Search

Sulfate crystals typically exhibit minimal optical anisotropy due to the near‐zero polarizability anisotropy (δ) of [SO4]2− tetrahedra, arising from highly symmetrical electron clouds. Recent research sought to enhance δ via chemical modifications, such as fluorination. However, the resultant crystals often maintain subpar optical anisotropy, frequently with birefringence values below 0.1. In this study, we have uncovered that δ can be significantly strengthened by chemically tailoring the tetrahedral [SO4]2− with anisotropic π‐conjugated modules. This has been demonstrated by several newly proposed S−O‐Org (Org: π‐conjugated organic species) moieties, which show a sharp increase in δ based on theoretical computations. To further validate this experimentally, we synthesized and characterized six new 3‐pyridinesulfonate crystals with the formula A(3‐C5H4NSO3) ⋅ xH2O (A=Li, Ag, K, Rb, Cs, and NH4; x=0 and 1). Notably, these materials exhibit strong optical anisotropy, with birefringence values ranging from 0.240 to 0.312 at 546 nm. These values are approximately 23 to 145.5 times greater than those of corresponding sulfates, and they outperform a vast number of sulfate‐related optical materials, thus verifying the effectiveness of the proposed strategy. Furthermore, the title compounds exhibit diverse microstructure peculiarities influenced by the size and binding natures of the counter cations. [ABSTRACT FROM AUTHOR]

Four chiral coordination polymers (CPs), M[(S,S)‐C14H14N2O6] and M[(R,R)‐C14H14N2O6] (M=Zn or Cd), have been exclusively synthesized in high yields with the aid of newly designed chiral ligand under hydrothermal condition. The CPs crystallizing in the orthorhombic nonpolar space group, C2221, reveal three‐dimensional framework structures composed of MO4 tetrahedra and the corresponding homochiral linkers. Powder second‐harmonic generation (SHG) measurements indicate that the nonpolar CPs reveal very strong SHG efficiency of ca. 5–9 times that of KH2PO4 and exhibit type‐I phase‐matching behavior. Density functional theory calculations suggest that the unusually large SHG efficiency found from the nonpolar CPs should be attributable to the synergistic effect of polarizable metal cations and enhanced hyperpolarizability in the donor‐acceptor system originating from the hydrogen bonding in the coordinated linkers. [ABSTRACT FROM AUTHOR]

Keywords: Birefringence; Optical Anisotropy; Sulfate Crystals; TetrahedraA design strategy for significantly enhancing the polarizability anisotropy of isotropic tetrahedra in sulfate crystals is reported by Zhiyong Bai and Kang Min Ok in their Research Article (e202315311). This strategy involves chemically alternating tetrahedral [SO4]2− units with π‐conjugated organic groups. Experimental validation of the approach utilized 3‐pyridinesulfonate anion functional building blocks for crystal synthesis...By Zhiyong Bai and Kang Min OkReported by Author; Author [Extracted from the article]

Keywords: coordination compounds; hydrogen bonds; hyperpolarizability; nonpolar; second-harmonic generation EN coordination compounds hydrogen bonds hyperpolarizability nonpolar second-harmonic generation 20734 20734 1 09/08/21 20210913 NES 210913 B Systematisch synthetisierte b nicht-zentrosymmetrische, unpolare, chirale Koordinationspolymere zeigen eine ungewöhnlich effiziente Obertonbildung, was auf den synergistischen Effekt der polarisierbaren Metallkationen und die erhöhte Hyperpolarisierbarkeit im Donor-Akzeptor-System zurückzuführen ist, die von den robusten Wasserstoffbrücken in den koordinierten Linkern herrühren. Coordination compounds, hydrogen bonds, hyperpolarizability, nonpolar, second-harmonic generation Innentitelbild: Hydrogen-Bond-Driven Synergistically Enhanced Hyperpolarizability: Chiral Coordination Polymers with Nonpolar Structures Exhibiting Unusually Strong Second-Harmonic Generation (Angew. [Extracted from the article]

Enhancing anisotropy through the controlled arrangement of anionic groups is essential for improving the nonlinear optical (NLO) performance of non‐π‐conjugated NLO materials. In this study, we present the successful synthesis of the first examples of mixed alkali metal‐alkaline earth metal sulfamate materials, including noncentrosymmetric Cs2Mg(NH2SO3)4 ⋅ 4H2O (1), as well as centrosymmetric K2Ca(NH2SO3)4 (2) and Rb2Ca(NH2SO3)4 (3). All three compounds feature promising deep ultraviolet cut‐off edges, notably 1 with a cut‐off edge below 180 nm. The synergy of Cs+ and Mg2+ cations in 1 facilitated the successful alignment of polar [NH2SO3] tetrahedra in a uniform orientation. Remarkably, 1 stands as the sole instance among reported sulfamate compounds with a co‐parallel anionic arrangement, yielding a very large dipole moment compared to other non‐π‐conjugated NLO materials. Moreover, the substantial dipole moment of 1 yields an enhanced second harmonic generation response, approximately 2.3 times that of KH2PO4, and a large birefringence of 0.054 at 546.1 nm. The approach of regulating the arrangement of anionic groups using aliovalent cations holds promise for advancing the exploration of non‐π‐conjugated NLO materials. [ABSTRACT FROM AUTHOR]

To develop high‐performance nonlinear optical (NLO) materials for infrared (IR) applications, we have applied a rational element‐composition design strategy and investigated the unexplored PbO–PbCl2–PbI2 system. By doing so, we discovered a new polar lead mixed oxyhalide, Pb18O8Cl15I5, the first synthetic metal oxyhalide combining both Cl− and I−. Pb18O8Cl15I5 reveals an unprecedented structural feature with two different dimensional types of oxocentered Pb–O units, namely, [O4Pb8]8+ clusters and [OPb2]2+ chains. Centimeter‐sized single crystals of Pb18O8Cl15I5 have been successfully grown under ambient conditions. Remarkably, Pb18O8Cl15I5 satisfies all fundamental yet rigorous criteria for high‐performance IR NLO materials, exhibiting the widest IR transparency (up to 16.0 μm) among oxide‐based crystals, strong second‐harmonic generation response (1.05×AgGaS2), superior birefringence (0.086 at 636 nm), and a high laser‐induced damage threshold (8.5×AgGaS2). [ABSTRACT FROM AUTHOR]

To design high‐performance mid‐infrared (mid‐IR) nonlinear optical (NLO) materials, we have focused on the combination of a heavy metal lone pair cation, Pb2+ and mixed oxyhalides. A systematic investigation in PbO‐PbCl2‐PbBr2 system led us to discover the first examples of NLO lead mixed oxyhalides, namely, Pb13O6Cl4Br10, Pb13O6Cl7Br7, and Pb13O6Cl9Br5. All the reported materials have remarkably comprehensive properties including broad IR transparency (up to 14.0 μm), qualified second harmonic generation (SHG) responses (0.6–0.9×AgGaS2), wide band gaps (3.05–3.21 eV), and ease of crystal growth. Interestingly, a centimeter‐sized single crystal (2.9×1.3×0.5 cm3) of Pb13O6Cl9Br5 revealing a wide transparent range (0.384–14.0 μm) and high laser damage threshold (LDT) (14.6×AgGaS2) has been successfully grown in an open system. The study suggests that all the reported mixed oxyhalides are outstanding candidates for mid‐IR NLO materials. [ABSTRACT FROM AUTHOR]

The residual tumor after surgery is the most significant prognostic factor of patients with epithelial ovarian cancer. Near‐infrared (NIR) fluorescence‐guided surgery is actively utilized for tumor localization and complete resection during surgery. However, currently available contrast‐enhancing agents display low on‐target binding, unfavorable pharmacokinetics, and toxicity, thus not ideal for clinical use. Here we report ultrabright and stable squaraine fluorophores with optimal pharmacokinetics by introducing an asymmetric molecular conformation and surface charges for rapid transporter‐mediated cellular uptake. Among the tested, OCTL14 shows low serum binding and rapid distribution into cancer tissue via organic cation transporters (OCTs). Additionally, the charged squaraine fluorophores are retained in lysosomes, providing durable intraoperative imaging in a preclinical murine model of ovarian cancer up to 24 h post‐injection. OCTL14 represents a significant departure from the current bioconjugation approach of using a non‐targeted fluorophore and would provide surgeons with an indispensable tool to achieve optimal resection. [ABSTRACT FROM AUTHOR]

Discovering novel sulfate optical materials with strong second‐harmonic generation (SHG) and large birefringence is confronted by a great challenge attributed to the intrinsically weak polarizability and optical anisotropy of tetrahedral SO4 groups. Herein, two superior‐performing sulfate optical materials, namely, noncentrosymmetric Hg3O2SO4 and centrosymmetric CsHgClSO4 ⋅ H2O, have been successfully synthesized through the introduction of a highly polarizable d10 metal cation, Hg2+. The unique component layers in the reported compounds, [Hg3O2SO4]∞ layers in Hg3O2SO4 and [HgClSO4(H2O)]∞- layers in CsHgClSO4 ⋅ H2O, induce enlarged birefringence in each sulfate. Remarkably, Hg3O2SO4 exhibits a very large SHG response (14 times that of KH2PO4), which is the strongest efficiency among all the reported nonlinear optical sulfates. Detailed theoretical calculations confirm that the employment of highly polarizable Hg2+ is an effective strategy to design superior optical materials with large birefringence and strong SHG response. [ABSTRACT FROM AUTHOR]

Metal‐coordinated frameworks derived from small peptidic ligands have received much attention thanks to peptides' vast structural and functional diversity. Various peptides with partial conformational preferences have been used to build metal–peptide frameworks, however, the use of conformationally constrained β‐peptide foldamers has not been explored yet. Herein we report the first metal‐coordination‐mediated assembly of β‐peptide foldamers with 12‐helical folding propensity. The coordination of Ag+ to the terminal pyridyl moieties afforded a set of metal–peptide frameworks with unique entangled topologies. Interestingly, formation of the network structures was accompanied by notable conformational distortions of the foldamer ligands. As the first demonstration of new metal–peptide frameworks built from modular β‐peptide foldamers, we anticipate that this work will be an important benchmark for further structural evolution and mechanistic investigation. [ABSTRACT FROM AUTHOR]

An unprecedented example of a chiral phosphoric acid‐catalyzed atroposelective Pictet–Spengler reaction of N‐arylindoles is reported. Highly enantioenriched N‐aryl‐tetrahydro‐β‐carbolines with C−N bond axial chirality are obtained via dynamic kinetic resolution. The hydrogen bond donor introduced on the bottom aromatic ring, forming a secondary interaction with the phosphoryl oxygen, is essential to achieving high enantioselectivity. A wide variety of substituents are tolerable with this transformation to provide up to 98 % ee. The application of electron‐withdrawing group‐substituted benzaldehydes enables the control of both axial and point stereogenicity. Biological evaluation of this new and unique scaffold shows promising antiproliferative activity and emphasizes the significance of atroposelective synthesis. [ABSTRACT FROM AUTHOR]

NLO Materials. Deep‐ultraviolet transparent mixed metal sulfamates with enhanced nonlinear optical properties and birefringence are presented by Qun Jing, Kang Min Ok et al. in their Research Article (e202315434)...By Xuefei Wang; Xudong Leng; Yunseung Kuk; Jihyun Lee; Qun Jing and Kang Min OkReported by Author; Author; Author; Author; Author; Author [Extracted from the article]

Discovering new functional genes, designing perfect crystal structures, and developing high‐performance materials are the goals being pursued by scientists. Herein, the first antimony pyrophosphate, K2Sb(P2O7)F, possessing an optimal layered structure, is reported, where the perfect structural arrangement induces excellent optical properties. K2Sb(P2O7)F not only displays a sharply enhanced birefringence (0.157@546 nm) compared to the existing phosphate optical materials, but also exhibits a strong second‐harmonic generation response (4.0×KDP). Remarkably, a new bifunctional gene, the square‐pyramidal SbO4F group, was discovered, and a unique two‐dimensional arrangement of Cairo pentagonal tiling units was observed in inorganic compounds for the first time. [ABSTRACT FROM AUTHOR]

Innentitelbild: Lead Mixed Oxyhalides Satisfying All Fundamental Requirements for High-Performance Mid-Infrared Nonlinear Optical Materials (Angew. Keywords: crystal growth; metal mixed oxyhalides; mid-IR NLO materials; nonlinear optics EN crystal growth metal mixed oxyhalides mid-IR NLO materials nonlinear optics 7342 7342 1 04/24/20 20200504 NES 200504 B Die gemischten Bleioxyhalogenide b Pb SB 13 sb O SB 6 sb Cl SB 4 sb Br SB 10 sb , Pb SB 13 sb O SB 6 sb Cl SB 7 sb Br SB 7 sb und Pb SB 13 sb O SB 6 sb Cl SB 9 sb Br SB 5 sb , die passende Bandlücken ( I E i SB I g i sb ) und NLO-Koeffizienten ( I d i SB I ij i sb ) aufweisen, erfüllen alle fundamentalen Anforderungen an hochleistungsfähige nichtlineare mid-IR-Materialien. Crystal growth, metal mixed oxyhalides, mid-IR NLO materials, nonlinear optics. [Extracted from the article]

A novel noncentrosymmetric (NCS) polar fluoride sulfate, CsSbF2SO4, was obtained by ionothermal synthesis. A meticulously designed co‐substitution approach was used to successfully replace the [TiO6]8− and [PO4]3− functional groups in KTiOPO4 (KTP) with [SbO4F2]7− and [SO4]2− units, respectively. The structure of CsSbF2SO4 features a pseudo‐3D framework consisting of interconnected 1D [SbF2O2SO4]5− chains of corner‐sharing [SbO4F2]7− octahedra and [SO4]2− tetrahedra. The title compound exhibits a sharply enlarged band gap compared to its parent compound, KTP, benefitting from the introduction of F− ions and the displacement of Sb3+ cations. Second harmonic generation (SHG) measurements manifested that CsSbF2SO4 is phase‐matchable and revealed a strong SHG response of about 3.0 KH2PO4 (KDP), which is the highest value reported for any metal sulfate reported to date. The reported fluoride sulfate is a promising near ultraviolet (UV) nonlinear optical (NLO) material. [ABSTRACT FROM AUTHOR]

Abstract: A nonlinear optical (NLO) carbonatoperoxovanadate, Rb3VO(O2)2CO3, was synthesized through a simple solution‐evaporation method in phase‐pure form. Single‐crystal X‐ray diffraction revealed that the structure of Rb3VO(O2)2CO3 consists of important noncentrosymmetric (NCS) chromophores, that is, π‐delocalized (CO3)2− groups, a second‐order Jahn–Teller (SOJT) distortive V5+ cation, and π‐localized distorted O22− groups, as well as charge‐balancing polarizable Rb+ ions. The powder second‐harmonic generation (SHG) measurements indicated that Rb3VO(O2)2CO3 is phase‐matchable (Type I) and exhibits a remarkably strong SHG response circa 21.0 times that of potassium dihydrogen phosphate (KDP), which is the largest efficiency observed among carbonate NLO materials. First‐principles calculation analysis suggests that the extremely large SHG response of Rb3VO(O2)2CO3 is attributed to the synergistic effect of the cooperation of all the constituting NCS chromophores. [ABSTRACT FROM AUTHOR]

A meticulously designed, polar, non-centrosymmetric lead borate chloride, Pb2BO3Cl, was synthesized using KBe2BO3F2 (KBBF) as a model. Single-crystal X-ray diffraction revealed that the structure of Pb2BO3Cl consists of cationic [Pb2(BO3)]+ honeycomb layers and Cl− anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2BO3Cl indicated that the title compound is phase-matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near-UV to the mid-IR region. [ABSTRACT FROM AUTHOR]

In their Correspondence, Sergey V. Krivovichev and Luca Bindi argue that the novel excellent nonlinear optical material antimony pyrophosphate, K2Sb(P2O7)F, reported in our Research Article published in this journal belongs to the fresnoite Ba2[TiO(Si2O7)] group and its structure is not novel in terms of either topology or local coordination geometry around Sb3+ cations. We clarify that the statements regarding structural features of our original paper are valid in context. [ABSTRACT FROM AUTHOR]

Coordination polymers, foldamers, metal-peptide frameworks Keywords: coordination polymers; foldamers; metal-peptide frameworks EN coordination polymers foldamers metal-peptide frameworks 1 1 1 12/29/21 20220103 NES 220103 B Foldamere b In ihrem Forschungsartikel (e202108364) berichten Sunbum Kwon, Hee-Seung Lee et al. über die konformative Adaption von -Peptidfoldameren zur Bildung von Metall-Peptid-Gerüststrukturen. Frontispiz: Conformational Adaptation of -Peptide Foldamers for the Formation of Metal-Peptide Frameworks. [Extracted from the article]