Ligand functionalization is an attractive strategy for enhancing the performance of metal-based phosphorescent emitters. Here, we report the synthesis and characterization of cyclometalated Pt(II) complexes Pt3 and Pt4 containing organosilyl-substituted (2-(2-thienyl)pyridine) ligands and compare their properties with those of Pt1 (no substituent) and Pt2 (organocarbon substituent). The photophysical characteristics of these molecules, including their absorption and phosphorescence spectra, phosphorescence quantum yield and lifetime, were investigated. The molecular structures were revealed by X-ray diffraction analysis. Under UV light irradiation, Pt2−Pt4 emitted intense orange phosphorescence in the solid state because of the bulkiness of their side chains (up to Φ P : 0.49). Optically pure (−)-(S) Si -Pt4 and (+)-(R) Si -Pt4 were prepared using the optically active ligands (+)-L4 and (−)-L4, respectively. The chiroptical properties of (+)-(R) Si -Pt4, which has an asymmetric silicon atom, were investigated. Circular dichroism and circularly polarized luminescence measurements showed that these structural motifs are suitable for applications in chiroptical phosphorescent materials.

The origin of the large difference of room-temperature fluorescence yields (Φf(RT)) among tris­(trimethylsilyl)­silylated oligothiophene derivatives was investigated. Tris­(trimethylsilyl)­silylated thiophene (1) and tris­(trimethylsilyl)­silylated terthiophene (3) show low fluorescence yields while that of tris­(trimethylsilyl)­silylated bithiophene (2) is high. Nanosecond transient absorption measurements for 2 and 3 verified that the large difference between their intersystem crossing (ISC) rates from the lowest singlet excited state (S1) causes the large difference in Φf(RT). Quantum calculations indicated that the Si–Si σ bond of (Me3Si)3Si, corresponding to the highest occupied molecular orbital (HOMO), is closely involved in the ISC from S1. The planar conjugated core having much higher or comparable HOMO energy relative to the (Me3Si)3Si substituent, such as 1 and 3, induces large spin–orbit coupling (SOC) between S1 and the second-order triplet excited state (T2), resulting in fast ISC from S1 leading to a small Φf(RT). However, a planar conjugated core having slightly higher HOMO energy than that of the (Me3Si)3Si substituent, such as 2, minimizes SOC between S1 and T2, resulting in slow ISC from S1 leading to a large Φf(RT). Thus, the relationship between the HOMO level of the (Me3Si)3Si substituent and that of the planar conjugated core is key to controlling the ISC from S1.

The Jahn–Teller distortion, π-conjugation mode, and magnetic properties were coupled in the ferromagnetic CuII-radical chain, resulting in unique properties.

Of a variety of intercalated materials, 2D intercalated systems have attracted much attention both as materials per se, and as a platform to study atoms and molecules confined among nanometric layers. High‐precision fabrication of such structures has, however, been a difficult task using the conventional top‐down and bottom‐up approaches. The de novo synthesis of a 3‐nm‐thick nanofilm intercalating a hydrogen‐bonded network between two layers of fullerene molecules is reported here. The two‐layered film can be further laminated into a multiply film either in situ or by sequential lamination. The 3 nm film forms uniformly over an area of several tens of cm2 at an air/water interface and can be transferred to either flat or perforated substrates. A free‐standing film in air prepared by transfer to a gold comb electrode shows proton conductivity up to 1.4 × 10−4 S cm−1. Electron‐dose‐dependent reversible bending of a free‐standing 6‐nm‐thick nanofilm hung in a vacuum is observed under electron beam irradiation.