Acentric Organic–Inorganic Hybrid Halide [N(CH₃)₄]₂HgBr₂I₂ Featuring an Isolated [HgBr₂I₂]^2– Tetrahedron and Second-Order Nonlinearity

Abstract

A new hybrid compound [N(CH 3 ) 4 ] 2 HgBr 2 I 2 , obtained by a hydrothermal reaction, crystallized in the noncentrosymmetric space group P2 1 2 1 2 1 . Its structure contains an isolated asymmetric [HgBr 2 I 2 ] 2− tetrahedron with net polarization, connected by hydrogen bonds to form pseudo-one-dimensional chain structures. Moreover, its optical band gap, nonlinear optical (NLO) property, fluorescence property, and thermal property were characterized in detail. A rare high-temperature phase transition was observed in the compound. In addition, theoretical calculations were performed to elaborate the relation between electronic state, band structure, and their nonlinear optical response. These results indicate that [N(CH 3 ) 4 ] 2 HgBr 2 I 2 is a new potential candidate for future photoelectronic applications in fluorescence and nonlinear optics.

2,2′-Ethylenebis(1,3-dithiane) as a polydentate μ2-, μ4- and μ5-assembling ligand for the construction of sulphur-rich Cu(i), Hg(ii) and heterometallic Cu(i)/Hg(ii) coordination polymers featuring uncommon network architectures

“…A CSD survey revealed the existence of a zwitterionic 2-ammonioethylthiolato-linked Hg( ii ) coordination polymer bearing tribromomercurate units (refcode RASGEY), 67 but the occurrence of mixed-halide [HgIBr 2 ] − units is limited to ammonium salts such as [NMe 4 ][HgBr 2 I 2 ] (refcode ERIDUH) 68 or the molecular compound [HgBr 2 ( i )(PPh 2 CH 2 PPh 2 CH2C(O)Ph)] (refcode BOQVAF) 69 featuring a [HgIBr 2 P] − entity. It is worth mentioning that both the Hg–Br and Hg–I distances are very similar and range from 2.6107(5) to 2.6374(4) Å as was encountered in the molecular compound [HgBr 2 ( i )(PPh 2 CH 2 PPh 2 CH2C(O)Ph)], but the mean Hg–X distance of 2.6254 Å found in CP15 is much smaller than in the abovementioned molecular complex (mean Hg–X distance of 2.7051 Å).…”

Symmetry breaking of A3M2X9-type perovskite derivatives induced by polar quaternary ammonium cations: achieving efficient nonlinear optical properties

“…The birefringence (Δn) is 0.086 at 1064 nm, large enough to achieve phase matching for the SHG process, which is consistent with the experimental phase matchable behavior. Indeed, (BTA) 3 Bi 2 Cl 9 exhibits a much larger birefringence than most of the reported SHG-active hybrid metal halides such as [N(CH 3 ) 4 ] 2 HgBr 2 I 2 (0.031), 59 [N(CH 3 ) 4 GaBr 2 (0.021), 60 [N(CH 3 ) 4 ] InBr 2 (0.038), 60 and [N(C 2 H 5 ) 4 ]InCl 4 (0.01). 52…”

New Low-Dimensional Lead-Free Perovskite (2-AMP)2BiX7·H2O (X = Cl, Br) Crystals: Synthesis, Stability, and Nonlinear Optical Properties

“…Organic–inorganic hybrid metal halide perovskites, as an upcoming generation of functional materials, have currently intrigued tremendous interest due to their potential application in photovoltaics, optoelectronics, piezoelectrics, and ferroelectrics. − The abundant functionality of these materials is favored by their tunable structures, chemical compositions, morphologies, and dimensionality. Among them, the rapidly developing solar cells based on the light-absorbing materials organolead halides APbX 3 (where A is an organic cation, X is a halogen anion) have increased the power conversion efficiency more than 20% in merely several years. , However, the toxicity of lead to the environment and poor stability in the presence of moisture, heat, and extended light exposure have become key bottlenecks toward future commercialization and industrialization .…”