†Electronic Supplementary Information (ESI) available: X-ray crystallographic data in CIF format for the complexes Ir2 and Ir4 [CCDC 973778 (Ir2) and 1005716 (Ir4)], NMR and MASS spectra of ligands and complexes, TGA−DSC thermal curves, cyclic voltammograms, lifetime curves, selected bond lengths and angles, intermolecular interactions, calculated transitions of Ir1-Ir5 in CH2Cl2 media and composition of the MOs and the assignment of different fragments. CIF files. See Herein, we have synthesized a series of 2',6'-difluoro-2,3'-bipyridine cyclometalating ligands by substituting electronwithdrawing (-CHO, -CF3, -CN) and electron-donating (-OMe, -NMe2) groups at the 4′ posiƟon of the pyridyl moiety and utilized for the construction of five new iridium(III) complexes (Ir1-Ir5) in the presence of picolinate as an ancillary ligand. The photophysical properties of the developed iridium(III) compounds were investigated with a view to understand the substituent effects. The strong electron-withdrawing (-CN) group containing iridium(III) compound (Ir3) exhibits highly efficient genuine green phosphorescence (λmax= 508 nm) at room temperature in solution and in thin film, with an excellent quantum efficiency (ΦPL) of 0.90 and 0.98, respectively. On the other hand, the -CF3 group substituted iridium(III) compound (Ir2) displays a sky-blue emission (λmax = 468 nm) with a promising quantum efficiency (ΦPL = 0.88 and 0.84 in solution and in thin film, respectively). The -CHO substituted iridium(III) complex (Ir1) showed greenishyellow emission (λmax = 542 nm). Most importantly, the strong electron-donating -NMe2 substituted iridium(III) complex (Ir5) gives a structureless and a broad emission profile in the wavelength region 450 to 700 nm (λmax = 520 nm) with a poor quantum efficiency. An intense blue phosphorescence with impressive quantum efficiency, especially in thin-film noted in the case of -OMe substituted iridium(III) complex (Ir4). Comprehensive density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches have been performed on the ground and excited states of the synthesized iridium(III) complexes, in order to obtain information about the absorption and emission processes and to gain deeper insights into the photophysical properties. The combinations of a smaller ΔES1-T1 and higher contribution of 3 MLCT in the emission process result in the higher quantum yields and lifetime values for complexes Ir1-Ir3. Multi-layered Phosphorescence Organic Light Emitting Diodes (PhOLEDS) were designed using the phosphorescent dopants Ir2, Ir3 and Ir4 and evaluated their elecroluminescence properties. The compound Ir4 at a doping level of 5 wt% shows the best performance with an external quantum efficiency of 4.7% , in nonoptimized device, and power efficiency of 5.8 lm W −1 , together with a true-blue chromacity CIEx,y = 0.15, 0.17 recorded at maximum brightness of 33,180 cd/m 2 . 28,[45][46][47][48][49][50][51] Accordingly, several groups have demonstrated that phosphorescence emission wavelengths can be tuned in t...

Relativistic density functional theory has been employed to characterize [AnO2(L)]0/‑1 complexes, where An = U, Np, Pu, and Am, and L is the recently reported hexa-aza porphyrin analogue, termed dipyriamethyrin, which contains six nitrogen donor atoms (four pyrrolic and two pyridine rings). Shorter axial (AnO) and longer equatorial (An–N) bond lengths are observed when going from AnVI to AnV. The actinide to pyrrole nitrogen bonds are shorter as compared to the bonds to the pyridine nitrogens; the former also play a dominant role in the formation of the actinyl (VI and V) complexes. Natural population analysis shows that the pyrrole nitrogen atoms in all the complexes carry higher negative charges than the pyridine nitrogens. Upon binding actinyl ions with the ligand a significant ligand-to-metal charge transfer takes place in all the actinyl (VI and V) complexes. The formation energy of the actinyl­(VI,V) complexes in the gas-phase is found to decrease in the order of UO2L > PuO2L > NpO2L > AmO2L. This trend is consistent with results for the formation of complexes in dichloromethane solution. The calculated ΔG and ΔH values are negative for all the complexes. Energy decomposition analysis (EDA) indicates that the interactions between actinyl­(V/VI) and ligand are mainly controlled by electrostatic components over covalent orbital interactions, and the covalent character gradually decreases from U to Am for both pentavalent and hexavalent actinyl complexes.

Bent-core mesogens are an important class of thermotropic liquid crystals as they exhibit unusual properties as well as morphologies distinctly different from rodlike mesogens. Two bent-core mesogens with differing center rings namely benzene and thiophene are considered and investigated using high-resolution oriented solid state 13C NMR method in their liquid crystalline phases. The mesogens exhibit different phase sequences with the benzene-based mesogen showing a B1 phase, while the one based on thiophene showing nematic and smectic C phases. The 2-dimensional separated local field (2D-SLF) NMR method was used to obtain the 13C–1H dipolar couplings of carbons in the center ring as well as in the side-wing phenyl rings. Couplings, characteristic of the type of the center ring, that also provide orientational information on the molecule in the magnetic field were observed. Together with the dipolar couplings of the side-wing phenyl ring carbons from which the local order parameters of the different subunits of the core could be extracted, the bent angle of the mesogenic molecule could be obtained. Accordingly, for the benzene mesogen in its B1 phase at 145 °C, the center ring methine 13C–1H dipolar couplings were found to be significantly larger (9.5–10.2 kHz) compared to those of the side-wing rings (1.6–2.1 kHz). From the local order parameter values of the center (0.68) as well as the side-wing rings (0.50), a bent-angle of 130.3° for this mesogen was obtained. Interestingly, for the thiophene mesogen in its smectic C phase at 210 °C, the 13C–1H dipolar coupling of the center ring methine carbon (2.11 kHz) is smaller than those of the side-wing phenyl ring carbons (2.75–3.00 kHz) which is a consequence of the different structures of the thiophene and the benzene rings. These values correspond to local order parameters of 0.85 for the center thiophene ring and 0.76 for the first side-wing phenyl ring and a bent-angle of 149.2°. Thus, the significant differences in the dipolar couplings and the order parameter values between different parts in the rigid core of the mesogens are a direct consequence of the nature of the center ring and the bent structure of the molecule. The present investigation thus highlights the ability of the 13C 2D-SLF technique to provide the geometry of the bent-core mesogens in a straightforward manner through the measurement of the 13C–1H dipolar couplings.

Herein, we report a novel solution processable fluorenone based small molecule with an Aggregation Induced Emission Enhancement (AIEE) property. In contrast to previous reports, the presence of the fluorenone moiety in FF triggers the AIEE property.