Centrosymmetric Versus Noncentrosymmetric: Structural and Optical Studies on Inorganic‐Organic Hybrid Compounds of Bismuth Thiourea Iodide Resulting from Acid Effect

Abstract

A series of crystals of bismuth thiourea iodide (Bi[CS(NH2)2][CS(NH2)2H]2I5, Bi[CS(NH2)2H]3I6, and Bi[CS(NH2)2H]6I9) have been successfully grown from hydroiodic acid solution of thiourea and bismuth oxide by slow evaporation technique. Interestingly, they exhibit distinct crystal structures resulting from the proton effect on the cation coordination. Single crystal X‐ray diffraction reveals that they belong to three different crystal systems, P21/c for Bi[CS(NH2)2H]3I6, Rtrue3‾ c for Bi[CS(NH2)2H]6I9, and only Bi[CS(NH2)2][CS(NH2)2H]2I5 into a noncentrosymmetric space group Pca21, with unit cell dimensions of a=15.755(3) Å, b=9.3257(19) Å, c=14.855(3) Å, and Z=4. It is observed that thiourea molecules in Bi[CS(NH2)2][CS(NH2)2H]2I5 adopt a novel coordination mode with central ions in which they can be classified into two parts: the ones which coordinate with the central metal ions and the protonated ones which are isolated in the crystal lattice. Meanwhile, all the thiourea molecules are protonated in Bi[CS(NH2)2H]3I6, and the central Bi3+ coordinates only with I− as the acidity increases. Furthermore, central Bi3+ in Bi[CS(NH2)2H]6I9 employs the similar coordination mode with Bi[CS(NH2)2H]3I6. However, more thiourea molecules are protonated (up to 6 protonated thiourea molecules vs. 3 ones in Bi[CS(NH2)2H]3I6) as the acidity keeps increasing. It is noteworthy that acidity is confirmed to be the key factor of crystallization and crystallographic structures. Thermal analysis shows that all compounds have high thermal stability up to 180 oC. In addition, optical characterizations such as FTIR, diffuse reflectance spectra and NLO test are also conducted.

Yellow-Orange Emission in Sb3+-Doped Hexakis(thiocarbamidium) Hexabromoindium(III) Tribromide

“…The Br–In–Br angles are in the range of 87.69°–95.03° in (PMA) 3 InBr 6 and 88.08°–91.63° in (C 4 H 7 N 2 ) 4 [InBr 6 ]­[InBr 4 ]·2H 2 O. The bond lengths and bond angles in protonated thiourea for compounds 1 and 5 are in satisfactory agreement with those obtained previously. − …”

“…However, the effect of organic cations on the emission of 0D HMHs is relatively underexplored. Protonated primary, secondary, and tertiary amines as well as cations of quaternary ammonium and phosphonium bases are widely used as organic components of HMHs. , Much less studied are compounds containing S-protonated organic substances, for example, thiourea, the ability of which to form a singly charged S-protonated cation in strongly acidic solutions is well-known. , Thiourea and its derivatives are convenient and widely used nucleophiles for studying ligand substitution reactions in coordination chemistry due to their good solubility, neutral character, and high nucleophilicity and ability to form strong hydrogen bonds. , Among HMHs, only a few compounds containing protonated thiourea (CH 5 N 2 S + ) have been structurally characterized, for example, (CH 5 N 2 S) 2 (CH 5 N 2 ) 2 [PbI 4 ], (CH 5 N 2 S) 3 (CH 6 N) 2 [Pb 2 I 9 ], (CH 5 N 2 S) 3 [PbI 5 ], (CH 5 N 2 S)­(CH 6 N) 2 [Pb 2 I 7 ], (CH 5 N 2 S) 2 [OsX 6 ] (X = Cl, Br), (CH 5 N 2 S) 6 [BiI 6 ]­I 3 , and (CH 5 N 2 S) 6 [BiBr 6 ]­Br 3 . As in the case of N , N ′-dialkylthioureas, , thiourea compounds can have unique photophysical properties and find practical applications.…”

Novel zero-dimensional lead-free bismuth based perovskites: from synthesis to structural and optoelectronic characterization

“…The great amount of hydrogen bond donors avoids the iodide being shared, leading to a mononuclear bismuth complex, also observed for similar systems in the literature. [38][39][40][41] Although only one terpy unit is present in the asymmetric unit of this compound, half of them are doubly protonated (H 2 terpy 2+ ), and the other half singly protonated (Hterpy + ). In the difference Fourier map the second hydrogen atom was hardly found around the N1 or N3 atoms, suggesting that both can be protonated, and thus the occupancy of H1 and H3 was fixed as 0.25, for the sake of charge equilibrium.…”

Visualizing the alignment of lone pair electrons in La3AsS5Br2 and La5As2S9Cl3 to form an acentric or centrosymmetric structure

“…Understanding how to form acentric structures is very important for studying directional physical properties. 1–21…”

“…Compared with centrosymmetric solids, acentric solids draw growing attention from the research community due to the chance of studying directional physical properties such as second harmonic generation, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] nonreciprocal responses, [16][17][18][19][20][21] etc. From a chemistry perspective, various strategies have proved efficient to influence the creation of a noncentrosymmetric (NCS) structure, including incorporating second order Jahn-Teller distortion 22,23 and conjugated structure motifs such as distorted FeS 4 14, 24 or GeS 4 tetrahedra, 25,26 WO 5 , 27 LaO 6 Br 3 , 28 etc.…”