Polyamines XV. Thermodynamics of Metal Complex Formation of Linear Tetraamines Containing Two Ethylenediamine Residues

Anderegg, G.; Bläuenstein, Peter

doi:10.1002/hlca.19820650324

Cited by 23 publications

(4 citation statements)

References 37 publications

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“…A reduction in the equilibrium constants is observed for the Ni(II) complexes of ligands I and III (Table 1) as the chelate ring size increases from five to six. This reduction correlates well with the expected stability constant increase in solution for ligands with similar denticity to the ligands in our study [41][42][43]. We have observed for numerous metal complex ions with the same denticity that the extent of a complex's gas-phase reactivity with a reagent is roughly related to the formation constant of that complex in solution [47].…”

Section: Chelate Ring Size Effectssupporting

confidence: 87%

“…For many metal-ligand complexes in solution, five-membered chelate rings lead to greater complex stability than the presence of smaller or larger chelate ring sizes [39,40]. For metal-ligand complexes of high denticity (e.g., tetradentate ligands), however, it has been observed that a change in the chelate ring size from five to six actually stabilizes the complexes of small transition metal ions (e.g., Ni ) but not larger metal ions (e.g., Pb 2ϩ ) [41][42][43][44][45][46]. A reduction in the equilibrium constants is observed for the Ni(II) complexes of ligands I and III (Table 1) as the chelate ring size increases from five to six.…”

Section: Chelate Ring Size Effectsmentioning

confidence: 99%

“…Solution-phase reports indicate that when the chelate ring size is increased from six to seven a substantial decrease in stability constants is observed, which is independent of the metal ion size [41][42][43][44]. The decrease in the gas-phase equilibrium constants for the reaction of CH 3 CN with the Ni(II) complex of Ligand IV could be caused by at least two factors.…”

Section: Chelate Ring Size Effectsmentioning

confidence: 99%

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Gas-phase reactions of divalent Ni complex ions with acetonitrile: Chelate ring size, inductive, and steric effects

Combariza

Vachet

2004

J. Am. Soc. Mass Spectrom.

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Ni(II) complexes of a series of pentadentate polyamine ligands have been reacted with CH 3 CN in the gas phase using a modified quadrupole ion trap mass spectrometer. The ligands have structural features such that upon complexation, chelate ring size, sterics, and inductive effects can be evaluated in the gas phase. Rate and equilibrium constants for CH 3 CN addition to the metal complexes show that there is a general decrease in the gas-phase reactivity as the chelate ring size is increased. Density functional theory calculations at the B3LYP/LANL2DZ level of theory have been used to obtain minimum energy structures and Mulliken charges for the complexes. The decreased reactivity observed as the chelate ring size is increased correlates with a decrease in the atomic charge on the metal. A larger chelate ring size enhances ligand flexibility and improves the overlap of the ligand's donor atoms with the metal center. Adding methyl groups adjacent to or on the nitrogen donor groups of a ligand also decreases the rate and equilibrium constants for the reactions of a given complex with CH 3 CN. Analysis of Mulliken charges for these complexes indicates that both inductive and steric effects are responsible for lower complex reactivity. These results suggest that while the gas-phase reactivity of a metal complex with CH 3 CN is very dependent on the functional groups directly bound to the metal, in some cases steric effects can conceal the correlation between reactivity and coordination structure. T he chemistry of transition metal ions is quite diverse mainly because they can be tuned by the type, number, and orientation of the ligands coordinated to them. Knowledge of this coordination sphere provides insight into metal complex reactivity, and a variety of techniques including X-ray spectroscopies, NMR, and electron paramagnetic resonance (EPR) have been used to gather coordination structure information. If metal complexes are present at low concentrations or in complicated mixtures, though, these techniques can have difficulty providing coordination structure. Consequently, we have begun to investigate the advantage of using mass spectrometry (MS) to gather coordination structure information.For several reasons we have chosen not to rely on the typical dissociation methods (e.g., collision-induced dissociation [CID]) for acquiring metal complex structural information by MS. One reason is that, while the dissociation patterns and dynamics of metal complexes have not been exhaustively studied, most results indicate that rearrangement reactions involving the loss of small neutrals from large ligands or the loss of intact ligands from multi-ligated metal ions are typical [1][2][3][4][5][6][7][8][9][10][11]. Unfortunately, neither provides much insight into the coordination sphere, as they do not necessarily reveal whether the groups lost were coordinated to the metal or not. Furthermore, during collisional activation, even at low energies, scrambling of the metal's coordination sphere can occur because of relatively w...

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Section: Chelate Ring Size Effectssupporting

confidence: 87%

Section: Chelate Ring Size Effectsmentioning

confidence: 99%

Section: Chelate Ring Size Effectsmentioning

confidence: 99%

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Gas-phase reactions of divalent Ni complex ions with acetonitrile: Chelate ring size, inductive, and steric effects

Combariza

Vachet

2004

J. Am. Soc. Mass Spectrom.

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“…9.4γ, 9.5γ και 9.6Αα, Πίνακας 9.2). Όπως έχει αναφερθεί από τους J. H. Coates et al [181] [181,252,255,256,267]. Εν τούτοις, το σύστημα Ni(II)-2,2,3-tet χρήζει μιας σύντομης συζήτησης.…”

Section: α βunclassified

Σύνθεση Και Μελέτη Συμπλόκων Ενώσεων Με Παραμαγνητικά Μεταλλικά Ιόντα Με Σκοπό Τη Χρησιμοποίησή Τους Σε Εφαρμογές Φασματοσκοπίας NMR

Veneris¹,

Βενέρης²

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Στο σημείο αυτό θα ήθελα να εκφράσω τις θερμές μου ευχαριστίες στις κυρίες Δέσποινα Σταμπάκη-Χατζηπαναγιώτη, Άντα Λυμπεροπούλου-Καραλιώτα και Μαίρη Παπαρρηγοπούλου-Καμαριωτάκη (Τμήμα Χημείας, Πανεπιστήμιο Αθηνών), για την καθοδήγησή τους σε ολόκληρη τη διάρκεια των προσπαθειών μου. Ευχαριστώ τους κυρίους Αθανάσιο Γιωτάκη, Γεώργιο Κόκοτο, Κωνσταντίνο Μερτή και την κυρία Χριστιάνα Μητσοπούλου (Τμήμα Χημείας, Πανεπιστήμιο Αθηνών), για την τιμή που μου κάνουν ως μέλη της επταμελούς εξεταστικής επιτροπής. Ευχαριστώ το Εργαστήριο της Ανοργάνου Χημείας για την υλικοτεχνική υποστήριξη, καθώς και τον ΕΛΚΕ για τη χρηματοδότηση σε προγράμματα Καποδίστρια. Επίσης, ευχαριστώ τον κύριο Σπυρίδωνα Κοΐνη και την κυρία Χριστιάνα Μητσοπούλου (Τμήμα Χημείας, Πανεπιστήμιο Αθηνών) για τα «ιδιαίτερα» μαθήματα χρήσης του οργάνου NMR και μετρήσεων χρόνων χαλάρωσης. Ευχαριστώ την κυρία Ελένη Σιάπη (Ε.Ι.Ε.) και τον κύριο Γεώργιο Αθανασούλη (Ε.Μ.Π.) για τις στοιχειακές αναλύσεις, και τις κυρίες Αικατερίνη Σακελάρη και Μαγδαληνή Μάτζιαρη (Τμήμα Χημείας, Πανεπιστήμιο Αθηνών) για τις αναλύσεις νικελίου και λήψης φάσματος ESI-MS, αντίστοιχα. Ευχαριστώ τους κυρίους Simon Parsons (Πανεπιστήμιο του Εδιμβούργου) και Αριστείδη Τερζή (Ε.ΚΕ.Φ.Ε. Δημόκριτος), για τις X-ray αναλύσεις. Θέλω, ιδιαιτέρως, να ευχαριστήσω τις κυρίες Ελισάβετ Γαλανοπούλου και Θεοδώρα Στρατηγάκη, προϊσταμένες μου στο Κέντρο Υγιεινής και Ασφάλειας της Εργασίας (Υπουργείο Απασχόλησης & Κοινωνικής Προστασίας), όπου εργάζομαι, διότι χωρίς τη βοήθειά τους δεν θα μπορούσα να συνεχίσω τις προσπάθειές μου. Τέλος, ένα μεγάλο ευχαριστώ στη γυναίκα μου Βασούλα και στην κόρη μου Ελευθερία, που με στήριξαν και υπομείνανε την πολύχρονη «απουσία» μου! Στις δύο αυτές γυναίκες της ζωής μου αφιερώνω την παρούσα διατριβή.

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ChemInform Abstract: POLYAMINES. XV. THERMODYNAMICS OF METAL COMPLEX FORMATION OF LINEAR TETRAAMINES CONTAINING TWO ETHYLENEDIAMINE RESIDUES

Anderegg¹,

Blaêuenstein²

1982

Chemischer Informationsdienst

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Polyamines XV. Thermodynamics of Metal Complex Formation of Linear Tetraamines Containing Two Ethylenediamine Residues

Cited by 23 publications

References 37 publications

Gas-phase reactions of divalent Ni complex ions with acetonitrile: Chelate ring size, inductive, and steric effects

Gas-phase reactions of divalent Ni complex ions with acetonitrile: Chelate ring size, inductive, and steric effects

Σύνθεση Και Μελέτη Συμπλόκων Ενώσεων Με Παραμαγνητικά Μεταλλικά Ιόντα Με Σκοπό Τη Χρησιμοποίησή Τους Σε Εφαρμογές Φασματοσκοπίας NMR

ChemInform Abstract: POLYAMINES. XV. THERMODYNAMICS OF METAL COMPLEX FORMATION OF LINEAR TETRAAMINES CONTAINING TWO ETHYLENEDIAMINE RESIDUES

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