Cocrystals of 2-Aminopyrimidine with Boric Acid—Crystal Engineering of a Novel Nonlinear Optically (NLO) Active Crystal

Abstract

Crystal engineering of novel materials for nonlinear optics (NLO) based on 2-aminopyrimidine yielded two molecular cocrystals with boric acid-trigonal (P3 2 21 space group) 2-aminopyrimidineboric acid (3/2) and monoclinic (C2/c space group) 2-aminopyrimidine-boric acid (1/2). In addition to crystal structure determination by single crystal X-ray diffraction, the cocrystals were characterized by powder X-ray diffraction and vibrational spectroscopy (FTIR and FT Raman). Large single crystals of the non-centrosymmetric cocrystal 2-aminopyrimidine-boric acid (3/2) were grown to study the optical properties and determine the second harmonic generation (SHG) efficiency (using 800 nm fundamental laser line) of powder samples.

Driving Nonlinear Optical Activity with Dipolar 2-Aminopyrimidinium Cations in (C4H6N3)+(H2PO3)−

“…2APP is stable in air for at least 6 months and thermally stable up to 166 °C before decomposition by losing cal. 19.8% (obv. 20.0%) weight of 1 mole of NH 3 and H 2 O each (Figure 4b).…”

Inorganic Salts of N-phenylbiguanidium(1+)—Novel Family with Promising Representatives for Nonlinear Optics

“…The results clearly confirm the possibility of SHG phase matching for this salt. The small discrepancy between the two smallest fractions can be explained by problems in preparing powders with isometric particles and effective control of the particle size in the family of soft molecular crystals, which are quite common (e.g., [22,39,40]).…”

“…Furthermore, implementing a suitable hydrogen-bonded counter molecule/ion can counteract undesirable tendencies of the selected organic molecules (cations) to form centrosymmetric pairs. The concept [18], based on the use of chains/networks formed by inorganic hydrogenbonded anions (i.e., anions acting as hydrogen bonds donors), was successfully applied to several salts and cocrystals prepared in our laboratory, e.g., references [19][20][21][22]. However, the presence of deprotonated anions acting as strict hydrogen bond acceptors can also lead to the formation of promising non-centrosymmetric phases, e.g., references [19,[23][24][25].…”

Cis‐Trans Isomerism Inducing Cocrystal Polymorphism with Thermally Activated Delayed Fluorescence and Two‐Photon Absorption

“…[ 5 ] Among these interactions, CT interactions usually occur in the heterodimeric system, consisting of two different components: electron‐rich donor and electron‐deficient acceptor. [ 2 ] The type of conformer components and the strength of CT interactions fundamentally determine the physicochemical properties of cocrystal, including not only the single‐component properties but also some unexpected properties beyond those of single‐components, such as nonlinear optics (NLO), [ 6 ] ambipolar charge transportation, [ 7 ] high‐temperature superconductivity, [ 8 ] room‐temperature conductivity, [ 9 ] photoconductivity, [ 10 ] ferroelectricity, [ 11 ] and photothermal conversion. [ 12 ] In most cases, the planar donor and acceptor are preferentially formed into cocrystal as a result of the cooperative interaction between CT and π–π stacking (or hydrogen/halogen bonding).…”