scholarly journals Spectral evidence for generic charge → acceptor interactions in carbamates and esters

RSC Advances ◽  
2020 ◽  
Vol 10 (20) ◽  
pp. 11871-11875
Author(s):  
Erode N. Prabhakaran ◽  
Shama Tumminakatti ◽  
Kamal Vats ◽  
Sudip Ghosh
Keyword(s):  
Negative Charge ◽  
Carbonyl Oxygen ◽  
Spectral Evidence ◽  
Ft Ir ◽  
Charge Stabilization

NMR, FT-IR spectral correlations of the R–O–CO groups in carbamates and esters of homologous alcohols (R) reveal R-group-dependent negative charge stabilization at the carbonyl oxygen and its donation to generic acceptors at Cα of even alkyl R.

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VI

1988 ◽  
Vol 42 (1) ◽  
pp. 101-108 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Vapor Phase ◽  
Matrix Isolation ◽  
Spectral Structure ◽  
Absorption Bands ◽  
Rotational Isomers ◽  
Spectral Evidence ◽  
The Matrix ◽  
Ft Ir ◽  
Carbonyl Absorption

Matrix isolation Fourier transform spectral evidence is presented that documents the isolation of rotational isomers in an argon matrix. The spectral evidence is based on the presence of split carbonyl absorption bands in the spectra of selected derivatives of methyl acetate which do not vary in intensity with changes in the matrix-to-eluate ratios. The results compare very favorably with FT-IR data on the identical compounds obtained in the vapor phase. The low temperature of the matrix isolation experiment (10 K) allows for the observance of rotational isomers not seen at the high temperatures of the vapor-phase experiment (500 K). The presence of multiple carbonyl absorption bands dictates that careful attention must be paid to spectral/structure correlations employing MI/FT-IR data.

scholarly journals Synthesis, characterization, antimicrobial screening and cytotoxic properties of Cu(II) and Zn(II) complexes with bidentate hydroxylated 1,3-diaryl-2-propene-1-ones ligand

2020 ◽  
pp. 68-68
Author(s):  
Pravinkumar Patil ◽  
Sainath Zangade
Keyword(s):  
Antimicrobial Activity ◽  
Metal Complexes ◽  
Cytotoxic Activity ◽  
Anticancer Agents ◽  
Cancer Cell Line ◽  
Artemia Salina ◽  
Carbonyl Oxygen ◽  
Planar Geometry ◽  
Ft Ir

A series of binary metal complexes [halo, hydroxyl and methoxy sub-stituted bis (2-(E) acryloyl)naphthalen-1-yl)oxy)Cu(II) and Zn(II) (C1-C10)] of Cu2+ and Zn2+ ions derived from bi-coordinated hydroxylated 1,3-diaryl-2- -propene-1-ones were synthesized. The newly synthesized metal complexes were structurally determined by FT-IR, 1H NMR, 13CNMR, ESR spectral, XRD and TGA analysis. The FT-IR and ESR studies demonstrated that interactions between metal ions with ligands occur through carbonyl oxygen and deprotonated hydroxyl oxygen and corresponds to square-planar geometry for all complexes. In-vitro the metal complexes were screened and evaluated for their antimicrobial and cytotoxic activity. The complexes C1 and C4 showed the significant antimicrobial activity while the remaining complexes were showed the moderately antimicrobial activity against the tested pathogens. The complexes were evaluated for cytotoxic activity against the organism Artemia salina. The complexes C2, C3, C4 and C5 were showed the LC50 values as 630.45, 969.99, 921.94 and 918.41 ?M mL-1 respectively. Further complexes were evaluated for anticancer activity against liver cancer cell line (Hep G2) in comparison with 5-fluorouracil standard. The complex C5 showed the significant IC50 value 58.94 ?g mL-1. Therefore the present study is useful to develop the new class of antimicrobial and anticancer agents.

scholarly journals Synthesis and Structural Studies on some Dioxomolybdenum (VI) Complexes Bearing 1-(1-Hydroxynaphthalen-2-yl) Ethanone Moiety

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Electrochemical Techniques ◽  
Substituent Effects ◽  
Theoretical Data ◽  
Spectroscopic Studies ◽  
Carbonyl Oxygen ◽  
Hydrazone Ligand ◽  
Molybdenum Complexes ◽  
Ft Ir ◽  
The Stability ◽  
Lower Oxidation

A number of new molybdenum complexes Cis-MoO2 (NE)2 .CH3 OH, Cis-MoO2 (HRSB)2 .nH2 O {R= H, 4-Br, 4-OCH3 , 4-CH3 and n= 0, 1, 2} Cis-MoO2 (HL)(acac).nH2 O {HL= HNEBH, HNEINH, HNENH, HNEPH, n=0, 1}, Cis-[MoO2 (L\)2 .nH2 O], {L\= HNE-2-ABH, HNE-4-ABH, n = 0, 2} and Cis-[Mo2 O5 (HNEAH)2 ] have been synthesized and characterization by magnetic, spectroscopic (FT-IR, 1H and 13C-NMR spectra) and electrochemical techniques. The complexes were made reaction of Cis-MoO2 (acac)2 with the ligands, (1-hydroxynaphthalen-2-yl)ethenone (HNE), (E)-2-(1-(phenylimino)ethyl)naphthalen1-ol (HASB), (E)-2-(1-(p-tolylimino)ethyl) naphthalen-1-ol (HTSB), E-2-(1-(4-methoxyphenylimino)ethyl)naphthalen-1-ol (HMSB) and (E)-2-(1-(4-bromophenylimino)ethyl)naphthalen-1-ol (HBrSB) monobasic bidentate (NO) or 2-anmino-N/- (1-(1-hydroxynaphthalene-2-yl)ethylidene)benzohydrazide (HNE2-ABH), 4-anmino-N/-(1-(1-hydroxynaphthalene-2-yl) ethylidene)benzohydrazide (HNE4-ABH), N/-(1-(1-hydroxynaphthalene-2-yl)ethylidene)benzohydrazide (HNEBH), N-(1-(1-hydroxynaphthalene-2-yl)ethylidene)acetohydrazide (HNEAH), N/-(1-(1-hydroxynaphthalene-2-yl)ethylidene) nicotinohydrazide (HNENH), N/-(1-(1-hydroxynaphthalene-2-yl)ethylidene)isonicotinohydrazide (HNEINH), N/-(1- (1-hydroxynaphthalene-2-yl)ethylidene)picolinohydrazide (HNEPH), they coordinate as dibasic tridentate (OON). Both the molecular and the spectroscopic studies showed that, the complexes are octahedrally coordinated. The redox properties, of the electrode couples and the stability of some complexes towards reduction were linked to the electron withdrawing or ability releasing of the substituent in the Schiff bases and the hydrazones. Results show that, changes in E1/2 for the complexes due to remote substituent effects could be related to changes in basicity of the carbonyl oxygen of the hydrazide moiety in the hydrazone ligand. The electron-donating substituents stabilized Mo(VI) complexes while electron-withdrawing groups favored lower oxidation state of Mo(V) and/ or Mo(IV) species. The nature of mechanism and kinetic parameters of the electroactive chelates are strongly dependent on the substituent. The EHOMO and ELUMO level, of hydrazone and some of Cis-molybdenum complexes, from both electrochemical and theoretical data also backdonation energy (ΔEback-donation), ionization potential (I), molecular dipole moment (μ), electronegativity (χ), softness (σ) electron affinity (A), global hardness (η), and electrophilicity index (ω) were calculated.

scholarly journals Synthesis, characterization and antibacterial susceptibility testing of manganese complexes of doxycyline with bipyridine and phenanthroline

2019 ◽  
Vol 30 (2) ◽  
pp. 70-74
Author(s):  
Joshua A. Obaleye ◽  
Olufunso O. Abosede
Keyword(s):  
Susceptibility Testing ◽  
Manganese Atom ◽  
Carbonyl Oxygen ◽  
Manganese Complexes ◽  
Spectroscopic Techniques ◽  
Good Solubility ◽  
Electrospray Mass Spectroscopy ◽  
Ft Ir ◽  
Antibacterial Susceptibility ◽  
Central Manganese

Abstract Three manganese complexes of the antibiotic doxycyline viz.: manganese doxycyline, [MnDox2]Cl2‧2H2O (1), and manganese doxycyline with bipyridine, [MnDox2(bpy)]Cl2‧8H2O (2), and phenanthroline, [MnDox2(phen)]Cl2‧8H2O (3), as the ancillary ligand were synthesized and characterized by FT-IR, elemental analysis and electrospray mass spectroscopy. The three complexes show good solubility in DMF and DMSO. Data obtained from spectroscopic techniques used show that doxycycline coordinates to the central manganese atom through the oxygen of the amide group and the carbonyl oxygen atom of ring A while bipyridine/phenanthroline coordinates through the two diimine nitrogen atoms. The stoichiometry of manganese-doxycycline is 1:2 and octahedral geometry is the preferred coordination in all the complexes.

Magnitudes of 18O isotope shifts in 13C nuclear magnetic resonance spectra of ketones and alcohols

1980 ◽  
Vol 58 (13) ◽  
pp. 1311-1315 ◽  
Author(s):  
James Diakur ◽  
Thomas T. Nakashima ◽  
John C. Vederas
Keyword(s):  
Nmr Spectra ◽  
Negative Charge ◽  
Carbonyl Oxygen ◽  
Upfield Shift ◽  
Isotope Shifts ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
18O Isotope ◽  
Negative Charge Density ◽  
C Nmr

The magnitudes of 18O-induced isotope shifts in 13C nmr spectra of ketones and aldehydes are dependent on structure and range from about 0.05 ppm to 0.03 ppm for the carbon attached to 18O. An increase in negative charge density on the carbonyl oxygen or conjugation to an aromatic ring reduces the size of the upfield shift. The shifts in [18O]alcohols are solvent-dependent, range from 0.03 ppm to 0.01 ppm, and tend to decrease in the order tertiary ≥ secondary ≥ primary ≥ phenols.

scholarly journals Synthesis and structural characterization of the complexes of 2-(menthoxycarbonyl)ethyltin chloride

2019 ◽  
Vol 42 (1) ◽  
pp. 37-45
Author(s):  
Yichao Lin ◽  
Minghui Guo ◽  
Jin Liu ◽  
Laijin Tian ◽  
Xicheng Liu
Keyword(s):  
Oxygen Atom ◽  
Carbonyl Oxygen ◽  
Octahedral Geometry ◽  
Phen Ligand ◽  
X Ray Diffraction ◽  
Centrosymmetric Dimer ◽  
X Ray ◽  
Ester Moiety ◽  
Ft Ir

AbstractThe complexes of 2-(menthoxycarbonyl)ethyltin chloride, MenOCOCH2CH2SnCl3⋅L (Men = Menthyl, L = benzyl phenyl sulfoxide (bpSO), 1; 2,2’-bipyridine (bpy), 2; 1,10-phenanthroline (phen), 3) and [MenOCOCH2CH2SnCl2(OCH3)]2 (4), have been synthesized and characterized by means of elemental analysis, FT-IR, NMR (1H, 13C and 119Sn) spectra. The crystal structures of 1, 3 and 4 have been determined by single crystal X-ray diffraction. The tin atoms in 1-4 are all hexa-coordinated. The tin atom in 1 adopts a distorted [CSnCl3O2] octahedral geometry with an oxygen atom of the ligand and an intramolecular coordination of the oxygen atom from the carbonyl group to the tin atom. Complex 3 possesses a distorted [CSnCl3N2] octahedral geometry with two nitrogen atoms of a chelating phen ligand. The carbonyl oxygen atom of the ester moiety is not coordinating. Compound 4 is a centrosymmetric dimer with a four-membered Sn2O2 ring, and the tin atom has a distorted [CSnCl2O3] octahedral geometry with an intramolecular C=O→Sn coordination and intermolecular methoxy bridging.

PYRIDINIUM BETAINES OF 1,3-INDANDIONE SERIES

1959 ◽  
Vol 37 (5) ◽  
pp. 835-842 ◽  
Author(s):  
Gerassimos Frangatos ◽  
Alfred Taurins
Keyword(s):  
Negative Charge ◽  
Carbonyl Oxygen ◽  
Carboxylic Group ◽  
Pyridinecarboxylic Acids ◽  
Oxygen Atoms

2-Bromo- (II) and 2,2-dibromo-1,3-indandione (III) react with pyridine, 3- and 4-methylpyridine, and 2-, 3-, and 4-pyridinecarboxylic acids to give 1-(3-hydroxy-1-oxo-2-indenyl)-pyridinium hydroxide betaines. In the betaines derived from pyridinecarboxylic acids the negative charge is located not in the carboxylic group but on the carbonyl oxygen atoms.

Synthesis and structure of [2-((L)-menthoxycarbonyl)ethyl]diphenyltin halides

2015 ◽  
Vol 38 (3-4) ◽  
pp. 93-97
Author(s):  
Qingtao Liu ◽  
Xiaowen Shi ◽  
Changfa Zhang ◽  
Laijin Tian
Keyword(s):  
Single Crystal ◽  
Elemental Analysis ◽  
Halogen Atom ◽  
Chelate Ring ◽  
Carbonyl Oxygen ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Trigonal Bipyramidal ◽  
Ft Ir

Abstract Two [2-((L)-menthoxycarbonyl)ethyl]diphenyltin halides, (L)-MenOCOCH2CH2SnXPh2 (X=Cl, 1; I, 2), have been synthesized and characterized by means of elemental analysis, FT-IR, NMR (1H, 13C, and 119Sn) spectroscopy, and X-ray single crystal diffraction. The tin atoms in 1 and 2 are both five-coordinated and possess the [C3SnOX] (X=Cl and I) trigonal bipyramidal environment with the trigonal plane defined by the three carbon atoms and the axial positions occupied by the halogen atom and internal carbonyl oxygen. There is a five-membered chelate ring in 1 and 2 with the Sn-O distance being 2.4781(16) and 2.512(2) Å, respectively.

scholarly journals Evaluasi Aktivitas Antibakteri Hidrogel Hibrid Maleoil Kitosan – Dialdehid Alginat

2019 ◽  
Vol 2 (1) ◽  
pp. 9-14
Author(s):  
Subur P Pasaribu ◽  
Jamaran Kaban ◽  
Mimpin Ginting ◽  
Kasmirul Ramlan Sinaga
Keyword(s):  
Antibacterial Activity ◽  
Schiff Base ◽  
Biomedical Applications ◽  
Negative Charge ◽  
Aldehyde Group ◽  
Hybrid Hydrogel ◽  
E Coli ◽  
Hybrid Hydrogels ◽  
Stretching Vibration ◽  
Ft Ir

Telah dilakukan sintesa hidrogel hibrid maleoil kitosan (MKS)-dialdehid alginat (DAA) melalui reaksi basa Schiff antara gugus amina dari MKS dengan gugus aldehid dari DAA pada berbagai rasio perbandingan dalam larutan buffer fosfat pH 7,4. Hidrogel yang diperoleh dikarakterisasi dengan spektrofotometer FT-IR dan dilakukan uji aktivitas antibakterinya terhadap E.coli dan S. aureus untuk mengevaluasi potensinya sebagai antibakteri. Berdasarkan spektrum FT-IR, hidrogel telah berhasil disintesa dengan munculnya puncak karakteristik dari struktur hemiasetal pada 864,11 cm-1 merupakan vibrasi stretching dari ikatan -C-N- yang menunjukkan bahwa telah terjadi reaksi kopling diantara gugus CHO pada DAA dan NH2 dari MKS dan didukung dengan adanya puncak pada 1627,92 cm-1 yang berhubungan dengan terbentuknya gugus –C=N-. Pada uji aktivitas antibakteri hidrogel hanya perbandingan 5:5, 3:7 dan 1:9 (MKS:DAA) yang menunjukkan adanya aktivitas terhadap E.coli masing-masing 6,18 , 8,15 dan 6,80 (mm), sedangkan terhadap S. aureus seluruh hidrogel menunjukkan aktivitas yaitu, 8,00, 10,10, 10,08, 8,15 dan 7,00 (mm). Aktivitas antibakteri akan meningkat seiring dengan peningkatan jumlah DAA tetapi menurun kembali seiring dengan penurunan MKS. Hal ini dapat dikaikan dengan banyaknya ikatan basa Schiff yang terbentuk pada saat pembentukan hidrogel yang menyebabkan atom N bersifat kationik sehingga dapat mengikat muatan negatif pada permukaan sel bakteri. Hidrogel hibrid MKSDAA dengan rasio perbandingan 5:5 sangat potensial digunakan sebagai hidrogel yang bersifat antibakteri untuk aplikasi biomedis.   Maleoyl chitosan (MaCs) – alginate dialdehyde (AD) hybrid hydrogel had been synthesized through Schiff base reaction between amine group from MaCs and aldehyde group from AD at various ratio in pH phosphate buffer pH 7.4. The obtained hydrogels were characterized by FT-IR spectrophotometer and their antibacterial activity was tested against E. coli and S. aureus to evaluate their potential as antibacterial. Based on the FT-IR spectrum, the hydrogel was successfully synthesized with the appearance of the characteristic peaks of the hemiasetal structure at 864.11 cm-1 which was a stretching vibration of the -CN bond showing that there had been a reaction of coupling between CHO groups in DAA and NH2 from MaCs and supported with the peak at 1627.92 cm-1 associated with the formation of the group –C = N-. In the test of the antibacterial activity of the hydrogels, only the ratio of 5 : 5, 3 : 7 and 1 : 9 (MaCs : AD) showed there were activities of E. coli 6.18, 8.15 and 6.80 mm respectively, whereas against S. aureus the entire hydrogel showed activity namely, 8.00, 10.10, 10.08, 8.15 and 7.00 mm. Antibacterial activity would increase along with the increase in the amount of ADA but decreased again as the MaCS decreased. This could be attributed to the number of Schiff base bonds formed during the formation of the hydrogel which caused the N atom to be cationic so that it could bind the negative charge on the surface of the bacterial cell. MaCs - AD hybrid hydrogels with a ratio of 5: 5 were very potential to be used as antibacterial hydrogels for biomedical applications.

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