Trinuclear Silver(I) Complexes of Fluorinated Pyrazolates

Abstract

Silver pyrazolates [[3-(CF3)Pz]Ag]3, [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(Ph)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 have been synthesized by treatment of the corresponding pyrazole with a slight molar excess of silver(I) oxide. This economical and convenient route gives silver pyrazolates in high (>80%) yields. X-ray crystal structures of [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 show that these molecules have trinuclear structures with essentially planar to highly distorted Ag3N6 metallacycles. [[3-(CF3),5-(CH3)Pz]Ag]3 forms extended columns via intertrimer argentophilic contacts (the closest Ag...Ag separation between the neighboring trimers are 3.355 and 3.426 A). The trinuclear [[3-(CF3),5-(But)Pz]Ag]3 units crystallize in pairs, basically forming "dimers of trimers", with the six silver atom core of the adjacent trimers adopting a chair conformation. However, in these dimers of trimers, even the shortest intertrimer Ag...Ag distance (3.480 A) is slightly longer than the van der Waals contact of silver (3.44 A). [[3-(C3F7),5-(But)Pz]Ag]3, which has two bulky groups on each pyrazolyl ring, shows no close intertrimer Ag...Ag contacts (closest intertrimer Ag...Ag distance = 5.376 A). The Ag-N bond distances and the intratrimer Ag...Ag separations of the silver pyrazolates do not show much variation. However, their N-Ag-N angles are sensitive to the nature (especially, the size) of substituents on the pyrazolyl rings. The pi-acidic [[3,5-(CF3)2Pz]Ag]3 and [[3-(C3F7),5-(But)Pz]Ag]3 form adducts with the pi-base toluene. X-ray data show that they adopt extended columnar structures of the type [[Ag3]2.[toluene]]infinity and [[Ag3]'.[toluene]]infinity ([[3,5-(CF3)2Pz]Ag]3 = [Ag3],[[3-(C3F7),5-(But)Pz]Ag]3 = [Ag3]'), in which toluene interleaves and makes face-to-face contacts with [[3-(C3F7),5-(But)Pz]Ag]3 or dimers of [[3,5-(CF3)2Pz]Ag]3.

Silver Pyrazolates as Coordination‐Polymer Luminescent Metallomesogens

“…[3] We also synthesized [Agpz 3,2 ] n by using the method reported by Dias et al for silver CTCs, [9] with Ag 2 O as the source of silver and base, and toluene as solvent. The resulting material gave the same 1 H NMR spectrum as in Figure 1.…”

“…[3] In the case of substituted pyrazoles, although a tetrameric structure has been described for the complex with 3,5-di(tert-butyl)pyrazolate ligands [Ag(m-3,5-tBupz)] 4 , [5] the most common structural type is the trimeric ring structure. [6][7][8][9] The trimeric structure consists of a ninemembered Ag 3 N 6 metallacycle with a planar array of N,N'-bridging pyrazolates and linearly coordinated silver ions. These materials were recently reported to show fascinating properties as a consequence of their tunable supramolecular organization.…”

Cyclic trinuclear copper(i), silver(i), and gold(i) complexes: a theoretical insight

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Vaughan and coworkers 17 synthesized the first gold(I) cyclic trinuclear complex (CTC) [Au(I) 3 (μ-1,2-piridyl) 3 ], which presents a planar 9-membered ring structure, exhibiting roughly a D 3h symmetry.…”

New Hexanuclear Group 11 Pyrazolate Complexes: Synthesis and Photophysical Features

“…[4] In particular, fluorinated pyrazolate ligands were investigated by Dias et al due to their structural and photophysical properties. [5,6,7] In recent years we have been applying pyrazole-based lig-A C H T U N G T R E N N U N G ands in transition-metal-catalysed reactions.…”