Supramolecular architecture in azaheterocyclic phosphonates. III. Structures of an ethyl phosphonamidate and an ethyl phosphonate

2018 ◽  
Vol 74 (8) ◽  
pp. 907-916
Author(s):  
Anna Pietrzak ◽  
Jakub Modranka ◽  
Jakub Wojciechowski ◽  
Tomasz Janecki ◽  
Wojciech M. Wolf

The novel crystal structures of ethyl (S)-P-(4-oxo-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-3-yl)-N-[(R)-1-phenylethyl]phosphonamidate, C20H20N3O3PS, I, and diethyl (4-isopropyl-2-oxo-3,4-dihydro-2H-benzo[4,5]thiazolo[3,2-a]pyrimidin-3-yl)phosphonate, C18H25N2O4PS, II, were characterized by X-ray diffraction analysis. The crystal packing of I is dominated by two infinite stacks composed of symmetry-independent molecules linked by distinctively different hydrogen-bond systems. The structure of II shows a ladder packing topology similar to those observed in related phosphorylated azaheterocycles. Structural studies are supplemented by calculations on the interactions stabilizing the molecular assemblies using the PIXEL method. Additionally, fingerprint plots derived from the Hirshfeld surfaces were generated for each structure to characterize the crystal packing arrangements in detail. The aromaticities of the heterocyclic moieties have been investigated using HOMA and HOMHED parametrization and compared with structures reported previously.

2020 ◽  
Vol 76 (7) ◽  
pp. 681-689
Author(s):  
Wojciech Nitek ◽  
Agnieszka Kania ◽  
Henryk Marona ◽  
Anna M. Waszkielewicz ◽  
Ewa Żesławska

Four crystal structures of 2-amino-N-(dimethylphenoxyethyl)propan-1-ol derivatives, characterized by X-ray diffraction analysis, are reported. The free base (R,S)-2-amino-N-[2-(2,3-dimethylphenoxy)ethyl]propan-1-ol, C13H21NO2, 1, crystallizes in the space group P21/n, with two independent molecules in the asymmetric unit. The hydrochloride, (S)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium chloride, C13H22NO2 +·Cl−, 2c, crystallizes in the space group P21, with one cation and one chloride anion in the asymmetric unit. The asymmetric unit of two salts of 2-picolinic acid, namely, (R,S)-N-[2-(2,3-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium pyridine-2-carboxylate, C13H22NO2 +·C6H4NO2 −, 1p, and (R)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium pyridine-2-carboxylate, C13H22NO2 +·C6H4NO2 −, 2p, consists of one cation and one 2-picolinate anion. Salt 1p crystallizes in the triclinic centrosymmetric space group P\overline 1, while salt 2p crystallizes in the space group P41212. The conformations of the amine fragments are contrasted and that of 2p is found to have an unusual antiperiplanar arrangement about the ether group. The crystal packing of 1 and 2c is dominated by hydrogen-bonded chains, while the structures of the 2-picolinate salts have hydrogen-bonded rings as the major features. In both salts with 2-picolinic acid, the specific R 1 2(5) hydrogen-bonding motif is observed. Structural studies have been enriched by the generation of fingerprint plots derived from Hirshfeld surfaces.


1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.


1979 ◽  
Vol 57 (13) ◽  
pp. 1691-1693 ◽  
Author(s):  
Jean-Claude Braekman ◽  
Claude Hootele ◽  
Noah Miller ◽  
Jean-Paul Declercq ◽  
Gabriel Germain ◽  
...  

The isolation of the novel pentacyclic base megastachine (1), representative of a new type of Lycopodium alkaloid, is reported. Its structure has been determined by X-ray diffraction analysis.


1988 ◽  
Vol 53 (11) ◽  
pp. 2863-2876 ◽  
Author(s):  
Giovanni Valle ◽  
Marco Crisma ◽  
Kuo-Long Yu ◽  
Claudio Toniolo ◽  
Ram K. Mishra ◽  
...  

The synthesis of an analogue of the neuropharmacologically active peptide Pro-Leu-Gly-NH2 in which the Leu-Gly peptide bond has been replaced with a tetrazole moiety was carried out. The molecular and crystal structure of the tetrazole analogue Pro-Leuψ[CN4]Gly-NH2 was determined by X-ray diffraction and a comparison was made with the published X-ray structure of Pro-Leu-Gly-NH2. The tetrazole annular system turns out to be a good conformationally-restricted replacement for the cis-peptide bond in terms of bond lengths, bond angles and the ω torsion angle. The molecule was found to be folded at the -Leuψ[CN4]Gly- sequence, but it did not form the intramolecular N-H···O=C hydrogen bond characteristic of the type Vla β-bend conformation. In contrast to Pro-Leu-Gly-NH2, Pro-Leuψ[CN4]Gly-NH2 was found to be unable to enhance the binding of dopamine receptor agonists to the dopamine receptor.


Author(s):  
M. Rajasekar ◽  
K. Muthu ◽  
A. Aditya Prasad ◽  
R. Agilandeshwari ◽  
SP Meenakshisundaram

Single crystals of molybdenum-incorporated tris(thiourea)zinc(II) sulfate (MoZTS) are grown by the slow evaporation solution growth technique. Crystal composition as determined by single-crystal X-ray diffraction analysis reveals that it belongs to the orthorhombic system with space groupPca21and cell parametersa= 11.153 (2),b= 7.7691 (14),c= 15.408 (3) Å,V= 1335.14 (4) Å3andZ= 4. The surface morphological changes are studied by scanning electron microscopy. The vibrational patterns in FT–IR are used to identify the functional group and TGA/DTA (thermogravimetric analysis/differential thermal analysis) indicates the stability of the material. The structure and the crystallinity of the material were confirmed by powder X-ray diffraction analysis and the simulated X-ray diffraction (XRD) closely matches the experimental one with varied intensity patterns. The band gap energy is estimated using diffuse reflectance data by the application of the Kubelka–Munk algorithm. The relative second harmonic generation (SHG) efficiency measurements reveal that MoZTS has an efficiency comparable to that of tris(thiourea)zinc(II) sulfate (ZTS). Hirshfeld surfaces were derived using single-crystal X-ray diffraction data. Investigation of the intermolecular interactions and crystal packingviaHirshfeld surface analysis reveal that the close contacts are associated with strong interactions. Intermolecular interactions as revealed by the fingerprint plot and close packing could be the possible reasons for facile charge transfer leading to SHG activity.


2021 ◽  
Vol 77 (1) ◽  
pp. 11-19
Author(s):  
Damian Rosiak ◽  
Andrzej Okuniewski ◽  
Jarosław Chojnacki

By the reaction of benzoyl chloride, potassium isothiocyanate and the appropriate halogenoaniline, i.e. 2/3/4-(bromo/iodo)aniline, we have obtained five new 1-benzoyl-3-(halogenophenyl)thioureas, namely, 1-benzoyl-3-(2-bromophenyl)thiourea and 1-benzoyl-3-(3-bromophenyl)thiourea, C14H11BrN2OS, and 1-benzoyl-3-(2-iodophenyl)thiourea, 1-benzoyl-3-(3-iodophenyl)thiourea and 1-benzoyl-3-(4-iodophenyl)thiourea, C14H11IN2OS. Structural and conformational features of the compounds have been analyzed using X-ray diffraction and theoretical calculations. The novel compounds were characterized by solid-state IR and 1H/13C NMR spectroscopy. The conformations and intermolecular interactions, such as hydrogen bonds, π–π and S(6)...π stacking, and X...O (X = I or Br), I...S and I...π, have been examined and rationalized, together with four analogous compounds described previously in the literature. The set of nine compounds was chosen to examine how a change of the halogen atom and its position on the phenyl ring affects the molecular and crystal structures.


2018 ◽  
Vol 37 (1) ◽  
pp. 61 ◽  
Author(s):  
Nilgun Sen

A 1:1 co-crystal of trinitrotoluene (TNT) and 2,3-diaminotoluene was prepared by solvent evapo- ration, and the structure of the co-crystal was determined by single-crystal and powder X-ray diffraction. The results indicate that the main mechanism of co-crystallization originates from the intermolecular hy- drogen bonding (amino-nitro) and π-π stacking. We also examined the Hirshfeld surfaces and associated fingerprint plots of the co-crystal and reveal that the structures are stabilized by H…H, O–H, O…O and C…C (π-π) intermolecular interactions. We analyzed the crystal packing and show its influence upon im- pact sensitivity. The results highlight that co-crystallization is an effective way to modify the sensitivity, oxygen balance and density of explosives. 


1997 ◽  
Vol 53 (4) ◽  
pp. 708-718 ◽  
Author(s):  
A. Gjerløv ◽  
S. Larsen

The crystal structures have been determined for the diastereomeric salts formed by cinchonidine and the two enantiomers of mandelic acid using low-temperature [122 (1) K] X-ray diffraction data. The less soluble salt is cinchonidinium (S)-mandelate, C19H23N20O+.C8H7O3 −, M r = 446.53, monoclinic, C2, a = 21.400 (2), b = 6.2777 (6), c = 17.853 (2) Å3, \beta = 109.304 (8)°, V = 2263.6 (4) Å3, Z = 4, D x = 1.310 g cm−3, \lambda(Cu K\alpha = 1.54184 Å, Z = 7.08 cm−1, F(000) = 952, R 1 = 0.0259 for 2684 observed reflections. The cinchonidine salt with (R)-mandelic acid, C19H23N2O+.C8H7O3, has M r = 446.53, monoclinic, P21, a = 6.410 (3), b = 32.808 (11), c = 11.222 (2) Å, \beta = 100.67 (2)°, V = 2319.2 (13) Å3, Z = 4, D x = 1.279 g cm−3, \lambda(Cu K\alpha) = 1.54184 Å, \mu = 6.91 cm−1, F(000) = 952, R 1 = 0.0380 for 8951 observed reflections. The two salts have virtually identical hydrogen-bond patterns and similar herringbone stacking of the quinoline ring systems. The crystal packing of the two salts differ only with respect to the packing of the phenyl groups. The packing of the cinchonidinium mandelates is significantly different from the crystal packing in the corresponding mandelates of cinchonine. The lack of a quasidiastereomeric relationship between the two sets of salts can be attributed to the steric effects of the vinyl group. The similarities between the two cinchonidinium mandelate structures is a possible explanation to the similar solubilities of the salts. DSC and NMR measurements showed that the cinchonidinium salts undergo a chemical opening reaction in the solid state. The arrangement of hydrogen-bonded chains of alternating cations and anions appear to be important for the solid-state reaction to take place.


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