Coordination tendencies of a series of tetraazacycloalkanes related to 1,4,7,10-tetraazadecane (trien): synthetic, thermodynamics, and structural aspects

Bianchi, Antonio; Bologni, Lucia; Dapporto, P.; Micheloni, Mauro; Paoletti, Piero

doi:10.1021/ic00177a007

Cited by 123 publications

(76 citation statements)

References 6 publications

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“…[59] The combined Ingold 405 S7/120 electrode was calibrated as a hydrogen concentration probe by titrating known amounts of HCl with CO 2 -free Me 4 NOH solutions and determining the equivalent point by Gran's method, [60,61] which allows the determination of the standard potential, E The emf data were treated with the computer program HYPERQUAD [62] which furnished the equilibrium constants reported in Table 1 and Table 4. All titrations were treated either as single sets or as separate entities for each system without significant variation in the values of the determined constants.…”

Section: Potentiometric Measurementsmentioning

confidence: 99%

Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

et al. 2005

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The basicity and coordination properties towards Cu II and Zn II of the bis(macrocycles) L1, L2 and L3 have been investigated by means of potentiometric, 1 H NMR and UV/Vis spectroscopic titrations in aqueous solutions. The synthesis of L1 and L3 is also described. The three ligands are composed of two [12] In all structures the metal ion is pentacoordinate, and is bound to the four nitrogen donors of the cyclic unit and to the amine group of the side arm. The sta-

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Section: Potentiometric Measurementsmentioning

confidence: 99%

Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

et al. 2005

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“…1 ]) that were employed for the determination of equilibrium constants were carried out in 0.1 m NMe 4 Cl solutions at 298.1 AE 0.1 K, by using equipment and methodology already described. [57] The combined Hamilton glass electrode (LIQ-GLASS 238000/08) was calibrated as a hydrogen concentration probe by titrating known amounts of HCl with CO 2 -free NaOH solutions and by determining the equivalent point by Grans method [58] which allows one to determine the standard potential, E o , and the ionic product of water (pK w = 13.83(1) at 298.1 K in 0.1 m NMe 4 Cl). At least three measurements were performed for each system in the pH ranges 2.5-10.5.…”

mentioning

confidence: 99%

DNA Binding by a New Metallointercalator that Contains a Proflavine Group Bearing a Hanging Chelating Unit

Bazzicalupi

Bencini

Bianchi

et al. 2007

Chemistry A European J

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The new bifunctional molecule 3,6‐diamine‐9‐[6,6‐bis(2‐aminoethyl)‐1,6‐diaminohexyl]acridine (D), which is characterised by both an aromatic moiety and a separate metal‐complexing polyamine centre, has been synthesised. The characteristics of D and its ZnII complex ([ZnD]) (protonation and metal‐complexing constants, optical properties and self‐aggregation phenomena) have been analysed by means of NMR spectroscopy, potentiometric, spectrophotometric and spectrofluorimetric techniques. The equilibria and kinetics of the binding process of D and [ZnD] to calf thymus DNA have been investigated at I=0.11 M (NaCl) and 298.1 K by using spectroscopic methods and the stopped‐flow technique. Static measurements show biphasic behaviour for both D–DNA and [ZnD]–DNA systems; this reveals the occurrence of two different binding processes depending on the polymer‐to‐dye molar ratio (P/D). The binding mode that occurs at low P/D values is interpreted in terms of external binding with a notable contribution from the polyamine residue. The binding mode at high P/D values corresponds to intercalation of the proflavine residue. Stopped‐flow, circular dichroism and supercoiled‐DNA unwinding experiments corroborate the proposed mechanism. Molecular‐modelling studies support the intercalative process and evidence the influence of NH+⋅⋅⋅O interactions between the protonated acridine nitrogen atom and the oxygen atoms of the polyanion; these interactions play a key role in determining the conformation of DNA adducts.

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“…[21][22][23][24] we demonstrated that crystals obtained by conglomerate crystallization are isomorphous and isostructural with those obtained from preresolved material. Certainly under comparable crystallization conditions this appears to be the case.…”

Section: Relationship Between Linear Tetradentate Tetraamines and Tetmentioning

confidence: 59%

“…(d) [Ni( [13]aneNa)Br2]Br crystallizes in space group P42, and its four quaternary nitrogens appear to be (R,S,S,R) [20], in accord with the above ideas. (e) Finally, the [13]ane compound [transCu(2,2,2,4)-tet](ClO4)2 crystallizes in space group P212,2~, and its four quaternary nitrogens are (R,R,S,S), which implies that the chirality requirements of the seven-membered ring prevail over those of the five-membered ones [21]. Thus, it seems that the chirality pattem of the secondary nitrogens of metal macrocycles (of the type 5 + 6) is a linear combination of the chiral behavior of the central ring observed in linear tetraamines.…”

Section: Relationship Between Linear Tetradentate Tetraamines and Tetmentioning

confidence: 99%

The phenomenon of conglomerate crystallization. Part 40: The crystallization behavior oftrans- Co(III) amines (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), (−)589 -trans-[Co(3,2,3-tet)Cl2]NO3 (II), and of (+)546-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III)

et al. 1995

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A racemic solution of (I) crystallizes as a conglomerate from which a crystal we selected was found to be (+) 2, . A total of 2305 data were collected over the range of 4 ~ _< 20 _ 55~ of these, 1724 (independent and with I >_ 3a(1)) were used in the structural analysis. Data were corrected for absorption (~t = 11.920 cm-I), and the relative transmission coefficients ranged from 0.8258 to 0.9565. Refinement was carded out for both lattice enantiomorphs, and at this stage the R(F) and R~.(F) residuals were, respectively, 0.0381 and 0.0479 for (+ + +) and 0.0448 and 0.0532 for (---). Thus, the former was selected as correct for our specimen, and the final cycle of refinement with the (++ +) model converged to R(F) and R,.(F) of 0.0315 and 0.0365. A racemic solution of (II) crystallizes as a conglomerate from which a crystal we selected was found to be 2,Cl2]N03 (II), CoCIzO3NsCsH22. It crystallizes in the enantiomorphic space groujp, P21 with lattice constants a = 6.395(2) ,~, b = 8.886(2) ,~., c = 13.185(2) :k, and/3 = 99.24(2)~ V = 739.59 ,~3 and d(calc. M.W. = 366.14, Z = 2) = 1.646 g cm -3. A total of 2912 data were collected over the range of 4 ~ _< 20 _< 64~ of these, 2147 (independent and with I >_ 3a(1)) were used in the structural analysis, Data were corrected for absorption (/z = 15.424 cm-I), and the relative transmission coefficients ranged from 0.9632 to 0.9985. Refinement was carded out for both lattice enantiomorphs, and the final R(F) and R,,.(F) residuals were, respectively, 0.0326 and 0.0328 for (+ + +) and 0.0347 and 0.0348 for (---). Thus, the (+ + +) was selected as correct for our specimen. A racemic solution of (III) crystallizes as a conglomerate from which a crystal we selected was found to be (+) 2, Bernal, Cetrullo, Cai, and Massoud correct for our specimen, and the final cycle of refinement with the (---) model converged to R(F) and Rw(F) of 0.0436 and 0.0421. For all three compounds, the six-membered rings are chairs; the secondary nitrogens are chiral centers, and the five-membered rings are ordered and conformationally dissymmetric, as expected. Coincidentally, in (I), (II), and (III) the central rings are right-handed helices with ~t(+50.0~ ~5(+53.3~ and t5(+48.3~ respectively. Thus, the secondary nitrogens of all three cations are (R), rendering the cations chiral. The incidence of conglomerate crystallization in trans coordination compounds is rare, and those known are asymmetrically substituted (see Ref. 4 for the four known cases). Thus, the incidence of such crystallization mode in a new series of [trans-Co(amine ligands)X2] § cations bearing symmetrical pairs of trans ligands was an unexpected and welcomed event. In all three cases, the counteranions are bonded to the hydrogens of the terminal --NH2 moieties, thus forming an overall entity which resembles a macrocycle. In fact, parallels between the crystallization behavior of our compounds and that of macrocycles bearing related fragments is discussed. Finally, in the three compounds, homochiral cations are linked into infin...

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Coordination tendencies of a series of tetraazacycloalkanes related to 1,4,7,10-tetraazadecane (trien): synthetic, thermodynamics, and structural aspects

Cited by 123 publications

References 6 publications

Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

DNA Binding by a New Metallointercalator that Contains a Proflavine Group Bearing a Hanging Chelating Unit

The phenomenon of conglomerate crystallization. Part 40: The crystallization behavior oftrans- Co(III) amines (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), (−)589 -trans-[Co(3,2,3-tet)Cl2]NO3 (II), and of (+)546-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III)

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Coordination tendencies of a series of tetraazacycloalkanes related to 1,4,7,10-tetraazadecane (trien): synthetic, thermodynamics, and structural aspects

Cited by 123 publications

References 6 publications

Mono‐ and Dinuclear CuII and ZnII Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

Mono‐ and Dinuclear CuII and ZnII Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

DNA Binding by a New Metallointercalator that Contains a Proflavine Group Bearing a Hanging Chelating Unit

The phenomenon of conglomerate crystallization. Part 40: The crystallization behavior oftrans- Co(III) amines (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), (−)589 -trans-[Co(3,2,3-tet)Cl2]NO3 (II), and of (+)546-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III)

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Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths

Mono‐ and Dinuclear Cu^II and Zn^II Complexes of Cyclen‐Based Bis(macrocycles) Containing Two Aminoalkyl Pendant Arms of Different Lengths