scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

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.

2018 ◽  
Vol 73 (5) ◽  
pp. 281-288
Author(s):  
Qing Zhao ◽  
Ying-Qi Pan ◽  
Xiao-Yan Li ◽  
Han Zhang ◽  
Wen-Kui Dong

AbstractA discrete heterotrinuclear complex [{Ni2LDy(OAc)3(CH3OH)}2] · 2CH3OH · 3CH2Cl2, with a naphthalenediol-based acyclic bis(salamo) ligand H4L, has been synthesized and structurally characterized using elemental analyses, IR, UV/Vis and fluorescence spectra and single crystal X-ray diffraction. The crystal structure shows two crystallographically independent but chemically identical molecules (molecules I and II). All the Ni(II) atoms are hexa-coordinated with slightly distorted octahedral geometries. The central Dy atoms are nona-coordinated with slightly distorted tricapped trigonal prism geometries. An infinite 3D supramolecular structure is formed via intermolecular hydrogen bonding and C–H…π interactions.


Synthesis ◽  
2017 ◽  
Vol 49 (11) ◽  
pp. 2389-2393 ◽  
Author(s):  
Stefanie Pelzer ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
Nikolai Ignat’ev ◽  
Reint Eujen ◽  
...  

This paper describes the synthesis and comprehensive characterization of tetrakis(pentafluoroethyl)germane. In addition to a complete NMR spectroscopic characterization, including the rarely used 73Ge NMR spectroscopy, Ge(C2F5)4 was studied by IR spectroscopy, mass spectrometry as well as X-ray diffraction analysis. A 73Ge NMR investigation as well as an X-ray diffraction study of the related germane Ge(CF3)4 are also included.


The crystal structure of naphthazarin C has been determined by neutron diffraction at 60 and 300 K (λ ═ 0.895 Å; 1 Å ═ 10 -10 m ═ 10 -1 nm) and X-ray diffraction at 300 K. The space group is Pc at 60 K, but P 2 1 /c at 300 K. There are small but significant differences in cell dimensions at the two temperatures: a ═ 7.664 (7.915), b ═ 7.304 (7.262), c ═ 15.16 (15.284) Å; β ═ 114.60 (114.20)°; Z ═ 4; U ═ 771.6 (801.3) Å 3 (values at 300 K in parentheses). Neutron diffraction shows that the Pc and P 2 1 /c structures are related by an order-disorder transition at 110±1 K. Structure analysis (1771 reflections; R F ═ 0.035; R W ═ 0.036) showed that the hydroxyl hydrogens are largely ordered at 60 K, the appropriate molecular formula being 5, 8-dihydroxy-1, 4-naphthadione. Neutron diffraction measurements at 300 K (1769 reflections; R F ═ 0.052) indicated a disordered molecular model with one-half of an hydrogen atom attached to each oxygen. X -ray diffraction measurements on naphthazarin C at 300 K (two independent sets of intensity measurements, one with CuKα and the other with MoKα) support this disordered model. The molecular dimensions for naphthazarin A and B also fit this model. Comparison of the crystal structure of naphthazarin C with those of the A and B polymorphs shows that only the former has intermolecular O─H • • • O hydrogen bonding. The diffraction results combined with the available solid-state n. m. r. data show that there is at room temperature a rapid intramolecular exchange of hydroxylic protons between each pair of oxygen atoms in all three naphthazarin polymorphs. Many 1, 3-diketones exist in an enol form in the solid. These enol forms have been reported to be disordered for about twenty molecules at room temperature (this total includes one molecule studied at 108 K, and four amino-imino systems) and ordered systems have been reported for about fifteen molecules. Intermolecular hydrogen bonding occurs only in a few of these crystals.


2001 ◽  
Vol 56 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Josef Engering ◽  
Eva-Maria Peters ◽  
Martin Jansen

Abstract [Si(N(CH3)2)2(NLiC(CH3)3)2]2 results from the reaction of silicon tetrachloride with excess terf-butylamine, followed by halogen substitution with LiN(CH3)2, and treatment with n-butyllithium in hexane. The title compound, found to be dimeric in the solid state, was characterised by single crystal X-ray diffraction (triclinic, Pi , a = 10.208(2), b = 12.140(2), c = 15.658(3) Å , a = 79.02(3), ß = 82.80(3), γ = 67.19(3)°, Z = 2, C24H60Li4N8Si2 ), and by solid state and solution NMR-spectroscopy and mass spectrometry.


2011 ◽  
Vol 66 (3) ◽  
pp. 262-268
Author(s):  
Laurent Plasseraud ◽  
Hélène Cattey ◽  
Philippe Richard

The new dodecanuclear organostannoxane {[(PhCH2Sn)12(μ3-O)14(μ-OH)6](F3CSO3)2} (2) has been isolated as single crystals from the reaction of trifluoromethanesulfonic acid (F3CSO3H) with the decanuclear dibenzyltin(IV)-oxo cluster, [(PhCH2)2SnO]6{[(PhCH2)2SnOH]2(CO3)}2 (1), in [D3]acetonitrile, at room temperature. Compound 2 was structurally characterized by X-ray diffraction analysis, multinuclear NMR and IR spectroscopy, mass spectrometry, and thermogravimetry. The structure of 2 can be described as a football cage framework containing twelve tin atoms, exhibiting two distinct coordination geometries, penta- and hexacoordinated respectively, and linked together through μ3-O and μ-OH ligands. Resulting from Sn-C bond cleavage, all tin atoms are only connected to one benzyl ligand. Furthermore, two of the three oxygen atoms of each trifluoromethanesulfonate counteranions are involved in hydrogen bonding interactions with bridging μ-OH groups of two distinct Sn12 cations leading to the propagation of a two-dimensional polymeric network.


2012 ◽  
Vol 67 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Xian Feng Zhu ◽  
Li Zhi Zhang ◽  
Min Yang ◽  
Yan Ke Li ◽  
Ming Xue Li

The diorganotin(IV) complex [Ph2Sn(L)(CH3COO)] (1), where HL = 2-acetylpyrazine N4-methyl thiosemicarbazone, has been synthesized and characterized by elemental analysis, IR, UV/Vis and NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. Complex 1 contains mononuclear neutral molecules composed of one N2S tridentate anionic thiosemicarbazone ligand, one acetato group, and one Ph2Sn(IV) group with a seven-coordinated tin atom. In vitro biological studies have indicated that complex 1 shows effective cytotoxicity with IC50 = 5.4 μM against the K562 leukaemia cell line.


2006 ◽  
Vol 61 (11) ◽  
pp. 1421-1425 ◽  
Author(s):  
Maasoomeh Tabatabaee ◽  
Mitra Ghassemzadeh ◽  
Behnaz Zarabi ◽  
Bernhard Neumüllerc

Reaction of 4-amino-6-methyl-3-thio-3,4-dihydro-1,2,4-triazin-5(2H)-one (1) with 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2-pyridinecarbaldehyde, and 2,4-dichlorobenzaldehyde under classical heating and microwave irradiation in a solventfree system led to the corresponding imines (Schiff bases) 2-5. All synthesized compounds have been characterized by IR and NMR spectroscopy, mass spectrometry and by X-ray diffraction studies.


2000 ◽  
Vol 78 (11) ◽  
pp. 1380-1387
Author(s):  
Reinhold Tacke ◽  
Alistair Stewart ◽  
Joachim Becht ◽  
Christian Burschka ◽  
Ingo Richter

Treatment of Si(OMe)4 with three molar equivalents of 1,2-C6H4(OH)2 (= 1,2-dihydroxybenzene) and two molar equivalents of HO(CH2)nNMe2 (n = 2, 3) in acetonitrile at room temperature yields the λ6Si-silicates (HO(CH2)nNMe2H)2(SiL3) (5: n = 2; 6: n = 3; L2– = 1,2-C6H4(O)22– (= benzene-1,2-diolato(2–))). The analogous λ6Ge-germanates (HO(CH2)nNMe2H)2(GeL3) (7: n = 2; 8: n = 3) were synthesized analogously starting from Ge(OMe)4. Compounds 5·2CH3CN and 6-8 were structurally characterized by single-crystal X-ray diffraction. In addition, aqueous solutions of the Si/Ge analogs 5/7 and 6/8 were studied by NMR spectroscopy. The title compounds may be regarded as model systems for the transport and storage of silicon in biological systems and as tools to investigate biosilification.Key words: hexacoordinate silicon, hexacoordinate germanium, silicon biochemistry


2014 ◽  
Vol 10 (2) ◽  
pp. 2262-2265
Author(s):  
Salwa Hamzaoui ◽  
Bochra Ben Salah ◽  
Awatef Rekik ◽  
Mohamed Kossentini

The condensation of two molar equivalents of N1-tosylhydrazonate 1 with one molar equivalent of 1,2-diaminoethane give birth to amidrazone in good yields. The structure of the synthesized compound was identified by X-ray diffraction, IR spectroscopy and nuclear magnetic resonance. 


2009 ◽  
Vol 64 (4) ◽  
pp. 423-426 ◽  
Author(s):  
Constantin Mamat ◽  
Helmut Reinke ◽  
Peter Langer

Three new CF3-substituted bicyclic salicylate derivatives were synthesized by the TiCl4-mediated cyclization of trifluoromethyl-containing ketones with 1,3-bis(silyl enol ethers) and characterized by NMR and IR, spectroscopy, mass spectrometry and elemental analysis. The crystal structures of the bicyclic derivatives have been determined by single crystal X-ray analysis. All structures exhibit hydrogen bonding.


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