Kinetic and spectroscopic studies on α- and β-cyclodextrin rotaxanes with (µ-N,N′- bis(4-pyridinylmethylene)-α,ω-alkanediimine)bis[pentacyanoferrate(II)] threads

2005 ◽  
Vol 83 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Victor X Jin ◽  
Donal H Macartney ◽  
Erwin Buncel
Keyword(s):  
Chemical Shift ◽  
Metal Complexes ◽  
Key Words ◽  
Rate Constants ◽  
Self Assembly ◽  
Spectroscopic Studies ◽  
Ligand Substitution ◽  
H Nmr ◽  
End Groups ◽  
The Stability

[2]Pseudorotaxanes have been prepared by threading N,N′-bis(4-pyridinylmethylene)-1,2-ethanediimine (L2), -1,4-butanediimine (L4), and -1,6-hexanediimine (L6) ligands through α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), and have subsequently been converted to the corresponding [2]rotaxane species by coordinating bulky [Fe(CN)5]3– end groups. The stability constants for the [2]pseudorotaxanes were determined by 1H NMR chemical shift titrations and increase with the polymethylene chain length n. The rate constants for both the formation of the [Fe(CN)5(Ln)]3– complexes from the [Fe(CN)5OH2]3– ion and Ln, and the rate constants for the dissociation of Ln from the metal complexes, exhibit significant diminutions in the presence of α- and β-CD, owing to inclusions of the free and coordinated ligands, respectively. The lability of the iron(II)–pyridine bonds also permits the spontaneous self-assembly of the [2]rotaxane upon the addition of cyclodextrin to the iron dimer complexes. The mechanism for this process involves the rate-determining dissociation of a [Fe(CN)5]3– unit from [(NC)5Fe(Ln)Fe(CN)5]6–, followed by CD inclusion of the Ln ligand to form a semirotaxane, and subsequent recomplexation by the [Fe(CN)5OH2]3– ion. Key words: cyclodextrins, rotaxanes, pentacyanoferrate(II), ligand substitution, kinetics.

scholarly journals NMR spectroscopic study of inclusion complexes of cetirizine dihydrochloride and β-cyclodextrin in solution

2007 ◽  
Vol 21 (3) ◽  
pp. 177-182 ◽  
Author(s):  
Syed Mashhood Ali ◽  
Santosh Kumar Upadhyay ◽  
Arti Maheshwari
Keyword(s):  
Aqueous Solution ◽  
Chemical Shift ◽  
Spectroscopic Study ◽  
Inclusion Complexes ◽  
Binding Constant ◽  
Spectroscopic Studies ◽  
Chemical Shift Change ◽  
Nmr Chemical Shift ◽  
H Nmr ◽  
Shift Change

Cetirizine dihydrochloride (CTZ), an antihistamine, forms two 1:1 inclusion complexes with β-cyclodextrin (β-CD) in aqueous solution as confirmed by detailed1H NMR, COSY and ROESY spectroscopic studies. The stoichiometry and overall binding constant of the complexes were determined by the treatment of1H NMR chemical shift change (Δδ) data. Most of the CTZ protons exhibited splitting in the presence of β-CD.

Ligand substitution reactions of pentacyanoferrate(II) complexes with N-heterocyclic cations in aqueous solution

1989 ◽  
Vol 67 (11) ◽  
pp. 1774-1779 ◽  
Author(s):  
Donal Hugh Macartney ◽  
Lauren Jean Warrack
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Dissociation Constants ◽  
Formation Rate ◽  
Spectroscopic Studies ◽  
Ligand Substitution ◽  
Acid Dissociation ◽  
Specific Rate ◽  
Dissociative Mechanism ◽  
Heterocyclic Cations

Kinetic and spectroscopic studies have been carried out in aqueous solution on the formation (from Fe(CN)5OH23−) and dissociation of pentacyanoferrate(II) complexes containing 1-(4-pyridyl)pyridinium and the neutral, protonated, and N-methylated forms of 4,4′-bipyridine (BPY), 1,2-bis(4-pyridyl)ethane (BPA), and trans-1,2-bis(4-pyridyl)ethylene (BPE). The pH dependences of the formation kinetics have been analyzed in terms of the specific rate and acid dissociation constants for these ligands. The rate constants (25.0 °C, I = 0.10 M) for the formation of the dinuclear complexes (NC)5FeLFe(CN)56− have been determined for BPY (50 M−1 s−1), BPA (66 M−1 s−1), BPE (95 M−1 s−1), and pyrazine (10 M−1 s−1), and are compared with the respective rate constants for the formation of (NC)5FeLCo(NH3)5. The relationships between the formation rate constants and the size of the ligand, the number of donor sites, and the magnitude and position of charges on the ligand are discussed in terms of an ion-pair dissociative mechanism. Keywords: pentacyanoferrate(II) complexes, N-heterocycles, ligand substitution, kinetics.

α- and β-Cyclodextrin [2]rotaxanes with (diethylenetriamine)platinum(II) stoppers

2005 ◽  
Vol 83 (12) ◽  
pp. 2091-2097 ◽  
Author(s):  
Victor X Jin ◽  
Donal H Macartney ◽  
Erwin Buncel
Keyword(s):  
Self Assembly ◽  
Electrospray Mass Spectrometry ◽  
Platinum Complexes ◽  
H Nmr ◽  
Bridging Ligand ◽  
Dinuclear Platinum ◽  
End Groups ◽  
Group A ◽  
Kinetics Of ◽  
End Group

A series of dinuclear platinum(II) complexes, [(dien)Pt(NH2(CH2)nNH2)Pt(dien)]Cl4 (dien = diethylenetriamine, n = 8, 9, 10, and 12) and their corresponding [2]rotaxanes with α-cyclodextrin (α-CD), [(dien)Pt{NH2(CH2)nNH2·α-CD}Pt(dien)]Cl4, have been synthesized and characterized by 1H, 13C, and 195Pt NMR spectroscopy and electrospray mass spectrometry. The rotaxanes were prepared by reacting the {NH2(CH2)nNH2·α-CD} pseudorotaxanes with [Pt(dien)]Cl, to stopper the included linear α,ω-diaminoalkane chains with the inert Pt(II) end groups. The kinetics of the self-assembly and dissociation of the β-CD rotaxane, [(dien)Pt{NH2(CH2)10NH2·β-CD}Pt(dien)]4+, were investigated by using 1H NMR and are indicative of a slippage mechanism, owing to the comparable sizes of the β-CD cavity and the [Pt(dien)]+ end group. A relatively weak inclusion of the end group in the β-CD cavity precedes a thermally promoted passage of the β-CD over the [Pt(dien)]+ end group onto the hydrophobic polymethylene chain of the bridging ligand of the thread. Key words: rotaxanes, pseudorotaxanes, cyclodextrin, platinum complexes, slippage mechanism.

Proof of ion-pair structures in ammonium-based protic ionic liquids using combined NMR and DFT/PCM-based chemical shift calculations

2017 ◽  
Vol 19 (36) ◽  
pp. 25033-25043 ◽  
Author(s):  
M. Lozynski ◽  
J. Pernak ◽  
Z. Gdaniec ◽  
B. Gorska ◽  
F. Béguin
Keyword(s):  
Ionic Liquids ◽  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Self Assembly ◽  
Ion Pair ◽  
The Self ◽  
Prediction Methods ◽  
Protic Ionic Liquids ◽  
H Nmr ◽  
Chemical Shift Calculations

The self-assembly of triethylammonium bis(trifluoromethylsulfonyl)imide, i.e. [(C2H5)3NH][TFSI], in chloroform and aqueous solutions has been investigated using 1H NMR spectroscopy and computational (DFT/PCM prediction) methods.

scholarly journals Spektroskopische Untersuchungen an Cyclopentadienyl-dinitrosylvanadium-Komplexen CpV(NO)2L (L = Lewis-Base) / Spectroscopic Studies with Cyclopentadienyl Dinitrosylvanadium Complexes CpV(NO)2L (L = Lewis Base)

1982 ◽  
Vol 37 (5) ◽  
pp. 614-619 ◽  
Author(s):  
Max Herberhold ◽  
Herbert Trampisch
Keyword(s):  
Chemical Shift ◽  
Chemical Shifts ◽  
Spectroscopic Studies ◽  
Lewis Base ◽  
Nmr Chemical Shift ◽  
Nmr Chemical Shifts ◽  
Lewis Bases ◽  
H Nmr ◽  
Ligand Atom

Displacement of the CO ligand in CpV(NO)2CO (Cp = η5-cyclopentadienyl) by various Lewis bases (L) in solution leads to a series of (28) complexes CpV(NO)2L which were characterised by the 51V NMR chemical shift, the 13C and 1H NMR chemical shifts of the cyclopentadienyl ring, and by the NO stretching frequencies of the two nitrosyl ligands. The chemical shift δ(51V) varies over the range of ca. -1300 and -500 ppm depending on the nature of L, whereas δ(13C) of the cyclopentadienyl ring varies only between 98 and 102 ppm. The shielding of the 51V and 13C nuclei decreases as the electronegativity of the ligand atom bound to the metal increases in the order P <S <N <O

scholarly journals Towards new multivalent supramolecular helical structures based on phthalocyanines for PDT applications

2017 ◽  
Vol 21 (11) ◽  
pp. 745-750 ◽  
Author(s):  
Miguel García-Iglesias ◽  
Elisa Huerta
Keyword(s):  
Nmr Spectroscopy ◽  
Self Assembly ◽  
Aqueous Media ◽  
The Self ◽  
Supramolecular Polymers ◽  
Helical Structures ◽  
H Nmr ◽  
Sugar Moiety ◽  
The Stability ◽  
And Diffusion

The self-assembly of [Formula: see text]-D-glucose octafunctionalized Zn(II) phtalocyanine (ZnPc) in aqueous media has been investigated using different techniques such as UV, CD and diffusion-ordered [Formula: see text]H-NMR spectroscopy (DOSY). The formation of supramolecular columnar helical aggregates with a preferred handedness due to the presence of the sugar moiety has been confirmed by these techniques. Moreover, the stability of the supramolecular polymers formed has been assessed by using pyridine as a zinc ligand, disrupting the aggregates or inducing their formation by dilution of the system.

Potentiometric titration study of two novel polydenate ligands and investigations of their complexes

2001 ◽  
Vol 79 (4) ◽  
pp. 455-460 ◽  
Author(s):  
Dengke Cao ◽  
Hua-Kuan Lin ◽  
Zhi-Fen Zhou ◽  
Shou-Rong Zhu ◽  
Xun-Cheng Su ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Metal Complex ◽  
Metal Complexes ◽  
Molar Ratio ◽  
Complex Stability ◽  
Binding Ability ◽  
H Nmr ◽  
Binuclear Metal ◽  
The Stability ◽  
Titration Study

Two novel linear polyamine ligands, N,N'-bis-(2-(N''-2-hydroxyl-5-bromobenzyl)aminoethyl) malondiamide (L1) and N,N'-bis-(3-(N''-2-hydroxyl-5-bromobenzyl)aminopropyl) malondiamide (L2), have been synthesized and fully characterized by elemental analysis (1H NMR and IR spectroscopy) (Fig. 1). The binding ability of ligands L1 and L2 to metal ions such as Cu(II), Zn(II), Co(II), Mn(II), Mg(II), and Ca(II) has been investigated by the potentiometric method in 1,4-dioxane–water (v/v = 15:100) and KNO3 (0.1 mol dm–3) at 25.0°C. In view of the linear structures of L1 and L2, binuclear metal complexes can be formed in solution by controlling Cu(II)-5-substituted o-phenanthroline (Rphen, R = CH3, H, Cl, NO2):L to a 2:1 molar ratio, whereas the mononuclear metal complexes form at molar ratio M(II):L of 1:1, where M(II) is Cu(II), Zn(II), Co(II), Mn(II), Mg(II), and Ca(II). The stability constants of metal complexes have been determined and further discussed. In addition, two manganic complexes have been synthesized and IR and electronic spectra showed their coordination nature.Key words: linear polyamine ligand, 5-substituted o-phenanthroline, mononuclear and binuclear metal complex, stability, spectrum.

31P-NMR-und 57Fe-Mößbauer-spektroskopische Untersuchungen an Pentacyano(phosphan oder phosphit)ferraten(II) / 31P NMR and 57Fe Mössbauer Spectroscopic Studies on Pentacyano(phosphane or phosphite)ferrates(II)

1985 ◽  
Vol 40 (1) ◽  
pp. 22-25 ◽  
Author(s):  
Hidenari Inoue ◽  
Masahiro Sasagawa ◽  
Ekkehard Fluck
Keyword(s):  
Chemical Shift ◽  
Nmr Spectra ◽  
31P Nmr ◽  
Chemical Shifts ◽  
Spectroscopic Studies ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
H Nmr ◽  
Phosphine Complexes ◽  
Low Field

The 31P{1H}NMR spectra for a series of pentacyanoferrates(II) of the type Na3[Fe(CN)5L] (L = phosphine or phosphite) have been measured. A low field chemical shift range of 48.1-88.7 ppm for phosphine complexes and of 32.5-48.4 ppm for phosphite complexes is observed when one compares free vs. coordinated ligands. The correlation between chemical shifts in the 31P NMR spectra and isomeric shifts in the Mössbauer spectra is investigated and discussed

Synthesis, IR, and multinuclear NMR spectroscopic studies of complexes of the type cis- and trans-Pt(amine)2(NO3)2

2004 ◽  
Vol 82 (4) ◽  
pp. 524-532 ◽  
Author(s):  
Fernande D Rochon ◽  
Viorel Buculei
Keyword(s):  
Key Words ◽  
Secondary Amine ◽  
Spectroscopic Studies ◽  
Coupling Constants ◽  
Primary Amines ◽  
Trans Isomers ◽  
H Nmr ◽  
Cis And Trans ◽  
Ir Bands ◽  
C Nmr

Compounds of the types cis- and trans-Pt(amine)2NO3)2 have been synthesized and characterized by IR and multinuclear (195Pt, 13C, and 1H) NMR spectroscopies. The nitrato IR bands were compared for the two isomers. The 195Pt NMR resonances of the trans complexes were observed at lower fields (avg. –1570 ppm for primary amines) than the cis analogues (avg. –1698 ppm) for an average Δδ value of 124 ppm. The complexes containing a secondary amine were observed at about the same field for the cis isomers (avg. –1682 ppm) and surprisingly at much higher fields for the trans compounds (avg. –1638 ppm). In 1H NMR, the coupling constants 2J(195Pt-1HN) are larger for the cis isomers (avg. 67 Hz) than for the trans compounds (avg. 58 Hz). The 3J(195Pt-1H) are also larger for the cis complexes (avg. 40 vs. 33 Hz). In 13C NMR, the coupling constants are also geometry dependent. The 3J(195Pt-13C) are larger for the cis isomers (avg. 37 Hz) than for the trans compounds (avg. 28 Hz). The 2J(195Pt-13C) are much smaller (avg. 18 Hz for the cis complexes and 16 Hz for the trans isomers).Key words: platinum, amine, nitrato, NMR, IR.

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