<i>N</i>-(Tropon-2-yl)-1,4,7,10-tetraoxa-13-azacyclopentadecane with calcium thiocyanate

Kubo, Kanji; Yamamoto, Etsuji; Kato, Nobuo; Mori, Akira

doi:10.1107/s0108270199009300

Cited by 8 publications

References 4 publications

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Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

et al. 2004

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The μ3‐methylidyne group of the complex [{TiCp*(µ‐O)}3(µ3‐CH)] (1) (Cp* = η5‐C5Me5) was deprotonated by amides of the group 1 elements, [MN(SiMe3)2] (M = Li, Na, K, Rb, Cs) to form the oxoheterometallocubane complexes [M(μ3‐O)3{Ti3Cp*3(μ3‐C)}] [M = Li (3), Na (4), K (5), Rb (6), Cs (7)]. Similar treatments of 1 with the alkaline‐earth amides [M{N(SiMe3)2}2(thf)2] (M = Mg, Ca, Sr) afforded the heterometallocubane derivatives [{(thf)x(Me3Si)2NM}(μ3‐O)3{Ti3Cp*3(μ3‐C)}] [M = Mg, x = 0, (8); Ca, x = 1, (9); Sr, x = 1, (10)] in high yields. The addition of ligands such as cyclopentadiene (C5H6) or pentamethylcyclopentadiene (C5Me5H) to the compounds 3−7 allowed recovery of the μ3‐methylidyne oxocomplex 1. The analogous reaction of 8−10 with C5H6 caused the displacement of the amide fragment to give the heterometallocubanes [(CpM)(μ3‐O)3{Ti3Cp*3(μ3‐C)}] [M = Mg (11), Ca (12), Sr (13)], while C5Me5H reacts only with 9 and 10 to give the compounds [(Cp*M)(μ3‐O)3{Ti3Cp*3(μ3‐C)}] [M = Ca (14), Sr (15)]. Furthermore, heating of the species 8−10 in the presence of the starting complex 1 produced amine elimination and afforded the corner‐shared heterometallodicubanes [M{(μ3‐O)3Ti3Cp*3(μ3‐C)}2] [M = Mg (16), Ca (17), Sr (18)]. Treatment of 1 with the amide [Ba{N(SiMe3)2}2(thf)2] or dialkyl derivatives of magnesium [MgR2(thf)2] (R = CH2Ph, tBu) and barium [Ba(CH2Ph)2] provided the corner‐shared metallodicubanes [M{(μ3‐O)3Ti3Cp*3(μ3‐C)}2] [M = Mg(16), Ba(19)]. The molecular structures of complexes 9, 16, 17 and 18 have been established by single‐crystal X‐ray analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

et al. 2004

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Recoordination of a metal ion in the cavity of a crown compound: a theoretical study 2.* Effect of the metal ion— solvent interaction on the conformations of calcium complexes of arylazacrown ethers

et al. 2005

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The effect of the local interaction of a metal ion with the solvent on the conformations of calcium complexes of arylazacrown ethers and an azacrown containing dye was studied using the density functional method with the PBE and B3LYP functionals. The structures were studied and the interaction energies were determined for the calcium complexes with n = 1-12 water or acetonitrile molecules. It was found that the inner coordination sphere of the free Ca 2+ cation contains six H 2 O or seven MeCN molecules. The cation-acetonitrile interaction energy is higher than the cation-water interaction energy up to the moment the second solvation shell of the cation is almost complete (n = 11). The inner coordination sphere of Ca 2+ in the macrocycle cavity contains at most three water molecules, while the fourth one is displaced to the second coordination sphere. Taking into account the local interaction with the solvent (H 2 O or MeCN), the conformers of the calcium complexes of arylazacrown ethers and the azacrown containing dye were studied. It was shown that the presence of two to four water molecules in the coordination sphere of the cation reduces the relative energies of the conform ers with broken metal-nitrogen bond, thus favoring ground state metal recoordination.Key words: arylazacrown ethers, azacrown containing dyes, complexes with Ca 2+ , photo induced recoordination, solvation, ab initio quantum chemical calculations, density functional theory.UV absorption spectra of the alkaline earth metal com plexes of azacrown containing dyes 1-5 recorded at a large excess of the cation ensuring the absence of the free dye in solution exhibit a long wavelength shoulder, which can not be attributed to the residual absorption of the free ligand. It was shown 4,5 that, in the excited state of the azacrown containing dyes 1a,b, the cation undergoes a photoinduced recoordination in the macrocycle cavity (Scheme 1). It was supposed that this recoordination could also occur in the ground state of the complex.The fact that two types of cation coordination sepa rated by an energy barrier can exist in the macrocycle cavity is nontrivial by itself. Our theoretical density functional study of the model N arylaza 15 crown 5 (ArN15C5) compounds and the real dye 1a (see Ref. 1) has demonstrated that the recoordination can occur only due to the transitions between the axial (Ax) and equato rial (Eq) forms of the arylazacrown ether complex. In the axial type conformers, the aromatic ring axis passing through the crown ether nitrogen N cr and the opposite * For Part 1, see Ref. 1. ** Dedicated to Academician A.L. Buchachenko on the occa sion of his 70th birthday. Scheme 11a: X = S, R = Et, R´ = H, n = 1; 1b: X = CMe 2 , R = Me, R´ = 4,6 Me 2 , n = 2

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Group 1s and 2s Metals

Hanusa

2003

Comprehensive Coordination Chemistry II

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N-(Tropon-2-yl)-1,4,7,10-tetraoxa-13-azacyclopentadecane with calcium thiocyanate

Cited by 8 publications

References 4 publications

Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

Recoordination of a metal ion in the cavity of a crown compound: a theoretical study 2.* Effect of the metal ion— solvent interaction on the conformations of calcium complexes of arylazacrown ethers

Group 1s and 2s Metals

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N-(Tropon-2-yl)-1,4,7,10-tetraoxa-13-azacyclopentadecane with calcium thiocyanate

Cited by 8 publications

References 4 publications

Deprotonation of μ3‐Methylidyne Groups on a Ti3O3 Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

Deprotonation of μ3‐Methylidyne Groups on a Ti3O3 Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

Recoordination of a metal ion in the cavity of a crown compound: a theoretical study 2.* Effect of the metal ion— solvent interaction on the conformations of calcium complexes of arylazacrown ethers

Group 1s and 2s Metals

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Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals

Deprotonation of μ₃‐Methylidyne Groups on a Ti₃O₃ Support: A Way to Build Oxotitanocubanes Containing Alkali and Alkaline‐Earth Metals