Tetraaza macrocyclic metal complexes containing a medium-sized chelate ring. 1. Syntheses and characterization of nickel(II) complexes with 1,4,7,10-tetraazacyclotetradecane, -cyclopentadecane, and -cyclohexadecane

Sugimoto, Masako; Nonoyama, Matsuo; Ito, Tasuku; Fujita, Junnosuke

doi:10.1021/ic00148a020

Cited by 30 publications

(9 citation statements)

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“…are considerably large compared with the natural linewidth of 0.195 mm s-'. Values of 7(2) 9 1.7( 2) 89.4(2) 89.1(2) 89.3(2) 90.1 (2) 89.4(2) 88.2( 2 5) 1 1 7.0 (7) 114.7( 7) 1 1 6.4 ( 7) 113.1 (7) 110.1 (7) 103.4(6) 102.8(6) 1 1 3.0 (7) 114.5 (7) 124.3 (7) 119.6 (7) 1 15.0 (7) 122.3(8) 118.8(8) 120.5 (8) 1 lR.l (8) 6 in the case where the spectra are analyzed as a doublet are 0.309 (78), 0.263 (1 13), 0.244 (1 58), 0.225 (22 l), 0.2 17 (252), 0.208 (285), and 0.214 mm s-l (327 K). The increase of 6 at 327 K supports the fact that the rapid spin interchange occurs at this temperature.…”

Section: Resultsmentioning

confidence: 99%

Studies on spin-equilibrium iron(III) complexes. Part 1. Syntheses and magnetic properties of a new family of spin cross-over iron(III) complexes with a unidentate ligand over a wide range of the spectrochemical series and a quinquedentate ligand derived from salicylaldehyde and di(3-aminopropyl)amine. X-Ray crystal structure of [4-azaheptamethylene-1,7-bis(salicylideneiminato)](4-methylpyridine)iron(III) tetraphenylboratet

Matsumoto¹,

Ohta²,

Yoshimura³

et al. 1985

J. Chem. Soc., Dalton Trans.

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12, Japan lron(ii1) complexes of general formula [ Fe(X) L]"+ ( n = 0 or 1 ) have been prepared and characterized, where X is a unidentate ligand such as CI-, N,-, NCO-, CN-, pyridine (py), 3met hy I pyrid i ne (3 Mepy ) , 4 -met h y I pyr id i ne (4 Mepy ) , 4 -am i no pyrid i ne (a py ) , 3,4dimethylpyridine (3,4Me2-py), imidazole (Him), N-methylimidazole (mim), or 2methylimidazole (2Me-im), and L denotes a quinquedentate Schiff base derived from salicylaldehyde and di(3-aminopropy1)amine. On the basis of the cryomagnetic data, these complexes can be classified into three groups: high spin ( S =+) for X = CI, N, , Him, mim; low spin (S =+) for) for X = py, 3Me-py, 4Me-py, 3,4Me2-py, 2Me-im. This indicates that the spin state for the series of complexes depends predominantly on the order in the spectrochemical series of the ligand X. The magnetic moments for the spin cross-over complexes increased gradually with increase of the temperature and showed no thermal hysteresis, indicating that the present complexes are of continuous spin-transition type. The spin cross-over complexes showed a thermochromism both in the solids and solutions, changing colour from dark violet to blue green, with decreasing temperature, and the thermochromism was studied by the temperature dependence of the electronic spectra in dichloromethane solution. The temperature dependence of the Mossbauer spectra for [Fe(2Me-im)L] BPh, and [Fe(4Me-py)L] BPh, has also provided evidence that the spin transition between the high-and low-spin states takes place and that the rate of spin interexchange is as fast as the inverse of the lifetime (1 x 1 O-' s) of the Mossbauer nucleus. One of the complexes, [Fe(4Me-py) L] BPh,, was also subjected to a single-crystal X-ray analysis. The result verified the detailed structure in which the iron( 111) atom assumes a pseudo-octahedral co-ordination geometry with a trans geometry for the two salicylideneiminate moieties, and the two axial positions are occupied by the secondary amine nitrogen of the di(3-aminopropy1)amine moiety of L and the nitrogen atom of the 4-methylpyridine ligand.

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Section: Resultsmentioning

confidence: 99%

Studies on spin-equilibrium iron(III) complexes. Part 1. Syntheses and magnetic properties of a new family of spin cross-over iron(III) complexes with a unidentate ligand over a wide range of the spectrochemical series and a quinquedentate ligand derived from salicylaldehyde and di(3-aminopropyl)amine. X-Ray crystal structure of [4-azaheptamethylene-1,7-bis(salicylideneiminato)](4-methylpyridine)iron(III) tetraphenylboratet

Matsumoto¹,

Ohta²,

Yoshimura³

et al. 1985

J. Chem. Soc., Dalton Trans.

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“…The complexation chemistry of macrocylces with a large variety of metal ions have been known and studied thoroughly, for several decades [17][18][19][20][21][22][23][24][25]. Such macrocyclic ligands often lead to complexes with enhanced thermodynamic and kinetic stability with respect to metal ion dissociation, compared to their open-chain analogues.…”

Section: Introductionmentioning

confidence: 99%

The macrocyclic effect and vasodilation response based on the photoinduced nitric oxide release from trans-[RuCl(tetraazamacrocycle)NO]2+

Oliveira

Ferreira²,

Bonaventura

et al. 2007

Journal of Inorganic Biochemistry

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“…[3][4][5] On the other hand, the increase of the ring size up to six become disadvantageous due to the enhanced ring strain and configurational energy for the arrangement of the donor atoms for the complexation. 7 Other 14-membered tetraazamacrocycles have been studied, among them bu [14]N 4 , which has the same number of atoms in the macrocyclic backbone but a different chelate ring sequence, 5,5,5,7 instead of the 5,6,5,6 of cyclam, see Scheme 1. It was verified that in spite of a decrease in the enthalpy of formation of the Cu 2ϩ and Ni 2ϩ complexes of the 5,5,5,7 arrangement when compared with that of the 5,6,5,6 ligand, an entropic gain was observed when compared with the linear ligand, trien (triethylenetetraamine), reflecting an effective configurational entropy gain of the macrocyclic compound on complexation.…”

Section: Introductionmentioning

confidence: 99%

Metal complexes of a tetraazacyclophane: solution and molecular modelling studies

et al. 2003

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Tetraaza macrocyclic metal complexes containing a medium-sized chelate ring. 1. Syntheses and characterization of nickel(II) complexes with 1,4,7,10-tetraazacyclotetradecane, -cyclopentadecane, and -cyclohexadecane

Cited by 30 publications

References 0 publications

The macrocyclic effect and vasodilation response based on the photoinduced nitric oxide release from trans-[RuCl(tetraazamacrocycle)NO]2+

Metal complexes of a tetraazacyclophane: solution and molecular modelling studies

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