Reversible Solid-State Phase Transitions between Au–P Complexes Accompanied by Switchable Fluorescence

Abstract

Six complexes {(3-bdppmapy)(AuCl) 2 } n (1−6; 3-bdppmapy = N,N′-bis(diphenylphosphanylmethyl)-3-aminopyridine and tht = tetrahydrothiophene) were simultaneously formed by the reaction of Au(tht)Cl and 3-bdppmapy in CH 2 Cl 2 followed by infusion with hexane. Complexes 4−6 could be produced independently by volatilizing solvent in air, solidstate heating, or solvothermal reaction. The PPh 2 −Au−Cl moieties extended in different directions, forming Au−Au and Au−Au−Au interactions. Complex 4 could be converted to 5 by heating to 130 °C, with the cleavage of one Au−Au bond, while 5 reverted back to 4 upon exposure to CH 2 Cl 2 vapor over 11 h. This solid-state phase transition could be recycled and was accompanied by a change in solid-state fluorescence, without obvious intensity decay over five cycles. The reason for both the phase transition and difference in photoluminescence is related to the different numbers and strengths of aurophilic interactions in each complex that could be modeled by density functional theory calculations.

Innovative Molecular Design Strategies in Materials Science Following the Aurophilicity Concept

“…Slow evaporation from a 2:1 molar ratio of [AuCl­(tht)] and 3-bdppmapy [tht = tetrahydrothiophene, 3-bdppmapy = N , N ′-bis­(diphenylphosphanylmethyl)-3-aminopyridine] in CH 2 Cl 2 /hexane afforded [(AuCl) 2 (3-bdppmapy)]·CH 2 Cl 2 ·2H 2 O ( 156a ) . In the structure of 156a , determined by X-ray crystallography, a pair of [(AuCl) 2 (3-bdppmapy)] units are in close proximity with an intermolecular Au···Au separation of 3.2197(6) Å and one intramolecular Au···Au separation of 3.0687(6) Å.…”

Low-Dimensional Architectures in Isomeric cis-PtCl2{Ph2PCH2N(Ar)CH2PPh2} Complexes Using Regioselective-N(Aryl)-Group Manipulation

“…We [11][12][13][14][15][16]29], and others [17,[19][20][21][22], have previously used Mannich condensations as a versatile method for the synthesis of aminomethylphosphines. Accordingly, two equivalents of Ph 2 PCH 2 OH were reacted with one equivalent of the amine, for 24 h at r.t. under N 2 , yielding the desired phenol-substituted ditertiary phosphines 1a-e and 3 (Scheme 1).…”

“…For a number of years, we [11][12][13][14][15][16], and others [17][18][19][20][21][22], have been interested in aminomethylphosphines, readily amenable by Mannich condensation reactions. Such interest stems from the relative ease of accessing P-monodentate ligands based on a P-C-N linker [11,15,16,19,20,22] or P/P-bidentate derivatives bearing a P-C-N-C-P backbone [12][13][14][17][18][19]21]. Previously, we have shown that the N-arene group can be easily tuned with, for example, various H-bonding donor/acceptor sites based on -CO 2 H/OH groups [12][13][14][15][16].…”

Thermo-responsive light-emitting metal complexes and related materials

“…In addition to the thermal-activated non-radiative decay, many other factors may be activated or influenced by temperature, including the effective molecular conformation or configuration transformation of flexible systems, 61,62 the degree of inter-or intramolecular π-π stacking and metal-metal interactions existing in aggregates or clusters of Rh(I), Pt(II), Cu(I), Ag(I), and Au(I) complexes, 39,[63][64][65] the dynamic association or dissociation process of metal and lanthanide complexes, 66,67 phase transition, [68][69][70][71] the degree of inter-or intramolecular energy transfer of donor/acceptor systems, 72,73 as well as the thermal equilibrium of different excited states. 74,75 These mechanisms will be discussed in more detail in specific examples in the following chapters.…”

“…However, the emission intensity changes could also be caused by many other factors, such as the dynamic association/dissociation process or phase transition. 66,71 The shift of λ emi is another general readout during the studies of thermo-responsive materials, which could be a result of dynamic thermal-equilibrium of different excited states or the change of the energy/electron transfer efficiency. 76,77 The shift of λ emi often leads to the emission color changes of materials, allowing us to conveniently monitor the thermo-responsive process.…”