Sensitization of Naphthalene Monomer Phosphorescence in a Sandwich Adduct with an Electron-Poor Trinuclear Silver(I) Pyrazolate Complex

Abstract

Facial complexation of naphthalene to {[3,5-(CF(3))(2)Pz]Ag}(3) (Ag(3)) gives rise to a stacked binary adduct (1) that exhibits phosphorescence corresponding to T(1) monomer emission of naphthalene. Crystals and powders of 1 exhibit bright-green phosphorescence at room temperature with a 830 mus lifetime, whereas cooling to cryogenic temperatures increases the intensity, lifetime, and vibronic resolution. The binary adduct exhibits a drastically shorter phosphorescence lifetime of 6.7 ms versus free naphthalene (2.4 s) in a frozen dichloromethane matrix, which results from the external heavy-atom effect of silver. Adduct 1 represents a new class of phosphors containing lighter but more benign silver than mercury atoms in trinuclear d(10) pi-acid complexes as arene triplet sensitizers.

Phosphorescence sensitization via heavy-atom effects in d10 complexes

“…shows that the emission spectra of the resulting adduct feature emission bands that correspond to the phosphorescence of the aromatic molecule [12]. Crystals and powders of the adduct exhibit bright green phosphorescence at room temperature with 830 ls lifetime, whereas cooling to cryogenic temperatures increases the intensity, lifetime, and vibronic resolution (Fig.…”

“…Because non-fluorinated coinage metal trimers are electron-rich, particularly gold compounds (Figs. 4, 5, 6), [4][5][6][7][8][9][11][12][13][14][15][16][17] such Au 3 species can complex and sensitize the triplet emission of electron-poor organic molecules such as perfluorinated arenes [8,9,11]. The color chromaticity can be easily improved in phosphors synthesized by the strategies in this section because the emission of the binary adducts is essentially the unperturbed T 1 emission of the arene.…”

Anion-tuning of supramolecular gel properties

“…54 Azobenzene moieties are one of the more commonly used groups. 110,[112][113][114] The UV induced change from the trans conformation to the cis conformation often results in disruption of the gel state resulting in a solution. Shinkai was one of first to use this principle although many others have followed this work up with many applications, such as drug delivery, 1 and insightful studies such as the cooperative effects of this transformation within the self-assembled fibres.…”

“…[1][2][3][4][5]8,18,[111][112][113][114][115][116][117][118] Prior to 1997, the coordination modes established for pyrazolate by crystallographic means consisted of just the simple μ-η The synthesis of homoleptic pyrazolate complexes of both d-block, f-block and main group metals has also been achieved. 119,123,124 In all these cases, there is significant competition between the formation of the homoleptic complex and complexes with coordinated solvent.…”

“…113 The transition was reversible by using the appropriate wavelength to cause the cis-trans photoisomerisation. Carbon-carbon double bonds also undergo a trans-to-cis transformation under UV irradiation and this has also been utilized in the formation of gels that can be transformed to sols upon exposure to UV radiation.…”