Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand

Nami Saeki; Yuji Hirano; Yasunari Sasamoto; Ichiro Sato; Tsuyoshi Toshida; Sousei Ito; Noriko Nakamura; Koji Ishihara; Kazuko Matsumoto

doi:10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m

Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand

Nami Saeki, Yuji Hirano, Yasunari Sasamoto, Ichiro Sato, Tsuyoshi Toshida, Sousei Ito, Noriko Nakamura, Koji Ishihara^*, Kazuko Matsumoto

^*Corresponding author for this work

School of Advanced Science and Engineering

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Abstract

Acid dissociation constant of the axial aqua ligand in the Head-to-Tail (HT) α-pyridonate-bridged cis-diammineplatinum(III) dimer complex {[(H₂O)Pt(NH₃)₂(μ-C₅H ₄NO)₂Pt-(NH₃)₂(H₂O)] ⁴⁺} was determined spectrophotometrically to be -log(K_h1/M) = 1.98±0.01 at 25°C and I = 2.00 M. Successive substitution reaction of the HT dimer with halide ions X^- (X^- = Cl^- and Br) at the two axial sites to give monohalo and dihalo complexes was studied kinetically: [(H₂O)Pt(NH₃)₂(μ-C₅H ₄NO)₂Pt(NH₃)₂(H₂O) ⁴⁺ + X^- ⇄ [(H₂O)Pt(NH₃)₂(μ-C₅H ₄NO)₂Pt(NH₃)₂(X)³⁺ + H₂O (k_obs1) [(H₂O)Pt(NH₃)₂(μ-C₅H ₄NO)₂Pt(NH₃)₂(X)³⁺ + X^- ⇄ [(X)Pt(NH₃)₂(μ-C₅H₄NO) ₂Pt(NH₃)₂(X)]²⁺ + H₂O (k_obs2) Formation constants of the monohalo and dihalo complexes were determined spectrophotometrically to be log(K₁^Cl/M^-1) = 5.27±0.02 and log(K₂^Cl/M^-1) = 3.83±0.01 for the reaction with Cl^-, and log(K₁^Br/M^-1) = 5.33±0.03 and log(K₂^Br/M^-1) = 4.44±0.02 for the reaction with Br^-. In the HT dimer having two equivalent platinum atoms, the deprotonation occurs to the water molecule on one of the two Pt atoms, whereas the first nucleophilic substitution with X^- occurs to the other Pt atom. Substitution of the second water ligand with Cl^- proceeds by a simple substitution path, whereas the second substitution with Br^- proceeds by two parallel paths: one includes the dissociation of the axially coordinated water molecule followed by the Br^- coordination, and the other is the simple one-step substitution path. The difference of the reaction paths is reasonably explained by the different trans effect of the halide ions exerted through the Pt-Pt bond to the other terminal Pt atom in the monohalo complexes.

Original language	English
Pages (from-to)	2081-2088
Number of pages	8
Journal	European Journal of Inorganic Chemistry
Issue number	8
DOIs	https://doi.org/10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m
Publication status	Published - 2001

Keywords

Kinetics
Platinum
Pt dimer
Reaction mechanisms
α-Pyridone

ASJC Scopus subject areas

Inorganic Chemistry

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Saeki, N., Hirano, Y., Sasamoto, Y., Sato, I., Toshida, T., Ito, S., Nakamura, N., Ishihara, K., & Matsumoto, K. (2001). Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand. European Journal of Inorganic Chemistry, (8), 2081-2088. https://doi.org/10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m

Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand. / Saeki, Nami; Hirano, Yuji; Sasamoto, Yasunari et al.
In: European Journal of Inorganic Chemistry, No. 8, 2001, p. 2081-2088.

Research output: Contribution to journal › Article › peer-review

Saeki, N, Hirano, Y, Sasamoto, Y, Sato, I, Toshida, T, Ito, S, Nakamura, N, Ishihara, K & Matsumoto, K 2001, 'Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand', European Journal of Inorganic Chemistry, no. 8, pp. 2081-2088. https://doi.org/10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m

Saeki N, Hirano Y, Sasamoto Y, Sato I, Toshida T, Ito S et al. Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand. European Journal of Inorganic Chemistry. 2001;(8):2081-2088. doi: 10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m

Saeki, Nami ; Hirano, Yuji ; Sasamoto, Yasunari et al. / Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex : Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand. In: European Journal of Inorganic Chemistry. 2001 ; No. 8. pp. 2081-2088.

@article{272d7346869c4b389f9f1d66c5437d58,

title = "Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand",

abstract = "Acid dissociation constant of the axial aqua ligand in the Head-to-Tail (HT) α-pyridonate-bridged cis-diammineplatinum(III) dimer complex {[(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt-(NH3)2(H2O)] 4+} was determined spectrophotometrically to be -log(Kh1/M) = 1.98±0.01 at 25°C and I = 2.00 M. Successive substitution reaction of the HT dimer with halide ions X- (X- = Cl- and Br) at the two axial sites to give monohalo and dihalo complexes was studied kinetically: [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(H2O) 4+ + X- ⇄ [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + H2O (kobs1) [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + X- ⇄ [(X)Pt(NH3)2(μ-C5H4NO) 2Pt(NH3)2(X)]2+ + H2O (kobs2) Formation constants of the monohalo and dihalo complexes were determined spectrophotometrically to be log(K1Cl/M-1) = 5.27±0.02 and log(K2Cl/M-1) = 3.83±0.01 for the reaction with Cl-, and log(K1Br/M-1) = 5.33±0.03 and log(K2Br/M-1) = 4.44±0.02 for the reaction with Br-. In the HT dimer having two equivalent platinum atoms, the deprotonation occurs to the water molecule on one of the two Pt atoms, whereas the first nucleophilic substitution with X- occurs to the other Pt atom. Substitution of the second water ligand with Cl- proceeds by a simple substitution path, whereas the second substitution with Br- proceeds by two parallel paths: one includes the dissociation of the axially coordinated water molecule followed by the Br- coordination, and the other is the simple one-step substitution path. The difference of the reaction paths is reasonably explained by the different trans effect of the halide ions exerted through the Pt-Pt bond to the other terminal Pt atom in the monohalo complexes.",

keywords = "Kinetics, Platinum, Pt dimer, Reaction mechanisms, α-Pyridone",

author = "Nami Saeki and Yuji Hirano and Yasunari Sasamoto and Ichiro Sato and Tsuyoshi Toshida and Sousei Ito and Noriko Nakamura and Koji Ishihara and Kazuko Matsumoto",

year = "2001",

doi = "10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m",

language = "English",

pages = "2081--2088",

journal = "European Journal of Inorganic Chemistry",

issn = "1434-1948",

publisher = "Wiley-VCH Verlag",

number = "8",

}

TY - JOUR

T1 - Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex

T2 - Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand

AU - Saeki, Nami

AU - Hirano, Yuji

AU - Sasamoto, Yasunari

AU - Sato, Ichiro

AU - Toshida, Tsuyoshi

AU - Ito, Sousei

AU - Nakamura, Noriko

AU - Ishihara, Koji

AU - Matsumoto, Kazuko

PY - 2001

Y1 - 2001

N2 - Acid dissociation constant of the axial aqua ligand in the Head-to-Tail (HT) α-pyridonate-bridged cis-diammineplatinum(III) dimer complex {[(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt-(NH3)2(H2O)] 4+} was determined spectrophotometrically to be -log(Kh1/M) = 1.98±0.01 at 25°C and I = 2.00 M. Successive substitution reaction of the HT dimer with halide ions X- (X- = Cl- and Br) at the two axial sites to give monohalo and dihalo complexes was studied kinetically: [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(H2O) 4+ + X- ⇄ [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + H2O (kobs1) [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + X- ⇄ [(X)Pt(NH3)2(μ-C5H4NO) 2Pt(NH3)2(X)]2+ + H2O (kobs2) Formation constants of the monohalo and dihalo complexes were determined spectrophotometrically to be log(K1Cl/M-1) = 5.27±0.02 and log(K2Cl/M-1) = 3.83±0.01 for the reaction with Cl-, and log(K1Br/M-1) = 5.33±0.03 and log(K2Br/M-1) = 4.44±0.02 for the reaction with Br-. In the HT dimer having two equivalent platinum atoms, the deprotonation occurs to the water molecule on one of the two Pt atoms, whereas the first nucleophilic substitution with X- occurs to the other Pt atom. Substitution of the second water ligand with Cl- proceeds by a simple substitution path, whereas the second substitution with Br- proceeds by two parallel paths: one includes the dissociation of the axially coordinated water molecule followed by the Br- coordination, and the other is the simple one-step substitution path. The difference of the reaction paths is reasonably explained by the different trans effect of the halide ions exerted through the Pt-Pt bond to the other terminal Pt atom in the monohalo complexes.

AB - Acid dissociation constant of the axial aqua ligand in the Head-to-Tail (HT) α-pyridonate-bridged cis-diammineplatinum(III) dimer complex {[(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt-(NH3)2(H2O)] 4+} was determined spectrophotometrically to be -log(Kh1/M) = 1.98±0.01 at 25°C and I = 2.00 M. Successive substitution reaction of the HT dimer with halide ions X- (X- = Cl- and Br) at the two axial sites to give monohalo and dihalo complexes was studied kinetically: [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(H2O) 4+ + X- ⇄ [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + H2O (kobs1) [(H2O)Pt(NH3)2(μ-C5H 4NO)2Pt(NH3)2(X)3+ + X- ⇄ [(X)Pt(NH3)2(μ-C5H4NO) 2Pt(NH3)2(X)]2+ + H2O (kobs2) Formation constants of the monohalo and dihalo complexes were determined spectrophotometrically to be log(K1Cl/M-1) = 5.27±0.02 and log(K2Cl/M-1) = 3.83±0.01 for the reaction with Cl-, and log(K1Br/M-1) = 5.33±0.03 and log(K2Br/M-1) = 4.44±0.02 for the reaction with Br-. In the HT dimer having two equivalent platinum atoms, the deprotonation occurs to the water molecule on one of the two Pt atoms, whereas the first nucleophilic substitution with X- occurs to the other Pt atom. Substitution of the second water ligand with Cl- proceeds by a simple substitution path, whereas the second substitution with Br- proceeds by two parallel paths: one includes the dissociation of the axially coordinated water molecule followed by the Br- coordination, and the other is the simple one-step substitution path. The difference of the reaction paths is reasonably explained by the different trans effect of the halide ions exerted through the Pt-Pt bond to the other terminal Pt atom in the monohalo complexes.

KW - Kinetics

KW - Platinum

KW - Pt dimer

KW - Reaction mechanisms

KW - α-Pyridone

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DO - 10.1002/1099-0682(200108)2001:8<2081::aid-ejic2081>3.0.co;2-m

M3 - Article

AN - SCOPUS:0034920294

SN - 1434-1948

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JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

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Kinetic and equilibrium study on the axial-ligand substitution reaction of the head-to-tail α-pyridonate-bridged cis-diammineplatinum(III) dinuclear complex: Trans effect of the axial ligand through the Pt-Pt bond to the opposite axial ligand

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