scholarly journals Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

2019 ◽  
Vol 15 ◽  
pp. 1795-1804 ◽  
Author(s):  
Jing Li ◽  
Qiang Shi ◽  
Ying Han ◽  
Chuan-Feng Chen
Keyword(s):  
Association Constants ◽  
The Other ◽  
Acid Base ◽  
Polar Solvents ◽  
X Ray ◽  
H Nmr ◽  
Hydrogen Bonding Interactions ◽  
Acids And Bases ◽  
Multiple Hydrogen Bonding ◽  
Nmr Titrations

2,6-Helic[6]arene and its derivatives were synthesized, and their complexation with 1,1′-dimethyl-4,4′-bipyridinium and protonated 4,4'-bipyridinium salts were investigated in detail. It was found that the helic[6]arene and its derivatives could all form 1:1 complexes with both 1,1′-dimethyl-4,4'-bipyridinium salts and protonated 4,4'-bipyridinium salts in solution and in the solid state. Especially, the helic[6]arene and its derivatives containing 2-hydroxyethoxy or 2-methoxyethoxy groups exhibited stronger complexation with the guests than the other helic[6]arene derivatives for the additional multiple hydrogen bonding interactions between the hosts and the guests, which were evidenced by 1H NMR titrations, X-ray crystal structures and DFT calculations. Moreover, it was also found that the association constants (K a) of the complexes could be significantly enhanced with larger counteranions of the guests and in less polar solvents. Furthermore, the switchable complexation between the helic[6]arene and protonated 4,4'-bipyridinium salt could be efficiently controlled by acids and bases.

Über Metallalkyl- und -arylverbindungen, 51. Mittlg.* Unsymmetrische Diorganomagnesiumverbindungen. MgRR'(L) und solvensgetrennte Ionenpaare mit R = Me, Et, R' = Cyclopentadienyl, Indenyl, Fluorenyl, Phenylethinyl, L = Tetramethylethylendiamin, Pentamethyldiethylentriamin / On Metal Alkyl and Aryl Compounds, Part 51 Unsymmetrical Diorganomagnesium Compounds. MgRR'(L) and Solvens Separated Ion Pairs with R = Me, Et, R' = Cyclopentadienyl, Indenyl, Fluorenyl, Phenylethynyl, L = Tetramethylethylenediamine, Pentamethyldiethylenetriamine

1994 ◽  
Vol 49 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Heiko Viebrock ◽  
Dirk Abein ◽  
Erwin Weiss
Keyword(s):  
Ion Pairs ◽  
Direct Interaction ◽  
The Other ◽  
Steric Repulsion ◽  
Complicated Structure ◽  
Acid Base ◽  
Polar Solvents ◽  
X Ray ◽  
Ch Acids ◽  
Amine Adducts

Abstract Amine adducts of diorganomagnesium compounds MgR2(L) are soluble in hydrocarbons and therefore valuable synthons for reactions in non-polar solvents. In this way unsymmetrically substituted derivatives MgRR'(L) become available by substituting one organic group by a different carbanion via acid-base reactions, according to eq. (1): R2Mg(L) + HR' -> RR'Mg(L) + HR (1) with HR' being stronger CH-acids than HR. Using the amin adducts R2Mg(L) (R = Me, Et) with chelating amines (L = tetramethyl­ ethylenediamine, TMEDA, pentamethylethylenetriamine, PMDTA) and the strong CH-acids cyclopentadiene, indene, fluorene and alkynes the following compounds have been synthesized and their structures derived by X-ray analyses: MgMe(η3-cyclopentadienyl)(tmeda) (1), MgMe(η3-indenyl)(tmeda) (2), MgMe(η1-fluorenyl)(tmeda) (3), [Mg2Me2(pmdta)2]2+[fluorenyl]−2benzene (4) and [Mg2Et(phenylethynyl)3(tmeda)]2 ∙ benzene (5). It is remarkable, that cyclopentadienyl, indenyl, and fluorenyl ligands have a lower hapticity than η5 to the metal, due to steric repulsion by the other ligands. In 4 the bulky tridentate base PMDTA prevents any direct interaction between the fluorenide anion and magnesium, giving solvens separated ion pairs with the unusual and hitherto rare example of an organomagnesium cation [Mg2Me2(pmdt)2]2+. The 1:3 compound 5 has a more complicated structure, related to that of alkali metal alkynyl magnesates.

Liquid crystalline polyureas with oligo(ethylene glycol) sequences

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shahram Mehdipour-Ataei ◽  
Leila Akbarian-Feizi
Keyword(s):  
Liquid Crystalline ◽  
Spectroscopic Method ◽  
Polymerization Reaction ◽  
X Ray Diffraction ◽  
Subsequent Reaction ◽  
Scanning Calorimetry ◽  
Polar Solvents ◽  
X Ray ◽  
H Nmr ◽  
Ft Ir

AbstractA diamine monomer containing ester, amide and ether functional groups was prepared and its polymerization reaction with different diisocyanates to give main chain poly(ester amide ether urea)s was investigated. The monomer was synthesized via reaction of terephthaloyl chloride with 4-hydroxybenzoic acid and subsequent reaction of the resulted diacid with 1,8-diamino-3,6-dioxaoctane. The polymers were characterized by FT-IR and 1H-NMR spectroscopic method and elemental analysis. The resulting polymers exhibited excellent solubility in polar solvents. Crystallinity of the resulted polymers was evaluated by wide-angle X-ray diffraction (WXRD) method, and they exhibited semi-crystalline patterns. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were in the range of 88-112 °C. The temperatures for 10% weight loss (T10) from their thermogravimetric analysis (TGA) curves were found to be in the range of 297-312 °C in air. Also the prepared polyureas showed liquid crystalline character.

Synthesis of β-amino-α-ferrocenyl alcohols

2005 ◽  
Vol 2005 (11) ◽  
pp. 712-715 ◽  
Author(s):  
Hai-Ying Zhao ◽  
Zhan-Xi Bian ◽  
Bao-Guo Li
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Chain Structure ◽  
Lithium Aluminum ◽  
Polymeric Chain ◽  
X Ray ◽  
H Nmr ◽  
Hydrogen Bonding Interactions ◽  
Trimethylsilyl Ethers ◽  
New Compounds

β-Amino-α-ferrocenyl alcohols [FcC(OH)(R)CH2NH2] (R = Me, Et, nPr, iPr, Ph, p-MeOC6H4, o-ClC6H4, m-ClC6H4, p-ClC6H4, Fc; Fc = C5H4FeC5H5) were prepared by the reduction of cyanohydrin trimethylsilyl ethers of acylferrocenes with lithium aluminum hydride. All new compounds were characterised by elemental analysis, IR and 1H NMR spectroscopies. The X-ray crystal structure of β-amino-α,α-diferrocenylethanol shows that it has a polymeric chain structure with hydrogen bonding interactions between the OH proton and the N of NH2.

scholarly journals Crystal structure oftrans-cyclohexane-1,2-diammonium chromate(VI) from synchrotron X-ray diffraction data

2016 ◽  
Vol 72 (12) ◽  
pp. 1872-1874
Author(s):  
Dohyun Moon ◽  
Jong-Ha Choi
Keyword(s):  
Hydrogen Bonds ◽  
Organic Cation ◽  
Chair Conformation ◽  
The Other ◽  
X Ray Diffraction ◽  
Hybrid Compound ◽  
Acceptor Interaction ◽  
X Ray ◽  
Compound C ◽  
Hydrogen Bonding Interactions

The structure of the title hybrid compound, (C6H16N2)[CrO4], has been determined from synchrotron data. The organic cation adopts a chair conformation. The inorganic CrO42−anion is slightly distorted owing to its involvement in N—H...O hydrogen-bonding interactions with neighbouringtrans-cyclohexane-1,2-diammonium cations, whereby the two Cr—O bonds to the O atoms acting as acceptor atoms for two hydrogen bonds are slightly longer than the other two Cr—O bonds for which only one acceptor interaction per O atom is observed. In the crystal, cations and anions are packed into layers parallel to (001), held together through the aforementioned N—H...O hydrogen bonds.

Halogenation of Tris(amido)tantalacarboranes with Dihalomethanes CH2X2 (X = Cl, Br)

2002 ◽  
Vol 67 (6) ◽  
pp. 791-807 ◽  
Author(s):  
Mark A. Fox ◽  
Andrés E. Goeta ◽  
Andrew K. Hughes ◽  
John M. Malget ◽  
Ken Wade
Keyword(s):  
Single Crystal ◽  
Prolonged Exposure ◽  
Chemical Shifts ◽  
Amide Group ◽  
The Other ◽  
X Ray ◽  
Nmr Chemical Shifts ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Hydrolysis Of

Slow reactions of isomeric metallacarboranes of general formulae [(NMe2)3TaC2B9H11] (3 isomers) and [(NMe2)3TaC2B9H10Me] (3 isomers) with CD2Cl2 afford quantitative yields of monochloro complexes [Cl(NMe2)2TaC2B9H11] and [Cl(NMe2)2TaC2B9H10Me]. Exposure to CD2Cl2 for months leads to solutions containing about 70% of the dichlorides in three cases. More prolonged exposure of these and the other monochlorides leads to a mixture of boron-substituted complexes. Hydrolysis of [3,3,3-(NMe2)3-3,1,2-TaC2B9H11] by moist toluene results in the formation of the oxo-bridged complex 3,3'-[3,3-(NMe2)2-3,1,2-TaC2B9H11]2(μ-O), characterised by single-crystal X-ray crystallography. The limited solubility of the latter complex in CD2Cl2 eliminates the presence of this compound in the reaction of [3,3,3-(NMe2)3-3,1,2-TaC2B9H11] with CD2Cl2. The reaction of [2,2,2-(NMe2)3-2,1,12-TaC2B9H11] with CH2Br2 in C6D6 quantitatively yields the monobromide [2-Br-2,2-(NMe2)2-2,1,12-TaC2B9H11]. Prolonged reaction with CH2Br2 leads directly to isomeric boron-substituted complexes with no evidence for dibromides. The influence on 11B, 13C and 1H NMR chemical shifts of replacing an amide group in [(NMe2)3TaC2B9H11] with chloride to give [Cl(NMe2)2TaC2B9H11] is also discussed.

Electronic Structure of 2,6-Bis{.N-(2-hydroxyphenyl)immoinethyl}-4-methylphenol

1999 ◽  
Vol 54 (7) ◽  
pp. 929-939 ◽  
Author(s):  
Miki Hasegawa ◽  
Yasunori Yamada ◽  
Ken-ichi Kumagai ◽  
Toshihiko Hoshi
Keyword(s):  
Diffraction Analysis ◽  
Electronic Absorption ◽  
Nmr Spectra ◽  
X Ray Diffraction ◽  
Mo Calculations ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Additional Band ◽  
X Ray ◽  
H Nmr

The electronic and molecular structure of 2,6-bis{N-(2-hydroxyphenyl)iminomethyl}-4- methylphenol (hpimp) is clarified from the measurements of electronic absorption and 1H NMR spectra in various solvents and an X-ray diffraction analysis, together with MO calculations. Electronic absorption bands of hpimp are at 422, 397.9, 359, 341, 294.3, 265.8, and 224 nm in the non-polar solvent cyclohexane. In polar solvents, such as methanol, an additional band which is assigned to a partly formed keto-amine hpimp, is observed at 499 nm. From the 1H NMR spectra it is seen that hpimp exists in the enol-imine form in non-polar solvents, and as an equilibrium mixture of enol-imine and keto-amine forms in polar solvents. Each electronic absorption band of solid hpimp in a KBr disk is broadened compared with the solution state, and an additional band, again assigned to the keto-amine form, appears around 499 nm. An X-ray diffraction analysis shows that hpimp assumes a keto-amine structure in the solid state, and forms a column structure along the c-axis. MO calculations suggest that the enol-imine hpimp has a twist structure around the two C−C single bonds, the twist angle being 100° to 120°.

Cyclopentadienyl–metal bond cleavage and stereospecific bromination. The structure of (η-C5H5)2Ti(OOCPh)2 and its reactions with bromine

1988 ◽  
Vol 66 (3) ◽  
pp. 429-434 ◽  
Author(s):  
C. Robert Lucas ◽  
Eric J. Gabe ◽  
Florence L. Lee
Keyword(s):  
Nmr Spectra ◽  
Bond Cleavage ◽  
The Other ◽  
Ring Cleavage ◽  
Radical Mechanism ◽  
Iodine Monochloride ◽  
Carboxylate Ligands ◽  
X Ray ◽  
H Nmr ◽  
Using Data

The 13C and 1H nmr spectra as well as the X-ray structure determination for (η-C5H5)2Ti(OOCPh)2 are described. The compound crystallizes in space group P21212I with a = 7.5135, b = 12.5166, c = 21.1416 Å, Z = 4, dcalcd = 1.40 g cm−3 (MoKα1, λ = 0.70932 Å). The structure was solved with MULTAN using data collected at 115 K and refined to the final R = 0.059 for 1500 significant reflections. The molecule has two different carboxylate ligands, one of which has a Ti—O—C angle of 135.4(6)° and longer Ti—O (1.976(5) Å) and O—C (1.300(10) Å) bonds while the other has a Ti—O—C angle of 157.0(7)° with shorter Ti—O (1.913(6) Å) and O—C (1.267(10) Å) bonds. With bromine, ring cleavage occurs giving C5H5Br3 or C5H5Br5 in which bromination has occurred stereospecifically. The same reaction occurs with chlorine but not with iodine or iodine monochloride. Related reactions have been observed with (η-C5H5)2MCl2 (M = Ti, Zr, and V). A non-radical mechanism is proposed in which the LUMO and HOMO of Br2 interact simultaneously with one cyclopentadienyl ring and with the metal. This interaction is a consequence of the structure of (η-C5H5)2M(OOCPh)2.

Exhibition of the Brønsted acid–base character of a Schiff base in palladium(ii) complex formation: lithium complexation, fluxional properties and catalysis of Suzuki reactions in water

2015 ◽  
Vol 44 (15) ◽  
pp. 6896-6908 ◽  
Author(s):  
Rajnish Kumar ◽  
Ganesan Mani
Keyword(s):  
Palladium Complex ◽  
Palladium Complexes ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Acid Base ◽  
X Ray ◽  
H Nmr ◽  
Suzuki Reactions ◽  
Nmr Method ◽  
Brönsted Acid

The Brønsted acid–base character of bis(iminopyrrolylmethyl)amine was shown through the X-ray structures of palladium complexes. The bischelated palladium complex is fluxional as studied by the VT 1H NMR method and effectively catalyzes Suzuki reactions in water.

scholarly journals Synthesis and structure of (E)-N-(4-methoxyphenyl)-2-[4-(3-oxo-3-phenylprop-1-en-1-yl)phenoxy]acetamide

2021 ◽  
Vol 77 (2) ◽  
pp. 184-189
Author(s):  
Cong Nguyen Tien ◽  
Trung Vu Quoc ◽  
Dat Nguyen Dang ◽  
Giang Le Duc ◽  
Luc Van Meervelt
Keyword(s):  
Title Compound ◽  
Crystal Packing ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Hydrogen Bonding Interactions ◽  
Hirshfeld Analysis ◽  
Phenyl Rings ◽  
C Nmr

The title compound N-(4-methoxyphenyl)-2-[4-(3-oxo-3-phenylprop-1-en-1-yl)phenoxy]acetamide, C24H21NO4, was prepared from reaction of N-(4-methoxyphenyl)-2-chloroacetamide and (E)-3-(4-hydroxyphenyl)-1-phenylprop-2-en-1-one, which was obtained from the reaction of 4-hydroxybenzaldehyde and acetophenone. The structure of the title compound was determined by IR, 1H-NMR, 13C-NMR and HR–MS spectroscopic data and further characterized by single-crystal X-ray diffraction. The asymmetric unit contains four molecules, each displaying an E-configuration of the C=C bond. The dihedral angle between the phenyl rings in each molecule varies between 14.9 (2) and 45.8 (2)°. In the crystal, C—H...O hydrogen-bonding interactions link the molecules into chains running along the [001] direction. In addition, C—H...π interactions further stabilize the crystal packing. A Hirshfeld analysis indicates that the most important contributions to the surface contacts are from H...H (43.6%), C...H/H...C (32.1%) and O...H/H...O (18.1%) interactions.

Synthesis and structural study of aminals derived from 8-aminoquinoline and 1-aminonaphtalene

1987 ◽  
Vol 65 (4) ◽  
pp. 687-692 ◽  
Author(s):  
Enrique Galvez ◽  
Isabel Iriepa ◽  
Antonio Lorente ◽  
Jose Miguel Mohedano ◽  
Feliciana Florencio ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Mass Spectra ◽  
The Other ◽  
Reaction Conditions ◽  
Schiff’S Base ◽  
Triclinic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Cell Dimensions

Reaction of 8-aminoquinoline with pyridine-2-carboxaldehyde (2), pyridine-3-carboxaldehyde (3), pyridine-4-carboxaldehyde (4), and benzaldehyde (5) yields the corresponding aminals or Schiff's bases according to reaction conditions; analogous results are obtained from the reaction of 1-amino-naphtalene with pyridine-2-carboxaldehyde (6). On the other hand, reaction of 8-aminoquinoline with thiophene-2-carboxaldehyde or pyrrole-2-carboxaldehyde yields neither the aminal nor the Schiff's base. Crystals of 4 (C24H19N5) belong to the triclinic space group [Formula: see text]. Cell dimensions are a = 11.547(3), b = 11.759(2), c = 15.687(5) Å, α = 98.50(2)°, β = 101.61(2)°, γ = 107.28(2)°, V = 1942.6(9) Å3. Final R = 0.077 and Rw = 0.064; 3160 reflections were observed. The ir, 1H nmr of 2–6, the mass spectra of 4 and 5 and the X-ray analysis of 4 are described and discussed. Preparative features, ir, 1H nmr, analyses and crystal structure indicate that the formation of 2–6 are governed mainly by the nucleophilicity at the aldehyde carbon atom and the existence of the hydrogen bonds in the aminal.

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