10.1021/ic0508730.s001
Mohammad A. Omary
Mohammad A.
Omary
Manal A. Rawashdeh-Omary
Manal A.
Rawashdeh-Omary
M. W. Alexander Gonser
M. W. Alexander
Gonser
Oussama Elbjeirami
Oussama
Elbjeirami
Tom Grimes
Tom
Grimes
Thomas R. Cundari
Thomas R.
Cundari
Himashinie V. K. Diyabalanage
Himashinie
V. K. Diyabalanage
Chammi S. Palehepitiya Gamage
Chammi
S. Palehepitiya Gamage
H. V. Rasika Dias
H.
V. Rasika Dias
Metal Effect on the Supramolecular Structure, Photophysics, and
Acid−Base Character of Trinuclear Pyrazolato Coinage Metal
Complexes<sup>†</sup>
American Chemical Society
2005
cyclic trinuclear pyrazolate complexes
luminescence thermochromic changes
form isomorphous crystals
Pz
acid
coinage metal
DFT
CF
Ag
Cu
energy phosphorescence band
trimer
Remarkable luminescence properties
M 3 complexes
2005-11-14 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Metal_Effect_on_the_Supramolecular_Structure_Photophysics_and_Acid_Base_Character_of_Trinuclear_Pyrazolato_Coinage_Metal_Complexes_sup_sup_/3257410
Varying the coinage metal in cyclic trinuclear pyrazolate complexes is found to significantly affect the solid-state
packing, photophysics, and acid−base properties. The three isoleptic compounds used in this study are {[3,5-(CF<sub>3</sub>)<sub>2</sub>Pz]M}<sub>3</sub> with M = Cu, Ag, and Au (i.e., <b>Cu</b><b><sub>3</sub></b>, <b>Ag</b><b><sub>3</sub></b>, and <b>Au</b><b><sub>3</sub></b>, respectively). They form isomorphous crystals
and exist as trimers featuring nine-membered M<sub>3</sub>N<sub>6</sub> rings with linear two-coordinate metal sites. On the basis of the
M−N distances, the covalent radii of two-coordinate Cu<sup>I</sup>, Ag<sup>I</sup>, and Au<sup>I</sup> were estimated as 1.11, 1.34, and 1.25 Å,
respectively. The cyclic {[3,5-(CF<sub>3</sub>)<sub>2</sub>Pz]M}<sub>3</sub> complexes pack as infinite chains of trimers with a greater number of
pairwise intertrimer M···M interactions upon proceeding to heavier coinage metals. However, the intertrimer distances
are conspicuously short in <b>Ag</b><b><sub>3</sub></b> (3.204 Å) versus <b>Au</b><b><sub>3</sub></b> (3.885 Å) or <b>Cu</b><b><sub>3</sub></b> (3.813 Å) despite the significantly larger
covalent radius of Ag<sup>I</sup>. Remarkable luminescence properties are found for the three <b>M</b><b><sub>3</sub></b> complexes, as manifested
by the appearance of multiple unstructured phosphorescence bands whose colors and lifetimes change qualitatively
upon varying the coinage metal and temperature. The multiple emissions are assigned to different phosphorescent
excimeric states that exhibit enhanced M···M bonding relative to the ground state. The startling luminescence
thermochromic changes in crystals of each compound are related to relaxation between the different phosphorescent
excimers. The trend in the lowest energy phosphorescence band follows the relative triplet energy of the three M<sup>I</sup>
atomic ions. DFT calculations indicate that {[3,5-(R)<sub>2</sub>Pz]M}<sub>3</sub> trimers with R = H or Me are bases with the relative
basicity order Ag ≪ Cu < Au while fluorination (R = CF<sub>3</sub>) renders even the Au trimer acidic. These predictions
were substantiated experimentally by the isolation of the first acid−base adduct, {[<b>Au</b><b><sub>3</sub></b>]<sub>2</sub>:toluene}<sub>∞</sub>, in which a
trinuclear Au<sup>I</sup> complex acts as an acid.