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Five- and six-coordinated silver(I) complexes formed by a metallomacrocyclic ligand with a “Au2N2” donor group: observation of pendulum and linear motions and dual phosphorescence

Nayeri, S ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1021/acs.inorgchem.0c00482
  3. Publisher: American Chemical Society , 2020
  4. Abstract:
  5. The six-coordinated silver(I) complex [Au2Ag(μ-(PPh2)2py)2(OTf)2](OTf), 4 (py = pyridine, OTf = CF3SO3), and the five-coordinated silver(I) complex [Au2Ag(acetone)(μ-(PPh2)2py)2](PF6)3, 6, were prepared by the reaction of the precursor complexes 1(OTf)2 and 1(PF6)2, in which 1 = [Au2(μ-(PPh2)2py)2]2+, with 1 equiv of Ag(OTf) in dichloromethane and excess of Ag(PF6) in a mixture of dichloromethane/acetone, respectively. Also, the five-coordinated silver(I) complex [Au2Ag(μ-(PPh2)2py)2(py)(OTf)](OTf)2, 5, was obtained by the reaction of 4 with pyridine. The clusters 4-6 were characterized using multinuclear NMR spectroscopy and elemental microanalysis. The single-crystal X-ray diffraction analysis revealed the octahedral and distorted square pyramidal geometries around the silver(I) centers in the crystal structures of 4 and 6, respectively; a dynamic structure was observed for cluster 5 due to pendulum motion of the Ag(pyridine) moiety, which was anchored in the metallomacrocyclic unit [Au2(μ-(PPh2)2py)2]2+. Although the crystal structure of 6 did not display disorders for the silver atom and the acetone ligand similar to that observed for 5, the low-temperature NMR spectroscopies and calculations show a dynamic structure for cluster 6 due to linear motion of the Ag(acetone) moiety. The reaction of the precursor complex 1(PO2F2)2 with 2 equiv of Ag(PO2F2) yielded the tetranuclear Au2Ag2 cluster [Au2Ag2(PO2F2)2(μ-(PPh2)2py)2](PO2F2)2, 7, with a planar-shaped {Au2Ag2} metal core in which alternating Au and Ag atoms occupy the tetragon vertices and showed a strong argentophillic interaction between the silver(I) centers. All clusters 4-7 are emissive in the solid state, and the origins of their emissive excited states were determined using time-dependent density functional theory calculations. Cluster 7 showed a dual phosphorescence emission, which displays strong dependence of the contributions of each emissive component onto the excitation wavelength. © 2020 American Chemical Society
  6. Keywords:
  7. Six-coordinated silver (I)complex ; Five-coordinated silver (I)complex ; Precursor complexes ; Dichloromethane ; Pendulum Motions ; Linear Motions ; Dual Phosphorescence ; Metallomacrocyclic Ligand ; NMR spectroscopy ; X-ray diffraction
  8. Source: Inorganic Chemistry ; Volume 59, Issue 8 , 31 March , 2020 , Pages 5702-5712
  9. URL: https://pubs.acs.org/doi/10.1021/acs.inorgchem.0c00482