Platinum(II) Metallomesogens: New External‐Stimuli‐Responsive Photoluminescence Materials

Abstract

New dicatenar isoquinoline-functionalized pyrazoles, [Hpz(R(n,n)iq) ] (R(n,n)=C6 H3 (OCn H2n+1 )2 ; n=4, 6, 8, 10, 12, 14, 16, 18), have been strategically designed and synthesized to induce mesomorphic and luminescence properties into the corresponding bis(isoquinolinylpyrazolate)platinum(II) complexes [Pt(pz(R(n,n)iq) )2 ]. Thermal studies reveal that all platinum(II) compounds exhibit columnar mesophases over an exceptionally wide temperature range, above 300 °C in most cases. The photophysical behavior was also investigated in solution and in the solid state. As a consequence of the formation of Pt⋅⋅⋅Pt interactions, the weak greenish emission of the platinum derivatives turns bright orange in the mesophase. Additionally, the complexes are sensitive to a great variety of external inputs, such as temperature, mechanical grinding, pressure, solvents, and vapors. On this basis, they are used as dopant agents of a polyvinylpyrrolidone or poly(methyl methacrylate) polymer matrix to achieve stimuli-responsive thin films.

Metal‐Free Facile Synthesis of Multisubstituted 1‐Aminoisoquinoline Derivatives with Dual‐State Emissions

“…Although the isoquinoline ring is known as an important structural motif in the alkaloids which have a wide range of biological activities in pharmaceutical chemistry, some isoquinoline derivatives have also been found to be widely used in the fields of fluorescent materials, such as fluorescent sensors, organic light‐emitting diodes, and molecular logic gates . Even so, compared with the quinoline unit, the isoquinoline unit is more used to construct various metal complexes emitters and pure organic isoquinoline fluorescent molecules are rarely reported . Furthermore, the isoquinoline derivatives often exhibit strong fluorescence in dilute solutions but emit dimly or even no fluorescence in the solid state because of the aggregation‐caused quenching effect caused by the rigid and planar isoquinoline ring .…”

Playing with PtII and ZnII Coordination to Obtain Luminescent Metallomesogens

“…Luminescent d-block metallomesogens are promising functional materials for practicala pplications.T hey have mainly been investigated in terms of obtaining polarised emission to be used as backlighting in displays, [1][2][3][4] but also some studies concerning their use as stimuli responsive materials for sensing [5,6] or security inks, [7] or high-hole mobility materials for electroluminescent devices [8] have been reported.D espite recentp rogress with square-planar Pt II and octahedral Ir III complexes, which are considered among the best emitters, there is still considerable work to be done to control the phase type and transition temperatures or to improvet he luminescence in the mesophase. [9] In fact, only af ew studies on the mesophases of luminescent liquid-crystalline transition metal complexes have been carried out, with, just to cite non-exhaustively,t he contributions of Bruce et al on Ir III , [8,[10][11][12] Espinet et al [13] and Tsutsumi et al [14,15] on Au I ,G imenØnez et al on Ag I [16] and Zn II , [17] Cârcu et al on Pd II , [18][19][20] Cano et al on Ag I [21][22] and Pucci, Crispini and Ghedini et al on Ru II , [23] Ag I , [24][25][26] Ir III [27] and Zn II [28,29] complexes.…”

Tuning the Aggregation of N^N^C Pt(II) Complexes by Varying the Aliphatic Side Chain and Auxiliary Halide Ligand: 1H and 195Pt NMR Investigation

“…Aggregation and self ‐organisation of square planar Pt(II) complexes is a widely used tool in supramolecular chemistry Driven by a variety of intermolecular forces, including metallophilic Pt–Pt interactions, many supramolecular architectures such as gels,, liquid crystals and polymers have been prepared. To study self‐aggregation is an important task because the properties of the aggregates are often very different to the ones of individual molecules.…”