NMR methods for molecular structure studies of paramagnetic lanthanide complexes in solutions. Applications to crown ether complexes

Babailov, Sergey P.; Krieger, Yu. G.

doi:10.1007/bf02903634

Cited by 38 publications

(21 citation statements)

References 45 publications

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“…Analysis of the temperature dependence of paramagnetic LISs of I in Fig. shows that it is substantial and well approximated by a linear anamorphose of the inverse temperature value (1/ T ) (like for [Ln(18‐crown‐6)(ptfa) 2 ] + , [Ln(diaza‐18‐crown‐6)(NO 3 ) 3 ], [Ln(18‐crown‐6)(NO 3 ) 3 ], and [LnH(oep)(tpp)], where Ln = La‐Eu, ptfa is 1,1,1‐trifluoro‐5,5‐dimethyl‐2,4‐hexanedione, tpp is tetraphenylporphyrin, and oep is octaethylporphyrin).…”

Section: Resultsmentioning

confidence: 97%

Intermolecular dynamics and paramagnetic properties of ethylenediaminetetraacetate complexes with the yttrium subgroup rare earth elements using nuclear magnetic resonance

Babailov

2012

Magnetic Reson in Chemistry

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(1)H nuclear magnetic resonance (NMR) measurements are reported for the D(2)O solutions of [Ln(3+)(EDTA(4-))](-) complexes, where EDTA(4-) is ethylenediaminetetraacetate anion, Ln(3+) = Tb(3+) (I), Ho(3+) (II), Tm(3+) (III), Yb(3+) (IV) and Lu(3+) (V). Temperature dependencies of the (1)H NMR spectra of paramagnetic I-IV have been analyzed using the dynamic NMR methods. It is found that the activation free energies (ΔG(‡)(298)) of the intermolecular EDTA ions exchange at [Ln(3+) (EDTA(4-))](-) complexes are 60±3 (I), 66±3 (II), 69±3 (III) and 74±3 (IV) kJ/mol (at pD = 7). A monotonic increase of the free energy of chemical exchange processes along the series of lanthanide [Ln(3+) (EDTA(4-))](-) complexes is probably related to the lanthanide contraction. The obtained results indicate that coordination compounds I-IV may be considered as thermometric NMR sensors and lanthanide paramagnetic probes for in situ temperature control in solution.

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Section: Resultsmentioning

confidence: 97%

Intermolecular dynamics and paramagnetic properties of ethylenediaminetetraacetate complexes with the yttrium subgroup rare earth elements using nuclear magnetic resonance

Babailov

2012

Magnetic Reson in Chemistry

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“…Here, kЈ 12 is an effective rate constant of a phototransmutation from A to B (kЈ 21 is an effective rate constant of a reverse photo transition), A* is a transient state, and k 12 and k 21 are relevant rate constants of "dark" chemical exchange. It is assumed that the transient state lifetime is in the range of 10 Ϫ11 Ϭ 10 Ϫ12 s. The magnetic nucleus X in the molecules A has magnetic environment 1 or takes site 1, and in the molecules B the nucleus X is in site 2.…”

Section: Methodicalmentioning

confidence: 99%

NMR in photo‐induced chemical exchange systems. Double‐resonance inverse fractional population transfer application for investigation of 1,2‐(2,2′‐dipyridyl)ethene photoisomerization kinetics

Babailov¹,

Kruppa²,

Glebov³

et al. 2006

Concepts Magnetic Resonance

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ABSTRACT:The analytical expression describing the dynamics of nuclear magnetization with the use of double-resonance NMR by the procedure of inverse fractional population transfer in requirements of photo-induced chemical exchange (PICE) is obtained in this article. Laser-induced ( ϭ 308 nm) photoisomerization of 1,2-(2,2Ј-dipyridyl)ethene was studied by NMR and UV absorption spectroscopy under irreversible and photostationary conditions.

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“…2 with v x = v w This proeedure is based on measuring the signal intensity v(oo, vA) at light exposure and v,(oo, vA) without it. The ratio of the respective values can be expressed as v(o% vA) _ 1 + T~Ak A v,(~,vA) l+r~A(k~+kA) (6) The measurement of the ratio v(oe, VA)/Vt(OO, VA) allows one to estimate the k 93 value provided that T~A is defined independently, for example, by the 180 ~ r-90 ~ procedure [15][16][17][20][21][22]. It is necessary to note that the described pseudo I-D NOE procedure essentially differs from the "pure" 1-D NOE procedure.…”

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confidence: 99%

NMR applications for a study of converted photochemical processes kinetics

Babailov

Krieger

2002

Appl. Magn. Reson.

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The analytical expression describing dynamics of the nuclear magnetization with the use of double resonance nuclear magnetic resonance of a procedure of transfer of spin saturation under photo-induced chemical exchange is obtained. Three different experimental procedures for the definition of the effective tate constants and the quantum yield of responses ate considered.One of the numerous applications of nuclear magnetic resonance (NMR) spectroscopy is the study of photochemical reactions [1][2][3][4][5]. The use of NMR for investigating the quantum yields of irreversible photochemical reactions [1] is widely known. Besides, photochemicaUy induced dynamic polarization of nucleus allows one to examine [2, 3] the short-lived radical alternate corpuscles which appear as a result of flash photolysis of substances. Recently it was shown that with the help of dynamic NMR (DNMR), the reversible photochemical processes [6-8] can be investigated in situ. DNMR procedures on the basis of the comparison of the band shapes are promising for the study of photo-induced chemical exchange (PICE) [6][7][8]. Use of the double NMR procedures for understanding the kinetics of PICE [9] was recently offered. The goal of the present investigation is the further development of this methodical approach. For this purpose the analytical expression describing the modification of the nuclear magnetization depending on the effective rate constant of PICE at the double NMR on the basis of the ForsenHoffman procedure [10] was obtained. In the long run, this methodicat approach can be used for studying converted photochemical reactions with a characteristic 9 This work was partially presented at the Joint 29th Ampere and 13th ISMAR lntemationaI Conference on Magnetic Resonance and Related Phenomena, Berlin, 1998.

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NMR methods for molecular structure studies of paramagnetic lanthanide complexes in solutions. Applications to crown ether complexes

Cited by 38 publications

References 45 publications

Intermolecular dynamics and paramagnetic properties of ethylenediaminetetraacetate complexes with the yttrium subgroup rare earth elements using nuclear magnetic resonance

Intermolecular dynamics and paramagnetic properties of ethylenediaminetetraacetate complexes with the yttrium subgroup rare earth elements using nuclear magnetic resonance

NMR in photo‐induced chemical exchange systems. Double‐resonance inverse fractional population transfer application for investigation of 1,2‐(2,2′‐dipyridyl)ethene photoisomerization kinetics

NMR applications for a study of converted photochemical processes kinetics

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