scholarly journals Effects of Halogen, Chalcogen, Pnicogen, and Tetrel Bonds on IR and NMR Spectra

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2822 ◽  
Author(s):  
Jia Lu ◽  
Steve Scheiner
Keyword(s):  
Nmr Spectra ◽  
Central Atom ◽  
Atomic Charges ◽  
Halogen Bonds ◽  
Frequency Shifts ◽  
Ir And Nmr Spectra ◽  
The Third ◽  
Noncovalent Bond ◽  
Spectroscopic Characteristics ◽  
Tetrel Bonds

Complexes were formed pairing FX, FHY, FH2Z, and FH3T (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) with NH3 in order to form an A⋯N noncovalent bond, where A refers to the central atom. Geometries, energetics, atomic charges, and spectroscopic characteristics of these complexes were evaluated via DFT calculations. In all cases, the A–F bond, which is located opposite the base and is responsible for the σ-hole on the A atom, elongates and its stretching frequency undergoes a shift to the red. This shift varies from 42 to 175 cm−1 and is largest for the halogen bonds, followed by chalcogen, tetrel, and then pnicogen. The shift also decreases as the central A atom is enlarged. The NMR chemical shielding of the A atom is increased while that of the F and electron donor N atom are lowered. Unlike the IR frequency shifts, it is the third-row A atoms that undergo the largest change in NMR shielding. The change in shielding of A is highly variable, ranging from negligible for FSnH3 all the way up to 1675 ppm for FBr, while those of the F atom lie in the 55–422 ppm range. Although smaller in magnitude, the changes in the N shielding are still easily detectable, between 7 and 27 ppm.

Reactivity of Some 1(N)‐[(para‐R2)‐Phenacyl]–4(N)‐[(para‐R1)‐phenyl]‐1,2,4‐triazolium‐methylides by UV‐VIS, IR, and NMR Spectra and Molecular Modeling

2004 ◽  
Vol 37 (5) ◽  
pp. 457-467 ◽  
Author(s):  
Nicoleta Melniciuc‐Puică ◽  
Virgil Bărboiu ◽  
Şerban Filoti ◽  
Dana‐Ortansa Dorohoi
Keyword(s):  
Molecular Modeling ◽  
Nmr Spectra ◽  
Ir And Nmr Spectra

Antimony-121 nuclear magnetic resonance study of hexahaloantimonate anions

1981 ◽  
Vol 59 (20) ◽  
pp. 2940-2949 ◽  
Author(s):  
R. Garth Kidd ◽  
H. Garth Spinney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectra ◽  
Central Atom ◽  
Chemical Shifts ◽  
Nuclear Magnetic Resonance Study ◽  
Acetonitrile Solution ◽  
Trans Isomers ◽  
Magnetic Resonance Study ◽  
Chlorine Substitution ◽  
Nuclear Shielding

The seven hexahaloantimonate anions in the series [SbClnBr6−n]− have been prepared and their antimony-121 nmr spectra show that for [SbCl4Br2]−, [SbCl3Br3]−, and [SbCl2Br4]−, only the cis isomers are present in acetonitrile solution. The pairwise additivity model for central atom shielding has been used for configuration assignments. Models relevant to the higher incidence of cis over trans isomers are discussed. The nuclear shielding of 121Sb is the most sensitive to halogen substitution of all the elements whose halide chemical shifts have been studied. Antimony shieldings exhibit normal halogen dependence, with bromine substitution causing upfield shifts relative to chlorine substitution.

Dppa als Komplexligand: Metall-Koordination und P-N-Spaltung in Komplexen des Typs [CpM(L)dppa]X (M = Fe, Mn; L = CO, NO) / Dppa as a Ligand: Metal Coordination and P-N Cleavage in Complexes of the Type [CpM(L)dppa]X (M = Fe, Mn; L = CO, NO)

1997 ◽  
Vol 52 (5) ◽  
pp. 593-603 ◽  
Author(s):  
Jan Geicke ◽  
Ingo-Peter Lorenz ◽  
Petra Mürschel ◽  
Kurt Polbom
Keyword(s):  
Nmr Spectra ◽  
Metal Coordination ◽  
Cleavage Reaction ◽  
Neutral Complex ◽  
Ir And Nmr Spectra ◽  
X Ray

Abstract The reactions of [CpMn(CO)2(NO)]BF4 or CpFe(CO)2Cl with PPh2NHR (R = Ph, PPh2) lead to the salts [CpML(CO)PPh2NHR]X with monodentate aminophosphine ligands. In the case of R = PPh2 (= dppa) the complexes [CpML(dppa)]X with bidentate dppa are also formed. The salt [CpFe(CO)(dppa)]Cl can be deprotonated to give the neutral complex CpFe(CO){(PPh2)2N)} with the diphosphinoamide ligand, which can be N-alkylated by Mel to afford [CpFe(CO){(PPh2)2NMe}]I. The complex [CpMn(NO)(dppa)]BF4 undergoes a P-N cleavage reaction by the solvent methanol to form [CpMn(NO)(PPh2NH2)(PPh2OMe)]BF4. The non-chelated complexes [CpFe(CO)2PPh2NHR]Cl are deprotonated by DBU to give the neutral ferrioiminophosphoranes CpFe(CO)2PPh2 = NR. For R = PPh2 photolysis leads to CO-elimination and to CpFe(CO)(PPh2NPPh2). CpFe(CO)2PPh2NPPh2 can be alkylated by Mel or metallated by CpFe(CO)2Cl to form [CpFe(CO)2PPh2NPPh2Me]I or [CpFe(CO)2PPh2NPPh2(CO)2FeCp]Cl, respectively. Oxidation of CpFe(CO)2PPh2NPPh2 is possible by (SiMe3)2O2, sulfur, or selenium to lead to the neutral complexes CpFe(CO)2PPh2=NPPh2 = E (E = O, S, Se) with a heterodiene system. The IR and NMR spectra of all species as well as the X-ray structures of the complexes [CpFe(CO)dppa]Cl, [CpMn(NO)dppa]BF4 and [CpMn(NO)(PPh2NH2)(PPh2OMe)]BF4 are reported and discussed.

Studies on Ylides: Reactions of N -Pyridinium Phenancylides with α,β-Unsaturated Ketones, I

1974 ◽  
Vol 29 (7-8) ◽  
pp. 552-555 ◽  
Author(s):  
Purshottam S. Kendurkar ◽  
Ram S. Tewari
Keyword(s):  
Acetic Acid ◽  
Nmr Spectra ◽  
Ammonium Acetate ◽  
Ir And Nmr Spectra ◽  
Unsaturated Ketones

Reactions of N-pyridinium phenancylides with different a, β-unsaturated ketones give 2,4,6-triarylsubstituted pyridines, 2,6-diphenyl-4-(2-pyridyl) pyridines, 2-benzylidene-4,6-diphenyl pyridines and 2,4,6-triphenyl-3-bromopyridine. Ammonium acetate in acetic acid was used as cyclization agent. The structure of the products are supported by IR and NMR spectra.

MECHANICAL PULPING: Characterization of dissolving pulp by multivariate data analysis of FT-IR and NMR spectra

2011 ◽  
Vol 26 (4) ◽  
pp. 398-409 ◽  
Author(s):  
Peter Strunk ◽  
Tommy Ö Öman ◽  
Mattias Hedenström ◽  
Bertil Eliasson ◽  
András Gorzsás
Keyword(s):  
Data Analysis ◽  
Multivariate Data Analysis ◽  
Nmr Spectra ◽  
Multivariate Data ◽  
Dissolving Pulp ◽  
Ir And Nmr Spectra ◽  
Ft Ir

Determination and Identification of Chondroitin Sulfate from Tilapia Byproducts

2013 ◽  
Vol 690-693 ◽  
pp. 1318-1321 ◽  
Author(s):  
Zhen Hua Duan ◽  
Chang Yu Cheng ◽  
Yang Hai ◽  
Ju Lan Wang
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Magnetic Resonance ◽  
Chondroitin Sulfate ◽  
Infrared Spectra ◽  
Oreochromis Niloticus ◽  
High Performance ◽  
Nmr Spectra ◽  
Ir And Nmr Spectra

In order to probe the structure of chondroitin sulfate (CS) from tilapia fish, the CS was extracted from tilapia (Oreochromis niloticus) byproducts with the combination of ultrasonic and microwave, some means including high performance liquid chromatography (HPLC), infrared spectra (IR) and nuclear magnetic resonance (NMR) were used in this paper. The data of HPLC exhibited that the obtained chondroitin sulfate is of highly purity (98.78%). IR and NMR spectra indicated that the sample consisted of both chondroitin-4-sulfate and chondroitin-6-sulfate, and the proportion of chondroitin-6-sulfate was higher than chondroitin-4-sulfate.

Synthesis of a Polysiloxane with High Reaction Activity

2014 ◽  
Vol 998-999 ◽  
pp. 15-18
Author(s):  
Сhao Hong Dong ◽  
Zhou Lu ◽  
Ping Zhu ◽  
Lei Wang
Keyword(s):  
Organic Synthesis ◽  
Methyl Iodide ◽  
Building Block ◽  
Nmr Spectra ◽  
Catalytic Amount ◽  
Reaction Conditions ◽  
Ir And Nmr Spectra ◽  
High Reaction ◽  
Ft Ir

A novel building block in organic synthesis, poly (4-iodobutoxylmethylsiloxane)(PIBMS) with high reaction activity was prepared by poly (hydromethylsiloxane)(PHMS), methyl iodide and tetrahydrofuran (THF) in the presence of a catalytic amount of PdCl2. The structure of PIBMS was characterized by the FT-IR and NMR spectra. The reaction conditions were optimized.

Organometallphosphin-substituierte Übergangsmetallkomplexe, ΧΧΠ Darstellung und komplexchemisches Verhalten von Dimethylstannandiylbis(di-t ert-butylphoshin).

1976 ◽  
Vol 31 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Herbert Schumann ◽  
Wolf-Walther Du Μοnt
Keyword(s):  
Uv Irradiation ◽  
Nmr Spectra ◽  
Ir And Nmr Spectra ◽  
New Compounds

Dimethylstannandiylbis(di-tert-butylphosphine) reacts with tetracarbonyl nickel under formation of tricarbonyl-dimethylstannandiylbis(di-tert-butylphosphine)nickel and polymeric dicarbonyl-dimethylstannanediylbis(di-tent-butylphosphine)nickel and with hexacarbonylchromium under UV-irradiation as well as with tetracarbonyl-norbornadienechromium yielding tetracarbonyl-dimethylstannandiylbis(di-tent-butylphosphine)-chromium. IR and NMR spectra of the new compounds are discussed

scholarly journals Ophiobolin O and 6-Epi-Ophiobolin O, Two New Cytotoxic Sesterterpenes from the Marine Derived Fungus Aspergillus Sp

2012 ◽  
Vol 7 (11) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Dahai Zhang ◽  
Seketsu Fukuzawa ◽  
Masayuki Satake ◽  
Xianguo Li ◽  
Takafumi Kuranaga ◽  
...  
Keyword(s):  
Cell Line ◽  
Catalytic Reaction ◽  
Nmr Spectra ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Mouse Leukemia ◽  
Ir And Nmr Spectra ◽  
Aspergillus Sp

Two new sesterterpenes, ophiobolin O (1) and 6-epi-ophiobolin O (2), together with the known ophiobolins G (3), H (4), and K (5), and 6-epi-ophiobolin K (6) were isolated from the marine derived fungus Aspergillus sp. The structures of these compounds were elucidated based on chemical and physicochemical evidence, including MS, UV, IR and NMR spectra. The stereochemistry of 1 was further confirmed by catalytic reaction of 5 with p-TsOH as a catalyst. Compounds 1 to 6 showed cytotoxicity against mouse leukemia cell line P388, with IC50 values of 4.7, 9.3, 24.6, 105.7, 13.3 and 24.9 μM, respectively.

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