{"title":"[C<sub>3</sub>H<sub>7</sub>N<sub>6</sub>]<sub>3</sub>[B<sub>3</sub>O<sub>5</sub>(OH)<sub>2</sub>] and [C<sub>3</sub>H<sub>8</sub>N<sub>6</sub>]<sub>4</sub>[B<sub>12</sub>O<sub>19</sub>(OH)<sub>6</sub>]: Two Melamine Borates with Large Birefringence.","authors":"Ya-Lan Deng, Chun-Li Hu, Jiang-Gao Mao","doi":"10.1021/acs.inorgchem.4c04170","DOIUrl":null,"url":null,"abstract":"<p><p>The π-conjugated [C<sub>3</sub>H<sub>6+<i>x</i></sub>N<sub>6</sub>]<sup><i>x</i>+</sup> (<i>x</i> = 0-3) cations are good functional groups, which are widely employed in the preparations of nonlinear optical (NLO) and birefringent materials due to their high hyperpolarizability and optical anisotropy. In this paper, the first melamine hydroxyborate [C<sub>3</sub>H<sub>7</sub>N<sub>6</sub>]<sub>3</sub>[B<sub>3</sub>O<sub>5</sub>(OH)<sub>2</sub>] (<b>MelBO-I</b>) was synthesized by the boric acid melting method under the molar ratio of H<sub>3</sub>BO<sub>3</sub>:C<sub>3</sub>H<sub>6</sub>N<sub>6</sub> = 1:1. <b>MelBO-I</b> (<i>P</i>2<sub>1</sub>/<i>c</i>) exhibits a two-dimensional (2D) {[C<sub>3</sub>H<sub>7</sub>N<sub>6</sub>]<sub>3</sub>[B<sub>3</sub>O<sub>5</sub>(OH)<sub>2</sub>]}<sub>∞</sub> layer composed of [C<sub>3</sub>H<sub>7</sub>N<sub>6</sub>]<sup>+</sup> cations and [B<sub>3</sub>O<sub>5</sub>(OH)<sub>2</sub>]<sup>3-</sup> anions interconnected via hydrogen bonds. <b>MelBO-I</b> exhibits significant birefringence (Δ<i>n</i> = 0.286@546 nm). Under the molar ratio of H<sub>3</sub>BO<sub>3</sub>/C<sub>3</sub>H<sub>6</sub>N<sub>6</sub> = 3:1, [C<sub>3</sub>H<sub>8</sub>N<sub>6</sub>]<sub>4</sub>[B<sub>12</sub>O<sub>19</sub>(OH)<sub>6</sub>] (<b>MelBO-II</b>) was isolated. In <b>MelBO-II</b> (<i>P</i>2<sub>1</sub>), highly polymerized [B<sub>12</sub>O<sub>19</sub>(OH)<sub>6</sub>]<sup>8-</sup> groups form a 3D network through hydrogen bonding, featuring 1D tunnels of 8-membered and 16-membered rings filled by [C<sub>3</sub>H<sub>8</sub>N<sub>6</sub>]<sup>2+</sup> cations. <b>MelBO-II</b> is the first noncentrosymmetric (NCS) bifunctional melamine borate with a moderate SHG response (0.4 × KDP) and large birefringence (Δ<i>n</i> = 0.285@546 nm). The results indicate that incorporating [C<sub>3</sub>H<sub>6+<i>x</i></sub>N<sub>6</sub>]<sup><i>x</i>+</sup> (<i>x</i> = 0-3) cations into borate can effectively induce birefringence. A high concentration of boric acid promotes the formation of large boric acid cluster anions and facilitates the transformation from the CS to NCS structure.</p>","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganic Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.inorgchem.4c04170","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
The π-conjugated [C3H6+xN6]x+ (x = 0-3) cations are good functional groups, which are widely employed in the preparations of nonlinear optical (NLO) and birefringent materials due to their high hyperpolarizability and optical anisotropy. In this paper, the first melamine hydroxyborate [C3H7N6]3[B3O5(OH)2] (MelBO-I) was synthesized by the boric acid melting method under the molar ratio of H3BO3:C3H6N6 = 1:1. MelBO-I (P21/c) exhibits a two-dimensional (2D) {[C3H7N6]3[B3O5(OH)2]}∞ layer composed of [C3H7N6]+ cations and [B3O5(OH)2]3- anions interconnected via hydrogen bonds. MelBO-I exhibits significant birefringence (Δn = 0.286@546 nm). Under the molar ratio of H3BO3/C3H6N6 = 3:1, [C3H8N6]4[B12O19(OH)6] (MelBO-II) was isolated. In MelBO-II (P21), highly polymerized [B12O19(OH)6]8- groups form a 3D network through hydrogen bonding, featuring 1D tunnels of 8-membered and 16-membered rings filled by [C3H8N6]2+ cations. MelBO-II is the first noncentrosymmetric (NCS) bifunctional melamine borate with a moderate SHG response (0.4 × KDP) and large birefringence (Δn = 0.285@546 nm). The results indicate that incorporating [C3H6+xN6]x+ (x = 0-3) cations into borate can effectively induce birefringence. A high concentration of boric acid promotes the formation of large boric acid cluster anions and facilitates the transformation from the CS to NCS structure.
期刊介绍：
Inorganic Chemistry publishes fundamental studies in all phases of inorganic chemistry. Coverage includes experimental and theoretical reports on quantitative studies of structure and thermodynamics, kinetics, mechanisms of inorganic reactions, bioinorganic chemistry, and relevant aspects of organometallic chemistry, solid-state phenomena, and chemical bonding theory. Emphasis is placed on the synthesis, structure, thermodynamics, reactivity, spectroscopy, and bonding properties of significant new and known compounds.
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