Exploration of silver borates with diverse low-dimensional anion frameworks by introducing monovalent heteroanions

Abstract

Borate crystals have gathered widespread focus due to their rich chemical structures and unique properties. Four centric Ag–borates, Ag₇B₉O₁₆(OH)₂(1), Ag₈B₈O₁₅Cl₂(2), Ag₈B₈O₁₅(OH)Br (3), and Ag₁₁B₈O₁₆I₃(4), with diverse B–O anion groups and frameworks have been successfully obtained by the mild hydrothermal methods. (1) and (4) have one-dimensional structures and contain {[B₁₁O₂₄(OH)₂]¹⁷⁻}_∞ and {[B₉O₂₀]¹³⁻}_∞ anion chains, respectively. (2) is 2D borate chloride with unprecedented [B₉O₂₁] (9B: 9 : 3[(3 : Δ + 2□)) fundamental building blocks. (3) is the first hydroxy-silver borate bromide and has novel B₈O₁₉(OH)] (8B: 3Δ5□ (2(3 : Δ + 2□) + (3□) + 1 : Δ)) fundamental building blocks. (2) and (3) possess the involuted 2D B–O framework with three types of channels, namely, 12-, 16- and 20-membered-ring (MR) channels. (4) represents the first one-dimensional structure in Ag–borate iodides. Complete experimental characterizations, structural features, optical properties, and theoretical calculation analyses of (1) to (4) are presented in this work. This work provided a reference for the syntheses of new borates with diverse boron–oxygen blocks.