 21.7312(2) Å, = 116.4076(4)° and Z = 8. In the crystal, the helical chirality is manifested as a pronounced twist in the phenanthrolinium moiety, with the pyridine and pyridinium rings inclined at 6.8(2)°. This distortion is attributed to intramolecular hydrogen bonding of type C–H···N involving the methylene group and the uncharged nitrogen atom of the phenanthrolinium moiety. In the crystal, the cations surround an intricate array of water molecules and bromide ions held together by O–H···Br^– hydrogen bonds and comprising infinite chains ···Br^–···H–O–H···Br^–···, cross-linked by water molecules.     

First example of cocrystals of polymorphic maleic hydrazide

The first cocrystals of polymorphic maleic hydrazide with 3-methyluracil have been studied by X-ray diffraction methods. They crystallize in the orthorhombic system, space group Pmcn, a = 6.440 (1) Å, b = 6.974 (1) Å, c = 22.829 (11) Å, V = 1025.3 (5) ų, Z = 4. The asymmetric unit contains one molecule of each compound. Planar ribbons of the (1:1) molecular complex are obtained through the formation of O–H···O and O–H···N intermolecular hydrogen bonds, just forming a well-known R² ₂(8) supramolecular synthon. Supramolecular assemblies are then formed by weak C–H···O and C–H···N hydrogen bonds through adjacent antiparallel ribbons.     

Dalspinin, an isoflavone from Dalbergia spinosa roots

The X-ray crystal structure of the plant isoflavone dalspinin from Dalbergia spinosa is determined. The compound, C₁₇H₁₂O₇, is monoclinic in P2₁/n with a = 3.970(1), b = 23.607(5), c = 14.633(3) Å, = 94.46(3)°, V = 1367.2(5) ų, D _calc = 1.595 g cm^–1 and Z = 4. The molecular structure is characterized by a short intramolecular O–H···O=C hydrogen bond, and a large tilt angle of the two rigid ring systems with respect to each other. The intermolecular interactions in the crystal are discussed.     

Crystal structure of N-benzylmethylammonium dihydrogen-monophosphate monohydrate, [C6H5CH2NH2CH3]H2PO4·H2O

The salt N-benzylmethylammonium dihydrogenmonophosphate monohydrate is monoclinic with the following unit cell dimensions: a = 6.356(1)Å, b = 8.385(7)Å, c = 11.472(5)Å, = 104.32(1)°, space group P2₁ with Z = 2. The structure consists of infinite parallel two-dimensional [110] planes built of mutually connected ions and water molecules by strong O–H···O and N–H···O hydrogen bonding. There are no contacts other than normal van der Waals interactions between the layers.     

Di-hydroxy malonic acid as a building block of hydrogen-bonded 3-dimensional architectures

An examination of the crystal structures of di-hydroxy malonic acid 1 (P2₁/na = 5.384(2), b = 6.268(2), c = 14.354(8) Å, = 103.57(3)°) and N-ethylbenzylammonium di-hydroxy hydrogenmalonate 2 (P2₁2₁2₁ a = 13.373(2), b = 15.342(4), c = 18.741(4) Å,) has highlighted the influence of directional O–H···O interactions in the assembly of hydroxy-substituted dicarboxylic acids. The complementarity of carboxylic and hydroxy groups in 1 creates a very dense 3-D structure (D _c = 1.919 g cm^–3) through four O–H···O hydrogen bonds. In 2, the anions form infinite, spiraling chains created by head-to-tail O–H···O hydrogen bonds. Neighbouring chains are crosslinked into a complex 3-D anionic network with channels parallel to a and b. The cations are positioned within these channels and held in place via two N–H···O interactions.     

A novel vanadyl selenite templated by organic salt: [(VO)(H2O)2(SeO3)]2[(H2pipe)SO4]

The title compound [(VO)(H₂O)₂(SeO₃)]₂[(H₂pipe)SO₄] was synthesized under hydrothermal condition with VOSO₄, piperazidine (pipe), and SeO₂, and its crystal structure was established using single-crystal X-ray diffraction method. The title compound was characterized with IRFluorescence. The crystal data: P-1 (No. 2), a = 8.633(2) Å, b= 9.223(2) Å, c= 12.508(3) Å, =109.28(3)°, =90.42(3)°, = 107.79(3)°, Mr = 644.08, V=888.5(3) ų, Z=2, Dc = 2.407 g cm^–3, =5.350 mm^–1, F(000)=632. The structure of the title compound consists of an infinite neutral ladder chain, which is built up from VO₆ octahedral and SeO₃ pyramidal units sharing vertices, and organic salt. The biprotonized pipe (piperazidine) and SO₄ ^2– interact with one another and the inorganic chain through strong hydrogen bonds N–H···O or O–H···O to give a 3D structure. Hydrogen bonds play a role of stabilization structure.     

Synthesis and crystal structure of two vanadium(V) hydroxylamido complexes with amino acid ligands

Two vanadium(V) hydroxylamido complexes with amino acid ligands including Alanine, [VO(NH₂O)₂(Ala)]·2H₂O, and Threonine, VO(NH₂O)₂(Thr), were synthesized and characterized by elemental analyses, IR spectrum, and single crystal X-ray diffraction. The two complexes are seven-coordinated with four nitrogen atoms and three oxygen atoms in pentagonal bipyramidal geometry. The different hydrogen bonds (N–H···O, O–H···O) observed in the two complexes result in the two-dimensional network structure. [VO(NH₂O)₂(Ala)]·2H₂O belongs to monoclinic: space group P2(1)/c, with a = 21.874(13) Å, b = 8.874(5) Å, c = 15.865(9) Å, = 100.423(8)°, V = 3029(3) ų, Z = 12, D _c = 1.678 g/cm³, (MoK) = 1.002 mm^–1, F (000) = 1584, and final R ₁ = 0.0375, wR ₂ = 0.0886 for observed reflections 1189 (IT > I> 2(I)). VO(NH₂O)₂(Thr) is rhombohedral: space group R-3, with a = 21.460(16) Å, b = 21.460(16) Å, c = 11.184(12) Å, = 120°, V = 4461(7) ų, Z = 18, D _c = 1.669 g/cm³, (MoK) = 1.012 mm^–1, F(000) = 2304, and final R ₁ = 0.0356, wR ₂ = 0.0924 for observed reflections 1306 (I > 2(I)).     

Regiospecificity of nucleotide–amino acid mating vs. water dynamics: a key to protein–nucleic acid assemblies: structure of unidecahydrated inosine-5′-monophosphate and L–glutamic acid (2C10H13N4O8P·C5H11NO4·11H2O) cocrystal at atomic resolution

The crystal structure of a unidecahydrated cocomplex between two Inosine-5-monophosphates (IMP) and one L-glutamic acid has been determined by X-ray crystallographic methods. The crystal belongs to the monoclinic space group P2₁ with cell dimensions a = 8.650(1), b = 21.900(1), c = 12.370(1) Å, and = 110.4°(9). This structure reveals extensive hydrogen bonding of glutamic acid to the nucleotide through direct and water-mediated interactions. The phosphate oxygens (O3B and O1B) seem to prefer nonspecific interaction with the functional sites of glutamic acid (OE2 ······O1B = 1.78 Å, NA······O3B = 2.73 Å, OH······O3B = 3.06 Å), whereas the bases prefer specific (O······N3B = 2.88 Å) binding. A solvent mediated N7A···W5···N7B hydrogen bond used for stabilization of the stacked purine bases has been observed as in other amino acid–nucleotide cocrystals. Glutamic acid occupies the same hydrophilic region in the nucleotide cocrystal as was found in glutamine–inosine monophosphate (Gln–IMP) and in serine–inosine monophosphate (Ser–IMP) complexes through substantial replacement of free and bound water molecules. This points to the dynamic hydrogen bonding nature of the water molecules and their stereochemical cooperation for the placement of amino acid through the polycoordination within the crystal.     

One-dimensional chain structure based on bifurcated hydrogen bonding

The structure of complex [PyH][Ni(mnt)₂], as determined by X-ray single crystal analysis, consists of pyridinium cations and [Ni(mnt)₂]^– anions. Crystallographic data for the complex: monoclinic P2₁/c, a = 16.5430(18) Å, b = 6.3847(9) Å, c = 17.430(2) Å, = 118.040(7)°, V = 1625.4(3) ų, Z = 4. The [Ni(mnt)₂]^– anion is not a planar and the CN groups bend away from the S₄ plane. The interactions between anions and cations via the formation of bifurcated N–H···NC hydrogen bonds give rise to an 1D zigzag chain of alternating cations and anions.     

Crystal structure of [Mn2(III)(salpa)2Cl2(H2O)2] (H2salpa = 1-(salicylaldeneamino)-3-hydroxypropane)

The manganese complex, (Mn₂(III)(salpa)₂Cl₂(H₂O)₂], has been prepared and its structure determined using x-ray crystallography. The dimer is a di-₂-alkoxo complex which is a six-coordinate manganese dimer with unsupported alkoxide bridges and a rare example of a chloride- and water-containing manganese dimer. The complex crystallizes in the monoclinic space group P2₁/c with a = 9.315(5), b = 11.130(4), c = 11.637(5) Å, = 104.33(3)°, V = 1169.0(9) ų, and Z = 2. The structure comprises discrete binuclear clusters in which the metal atoms are bridged by two alkoxo oxygens of the salpa^2– ligands. The Mn—O and Mn—N distances are in good agreement with those found for other manganese(III) Schiff base complexes. The Mn—Cl and Mn—O3 distances are 2.585(2) and 2.371(2) Å, respectively, and the Mn ··· Mn distance is 3.001(1) Å. In the crystal, there are two types of hydrogen bonding between the H₂O molecule and the Cl atom with Cl ··· H(H₂O) distance of 2.33(6) (intramolecule: –1 + x, y, –1 + z) and 2.68(6) Å (intermolecule: –1 + x, 0.5–y, –0.5 + z).     

Structures of 1,2,3,4-tetrahydro-6H-pyrimido[2,1-b]-quinazolin-6-one and its hydrochloride

C₁₁H₁₁N₃O, m.p. 243°C, P2/n,Z=4,a=5.843(2),b=14.241(3),c=11.102(1) Å, =93.30(2)°,R=0.046; C₁₁H₁₁N₃O·HCl·H₂O, Pca2₁,Z=8,a=18.640(2),b=8.894(2),c=14.404(2)Å,R=0.062. The molecules of the free base are in 1H-tautomeric form. N(1)-H...N(11) hydrogen bonds join molecules of the free base into dimers, which enable tautomeric rearrangement (not observed in this study) also in the solid state without any changes in molecular packing. The quinazoline system deviates slightly from planarity and benzene electrons are partially localized at C(7)–C(8) and C(9)–C(10) bonds as seen from their lengths of about 1.375 Å, while other bonds in the benzene ring are at least 0.02 Å longer.     

Stereochemistry of racemic hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) thiocyanate,C16H32N4Ni(SCN)2 · H2O

The diamagnetictrans-diene thiocyanate salt of the macrocyclic hexamethyl-1,4,8,11-tetraazacyclotetradecadienenickel(II) complex crystallizes in the triclinic system with unit cell dimensions:a = 7·334(4),b = 8·808(6),c = 21·04(2) Å; = 63·7(0·9), = 103·8(1·4), = 110·2(1·3) °; space groupP¯1;Z = 2. The positions of all 62 atoms of the formula unit C₁₆H₃₂N₄Ni(SCN)₂.H₂O have been determined and refined by least-squares methods toR= 0·071 for 3536 X-ray diffractometric reflections. The optical activity of the two amine groups yields a racemic isomer. The only local symmetry element of the macrocyclic complex is the twofold rotation axis with the N-H bonds oriented on the same side of the approximate ligand plane. Both the C(CH₃)₂ and the imine groups are in atrans-configuration in the ring. The space group ensures that the crystal is a racemate, containing equal numbers of both enantiomers. One of the (SCN)^– groups is at a distance Ni-S 3·28 Å, the other one is 4·65 Å. No rotational disorder of the CH₃ groups has been observed. The three C-H bonds of the CH₃ groups are in approximately antiprismatic orientations with respect to the three -bonds in the case of bonding to a C(sp³) atom. The average of the C(sp³)-C(sp²) bond lengths is 1·53 Å, and the mean value for the C(sp³)-C(sp²) bonds is 1·50 Å, with 3 = 0·03 to 0·04 Å. The distances N(sp²)-C(sp³) 1·47 Å and 1·48 Å are significantly longer than the bond lengths N(sp²)=C(sp²) of 1·28 and 1·30 Å.     

Conformation and structure of 1,3-bis(2-hydroxy-5-bromosalicylideneamine)propan-2-ol

The Schiff base, 1,3-bis(2-hydroxy-5-bromosalicylideneamine)propan-2-ol, has been studied by AM1 semiempirical quantum mechanical method and X-ray analysis. It crystallizes in the orthorhombic space group Pca2₁ with a = 8.458(3), b = 6.139(2), c = 32.957(4) Å, D_calc = 1.770 g cm^-3, V = 1711(1) ų, Z = 4 and (MoK) = 0.476. The structure was solved by direct methods and refined to R = 0.041 for 1715 independent reflections [I > 2 (I)]. The title compound is not planar. Intramolecular hydrogen bonds are found between the hydroxyl and the amine nitrogen with O—H···N distances of 2.601(6) and 2.629(4) Å. There is also an intermolecular O—H···N hydrogen bond [3.176(6) Å] linking the neighbouring molecules. Minimum energy conformations from AM1 were calculated as a function of eight torsion angles varied every 5°. The optimized geometry of the crystal structure corresponding to the nonplanar conformation is the most stable conformation in all calculations. The results strongly indicate that the minimum energy conformation is primarily determined by nonbonded hydrogen—hydrogen repulsions.     

Crystal structure of tris(triphenylsiloxy)borane·triphenylsilanol (1:1) adduct

The title compound crystallizes in the triclinic space group , with a = 14.458(6), b = 14.630(5), c = 14.721(8) Å, = 79.75(2), = 80.11(3), = 80.50(3)°, and Z = 2. The crystal structure consists of molecules of (Ph₃SiO)₃B and Ph₃SiOH linked by an weak B···(silanol) acceptor-donor bond, additionally stabilized by OH(silanol)···O(siloxy) hydrogen bonds. The average B–O, Si–O distances and B–O–Si angle are 1.369, 1.649 Å and 137.2°, respectively.     

The crystal structures of p-iodo-N-(p-cyanobenzylidene)aniline and p-cyano-N-(p-iodobenzylidene)aniline

The crystal structures of the isomers NC–C₆H₄–CH=N–C₆H₄–I (CN/I) and I–C₆H₄–CH=N–C₆H₄–CN (I/CN) have been determined. CN/I is triclinic, space group P1¯ with a = 7.504(3), b = 11.936(4), c = 7.304(2) Å, = 93.09(2), = 110.49(2), = 99.04(2)°, V = 601.1(3) ų, Z = 2, and D _x = 1.818(1) g cm^–3. In both compounds there are chains of molecules held together by CN···I interactions, with N···I distances of 3.15 and 3.26 Å, respectively. The chains form similar two-dimensional sheets, which, however, stack differently in the two compounds.     

Crystal structure of quinestrol hemiethanolate

The X-ray crystal structure of the synthetic sex steroid quinestrol (3-O-cyclopentyl-17-ethynylestradiol) as crystallized from ethanolic solution is determined. The asymmetric unit contains two steroid and one ethanol molecules. The conformation of the two steroid molecules differs in the orientation of the cyclopentane ring. The cocrystallized ethanol molecule facilitates formation of cooperative O—H···O hydrogen bonding. The title compound crystallizes in the monoclinic space group P2₁, with a = 13.950(6), b = 6.5945(8), c = 25.403(8) Å, = 104.78(4)°, and D _calc = 1.136 g cm^–1 for Z = 4.     

Crystal structure of a one-dimensional ladder-shape CoII complex through hydrogen bonds with an amino-acid-like ligand 1,5-diazacyclooctane-N,N′-diacetate acid

The crystal structure of a one-dimensional ladder-shape complex [CoL(H₂O)]·2H₂O, (L being 1,5-diazacyclooctane-N,N-diacetate acid), has been determined by X-ray diffraction analysis: monoclinic, space group P2₁/c with a = 14.406(4) Å, b = 7.380(2) Å, c = 14.594(5) Å, = 112.685(2)°, M _r = 341.23, V = 1431.5(8) ų, Z = 4. The Co^II center is penta-coordinated by two O atoms of the carboxylic pendant arms, two nitrogen donors of the 1,5-diazacyclooctane (DACO) moiety, and a water molecule. The coordination geometry of Co^II could be described as a distorted square pyramid and the DACO backbone adopts a normal boat/chair conformation. The complex forms a one-dimensional ladder-shape structure through inter- and intra-molecular O—H···O hydrogen bonds.     

Synthesis and structure of p-chlorophenylhydrazone of 3-(methylthio)-5-propanoyl-1,2,4-triazine

The reaction of 3-(methylthio)-5-propanoyl-1,2,4-triazine with p-chlorophenylhydrazine hydrochloride is completed within 5 min at room temperature in ethanol leading to p-chlorophenylhydrazone of 3-(methylthio)-5-propanoyl-1,2,4-triazine 1 in good yield. Title compound, 1 (R = C₂H₅, R₁ = Cl, Z = SCH₃), C₁₃H₁₄N₅SCl, crystallizes in the monoclinic system, space group P2₁/n, with cell constants a = 12.5206(6) Å, b = 9.3122(8) Å, c = 12.8524(9) Å, and = 98.822(5)°, Z = 4, T = 293 K, D_cal = 1.381 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0671 for 1,679 reflections. The molecule as a whole has an almost planar conformation and possesses (E) configuration with respect to the C=N double bond. The crystal structure is stabilized by a weak N(13)–H(13)···N(2) intermolecular hydrogen bond and significant stacking, characteristic for -electron systems.     

Synthesis and crystal structure of [Y(NO3)3(OH2)3]·(Me2-16-crown-5)·H2O

The complex [Y(NO₃)₃(OH₂)₃]·(Me₂-16-crown-5)·H₂O has been prepared and its crystal and molecular structure determined using single crystal X-ray diffraction. The colorless crystals belong to the monoclinic space group P2₁/n with Z = 4. Lattice parameters are a = 10.420(1), b = 17.257(3), c = 14.646(2) Å, = 96.79(1)°, V = 2615.1(6) ų. The yttrium(III) ion is nine-coordinate, bonded to three bidentate nitrate groups and three water molecules. The average Y–O(nitrate) and Y–O(water) distances are 2.42(3) and 2.33(1) Å, respectively. The average HO–H···O hydrogen bonded separation is 2.767Å.     

Crystal and molecular structure of 2,7-di-tert-butyl-9,9-dimethyl-4,5-xanthenedicarboxylic acid

The crystal and molecular structure of molecular cleft 2,7-di-tert-butyl-9,9-dimethyl-4,5-xanthenedicarboxylic acid (1) is reported. Crystal data for 1: triclinic, space group P, a = 7.934(2), b = 10.387(2), c = 14.084(3) Å, = 96.049(3), = 101.231(4), = 95.635(4)°, V = 1123.7(4) ų, and D _c = 1.21 g/cm³, for Z = 2. The molecule crystallizes as a cyclic, hydrogen-bonded dimer held together by four O–H······O hydrogen bonds involving four carboxyl groups each of which interact by way of a cyclic hydrogen-bonded motif. The complex organizes in the solid state to form a 2D layered structure.