Cooperative Effects in Aminothiols: Acid-Base Equilibria and the Molecular Structure of 2-(N, N-Dimethylaminomethyl)thiophenol

2008 ◽  
Vol 63 (10) ◽  
pp. 1199-1203
Author(s):  
Holger Fleischer ◽  
Dieter Schollmeyer
Keyword(s):  
Molecular Structure ◽  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Solid State ◽  
Ab Initio ◽  
Ab Initio Methods ◽  
Asymmetric Unit ◽  
Acid Base ◽  
Cooperative Effects ◽  
Independent Molecules

Abstract2-(N,N-Dimethylaminomethyl)thiophenol, (1, HL), is present as a non-zwitterionic aminothiol in the solid state, exhibiting an intramolecular S-H···N hydrogen bond. The S···N distances of the two independent molecules in the asymmetric unit are 2.929(10) and 3.050(10) Å. This structural feature is also present in an ab initio (MP2/6-31G*) optimized molecular structure. The investigation of the hydrogen bond by ab initio methods supports an n(N)-σ *(S-H) interaction as the reason for this bond type. On the basis of data from potentiometric acid-base titrations of a 0.01 M aqueous solution of [H2L]Cl with a 0.1 M aqueous solution of sodium hydroxide, values of 4.09±0.01 and 11.50±0.01 were obtained for pKa1 and pKa2 of [H2L]+. pKa1 is much smaller than pKa of thiophenol while pKa2 is bigger than pKa of benzyldimethylamine. The increased difference between pKa1 and pKa2 is attributed to the stabilization of HL by the intramolecular S-H···N hydrogen bond.

3-Oxoandrosta-4,6-dien-17β-yl 2-methyl-1H-imidazole-1-carboxylate and 3-oxo-5α-androst-17β-yl 2-methyl-1H-imidazole-1-carboxylate: C—H...π and π–π intermolecular interactions

2009 ◽  
Vol 65 (3) ◽  
pp. o88-o91
Author(s):  
Manuela Ramos Silva ◽  
Vânia M. Moreira ◽  
Cláudia Cardoso ◽  
Ana Matos Beja ◽  
Jorge A. R. Salvador
Keyword(s):  
Solid State ◽  
Ab Initio ◽  
Torsion Angle ◽  
Molecular Conformation ◽  
Asymmetric Unit ◽  
Compound I ◽  
The Mean ◽  
Independent Molecules ◽  
Compound Ii ◽  
Supramolecular Aggregation

The title compounds, C24H30N2O3, (I), and C24H34N2O3, (II), both contain an androstane backbone and a 2-methylimidazole-1-carboxylate moiety at the 17-position. Compound (I) contains two symmetry-independent molecules (denoted 1 and 2), while compound (II) contains just one molecule in the asymmetric unit. The C—C—O—C torsion angle that reflects the twisting of the 2-methylimidazole-1-carboxylate moiety from the mean steroid plane is 143.1 (2)° for molecule 1 of (I), 73.1 (3)° for molecule 2 of (I) and 86.63 (17)° for (II). The significance of this study lies in its observation of significant differences in both molecular conformation and supramolecular aggregation between the molecules of the title compounds. The solid-state conformations compared with those obtained theoretically fromab initiomethods for the isolated molecules show large differences, especially in the orientation of the methylimidazole substituent.

(4-Pyridyl)methyl N-phenylthiocarbamate

2006 ◽  
Vol 62 (7) ◽  
pp. o2852-o2853 ◽  
Author(s):  
Hai-Lian Xiao ◽  
Ke-Fei Wang ◽  
Fang-Fang Jian
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Title Compound ◽  
Intermolecular Hydrogen Bond ◽  
Phenyl Isothiocyanate ◽  
Dioxane Solution ◽  
Asymmetric Unit ◽  
Hydrogen Bond Interactions ◽  
Compound C ◽  
Independent Molecules

The title compound, C13H12N2OS, was prepared by the reaction of (4-pyridyl)methanol with phenyl isothiocyanate and NaOH in a 1,4-dioxane solution. The asymmetric unit contains two independent molecules. The molecular structure and packing are stabilized by N—H...N intermolecular hydrogen-bond interactions and C—H...π interactions.

scholarly journals Crystal structure of 3-[(E)-(2-hydroxy-3-methoxybenzylidene)amino]-1-methyl-1-phenylthiourea

2016 ◽  
Vol 72 (5) ◽  
pp. 608-611
Author(s):  
Rajeswari Gangadharan ◽  
Mathiyan Muralisankar ◽  
Anandaram Sreekanth ◽  
Abdullakutty Anees Rahman ◽  
K. Sethusankar
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Asymmetric Unit ◽  
Compound C ◽  
Benzene Rings ◽  
Independent Molecules

In the asymmetric unit of the title compound, C16H17N3O2S, there are two independent molecules (AandB), which show anEconformation with respect to the C=N bond. An intramolecular O—H...N hydrogen bond with anS(6) motif stabilizes the molecular structure. The terminal phenyl and benzene rings are almost orthogonal to each other, the dihedral angle being 87.47 (13)° for moleculeAand 89.86 (17)° for moleculeB. In the crystal, weak bifurcated N—H...(O,O) hydrogen bonds link the two independent molecules, forming a supramolecular chain with aC21(14)[R21(5)] motif along thebaxis. A weak C—H...O interaction is also observed in the chain.

Topochemically controlled solid-state methyl rearrangement in thiocyanurates

2001 ◽  
Vol 57 (3) ◽  
pp. 428-434 ◽  
Author(s):  
Mark Greenberg ◽  
Vitaly Shteiman ◽  
Menahem Kaftory
Keyword(s):  
Solid State ◽  
Driving Force ◽  
Mirror Plane ◽  
Energy Calculation ◽  
Asymmetric Unit ◽  
Methyl Transfer ◽  
Plate Shape ◽  
Polymorphic Forms ◽  
Independent Molecules ◽  
The Difference

4,6-Dimethoxy-3-methyl-1,3,5-triazine-2(3H)-thione crystallizes in two polymorphic forms, needles and plates. In the needle-shaped crystals (9a) the molecules occupy the crystallographic mirror plane, thus the layers are stacked along the b axis. The molecules of the other polymorph [plate-shape crystals, (9b)] are packed in a herringbone packing mode. Upon heating, (9b) undergoes a phase transition to form (9a). At 378 K the needles undergo O → S topochemically controlled methyl transfer in the solid state to produce 1-methyl-4-methoxy-6-methylthio-1,3,5-triazine-2(1H)-one in 75% yield. The enthalpy of the rearrangement is estimated to be −39.1 kJ mol−1. 1-Methyl-6-methoxy-4-methylthio-1,3,5-triazine-2(1H)-thione crystallizes in space group P21 with two crystallographically independent molecules in the asymmetric unit. Compound (9b) undergoes O → S methyl transfer in the solid state at 373 K. The rearrangement is topochemically assisted and the product, 1-methyl-2,4-bismethylthio-1,3,5-triazine-6(1H)-one, is obtained in quantitative yield. The enthalpy of the rearrangement is estimated to be −58.8 kJ mol−1. The crystal structures of the compounds as well as their DSC thermographs are described and discussed. Energy calculation by ab initio methods shows that the driving force for the reactions is the difference between the molecular energies of the pre-rearranged compounds and their products, 54.2 and 59.3 kJ mol−1 in the two cases, respectively.

scholarly journals Methyl 1-allyl-4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate

2013 ◽  
Vol 69 (11) ◽  
pp. o1698-o1698 ◽  
Author(s):  
Svitlana V. Shishkina ◽  
Igor V. Ukrainets ◽  
Lidiya A. Petrushova
Keyword(s):  
Hydrogen Bond ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Compound C ◽  
Two Component ◽  
Independent Molecules ◽  
Population Ratio ◽  
Intramolecular Hydrogen ◽  
Vinyl Group ◽  
Planar Fragment

There are two independent molecules in the asymmetric unit of the title compound, C13H13NO5S, in both of which the ester substituent is nearly coplanar [C—C—C—O torsion angles = 2.7 (7) and −0.8 (7)°] with the planar fragment of the bicycle due to the formation of a strong O—H...O intramolecular hydrogen bond. The vinyl group at the ring N atom is approximately orthogonal to the heterocyclic mean plane [C—N—C—C torsion angles = 103.1 (6) and 98.2 (5)°]. The refinement was performed on a two-component, non-merohedrally twinned crystal [population ratio = 0.483 (3):0.517 (3).

scholarly journals 2,3-Dihydrobenz[4,5]imidazo[2,1-b]thiazole

IUCrData ◽  
2016 ◽  
Vol 1 (12) ◽  
Author(s):  
Ahmed Moussaif ◽  
Youssef Ramli ◽  
Nada Kheira Sebbar ◽  
El Mokhtar Essassi ◽  
Joel T. Mague
Keyword(s):  
Hydrogen Bond ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Thiazole Ring ◽  
Asymmetric Unit ◽  
Π Interactions ◽  
Compound C ◽  
Centroid Distance ◽  
Independent Molecules ◽  
And Inversion

The asymmetric unit of the title compound, C9H8N2S, consists of two independent molecules (AandB) differing in the conformation of the thiazole ring: twisted for moleculeAand planar for moleculeB. In the crystal, molecules stack along thecaxis in alternatingAandBlayers. Within the layers, molecules are linked by C—H...π interactions, and inversion-relatedBmolecules are linked by offset π–π interactions [inter-centroid distance = 3.716 (1) Å]. The two molecules are also linked by a C—H...N hydrogen bond, which results finally in the formation of a three-dimensional structure.

scholarly journals Crystal structures of three indole derivatives: 3-ethnyl-2-methyl-1-phenylsulfonyl-1H-indole, 4-phenylsulfonyl-3H,4H-cyclopenta[b]indol-1(2H)-one and 1-{2-[(E)-2-(5-chloro-2-nitrophenyl)ethenyl]-1-phenylsulfonyl-1H-indol-3-yl}ethan-1-one chloroform monosolvate

2015 ◽  
Vol 71 (9) ◽  
pp. 1036-1041
Author(s):  
S. Gopinath ◽  
K. Sethusankar ◽  
Bose Muthu Ramalingam ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dihedral Angles ◽  
Indole Derivatives ◽  
Indole Ring ◽  
Asymmetric Unit ◽  
Ring Systems ◽  
Benzene Rings ◽  
Independent Molecules

The title compounds, C17H13NO2S, (I), C17H13NO3S, (II), and C24H17ClN2O5S·CHCl3, (III), are indole derivatives. Compounds (I) and (II) crystalize with two independent molecules in the asymmetric unit. The indole ring systems in all three structures deviate only slightly from planarity, with dihedral angles between the planes of the pyrrole and benzene rings spanning the tight range 0.20 (9)–1.65 (9)°. These indole ring systems, in turn, are almost orthogonal to the phenylsulfonyl rings [range of dihedral angles between mean planes = 77.21 (8)–89.26 (8)°]. In the three compounds, the molecular structure is stabilized by intramolecular C—H...O hydrogen bonds, generatingS(6) ring motifs with the sulfone O atom. In compounds (I) and (II), the two independent molecules are linked by C—H...O hydrogen bonds and C—H...π interactions, while in compound (III), the molecules are linked by C—H...O hydrogen bonds, generatingR22(22) inversion dimers.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

scholarly journals Crystal structure of {2,2′-[ethylenebis(nitrilomethanylylidene)]diphenolato-κ4O,N,N′,O′}oxidovanadium(IV) methanol monosolvate

2014 ◽  
Vol 70 (11) ◽  
pp. m380-m381
Author(s):  
Rachel E. Hsuan ◽  
Jemma E. Hughes ◽  
Thomas H. Miller ◽  
Nabila Shaikh ◽  
Phoebe H. M. Cunningham ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Basal Plane ◽  
Solvent Molecule ◽  
Vanadium Atom ◽  
Asymmetric Unit ◽  
Extended Structure ◽  
Independent Molecules ◽  
Ethylenediamine Ligand

Two independent molecules of the title solvated complex, [V(C16H14N2O2)O]·CH3OH, also known as [N,N′-bis(salicylidene)ethylenediamine]oxidovanadium(IV) or vanadyl salen, crystallize in the asymmetric unit. Each disordered methanol solvent molecule [occupancy ratios 0.678 (4):0.322 (4) and 0.750 (5):0.250 (5)] is linked to a [N,N′-bis(salicylidene)ethylenediamine]oxidovanadium(IV) molecule by an O—H...O hydrogen bond and to others by C—H...O hydrogen bonds. The resulting extended structure consists of a bilayer of molecules parallel to theabplane. Despite the fact that solvates are common in complexes derived from substituted analogues of theN,N′-bis(salicylidene)ethylenediamine ligand, the title solvate is the first one of [N,N′-bis(salicylidene)ethylenediamine]oxidovanadium(IV) to be structurally characterized. The two vanadyl species have very similar internal geometries, which are best characterized as distorted square-based pyramidal with the vanadium atom displaced from the N2O2basal plane by 0.5966 (9) Å in the direction of the doubly-bonded oxide ligand.

scholarly journals Metallorganische Verbindungen der Lanthanoide, 41 [1]. Die Kristall-und Molekülstruktur von (C5Me5)2HoCl(THF) / Organometallic Compounds of the Lanthanides, 41 [1]. The Crystal and Molecular Structure of (C5Me5)2HoCl(THF)

1988 ◽  
Vol 43 (3) ◽  
pp. 323-327 ◽  
Author(s):  
H. Schumann ◽  
J. Loebel ◽  
D. van der Helm ◽  
M. B. Hossain
Keyword(s):  
Molecular Structure ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Organometallic Compounds ◽  
Asymmetric Unit ◽  
Space Group ◽  
X Ray ◽  
Independent Molecules

The title compound (1) is obtained as brownish crystals by reaction of HOCl3 with NaC5Me5 in tetrahydrofuran. The structure of 1, which has two slightly different independent molecules per asymmetric unit, has been elucidated by X-ray analysis. The crystals are triclinic with a = 1686.2(8) pm, b = 1816(1) pm, c = 846.5(4) pm, α = 92.02(7)°, β = 92.47(9)°, γ = 63.21(5)°, space group P1̄, D(calcd) = 1.560 g/cm3, and R = 0.0286, for 6219 observed reflections with I > 3σ(I).

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