Joint Venture of Metal Cluster and Amphiphilic Cationic Minidendron Resulting in Near Infrared Emissive Lamellar Ionic Liquid Crystals

Abstract

Inorganic red‐NIR emissive materials are particularly relevant in many fields like optoelectronic, bioimaging or solar cells. Benefiting from their emission in devices implies their integration in easy‐to‐handle materials like liquid crystals, whose long‐range ordering and self‐healing abilities could be exploited and influence emission. Herein, we present red‐NIR emissive hybrid materials obtained with phosphorescent octahedral molybdenum cluster anions electrostatically associated with amphiphilic guanidinium minidendrons. Polarized optical microscopy and X‐ray analysis show that while the minidendron chloride salts self‐organize into columnar phases, their association with the dianionic metal cluster leads to layered phases. Steady‐state and time‐resolved emission investigations demonstrate the influence of the minidendron alkyl chain length on the phosphorescence of the metal cluster core.

Game of Crowns: Na+Is Coming! Red NIR-Emissive Hybrid Liquid Crystals Containing Discotic Crown Ethers and Na2Mo6X8iCl6(Xi= Cl or Br)

“…The diffraction pattern is characteristic of a columnar hexagonal Col h mesophase with the P6mm symmetry and a lattice parameter of 39.19 Å. In agreement with previous work on clustomesogens, broad peaks at 12.32 and 8.57 Å were observed due to the cluster. As summarized in Table and more detailed in Table S2 (Supporting Information), all other hybrids 12C4–Cl , 12C4–Br , 15C5–Cl , 18C6–Cl , and 18C6–Br exhibited similar Col h phases.…”

Counterion effects on the mesomorphic and electrochemical properties of guanidinium salts

“…The guanidinium salts Gua(14)X were prepared via salt metathesis from the known tristetradecyloxyphenylguanidinium chloride Gua(14)Cl 64 according to the procedure proposed by Butschies 18 (Scheme 1). After recrystallization, the resulting guanidinium salts Gua(14)X were isolated in 79–91% yield.…”

“…6), which we propose for these wedgeshaped ILCs in agreement with the previous work. 64,69,75,82,83 Details of the XRD data are summarized in Fig. S9-S11 (ESI †).…”

“…Under the POM, all mesomorphic guanidinium salts displayed fan-shaped textures, indicating the presence of a columnar mesophase in analogy to the known chloride salt Gua( 14)Cl. 64 Typical examples are shown in Fig. 4 for the bromides, Gua( 14)Br (Fig.…”

“…27,[72][73][74] Thus, in order to understand their liquid crystalline selfassembly in the bulk phase and their electrochemical behavior in solution, we investigated a series of wedge-shaped 3,4,5-trisalkoxy-phenyl-guanidinium salts Gua( 14)X with different counterions X = Cl, Br, I, BF 4 , PF 6 , OMs, SCN, N(CN) 2 , NO 3 , NTf 2 , OTf, OTs, N 3 , CN, OCN, OAc. The 3,4,5-trisalkoxyphenyl-guanidinium mesogen Gua( 14) was chosen as a cationic moiety because it is a very robust mesogen, forming a columnar mesophase in the presence of the chloride anion and undulated lamellar SmA phases for bulky divalent Mo cluster anions 64 (Fig. 1).…”