Investigations of the assignment of the 2190 cm−1 infrared band in polyfumaronitrile

1985 ◽  
Vol 63 (7) ◽  
pp. 1960-1966 ◽  
Author(s):  
Kenneth L. Gallaher ◽  
Dorothy Lukco ◽  
Jeanette G. Grasselli
Keyword(s):  
Solid State ◽  
Infrared Band ◽  
Spectral Similarity ◽  
H Nmr

Polyfumaronitrile exhibits a band at 2190 cm−1 which has at various times been associated with a β-aminonitrile, an iminonitrile, or with C=N in an α-pyrrolenine ring. This band is of particular interest because it sometimes appears in degraded polyacrylonitrile and nitrile-containing resins. The previous conflicting assignments were made on the basis of ir, uv, 1H nmr, and chemical results. This paper reports new infrared, esr, and solid-state carbon nmr results which indicate that the 2190 cm−1 band is most likely due to a β-aminonitrile functionality. The close spectral similarity with 3-amino crotonitrile is particularly noted. A mechanism is proposed which would explain the presence of such a nitrile in polyfumaronitrile.

scholarly journals Unusual piezochromic fluorescence of a distyrylpyrazine derivative crystals: phase transition through [2 + 2] photocycloaddition under UV irradiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Young-Jae Jin ◽  
Hyosang Park ◽  
Byung-Chun Moon ◽  
Jae Hong Kim ◽  
Wang-Eun Lee ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid State ◽  
Uv Irradiation ◽  
Mechanical Grinding ◽  
Green Color ◽  
H Nmr ◽  
Uv Visible ◽  
Stacking Structure ◽  
Orange Color ◽  
Molecular Stacking

AbstractThe piezochromic fluorescence (FL) of a distyrylpyrazine derivative, 2,3-diisocyano-5,6-distyrylpyrazine (DSP), was investigated in this study. Depending on the recrystallization method, DSP afforded two different crystals with green and orange FL emission. The orange color FL emission crystal (O-form) was easily converted to the green color FL emission one (G-form) by manual grinding. The G-form was also converted to a slightly different orange color FL emission crystal (RO-form) by a weak UV irradiation. When the RO-form was ground again, the G-form was regenerated. The FL colors changed between the G- and RO-forms over several ten times by repeated mechanical grinding and UV irradiation. The FL, UV–visible, 1H-NMR and XRD results showed that the O (or RO)-to-G transformation induced by mechanical stress results from the change of degree of molecular stacking from dense molecular stacking structure to relatively loose molecular stacking structure, whereas the G-to-RO reconversion by UV irradiation results from return to dense molecular stacking structure again due to lattice movement (lattice slipping) allowed by photocycloaddition in solid-state.

Synthesis, Characterization and Photophysical Properties of Rhenium(I) Complexe with 2-(naphthalen-2-yl)-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline

2014 ◽  
Vol 988 ◽  
pp. 66-69
Author(s):  
Qiang Li ◽  
Le Li ◽  
Rong Feng Zhong ◽  
Hai Di Cai ◽  
Feng Zhao
Keyword(s):  
Experimental Data ◽  
Solid State ◽  
Photophysical Properties ◽  
Broad Band ◽  
High Energy ◽  
H Nmr ◽  
Emission Maximum ◽  
Broad Band Emission ◽  
Band Emission

In this paper, a Re(I) complex [Re(CO)3(E2)Cl], where E2 = 2-(naphthalen-2-yl)-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline(E2), was synthesized and characterized by 1H NMR successfully. Experimental data confirm that Re(I) complex [Re(CO)3(E2)Cl] is high-energy-emitting one. The broad band emission upon excitation at λ = 400 nm with the emission maximum locates at λ = 581 nm in solid state and 614nm in CH2Cl2 solution were observed.

scholarly journals Synthesis of a One-Dimensional Coordination Polymer of Nickel(II) Complex with a β-Oxodithioester Ligand

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Ricardo Rosas-Reyes ◽  
Yasmi Reyes-Ortega ◽  
T. Jesus Morales-Juarez ◽  
Virginia Gómez-Vidales ◽  
Ivan García-Orozco
Keyword(s):  
Solid State ◽  
Coordination Polymer ◽  
Elemental Analysis ◽  
Chloroform Solution ◽  
Magnetization Measurements ◽  
One Dimensional ◽  
H Nmr

Bis-[methyl-1-hydroxy-1-cyclopentene-2-dithiocarboxylate-O,S]nickel(II) 1 was prepared starting from methyl 2-hydroxycyclopent-1-encarbodithioate ligand (CPDT) and Ni(II), and catena-[(μ2-4,4′-Bipyril)-bis-(methyl-2-hydroxy-1-cyclopentene-2-dithiocarboxylate-O,S)]nickel(ΙΙ) 2 was prepared in good yields from 1 plus 4,4′-bipyridyl (bpy) by shish-kebab methodology. The structure of 1 was confirmed by FTIR, elemental analysis, 1H NMR, UV–vis in chloroform solution and in solid, XPS, and PXRD. Compound 2 was characterized by FTIR, elemental analysis, UV–vis in chloroform solution, and in solid, XPS, PXRD, ESR, and solid state magnetization measurements. The structure of the polymer was established mostly by PXRD, ESR, and magnetization.

scholarly journals The Research of G–Motif Construction and Chirality in Deoxyguanosine Monophosphate Nucleotide Complexes

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanhong Zhu ◽  
Zhongkui Li ◽  
Pengfei Wang ◽  
Qi–Ming Qiu ◽  
Hongwei Ma ◽  
...  
Keyword(s):  
Solid State ◽  
Self Assembly ◽  
Genetic Diseases ◽  
Dna Interaction ◽  
Wave Direction ◽  
Base Pairing ◽  
X Ray Crystallography ◽  
Mismatched Dna ◽  
H Nmr ◽  
Guanine Base

A detailed understanding of the mismatched base-pairing interactions in DNA will help reveal genetic diseases and provide a theoretical basis for the development of targeted drugs. Here, we utilized mononucleotide fragment to simulate mismatch DNA interactions in a local hydrophobic microenvironment. The bipyridyl-type bridging ligands were employed as a mild stabilizer to stabilize the GG mismatch containing complexes, allowing mismatch to be visualized based on X-ray crystallography. Five single crystals of 2′-deoxyguanosine–5′–monophosphate (dGMP) metal complexes were designed and obtained via the process of self-assembly. Crystallographic studies clearly reveal the details of the supramolecular interaction between mononucleotides and guest intercalators. A novel guanine–guanine base mismatch pattern with unusual (high anti)–(high anti) type of arrangement around the glycosidic angle conformations was successfully constructed. The solution state 1H–NMR, ESI–MS spectrum studies, and UV titration experiments emphasize the robustness of this g–motif in solution. Additionally, we combined the methods of single-crystal and solution-, solid-state CD spectrum together to discuss the chirality of the complexes. The complexes containing the g–motif structure, which reduces the energy of the system, following the solid-state CD signals, generally move in the long-wave direction. These results provided a new mismatched base pairing, that is g–motif. The interaction mode and full characterizations of g–motif will contribute to the study of the mismatched DNA interaction.

Synthesis and antiaromatic character of alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex

2017 ◽  
Vol 21 (12) ◽  
pp. 850-856 ◽  
Author(s):  
Masataka Umetani ◽  
Koji Naoda ◽  
Takayuki Tanaka ◽  
Atsuhiro Osuka
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Potential Difference ◽  
Planar Structure ◽  
H Nmr ◽  
Antiaromatic Character ◽  
Homo Lumo ◽  
Nmr Signals

Antiaromatic molecules have recently been proven to display unique properties such as small HOMO–LUMO gaps, ambipolar carrier transporting and [Formula: see text]-stack-induced aromatic stabilizations. These intriguing properties have been demonstrated by stable antiaromatic molecules that exhibit a distinct antiaromatic character. Di-peri-dinaphthoporphyrins are peripherally [Formula: see text]-extended porphyrinoids that exhibit a planar structure and a distinct antiaromatic character stemming from their 24[Formula: see text] electron circuit. Herein, we report an alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex 5Ni bearing less peripheral bulkiness as compared with phenyl-substituted ones. 5Ni displayed upfield-shifted [Formula: see text]H NMR signals due to [Formula: see text]-protons, indicating its distinct antiaromaticity, and a slightly shorter intermolecular packing distance (ca. 3.402 Å) in the solid state. Cyclic voltammetry shows a larger potential difference between the first and second oxidation waves, implying that this molecule tends to stack favorably in its oxidized state.

Investigation of the disorder of dibromo- and dichloromethane in their tri-ortho-thymotide clathrates using X-ray diffraction and solid-state 2H NMR spectroscopy

2011 ◽  
Vol 89 (7) ◽  
pp. 854-862
Author(s):  
Glenn A. Facey ◽  
Ilia Korobkov
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Guest Molecule ◽  
Type B ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Twofold Axis ◽  
H Nmr ◽  
Heavy Atoms

The tri-ortho-thymotide (TOT) clathrates of dibromo- and dichloromethane were characterized by single crystal X-ray diffraction at 200 K and solid-state 2H NMR spectroscopy as a function of temperature. The host structure was found to be typical of other cage-type TOT clathrates. The X-ray results showed a substantial amount of disorder among the guest molecules. In both clathrates, multiple guest molecule positions could be modeled. The heavy atoms of all the guest molecule positions lie approximately in the same plane, with some out-of-plane distortion. The guest molecules were of two different types in positions symmetric about the crystallographic twofold rotation axis: type A guests, with carbon atoms well removed from the crystallographic twofold axis, and type B guests, with carbon atoms very close to the twofold axis. The 2H NMR spectra for the guests confirmed that the disorder was dynamic. The experimental results could be accounted for by the presence of three simultaneous types of molecular motion, all fast with respect to the 2H quadrupolar interaction: (i) twofold molecular flips about the molecular C2 symmetry axis, (ii) exchange between the type A and type B sites in a single plane, and (iii) a two-site libration of the plane containing the heavy atoms of the A and B guest sites with a temperature-dependent amplitude.

Synthesis and conformational studies of 9-benzyloxy-18-substituted [3.3]metacyclophanes

2015 ◽  
Vol 93 (11) ◽  
pp. 1161-1168 ◽  
Author(s):  
M. Monarul Islam ◽  
Tomiyasu Hirotsugu ◽  
Taisuke Matsumoto ◽  
Junji Tanaka ◽  
Takehiko Yamato
Keyword(s):  
Solid State ◽  
Intramolecular Cyclization ◽  
Acid Treatment ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Chair Conformation ◽  
Cyclization Reaction ◽  
Conformational Studies ◽  
X Ray ◽  
H Nmr

A series of syn-[3.3]metacyclophanes (MCPs) containing internal substituted benzyloxy group have been synthesized by the modified TosMIC coupling reaction followed by acid treatment and Wolff–Kishner reduction. anti-Mono- and di-benzyloxy[3.3]MCPs are synthesized by O-benzylation of the corresponding hydroxy[3.3]MCPs, which are obtained by demethylation of methoxy[3.3]MCPs with BBr3 at room temperature. An interesting and intriguing result was obtained when syn-6,15-di-tert-butyl-9-methoxy-18-methyl[3.3]MCP-2,11-dione was treated with TMSI to afford the formation of a dihydrobenzofuran ring by a nucleophilic intramolecular cyclization reaction. The 1H NMR and X-ray analysis of 6a confirms that it adopts a syn (chair–chair) conformation in both solution and solid state.

Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4-d]pyrimidine, purine and 7-deazapurine

2014 ◽  
Vol 70 (6) ◽  
pp. 555-561 ◽  
Author(s):  
Kamlakar Avasthi ◽  
Lakshmi Shukla ◽  
Ruchir Kant ◽  
Krishnan Ravikumar
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Crystalline State ◽  
Nmr Analysis ◽  
First Report ◽  
Π Interactions ◽  
H Nmr

The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7′-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by1H NMR analysis. This folding carries over to the crystalline state. Intramolecular π–π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C—H...π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π–π interactions, the crystal structures are also stabilized by other weak intermolecular C—H...S/N/O and/or S...N/S interactions.

Solid-state 2H NMR study of methyl-d3-cobalamin

1998 ◽  
Vol 76 (2-3) ◽  
pp. 423-428
Author(s):  
Jennifer R. Garbutt ◽  
Gillian R. Goward ◽  
Christopher W. Kirby ◽  
William P. Power
Keyword(s):  
Solid State ◽  
H Nmr ◽  
Nmr Study
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