109994-25-4

Basic information

• Product Name: Pd({9}aneN₃)2⁽³⁺⁾
• CAS NO: 109994-25-4
• Molecular Weight: 364.83
• Mol File: 109994-25-4.mol
• Article Data: 1

Chemical Properties

• CAS DataBase Reference: Pd({9}aneN₃)2⁽³⁺⁾(CAS DataBase Reference)
• NIST Chemistry Reference: Pd({9}aneN₃)2⁽³⁺⁾(109994-25-4)
• EPA Substance Registry System: Pd({9}aneN₃)2⁽³⁺⁾(109994-25-4)

Safety Data

• Hazardous Substances Data: 109994-25-4(Hazardous Substances Data)

Upstream product

• 22573-07-5 tetraaquapalladium(II) 
• 114977-76-3 Pd({9}aneN₃)2⁽²⁺⁾ 

Relevant articles and documents

Bis(1,4,7-triazacyclononane)palladium(III): Characterization and reactions of an unusually stable monomeric palladium(III) ion

The synthesis of the monomeric palladium(III) ion [Pd([9]aneN3)2]3+ ([9]aneN3: 1,4,7-triazacyclononane) as the hexafluorophosphate salt is described. Solutions of this ion exhibit exceptional kinetic stability in aqueous media as shown by the ESR spectrum of the d7 ion. With PdII([9]aneN3)22+, electrochemical oxidation yields two one-electron cyclic voltammograms associated with oxidation to the Pd(III) and Pd(IV) states. Electrode potentials are pH dependent owing to protonation (producing Pd(HL)(L)n+ and Pd(HL)2m+ (n = 3, 4; m = 4, 5)) of one or both of the ligands at an uncoordinated nitrogen site. For the nonprotonated couples, E°(Pd([9]aneN3)23+/2+) = 0.370 V (vs NHE) in ClO4- or NO3- media and is about 30 mV higher in acetate media. For the corresponding Pd([9]aneN3)24+/3+ couple, E° = 0.640 V (vs NHE). A detailed analysis of the pH dependences is provided. An isotropic ESR signal, giso = 2.077 (77 K) (giso = 2.08 (298 K)) is observed at low ionic strength. However, in saturated Li2SO4, a pseudoaxial spectrum is derived, g⊥ = 2.115 and g∥ = 2.007 (A = 26.2 G), owing to ion-pair formation. Stopped-flow kinetic experiments have been carried out with both Pd([9]aneN3)23+ and Pd([9]aneN3)22+ as reagents. Rates of reduction of the Pd(III) ion with Co([9]aneN3)22+ and Co(sepulchrate)2+ and rates of oxidation of the Pd(II) ion with Ni([9]aneN3)23+ and Ni(Me[9]aneN3)23+, when analyzed by using a Marcus cross-correlation, led to a value of (2 ± 1) × 10-6 M-1 s-1 for the Pd([9]aneN3)23+/2+ couple. The origin of this exceptionally low rate lies in the inner-sphere reorganization required to provide axial interaction of the noncoordinated nitrogens with the normally square-planar d8 Pd(II) ion. This rate constant is contrasted with that of (7 ± 3) × 102 M-1 s-1 for the Pd([9]aneN3)24+/3+ couple where both reagents are octahedral in configuration. The data are compared to other d7/d6 exchanges, and the steric role of the ligand in the electron-transfer process is described.