Variable Asymmetric Chains in Transition Metal Oxyfluorides: Structure-Second-Harmonic-Generation Property Relationships

Prediction of Large Second Harmonic Generation in the Metal-Oxide/Organic Hybrid Compound CuMoO3(p2c)

Noncentrosymmetric hybrid framework (HF) materials are an important system in discovering new practical second-order nonlinear optical materials. We calculated the second harmonic generation (SHG) response of a noncentrosymmetric (NCS) organic–inorganic HF compound, CuMoO3(p2c) (p2c = pyrazine-2-carboxylate) to find that it exhibits the largest SHG response among all known NCS HF materials with one-dimensional helical chains. Further atom response theory analysis revealed that the metal atoms Cu and Mo contribute much more strongly than do nonmetal atoms in determining the strength of the SHG response, which is a novel example in nonlinear optical materials known to date.

Ba(B2OF3(OH)2)2 with well-ordered OH/F anions and a unique B2OF3(OH)2 dimer

A new centimetre-scale fluorooxoborate crystal Ba(B₂OF₃(OH)₂)₂, with well-ordered OH/F units and a new dimer containing BOF₃ units, has been fabricated.

Influence of structure-directing polyhedra and heterocyclic ligands on the chain structures and O/F ordering in a series of zinc vanadium oxyfluorides

Transition metal oxyfluorides composed of distinctive structure-directing vanadium oxyfluoride polyhedra and highly polarizable Zn²⁺ cations were synthesized by mild hydrothermal reactions.

Ligand geometry directs the packing and symmetry of one-dimensional helical motifs in lead oxide naphthoates and biphenylcarboxylates

The orientation of a ligand's bulk with respect to the coordinating group controls packing and symmetry in new lead oxide carboxylates.

Histidinium-Driven Chirality Control of Self-Assembled Hybrid Molybdenum Oxyfluorides

Exploring macroscopic chiral materials with extended structures has become an important and fundamental topic in chemistry. To systematically control the chirality of novel organic-inorganic frameworks, histidinium-based cationic structure-directing agents containing specific chiral information are introduced. In this way, two chiral compounds, [(l-hisH₂ )MoO₂ F₄ ]₃ ⋅H₂ O (L) and [(d-hisH₂ )MoO₂ F₄ ]₃ ⋅H₂ O (D), and an achiral oxyfluoride, (l/d-hisH₂ )MoO₂ F₄ (LD) (his=histidine, C₆ H₉ N₃ O₂ ) have been successfully self-assembled by a slow evaporation method. The structures of these compounds are composed of histidinium cations and distorted [MoO₂ F₄ ]^2- octahedra. Surprisingly, the histidinium cations not only control macroscopic chirality, but also induce O/F ordering in MoO₂ F₄ octahedra through hydrogen-bonding interactions. Compounds L and D crystallize in the extremely rare polar space group P1, and exhibit positive second harmonic generation (SHG) signals attributable to a net moment originating from the MoO₂ F₄ groups. Solid-state circular dichroism (CD) spectra indicate that the MoO₂ F₄ units templated by histidinium cations are chirally aligned through ionic interactions. Crystallization processes influenced by the chirality of the reported materials are also discussed herein.

Cs2CdV2O6Cl2 and Cs3CdV4O12Br: two new non-centrosymmetric oxyhalides containing d0 and d10 cations and exhibiting second harmonic generation activity

Two new non-centrosymmetric oxyhalides containing d⁰ and d¹⁰ cations and exhibiting strong second harmonic generation activity.