scholarly journals Crystal structure of bis{(S)-1-[2-(diphenylphosphanyl)ferrocenyl]-(R)-ethyl}ammonium bromide dichloromethane monosolvate

Author(s):  
Afrooz Zirakzadeh ◽  
Berthold Stöger ◽  
Karl Kirchner

During the synthesis of an FeBr2complex with the PNP ligand (R,R,SFc,SFc)-[Fe2(C5H5)2(C38H35NP2)] (1), single crystals of the dichloromethane monosolvate of the Br−salt of the protonated ligand1H+were obtained serendipitously,i.e.[Fe2(C5H5)2(C38H36NP2)]Br·CH2Cl2. The crystal structure of1H·Br·CH2Cl2was determined by single-crystal X-ray diffraction. The mean bond lengths in the ferrocene units are Fe—C = 2.049 (3) Å and C—C = 1.422 (4) Å within the cyclopentadienyl rings. The mean C—N bond length is 1.523 (4) Å. The interplanar angle between the two connected cyclopentadienyl rings is 49.2 (2)°. One ferrocene moiety adopts a staggered conformation, whereas the other is between staggered and eclipsed. The Br−ions and the CH2Cl2molecules are located in channels extending along <100>. One ammonium H atom forms a hydrogen bond with the Br−ion [H...Br = 2.32 (4) Å and C—H...Br = 172 (3)°]. The second ammonium H atom is not involved in hydrogen bonding.

1998 ◽  
Vol 76 (3) ◽  
pp. 301-306
Author(s):  
Sengen Sun ◽  
James F Britten ◽  
Christopher N Cow ◽  
Chérif F Matta ◽  
Paul HM Harrison

The crystal structure of 3,4,7,8-tetramethylglycoluril (5) was determined by X-ray diffraction. The structure reveals a hydrogen-bonding motif in the crystal lattice that differs from that present in related glycolurils. The two sides of each molecule form part of two independent, but parallel, infinite helical chains. These chains are formed by the NH donor and C==O acceptor on one side of a glycoluril molecule, forming H-bonds to two different molecules at adjacent positions within the helix. On the other side of the same molecule, a similar motif generates another helix of opposite helicity to the first. The molecule has a crystallographic plane of symmetry through the two bridgehead carbon atoms and the two bridgehead methyl groups, which are syn-periplanar. Thus, 5 is similar to 3,4-dimethylglycoluril (3), but differs from some glycolurils, where there is a significant dihedral angle between the two bridgehead-to-bridgehead substituent bonds. Bond lengths and angles in 5 resemble those reported for 3, but bond lengths around the bridgehead positions are slightly lengthened relative to 3.Key words: glycoluril, 1,2,5,8-tetramethyl-2,6,7,8-tetraazabicyclo[3.3.0]octane-3,7-dione, X-ray diffraction, crystal structure, hydrogen-bond array.


1997 ◽  
Vol 52 (8) ◽  
pp. 901-905 ◽  
Author(s):  
Vera V Ponomareva ◽  
Victor V Skopenko ◽  
Konstantin V Domasevitch ◽  
Joachim Sieler ◽  
Thomas Gelbrich

Abstract The caesium hydrogen benzoylcyanoximate (L-) complex with 18-crown-6 of composition Cs(18-crown-6){H(L)2} has been prepared and studied by means of X-ray diffraction [monoclinic, space group P21/n, with a = 9.906(1), b = 18.387(3), c = 18.855(3)Å, β = 90.13(1)°, V = 3434.3(9) Å, Z = 4; final R1 = 0.043 for the 6431 independent reflections used. The lattice consists of Cs(18-crown-6)+ cations and complex hydrogen oximate anions {H(L)2}-, formed via strong hydrogen bonding between the oxygen atoms of nitroso-groups [O - - - O ca. 2.456(5)Å]. The caesium atom deviates by 1.492(3) Å from the mean plane of the oxygen atoms of the macrocyclic ether (dominant orientation of disordered ligand, 60%) and adopts a typical “sunrise coordination” [Cs-O (ether) 3.040(9)-3.312(7) Å]. The hydrogen oximate groups are bonded to the metal center only on one side of the crown ether plane via the oxygen atoms of nitroso-groups and the nitrogen atoms of cyano groups (Cs-O ca. 3.040(9), 3.312(7) Å; Cs-N ca. 3.469(5), 3.679(6) Å). The coordination polyhedron of Cs+ can be described as a distorted bicapped tetragonal prism.


Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.


2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.


2017 ◽  
Vol 74 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Urszula Anna Budniak ◽  
Paulina Maria Dominiak

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C5H6N5O+·Cl−, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50\overline{4}). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.


1979 ◽  
Vol 57 (1) ◽  
pp. 57-61 ◽  
Author(s):  
R. Melanson ◽  
F. D. Rochon

The crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2 has been determined by X-ray diffraction. The crystals are orthorhombic, space group P212121, with a = 12.486(6), b = 13.444(7), c = 14.678(11) Å, and Z = 4. The structure was refined by block-diagonal least-squares analysis to a conventional R factor of 0.050 and a weighted Rw = 0.045.The coordination around the platinum atom is square planar. Guanosine is bonded to platinum through N(7). The purine planar ring makes an angle of 62.7° with the platinum coordination plane. The structure is stabilized by hydrogen bonding.


2011 ◽  
Vol 75 (6) ◽  
pp. 2823-2832
Author(s):  
P. Elliott ◽  
A. Pring

AbstractThe crystal structure of the manganese phosphate mineral gatehouseite, ideally Mn52+(PO4)2(OH)4, space group P212121, a = 17.9733(18), b = 5.6916(11), c = 9.130(4) Å, V= 933.9(4) Å3, Z = 4, has been solved by direct methods and refined from single-crystal X-ray diffraction data (T = 293 K) to an R index of 3.76%. Gatehouseite is isostructural with arsenoclasite and with synthetic Mn52+(PO4)2(OH)4. The structure contains five octahedrally coordinated Mn sites, occupied by Mn plus very minor Mg with observed <Mn—O> distances from 2.163 to 2.239 Å. Two tetrahedrally coordinated P sites, occupied by P, Si and As, have <P—O> distances of 1.559 and 1.558 Å. The structure comprises two types of building unit. A strip of edge-sharing Mn(O,OH)6 octahedra, alternately one and two octahedra wide, extends along [010]. Chains of edge- and corner-shared Mn(O,OH)6 octahedra coupled by PO4 tetrahedra extend along [010]. By sharing octahedron and tetrahedron corners, these two units form a dense three-dimensional framework, which is further strengthened by weak hydrogen bonding. Chemical analyses by electron microprobe gave a unit formula of (Mn4.99Mg0.02)Σ5.01(P1.76Si0.07(As0.07)Σ2.03O8(OH)3.97.


2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.


1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.


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