Structural and Photoluminescent Properties of Near‐Infrared Emissive Bis(2,3‐Diphenylbenzoquinoxalinato)(2‐Pyrazinecarboxylato)ridium(III)

Bi3(SeO3)3(Se2O5)F: A Polar Bismuth Selenite Fluoride with Polyhedra of Highly Distortive Lone Pair Cations and Strong Second-Harmonic Generation Response

“…Oxides with noncentrosymmetric (NCS) crystal structures, key solid-state materials in the field of second-order nonlinear optical (NLO) phenomena, have been of continuous interest in a variety of technologically important second-order applications such as optical communications, cascaded frequency conversions via second-harmonic generation (SHG), high energy photolithography, and medical lasers with new coherent light. − A proven an adequate method to increase the possibility of crystallizing functional materials with macroscopic NCS structures is introducing units with a highly distorted asymmetric moiety in the initial synthesis step . A well-known class of unsymmetrical building blocks is cations with stereochemically active lone pairs formed through second-order Jahn–Teller (SOJT) distortions. − Commonly observed lone pair cations with an asymmetric coordination mode in oxides include Sn 2+ , Pb 2+ , Sb 3+ , Bi 3+ , Se 4+ , Te 4+ , and I 5+ . − Interestingly, many lone pair cations exhibit unique polyhedral geometry such as trigonal pyramids and seesaws and reveal variable coordination numbers with oxide ligands.…”

Crystal structure of 2,3-bis(4-methylphenyl)benzo[g]quinoxaline

“…The use of long conjugated compounds as metal coordination ligands could be an approach to develop novel emitters toward red-shift emission up to near-infrared (NIR) wavelengths due to intersystem crossing (Ahn et al, 2009). Recently, 2,3-diphenylbenzoquinoxaline (dpbqH), a more -extended ligand than dpqH, has been introduced, and its iridium(III) complex showed bathochromic shifted emission at 763 nm (Kim et al, 2018). The aromatic rings in dpqH formed dimeric aggregates byinteractions, and these dimers interact via van der Waals interactions in the solid state (Cantalupo et al, 2006;Kim et al, 2018).…”

“…Recently, 2,3-diphenylbenzoquinoxaline (dpbqH), a more -extended ligand than dpqH, has been introduced, and its iridium(III) complex showed bathochromic shifted emission at 763 nm (Kim et al, 2018). The aromatic rings in dpqH formed dimeric aggregates byinteractions, and these dimers interact via van der Waals interactions in the solid state (Cantalupo et al, 2006;Kim et al, 2018). In this work, we have synthesized 2,3-di-ptolylbenzo[g]quinoxaline (dmpbqH) from the reaction of 4,4dimethylbenzil with 2,3-diaminonaphthalene, and investigated its single crystal structure.…”

Sr2Nb6O13F8·4H2O and Sr3Nb2O2F12·2H2O: A Variant of Three-Dimensional Tungsten Bronze and a Polar Molecular Oxide Fluoride

“…Different types of interstitial channels also exist in which various cations with distinct size and concentration reside. On the basis of their structures, tungsten bronzes can be further classified to perovskite-type, tetragonal, hexagonal, and intergrowth tungsten bronzes. − The tungsten bronze family has also been exhibiting many fascinating characteristics including magnetic, electric, optical, and electrochromic properties. − Especially, tungsten bronzes with noncentrosymmetric (NCS) structures constructed by alignment of the distorted octahedra have revealed very interesting characteristics such as piezoelectricity, second-harmonic generation (SHG), and ferroelectricity. − The structure-related properties, mainly originating from the out-of-center distortion of second-order Jahn–Teller distortive cations, might be widely applied to operations in transducers, frequency conversions, medical lasers, optical communications, and memories. − We have been very interested in exploring tungsten bronze materials containing Nb 5+ , with the d 0 transition-metal cation exhibiting large octahedral distortion and F – being the most electronegative anion that can generate a wide transparency. , Thus far, several tungsten bronze-type niobium oxyfluorides such as NaNb 2 O 5 F, SrK 2 Nb 5 O 14 F, K 1– x Nb 3 O 9– x F x (0 ≤ x < 1), K 3 (Nb 3 Ti 2 )­O 11 F 4 , KNb 2 O 5 F, etc., have been known. In this paper, we report two new hydrothermally synthesized strontium niobium oxyfluorides, Sr 2 Nb 6 O 13 F 8 ·4H 2 O and Sr 3 Nb 2 O 2 F 12 ·2H 2 O.…”