π-Complexation of Biphenyl, Naphthalene, and Triphenylene to Trimeric Perfluoro-ortho-phenylene Mercury. Formation of Extended Binary Stacks with Unusual Luminescent Properties

Abstract

Trimeric perfluoro-ortho-phenylene mercury (1) crystallizes from CS(2) as a pure compound. In the crystal, 1 forms staggered cofacial dimers (centroid distance of 3.38 A). In the dimer, the individual components are associated via long mercury-pi interactions (3.443 < Hg...C < 3.650 A). Interestingly, this arrangement leads to the existence of relatively short intermolecular mercury-mercury distances (3.811 < Hg...Hg < 4.093 A). In this form, compound 1 is photoluminescent and exhibits a broad emission band with a maximum at 440 nm and a shoulder at 530 nm. Compound 1 interacts with biphenyl, naphthalene, or triphenylene to form 1.biphenyl (2), 1.naphthalene (3), and 1.triphenylene (4), respectively. These adducts have been characterized by elemental analysis and X-ray crystallography. Their structure reveals the existence of stacks in which molecules of 1 and molecules of arenes alternate. In each stack, secondary pi-interactions occur between the arene and the mercury centers of 1. The resulting Hg...C distances range from 3.25 to 3.55 A and are within the sum of the van der Waals radii. They reflect the presence of secondary polyhapto-pi interactions occurring between the electron-rich aromatic molecules and the acidic mercury centers. In the case of the triphenylene adduct 4, a arene-fluoroarene interaction is also observed (centroid distance of 3.605 A). Compounds 2-4 are photoluminescent. The emission observed for 2 and 3 corresponds to the phosphorescence of the aromatic substrate and suggests the occurrence of a mercury heavy atom effect. In the case of 4, the emission appears at longer wavelengths than those typically observed for triphenylene.

Mixed-stack architecture and solvatomorphism of trimeric perfluoro-ortho-phenylene mercury complexes with dithieno[3,2-b:2′,3′-d]thiophene

“…As a result, obtained energy gap is higher than the energy gap (2.36 eV) calculated from the electrochemical measurements of the oxidation potential of DTT (1) i For triphenylene, see [28], and the larger aromatic hydrocarbons, see [43]. Co-crystals with macrocycle I were reported as white solid.…”

“…Here, we report the X-ray single crystal analysis of the DTT and its mixed-stack complexes with trimeric perfluoroo-phenylene mercury (I) (Chart 1), an acceptor known to form mixed-stack co-crystals with a variety of donors [28][29][30]. Unexpectedly, two different mixed-stack complexes 2 and 3 were obtained from carbon disulfide-dichloromethane (DCM) and carbon disulfide-dichloroethane (DCE) solutions, respectively; in both cases the chlorinated solvent co-crystallized with the DTTmacrocycle I co-crystals.…”

The influence of counter ion and ligandmethyl substitution on the solid-state structures and photophysical properties of mercury(ii) complexes with (E)-N-(pyridin-2-ylmethylidene)arylamines

“…In this context, the luminescent and electroluminescent properties of alkynylmercury complexes and mercury bipyridine complexes have been examined. [24][25][26][27][28] Weak intermolecular d 10 ···d 10 interactions such as Au···Au and Hg···Hg contacts can play an important role in materials science and crystal engineering, [29][30][31][32][33][34][35][36] as their strength is comparable with those exhibited by hydrogen bonds and they are often responsible for the observed optical properties. [37][38][39] The formation of metal···metal and aryl···aryl interactions in the solid-state can cause a red shift in the emission band compared with that in solution phase.…”

19F and 199Hg NMR of trimeric perfluoro-ortho-phenylenemercury

“…These properties result from the electron-withdrawing nature of the fluorinated backbone, the accessibility of the mercury centers as well as from cooperative effects arising from the proximity of the mercury(II) centers. Structural investigations also point to the propensity of this trinuclear derivative to engage in non-covalent interactions including mercuriophilic interactions and dispersion interactions [3]. For example, free trimer forms compact cofacial dimers whose structure has been determined by single crystal Xray diffraction.…”

“…For example, free trimer forms compact cofacial dimers whose structure has been determined by single crystal Xray diffraction. As shown by recent developments, the trimer is also a remarkable supramolecular building block which readily forms binary stacks with various arenes including benzene and naphthalene [3,4]. The formation of these stacks, which results from secondary interactions occurring between the mercury centers and the -system of the arene, is likely assisted by attractive electrostatic and dispersion forces between the individual components.…”