ChemInform Abstract: The Complexation of Sodium Ion by the Cryptand (I), 4,7,13‐Trioxa‐1,10‐diazabicyclo(8.5.5)eicosane (C21C5), in a Range of Solvents. A 23Na NMR Kinetic Study (original) (raw)
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J Am Chem Soc, 1986
cis-9,10-Diethyl-9,1O-dihydroanthracene (cis-6) was prepared by reductive alkylation of anthra~ene.'~ trans -9,lO-Diethyl-9,10-dihydroanthracene (trans-6) was prepared by Li/NH, reduction of 9.1 0-diethylanthracene.'* 9,10-Ethano-9,10-dihydroanthracene (7) was prepared from dibenzobarrelene by Li/NH, reduction.20 Benzanthrene (8) was prepared from commercial benzanthrone by reduction with a fourfold excess of LiAIH4/AIC13.21 Ethylbenzanthrene (Sa) was prepared from 8 (0.55 g, 2.5 mmol) by proton abstraction with n-butyllithium (3.1 mmol) in THF at -78 OC followed by the addition of excess bromoethane. Ether extraction yielded Sa as a yellow oil which was microdistilled for analysis. NMR (CCI,) 6 0.5 (t, 3 H), 1.7 (quintet, 2), 4.1 (t. I), 7.5 (m, IO). Fieser, M. Reagents for Organic Synthesis; Wiley: cis-9-Ethyl-10-tert-butyl-9,lO-dihydroanthracene (9) was prepared by epimerization of 1,9-Ethano-9,10-dihydroanthracene (1 1) was prepared from ace-anthrene2, (230 mg, 1 mmol) and sodium (60 mg, 2.5 mmol) according to the general procedure for metal-ammonia reduction. After normal quenching with dilute ammonium chloride solution and ether extraction, the solid product was recrystallized from methanol/water to yield 1,9ethano-9,IO-dihydroanthracene as white crystals: mp 81-82 OC (60 mg, 0.3 mmol, 33%); NMR (CDCI,) 6 2.0 (m, 1 H), 2.9 and 3.1 (m, 3). 3.8 . (23) Aceanthrene was prepared starting from aceanthrenequinone according to the synthesis reported by Becker et al. (Becker, H. D.; Hansen, L.; Nadersson, K. J. Org. Chem. 1985, 50, 277) with one exception. 2-Aceanthrone was prepared with pyridine hydrochloride reagent as described by Plummer et al. (Plummer, B. F.; AI-Saigh, 2. Y.; Arfan, M. J . Org Chem. 1984, 49, 2069). Melting points of intermediate compounds were identical with those reported by Becker et al. The Complexation of Sodium Ion by the Cryptand 4,7,13-Trioxa-1 , 10-diazabicyclo[ 8.5.5leicosane (C2 l C5) in a Range of Solvents.
Inorganic Chemistry, 1991
Mg, 7439-95-4; glucose I-phosphate, 59-56-3; glucose 6-phosphate, 56-73-5; acetyl phosphate, 590-54-5. analysis programs. were obtained Registry NO. The cryptate (4,7,13,16-tetraoxa-l,l0-diazabicyclo[8.8.5] tricosane)sodium(I) perchlorate, Na.C22C5]CI0,, crystallizes in the A3 with Z = 8. The structure was refined by a full-matrix least-squares procedure to final R = 0.045 and R, = 0.054 for 1669 reflections with I 1 2.5u(I). The Na+ center is five-coordinate and lies in the same plane as the four oxygen atoms of C22C5, with the fifth coordination site occupid by a perchlorate oxygen atom above this plane completing a square-pyramidal coordination geometry. An unusual feature is that the two nitrogen atoms of C22C5 (which lie below the plane of the four oxygen atoms) are not within bonding distance of Nat. This contrasts with the structure of the closely related [Na.C221]+, (4,7,13,16,21-pentaoxa-I ,IO-diazabicycl0[8.8.5]tricosane)sodium(I), in which Nat is in the center of the cryptand cavity and is within bonding distance of all five oxygen atoms and both nitrogen atoms, and illustrates the major structural effect of the replacement of an oxygen donor atom of [Na.C221]+ by a methylene moiety to give [Na.C22C5]+. This replacement also has a substantial effect in solution where, in acetonitrile, propylene carbonate, water, acetone, methanol, dimethylformamide, dimethyl sulfoxide, and pyridine, log (Klmol dm-3) = 1 7 , 1 7 , 1.8, 6.09, 5.41, 3.66, 3.15, and 6.41, respectively at 298.2 K, which are substantially smaller values than those characterizing [Na.C221]+. In methanol, the decomplexation kinetic parameters kd(298.2 K) = 41.0 f 1.7 s-I, AHd* = 55.1 k 1.1 kJ mol-', and ASd* = -29.2 f 3.8 kJ mol-' characterizing [Na.C22C5]+ indicate that [Na.C22C51t is several orders of magnitude more labile than [Na.C221It. These characteristics of [Na.C22C5It are compared with those of related cryptates
Inorganic Chemistry, 1992
Complexation of Li+, Na+, K+, Rb+, Cs+, Ag+, and TI+ by 4,7,13,16-tetraoxa-1,10-diazabicyclo[8.8.8]hexacosane (C22Cs) to form the cryptate [M.C22C8]+ has been studied in five solvents by potentiometric titration and 7Li and 23Na NMR spectroscopy. A considerable variation in the stability of [M.C22Cs]+ occurs as M+ is varied in the sequence the figuresin bracketsarelog (Kldm3mol-1) andKis theapparent stabilityconstant of [M.C22Cs]+ in acetonitrile and dimethylformamide, respectively, at 298.2 K. The exchange of Na+ on [Na.C22C8]+, determined by 23Na NMR spectroscopy, is characterized by kd(298.2 K) = 443 f 5, 1253 f 7, and 10 800 f 300 s-1, AHd* = 38.2 f 0.6,37.1 f 0.3, and 46.8 f 0.6 kJ mol-I, and A, !&* = -66 f 2, -61 f 1, and-1 1 f 2 J K-l mol-', respectively, in acetonitrile, pyridine, and methanol. In dimethylformamide the [Na.C22Cs]+ exchange rate is in the very fast regime of the 23Na NMR time scale, and in acetonitrile, methanol, dimethylformamide, and pyridine the [Li.C22Cs]+ exchange rate is in the very fast regime of the 7Li NMR time scale. These data are discussed in terms of the effects of cryptand structure and of metal ion and solvent characteristics on cryptate stability and lability. 100.4412-4416. (26) Lincoln, S. F.; Horn, E.; Snow, M. R.; Hambley, T. W.; Brereton, M.; (27) Mathieu, F.; Metz, B.; Moras, D.; Weiss, R.
Inorganic Chemistry, 1991
Li+ and Ag+ by the clamlike cryptand 4,7,13,16-tetraoxa-l ,lO-diazabicyclo[8.8.2]eicosane (C22C2) to form the cryptate [Li.C22C2]+ has been studied in seven solvents by 7Li N M R spectroscopy and potentiometric titration. A considerable variation in the [Li.C22C2]+ and [Ag.C22C2]+ stability constants (shown as the respective log (K/dm3 mol-') values at 298.2 K after each solvent) occurs with solvent variation: acetonitrile (7.8, 9.4), acetone (8.9, 13.1)q water (<2, 6.0). methanol (4.0, 10.2). dimcthylformamide (3.5, 9.4), diethylformamide (3.1, 8.2), and pyridine (4.0, 5.0). The exchange of Li+ on [Li.C22C2]+ falls within thc 7Li N M R time scale in methanol, dimethylformamide, and diethylformamide, in which the monomolecular dccomplexation process is characterized by kd(298.2 K) = 971 f 42, 240 f 7, and 916 f 28 s-I, respectively, AH,' = 31.0 f 0.4, 22.5 f I .3, and 26.7 f 0.6 kJ mol-', respectively, and A&* = -83.9 f 1.8, -1 24 f 5, and -99 * 2 J K-' mol-', respectively. In acctonitrilc, acetone, and pyridine the exchange rate is in the very slow regime of the 7Li N M R time scale close to the solvent boiling point and in the very fast regime in water close to the freezing point. These data are discussed in the context of the effects of cryptand structure and solvent characteristics on cryptate lability and stability. The Hg2+-promoted reaction of r-[Co(tren)(NH3)XI2+ ions (hereafter r-CoX2+, X = Br, CI) in NaY electrolytes of varying type (Y = NO<, C104-, CF3S03-) and concentration ([Y-] = 0-1.0 M; [NO;] + [Y-] = 1.0 M) follows the rate law kobr = (k& + kyKyK~~[y-])[Hg]~/(1 + k&,[Y-] 4-(KO + Ky)[Hg]t), in which ko and ky represent first-order rate constants for aquation
Journal of Inclusion Phenomena, 1987
In the solid and solution state Li + and Na + form inclusive and exclusive cryptates respectively with C21C5, in which Li + resides inside and Na + resides outside the C21C5 cavity. Similar inclusive and exclusive structures are observed for [Li.C211] + and [Na.C211] +. The logarithms of the stability constants in dimethylformamide for [Li.C21Cs] +, [Li.C211] +, [Na.C21C5] + and [Na.C211] + are: 2.80, 6.99, 2.87 and 5.20; and the corresponding decomplexation rate constants are: 107, 0.013, 28800 and 12 s -I at 298.2 K.
Inorganic Chemistry, 1991
Li+ and Ag+ by the clamlike cryptand 4,7,13,16-tetraoxa-l ,lO-diazabicyclo[8.8.2]eicosane (C22C2) to form the cryptate [Li.C22C2]+ has been studied in seven solvents by 7Li N M R spectroscopy and potentiometric titration. A considerable variation in the [Li.C22C2]+ and [Ag.C22C2]+ stability constants (shown as the respective log (K/dm3 mol-') values at 298.2 K after each solvent) occurs with solvent variation: acetonitrile (7.8, 9.4), acetone (8.9, 13.1)q water (<2, 6.0). methanol (4.0, 10.2). dimcthylformamide (3.5, 9.4), diethylformamide (3.1, 8.2), and pyridine (4.0, 5.0). The exchange of Li+ on [Li.C22C2]+ falls within thc 7Li N M R time scale in methanol, dimethylformamide, and diethylformamide, in which the monomolecular dccomplexation process is characterized by kd(298.2 K) = 971 f 42, 240 f 7, and 916 f 28 s-I, respectively, AH,' = 31.0 f 0.4, 22.5 f I .3, and 26.7 f 0.6 kJ mol-', respectively, and A&* = -83.9 f 1.8, -1 24 f 5, and -99 * 2 J K-' mol-', respectively. In acctonitrilc, acetone, and pyridine the exchange rate is in the very slow regime of the 7Li N M R time scale close to the solvent boiling point and in the very fast regime in water close to the freezing point. These data are discussed in the context of the effects of cryptand structure and solvent characteristics on cryptate lability and stability. The Hg2+-promoted reaction of r-[Co(tren)(NH3)XI2+ ions (hereafter r-CoX2+, X = Br, CI) in NaY electrolytes of varying type (Y = NO<, C104-, CF3S03-) and concentration ([Y-] = 0-1.0 M; [NO;] + [Y-] = 1.0 M) follows the rate law kobr = (k& + kyKyK~~[y-])[Hg]~/(1 + k&,[Y-] 4-(KO + Ky)[Hg]t), in which ko and ky represent first-order rate constants for aquation
Journal of the American Chemical Society, 1971
A kinetic study of the complexation reaction of sodium ions with dibenzo-18-crown-6 (DBC) in DMF, using 23Na nmr spectroscopy, is reported. The chemical shifts of 23Na in the solvated sodium and in the DBC complex are very nearly the same, but due to the lack of cubic symmetry around sodium in the complex, fast quadrupole relaxation causes the line width in this species to be much broader (about 25 times) than in solvated sodium. In solutions containing both species, there is sodium exchange between the two. In the temperature range between-30 and 0", the rate of this exchange is of the order of the relaxation rate of the 23Na nuclei, thus affecting the nmr line shape. A quantitative analysis of the line shape yields values for the mean lifetimes of sodium in the two species. Measurements were performed in solutions containing 0.3-1.9 M NaSCN and 0.1-0.2 M DBC in the temperature range-60 to +SO0. The ionic strength was adjusted by using LiSCN. In some runs BPh4-was used as a counteranion instead of SCN-. Analysis of the concentration dependence of the results indicates that the dominant exchange mechanism involves the complexation equilibrium Na+ + DBC e Na+, DBC. The pseudofirst-order rate constant for the decomplexation reaction at 25", extrapolated to zero ionic strength, and the activation energy are found to bel o 5 sec-' and 12.6 i 0.6 kcal/mol, respectively. The equilibrium constant for the complexation reaction was determined conductometrically between 0 and 4 0 '. It is found to be-600 M-' at 25" with AH =-6 kcal/mol and A S =-7 eu. From these results, the rate constant of the complexation reaction at 25 o is estimated to be 6 x 107 M-1 sec-', with an activation energy of 6.5 kcal/mol.
Inorganic Chemistry, 1993
Complexation of Li+, Na+, K+, Rb+, Cs+, and Ag+ by the pendant arm macrocyclic ligand 1,4,7,10-tetrakis(2-hydroxyethy1)-1,4,7,1O-tetraazacyclododecane (thecl2) has been studied in methanol and dimethylformamide. A substantial variation in the stability of [M(thecl2)]+ occurs as M+ is varied in the sequence Li+ (3.09 f 0.06 and 2.99 f 0.12), Na+ (4.53 f 0.06 and 3.37 f 0.06), K+ (2.43 f 0.08 and 1.59 f 0-11), Rb+ (2.20 f 0.10 and 1.39 f 0.09), Cs+ (1.90 f 0.10 and 1.23 f 0.08), and Ag+ (12.57 * 0.04 and 11.16 f 0.05), where the figures in parentheses are log (K/dm3 mol-') and K represents the apparent stability constants of [M(thecl2)]+ in methanol and dimethylformamide, respectively, determined by potentiometric titration at 298.2 K. For [Li(thecl2)]+ and [Na(thecl2)]+ the monomolecular decomplexation processes in methanol are characterized by kd(298.2 K) = 729 f 17 and 209 f 3 s-I, A&* = 38.0 f 0.7 and 68.3 f 1.4 kJ mol-', and A&' = -62.8 f 1.2 and 28.4 f 0.8 J K-I mol-', respectively, determined by 'Li and 23Na NMR spectroscopy. The analogous parameters determined in dimethylformamide are kd(298.2 K) = 587 f 31 and 299 f 7 s-l, = 41.8 f 0.7 and 56.4 f 0.7 kJ mol-', and A&' = -51.9 f 3.3 and -8.4 f 2.4.5 K-I mol-I. These data are compared with those obtained for other alkali metal complexes, which together demonstrate a range of different mechanisms through which selectivity occurs in alkali metal ion complexation.