Application of Paramagnetic Shift Reagents in Nuclear Magnetic Resonance Studies of Complex Alcohols and Amines

Gillies, Elaine; Szarek, Walter A.; Baird, Michael C.

doi:10.1139/v71-037

Cited by 20 publications

(3 citation statements)

References 8 publications

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“…Again, paramagnetic chelates have already been used in the early days of NMR spectroscopy as so-called paramagnetic shift reagents to simplify complex NMR spectra by changing the chemical shifts of signals of protons binding or exchanging with the respective agents. 33 The term chemical-exchange saturation transfer (CEST) for the generation of contrast in MR images by utilizing diamagnetic (DIACEST, DIAmagnetic Chemical Exchange Saturation Transfer) and paramagnetic (PARACEST, PARAmagnetic Chemical Exchange Saturation Transfer) agents was introduced by Ward et al 34 The CEST efficiency depends on the rate of the chemical exchange and the chemical shift difference between the different proton populations.…”

Section: Contrast Based On Differences In Relaxation Ratesmentioning

confidence: 99%

CHAPTER 11. Magnetic Resonance‐Based Cell Imaging Using Contrast Media and Reporter Genes

Velde¹,

Himmelreich²

2013

New Developments in NMR

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Section: Contrast Based On Differences In Relaxation Ratesmentioning

confidence: 99%

CHAPTER 11. Magnetic Resonance‐Based Cell Imaging Using Contrast Media and Reporter Genes

Velde¹,

Himmelreich²

2013

New Developments in NMR

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“…Certain lanthanide complexes have been found to induce large shifts without excessive line-broadening, and use of such lanthanide shift reagents has been well documented in the literature (6) including THIS JOURNAL (7,8). Transition metal complexes such as Co(AcAc)2(H20)2 have been used also to simplify NMR spectra of alcohols and amines (9). Although somewhat less effective than the lanthanides, transition metal acetylacetonate complexes have for pedagogical purposes advantages of low cost, ease of preparation, and (unlike the lanthanide reagents) nonhygroscopic properties.…”

Section: Nmr Shift Reagent Workmentioning

confidence: 99%

Synthesis, characterization, and use of a cobalt(II) complex as an NMR shift reagent: An integrated laboratory experiment

Goff¹,

Hines²,

Griesel³

et al. 1982

J. Chem. Educ.

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A currently popular approach to advanced undergraduate laboratory organization involves integration of materia! from the various disciplines of chemistry. All too often, however, the integrated laboratory is composed only of standard experiments randomly selected from the individual disciplines. A recent laboratory manual entitled "Integrated Experimental Chemistry," in fact, follows this route {1). An approach which is seemingly more relevant to the usual research situation involves integration of diverse chemical concepts into each experiment. The typical organization is thus: synthesis -* analysis -* physical measurement. A paucity of such experiments are available.The following experiment was designed for and has been employed in our majors junior-level integrated laboratory. Approximately four 3-hr laboratory periods are required for completion, assuming ready access to instruments. The acetylacetonate complex of cobalt(II), Co(AcAc)2(H20)2, is prepared and isolated following modification of literature methods (2). Spectrophotometric analysis of the cobalt content serves to characterize the material. Additional characterization by a method(s) of the student's choice provides an open-ended dimension to the experiment. The paramagnetic complex is further employed as an NMR shift reagent to simplify the spectrum of a complex alcohol. SynthesisA large number of metal complexes have been prepared using ,3-diketone compounds (3). Complexes of acetylacetone (2,4-pentane-dione) with first row transition metal ions are rather easily prepared and are of considerable importance in analytical and inorganic chemistry. The sodium salt of acetylacetone is prepared and this adduct is allowed to react with an aqueous cobatt(ll) chloride solution:

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“…Acetylacetone (Hacac) is well known as one of useful bidentate ligands, which can form chelate complexes, such as [M II (acac) 2 ], [M III (acac) 3 ] and [M III (acac) 2 X 2 ] − , through reactions with various transition metal ions [1-28]. The complexes have been widely investigated, for example, as building blocks for magnetic materials [29][30][31], NMR shift reagents and paramagnetic relaxation reagents [32][33][34][35] and catalysts [36,37]. The trans-[Ru III (acac) 2 (CN) 2 ] − anion has an unpaired electron and has been reported to work as a paramagnetic linker in combination with Mn 2+ and [Fe III salen] + to produce ferri-or ferromagnetic compounds {Mn II [Ru III (acac) 2 (CN) 2 ] 2 } n and [{Fe III (salen)}{Ru III (acac) 2 (CN) 2 }] − with two-and one-dimensional structures, respectively [38,39].…”

Section: Introductionmentioning

confidence: 99%

Syntheses, Structures, and Properties of Mono- and Dinuclear Acetylacetonato Ruthenium(III) Complexes with Chlorido or Thiocyanato Ligands

Nakashima,

Hayami,

Nakashima

et al. 2024

Magnetochemistry

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The mononuclear and dinuclear ruthenium(III) complexes trans-Ph4P[RuIII(acac)2Cl2] (1), Ph4P[{RuIII(acac)Cl}2(μ-Cl)3] (2) and trans-Ph4P[RuIII(acac)2(NCS)2]·0.5C6H14 (3·0.5C6H14) were synthesized. Single crystals of 1, 2·H2O and 3·CH3CN suitable for X-ray crystal structure analyses were obtained through recrystallization from DMF for 1 and 2·H2O and from acetonitrile for 3·CH3CN. An octahedral Ru with bis-chelate-acac ligands and axial chlorido or κ-N-thiocyanido ligands (for 1 and 3·CH3CN) and triply µ-chlorido-bridged dinuclear Ru2 for 2·H2O were confirmed through the structure analyses. The Ru–Ru distance of 2.6661(2) of 2·H2O is indicative of the existence of the direct metal–metal interaction. The room temperature magnetic moments (μeff) are 2.00 and 1.93 μB for 1 and 3·0.5C6H14, respectively, and 0.66 μB for 2. The temperature-dependent (2–300 K) magnetic susceptibility showed that the strong antiferromagnetic interaction (J ≤ −800 cm−1) is operative between the ruthenium(III) ions within the dinuclear core. In the 1H NMR spectra measured in CDCl3 at 298 K, the dinuclear complex 2 showed signals for the acac ligand protons at 2.50 and 2.39 ppm (for CH3) and 5.93 ppm (for CH), respectively, while 1 and 3·0.5C6H14 showed signals with large paramagnetic shifts; −17.59 ppm (for CH3) and −57.01 ppm (for CH) for 1 and −16.89 and −17.36 ppm (for CH3) and −53.67 and −55.53 ppm (for CH) for 3·0.5C6H14. Cyclic voltammograms in CH2Cl2 with an electrolyte of nBu4N(ClO4) showed the RuIII → RuIV redox wave at 0.23 V (vs. Fc/Fc+) for 1 and the RuIII → RuII waves at −1.39 V for 1 and −1.25 V for 3·0.5C6H14 and the RuIII–RuIII → RuIII–RuIV and RuIII–RuIII → RuIII–RuIV waves at 0.91 V and −0.79 V for 2.

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Application of Paramagnetic Shift Reagents in Nuclear Magnetic Resonance Studies of Complex Alcohols and Amines

Abstract: The effects of Co(acetyla~etonate)~, Ni(acetylacet~nate)~, and Cu(ethy1 acetoa~etate)~ on the nuclear magnetic resonance spectra of a variety of alcohols and amines have been studied. Changes are produced in the spectra, which are useful for assigning the signals.

Cited by 20 publications

References 8 publications

CHAPTER 11. Magnetic Resonance‐Based Cell Imaging Using Contrast Media and Reporter Genes

CHAPTER 11. Magnetic Resonance‐Based Cell Imaging Using Contrast Media and Reporter Genes

Synthesis, characterization, and use of a cobalt(II) complex as an NMR shift reagent: An integrated laboratory experiment

Syntheses, Structures, and Properties of Mono- and Dinuclear Acetylacetonato Ruthenium(III) Complexes with Chlorido or Thiocyanato Ligands

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