Mixed halide/oxoanion-templated frameworks

A tetrahedral tetra-amidinium compound 14+ was crystallised in the presence of a range of anions (Cl−, Br−, NO3−, oxalate2−) giving a range of interesting solid state structures assembled through amidinium⋯anion hydrogen bonding interactions. Mixing the chloride or bromide salts of 14+, i.e.1·4Cl or 1·4Br, and inorganic oxalate salts in water gave crystals of ordered three-dimensional network structures containing both oxalate and halide anions. These interesting “mixed anion” frameworks exhibit high thermal stability to heat and hydrolysis but are not significantly porous. Importantly, these materials are significantly more robust than the analogous terephthalate-containing framework materials.NGW thanks the Australian Research Council for a Discovery Early Career Researcher Award fellowship (DE170100200)

Easily-prepared Hydroxy-containing Receptors Recognize Anions in Aqueous Media

Despite their ready availability, O−H groups have received relatively little attention as anion recognition motifs. Here, we report two simple hydroxy‐containing anion receptors that are prepared in two facile steps followed by anion exchange, without the need for chromatographic purification at any stage. These receptors contain a pyridinium bis(amide) motif as well as hydroxyphenyl groups, and bind mono‐ and divalent anions in 9:1 CD3CN:D2O, showing a selectivity preference for sulfate. Notably, a “model” receptor that does not contain hydroxy groups shows only very weak sulfate binding in this competitive solvent mixture. In the solid state, X‐ray crystallographic studies show that the receptors tend to form extended assemblies with anions; however, 1H and DOSY NMR studies as well as molecular dynamics simulations show that only 1:1 complexes are present in solution. Molecular dynamics simulations suggest that one of the receptors suffers from competing intramolecular hydrogen bonding, while another binds partially‐hydrated anions, with the receptor's O−H groups forming hydrogen bonds to water molecules within the anion's coordination sphere.We thank Michael McTigue (Australian National University) for contributing to preliminary synthetic work, and the Australian Research Council for supporting this research (Discovery Early Career Research Award, DE170100200)

Theoretical and experimental study of the protonated 2,4,6-tri(2-pyridyl)-1,3,5-triazine [TPTZH 2 ] 2+

The reaction between 2,4,6-tri(2-pyridyl)-1,3,5-triazine (TPTZ) and sulfuric acid in the presence of NH4PF6 yielded crystals of [TPTZH2](PF6)2·H2O, characterized by spectroscopic methods and single-crystal X-ray diffraction. The structural data indicat

Dynamic Permutational Isomerism in a closo-Cluster

Permutational isomers of trigonal bipyramidal [W2RhIr2(CO)9(η(5)-C5H5)2(η(5)-C5HMe4)] result from competitive capping of either a W2Ir or a WIr2 face of the tetrahedral cluster [W2Ir2(CO)10(η(5)-C5 H5)2] from its reaction with [Rh(CO)2(η(5)-C5HMe4)]. The permutational isomers slowly interconvert in solution by a cluster metal vertex exchange that is proposed to proceed by Rh-Ir and Rh-W bond cleavage and reformation, and via the intermediacy of an edge-bridged tetrahedral transition state. The permutational isomers display differing chemical and physical properties: replacement of CO by PPh3 occurs at one permutational isomer only, while the isomers display distinct optical power limiting behavior.We thank the Australian Research Council (Discovery Grant to M.G.H. and M.P.C., ARC Australian Research Fellowship to M.P.C.) for financial support. J.F. was the recipient of a China Scholarship Council ANU Postgraduate Scholarship

Exceptionally large two- and three-photon absorption cross-sections by OPV organometalation

Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12 500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 × 10⁻⁷⁶ cm⁶s² at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an “organometalation” approach to NLO-efficient organic materialsWe thank the Australian Research Council (ARC), the National Natural Science Foundation of China (51432006), the Chinese Government Ministry of Education, the Chinese Government State Administration of Foreign Experts Affairs (111 Project: B13025), and the National Science Centre of Poland (grant 2013/10/A/ST4/00114) for financial support. M. P. C. thanks the ARC for an Australian Research Fellowship and C. Q. thanks CONICYT (Chile) for a Chile PhD Scholarship Abroad

Syntheses and Optical Properties of Azo-Functionalized Ruthenium Alkynyl Complexes

We thank the Australian Research Council (ARC), the National Natural Science Foundation of China (51432006), and the Chinese Government Ministry of Education and State Administration of Foreign Experts Affairs (111 Project: B13025) for financial support. M.P.C. thanks the ARC for an Australian Research Fellowship

Synthesis, Optical, Electrochemical, and Theoretical Studies of Dipolar Ruthenium Alkynyl Complexes with Oligo(phenylenevinylene) Bridges

We thank the Australian Research Council (ARC), the National Natural Science Foundation of China (51432006), the Chinese Government Ministry of Education, and the Chinese Government State Administration of Foreign Experts Affairs (111 Project: B13025). M.P.C. thanks the ARC for an Australian Research Fellowship and C.Q. thanks CONICYT (Chile) for a Chile PhD Scholarship Abroad

Linear Optical, Quadratic and Cubic Nonlinear Optical, Electrochemical, and Theoretical Studies of "Rigid-Rod" Bis-Alkynyl Ruthenium Complexes

The syntheses of oligo(p‐phenylene ethynylene)s (OPEs) end‐functionalized by a nitro acceptor group and with a ligated ruthenium unit at varying locations in the OPE chain, namely, trans‐[Ru{(C≡C‐1,4‐C6H4)nNO2}(C≡CR)(dppe)2] (dppe=1,2‐bis(diphenylphosphino)ethane; n=1, R=1,4‐C6H4C≡C‐1,4‐C6H4C≡CPh, 1,4‐C6H4NEt2; n=2, R=Ph, 1,4‐C6H4C≡CPh, 1,4‐C6H4C≡C‐1,4‐C6H4C≡CPh, 1,4‐C6H4NO2, 1,4‐C6H4NEt2; n=3, R=Ph, 1,4‐C6H4C≡CPh), are reported. Their electrochemical properties were assessed by cyclic voltammetry, their linear optical properties and quadratic and cubic nonlinear optical properties were assayed by UV/Vis/NIR spectroscopy, hyper‐Rayleigh scattering studies employing nanosecond pulses at 1064 nm, and broad spectral range Z‐scan studies employing femtosecond pulses, respectively, and their linear optical properties and vibrational spectroscopic behavior in the formally RuIII state was examined by UV/Vis/NIR and IR spectroelectrochemistry, respectively. The potentials of the metal‐localized oxidation processes are sensitive to alkynyl‐ligand modification, but this effect is attenuated on π‐bridge lengthening. Computational studies employing time‐dependent density functional theory were undertaken on model complexes, with a 2D scan revealing a soft potential‐energy surface for intra‐alkynyl‐ligand aryl‐ring rotation; this is consistent with the experimentally observed blueshift in optical absorption maxima. Quadratic optical nonlinearities are significant and cubic NLO coefficients for these small complexes are small. The optimum length of the alkynyl ligands and the ideal metal location in the OPE to maximize the key coefficients have been defined.We thank the Australian Research Council, the Fund for Scientific Research–Flanders (FWO-Vlaanderen; FWO G.0312.08), and the Katholieke Universiteit Leuven (GOA/2006/03) for financial support, and Yuwen Wu (ANU) for providing a crystal of 14 suitable for the X-ray diffraction study

Nonlinear optical properties of meso-Tetra(fluorenyl)porphyrins peripherally functionalized with one to four ruthenium alkynyl substituents

The synthesis of a series of four porphyrin derivatives based on a meso-tetrafluorenylporphyrin core functionalized with one to four trans-chlorobis(dppe)ruthenium alkynyl units (dppe = 1,2-bis(diphenylphosphino)ethane) at the periphery, together with cyclic voltammetry (CV) and UV–Vis absorption and emission spectroscopy studies, are reported. In these multipolar assemblies, the organoruthenium endgroups are potential electron-donors and the central porphyrin core is a potential electron-acceptor. The third-order nonlinear optical (NLO) responses have been assessed by Z-scan, revealing that these extended π-networks incorporating polarizable organometallic units behave as nonlinear absorbers in the near-IR range. The role of the peripheral transition metal centers on the third-order NLO properties is discussed

Organometallic complexes for nonlinear optics.66. Synthesis and quadratic nonlinear optical studies of trans-[Ru{C=C{2,5-C4H2S-( E )-CH=CH}n-2,5-C4H2S(NO2 )}Cl(dppe)2](n1/40-2)

Oligo(2,5-thienylenevinylene)s (OTVs) end-functionalized with a ligated ruthenium alkynyl unit as adonor and a nitro as acceptor, namelytrans-[Ru{C^C-2,5-C4H2S(NO2)}Cl(dppe)2](Ru1T),trans-[Ru{C^C-2,5-C4H2S-(E)-CH]CH-2,5-C4H2S(NO2)}Cl(dppe)2](Ru2T), andtrans-[Ru{C^C-2,5-C4H2S-(E)-CH]CH-2,5-C4H2S-(E)-CH]CH-2,5-C4H2S(NO2)}Cl(dppe)2](Ru3T), have been synthesized, their elec-trochemical properties have been assessed by cyclic voltammetry (CV), their linear optical and quadratic nonlinear optical (NLO) properties have been assayed by UVeviseNIR spectroscopy and hyper-Rayleighscattering studies at 1300 nm, respectively, and their linear optical properties in the formally RuIII state have been examined by UVeviseNIR spectroelectrochemistry. The data for Ru1T-Ru3Thave beencompared to those of the oligo(p-phenylenevinylene) (OPV) analoguestrans-[Ru(C^C-1,4-C6H4NO2)Cl(dppe)2](Ru1P),trans-[Ru{C^C-1,4-C6H4-(E)-CH]CH-1,4-C6H4NO2}Cl(dppe)2](Ru2P), andtrans-[Ru{C^C-1,4-C6H4-(E)-CH]CH-1,4-C6H4-(E)-CH]CH-1,4-C6H4NO2}Cl(dppe)2](Ru3P). The RuII/IIIoxidationpotentials decrease on proceeding fromRu1TtoRu3T, while the wavelength of the UVevislmaxbandincreases on proceeding fromRu1TtoRu2T, but thereafter decreases on further progression toRu3T, similar trends to those seen proceeding fromRu1PtoRu3P. The quadratic nonlinearityb1300 increases on OTV lengthening from Ru1TthroughRu2TtoRu3T; the data are significantly larger than those of the Ru1PeRu3Panalogues which peak atRu2P. The formally RuIIIcomplexes exhibit low-energy bands thatred-shift significantly on proceeding fromRu1TtoRu3T. Computational studies employing time-dependent density functional theory were undertaken on model complexes to rationalize the optical observations and explore the impact of further OTV bridge lengthening. Computational studies on modelcomplexesRu1T′-Ru6T′are consistent with decreasing contributions of the electron donor (ligated Ru) and acceptor (NO2) groups to the HOMO and LUMO, respectively, up n-bridge lengthening.btotvalues increase on progression fromRu1T′toRu3T′, but thereafter further bridge lengthening affords little further increase in b-tot, consistent with a saturation in quadratic NLO response.We thank the Australian Research Council (ARC: DP170100408),the National Natural Science Foundation of China (51432006), theChinese Government Ministry of Education, and the Chinese Gov-ernment State Administration of Foreign Experts Affairs (111 Proj-ect: B13025). J. D. thanks the China Scholarship Council and theAustralian National University for a CSC-ANU PhD Scholarship