Rapid on-site measurements of arsenic (As) are essential for the timely remediation of As-contaminated groundwater for both municipal and emergency response applications. Current field tests suffer from either complicated end-user instructions or a lack of accuracy and specificity. The system presented here combines a whole-cell bacterial biosensor with an electrochemical measurement that provides enhanced accuracy and signal intensity compared to traditional bacterial-detection approaches. When integrated within a customized hardware system, this whole-cell sensor demonstrated excellent specificity and sensitivity. This fast, sensitive, and easy-to-use approach is a viable alternative for on-site arsenic testing.

The synthesis and characterization of a series of 3- or 4-substituted 1,8-naphthalic anhydride compounds, and their organophosphorus analogues, bearing a cyclic diketophosphanyl moiety, are reported.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Fourteen new dipolar cations have been synthesized, containing methoxy or tertiary amino electron donor groups attached to helquat (Hq) acceptors. These Hq derivatives have been characterized as their TfO- salts by using various techniques including NMR and electronic absorption spectroscopies. UV-vis spectra show intense, relatively low energy absorptions with λmax ≈ 400-600 nm, attributable to intramolecular charge-transfer (ICT) excitations. Single-crystal X-ray structures have been solved for two of the chromophores, one as its PF6- salt, revealing centrosymmetric packing arrangements (space groups Pbca and P1̅). Molecular quadratic nonlinear optical (NLO) responses have been determined directly by using hyper-Rayleigh scattering (HRS) with a 800 nm laser, and indirectly via Stark (electroabsorption) spectroscopy for the low energy absorption bands. The obtained static first hyperpolarizabilities β0 range from moderate to large: (9-140) × 10-30 esu from HRS in MeCN and (44-580) × 10-30 esu from the Stark data in PrCN. The magnitude of β0 increases upon either extending the π-conjugation length or replacing a methoxy with a tertiary amino electron donor substituent. Density functional theory (DFT) and time-dependent DFT calculations on selected tertiary amino chromophores confirm that the low energy absorptions have ICT character. Relatively good agreement between the simulated and experimental UV-vis absorption spectra is achieved by using the CAM-B3LYP functional with the 6-311G(d) basis set. The βtot values predicted by using DFT at the same level of theory are large ((472-1443) × 10-30 esu in MeCN). Both the theoretical and experimental results show that para-conjugation between Hq and electron donor fragments is optimal, and enlarging the Hq unit is inconsequential with respect to the molecular quadratic NLO response.

We report two unprecedent alkynyl bridging cyclometalated clusters [Ir2M2(ppy)4(μ-C[triple bond, length as m-dash]CC6H4-OMe3)4] where M is Ag (2) and Cu (3), which display distinctive luminescence properties. While 2 features a green phosphorescence/electroluminescence nature located at the ppy ligands ((3)LC), 3 shows an orange emission confined to the metals and alkynyl groups having a mixed (3)L'C/(3)L'MCT/(3)MMCT (L' = alkynyl) nature.

Helquat dyes combine a cationic hemicyanine with a helicene-like motif to form a new blueprint for chiral systems with large and tunable nonlinear optical (NLO) properties. We report a series of such species with characterization, including determination of static first hyperpolarizabilities β0 via hyper-Rayleigh scattering and Stark spectroscopy. The measured β0 values are similar to or substantially larger than that of the commercial chromophore E-4'-(dimethylamino)-N-methyl-4-stilbazolium. Density functional theory (DFT) and time-dependent DFT calculations on two of the new cations are used to probe their molecular electronic structures and optical properties. Related molecules are expected to show bulk second-order NLO effects in even nonpolar media, overcoming a key challenge in developing useful materials.

The compounds 4,4'-dicyano-2,2'-bipyridyl (dcbpy), 4,4'-bis(4-cyanophenyl)-2,2'-bipyridyl (bcpbpy), 4,4'-bisRE)-2-(4-cyanophenyl)viny1]-2,2'-bipyridyl (bcpvbpy), and 4,4'-bis[(E)-2-(4-pyridyl)vinyl]-2,2'-bipyridyl (bpvbpy) are used to prepare nine new complexes with fac{ReI(CO)(3)(L)}(n+) (L = Cl-, pyridine (py), or 4-yanopyridine (cpy)) centers. The cationic complexes are isolated as their OTt- salts. These new monometallic species are studied together with the known fac-(ReCl)-Cl-I(CO)(3)(qpy) (qpy = 4,4':2',2 '':4 '',4'''-quaterpyridyl) (de Wolf, P.; et al. Inorg. Chim. Acta 2003, 355, 280-285). Coordination of {Ru-II(NH3)(5)}(2+)centers to the peripheral N atoms, of fac-(ReCl)-Cl-I(CO)(3)(qpy) and fac-[Re-I(CO)(3)(bcpbpy)(py)(+) affords heterotrimetallic complexes that are isolated as their PF6- alts. Single-crystal X-ray structures are reported for the solvates fac-(ReCl)-Cl-I(CO)(3)(dcbpy)center dot Me2CO, fac-[(ReCl)-Cl-I(CO)(3)(dcbpy) (MeCN)]OTf center dot PhMe, fac-[(ReCl)-Cl-I(CO)(3)(dcbpy) OTf center dot(dcbpy)(cpy)]OTIO.SMe2CO, fac-(ReCl)-Cl-I(CO)(3)(bcpbpy)-0.513hMe, and fac-[(ReCl)-Cl-I(CO)(3)(bcpbpy)(MeCN)OTf MeCN. Cyclic voltammetry reveals irreversible Re-II/I processes in all cases, while the trimetallic compounds show a reversible two-electron Ru-III/(II) oxidation wave. Ligand-based reductions are generally irreversible, but reversible waves are observed for the dcbpy complexes. Electronic absorption spectra show strong d -> pi* metal-to-ligand charge-transfer (MLCT) and intraligand pi -> pi* absorptions. The Ru-II-based MLCT bands have lower energies and higher intensities than the ReI-based ones. The monometallic species emit weakly in the red/NIR region (lambda(em) = 594-732 nm; phi = 0.6-8.1%) when excited at 350-520 nm. Molecular first hyperpolarizabilities beta for the trimetallic complex salts are measured in MeCN solutions via the hyper-Rayleigh scattering technique at 1064 nm. Stark (electroabsorption)_ spectroscopic studies on the low-energy MLCT bands in frozen PrCN allow the indirect, estimation of static first hyperpolarizabilities beta(0). The trimetallic complexes have relatively large beta(0) values, ca. 500 x 10(-30) esu or more, which are substantially greater than those of the monometallic species.

The synthesis and characterisation of a series of eleven new 4,4'-diphenyl-2,2'-bipyridyl derivatives (N^N) with varying 4- or 3,5-substituents on the phenyl rings are reported. The molecular structures of two of these compounds, 4,4'-bis(3,5-diheptyloxyphenyl)-2,2'-bipyridyl and 4,4'-bis(3,5-di-4,4,5,5,5-pentafluoropentyloxyphenyl)-2,2'-bipyridyl are confirmed by X-ray crystallography. Fourteen neutral complexes trans-Ru(II)Cl2(N^N)(CO)2 are prepared by reacting the new proligands and three known ones with the polymeric precursor [Ru(II)Cl2(CO)2]n, and their optical and electrochemical properties are studied. Density functional theory (DFT) and time-dependent DFT calculations have been carried out on selected complexes in order to rationalise their electronic structures and absorption properties. The low energy electronic absorption bands have metal-to-ligand charge-transfer and ligand-to-ligand charge-transfer (LLCT) character, but these dominate only in the 4-substituted species. In the 3,5-disubstituted ones, intraligand charge-transfer (ILCT) within the bpy ligands becomes more important. The complexes show only irreversible reductive electrochemistry and no signs of polymerisation. The photocatalytic oxidation behaviour of selected trans-Ru(II)Cl2(N^N)(CO)2 complexes and their mono-aquo derivatives [Ru(II)(H2O)(CO)2Cl(N^N)](+) with 4-methoxybenzyl alcohol is studied. Turnover numbers of up to ca. 130 are achieved when using [Ru(II)(bpy)3](2+) (bpy = 2,2'-bipyridyl) as photosensitizer and [Co(III)(NH3)5Cl](2+) as a sacrificial oxidant.

Three new dipolar cations have been synthesised, containing ferrocenyl (Fc) electron donor groups attached to helquat (Hq) acceptors. These organometallic Hq derivatives have been characterised as their TfO- salts by using various techniques including NMR and electronic absorption spectroscopies and electrochemical measurements. UV-vis spectra show multiple intense low energy absorptions attributable to intramolecular charge-transfer (ICT) excitations. Each compound displays a reversible Fc+/0 redox process, together with two reversible one-electron reductions of the Hq fragment. Molecular quadratic nonlinear optical (NLO) responses have been determined by using hyper-Rayleigh scattering at 1064 nm, and Stark (electroabsorption) spectroscopic studies on the visible absorption bands. The obtained first hyperpolarizabilities β are moderate, consistent with the relatively short π-conjugation lengths between the Fc and attached pyridinium group. A single-crystal X-ray structure has been solved for one of the complexes as its PF6- salt, revealing a centrosymmetric packing in the triclinic space group P1[combining macron]. Density functional theory (DFT) and time-dependent DFT calculations indicate that the lowest energy absorption bands have mainly metal-to-ligand charge-transfer character. The donor orbitals involved in the electronic transitions forming the next lowest energy ICT band also have substantial contributions from the Fe atom. Good agreement between the simulated and experimental UV-vis absorption spectra is achieved by using the PBE0 functional with the 6-311++G(d)/LANL2DZ mixed basis set, and the theoretical β values are reasonably large. Oxidation of the Fc unit is predicted to cause the βtot value to decrease by more than 80% in one of the complexes.

Platinum solvate complexes [Pt(C6F5)(C^N)(S)] [C^N = phenylpyridinyl (ppy), S = dimethyl sulfoxide (DMSO) (A); C^N = benzoquinolinyl (bzq), S = CH3COCH3 (B)] react with [Tl(Spy)] (Spy = 2-pyridinethiolate) to afford binuclear [{Pt(C6F5)(C^N)}Tl(Spy)] [C^N = ppy (1) and bzq (2)] species containing a Pt-Tl bonding interaction, supported by a μ-Spy-κN,S bridging ligand, as confirmed by X-ray diffraction. However, the related reactions with [Tl(SpyCF3-5)] [SpyCF3-5 = 5-(trifluoromethyl)-2-pyridinethiolate] give neutral extended chains [{Pt(C6F5)(C^N)}Tl(SpyCF3-5)]n [C^N = ppy (3) and bzq (4)]. 3 features a zigzag -Pt-Tl···S-Pt- chain, generated by Pt-Tl and Tl···S bonds, with the SpyCF3 acting as a μ-κN:κ(2)S bridging ligand, whereas 4 displays an unsupported ···Tl-Pt···Tl-Pt··· backbone (angle of ca. 158.7°). The lowest-energy absorption bands in the UV-vis spectra in CH2Cl2, associated with (1)L'LCT transitions with minor (1)LC/(1)MLCT (L' = Spy or SpyCF3-5; L = C^N) character, are similar for all complexes 1-4, demonstrating that for 3 and 4 the chains break down in solution to yield similar bimetallic Pt-Tl units. For 2, two different forms, 2-o (orange) and 2-y (yellow), exhibiting different colors and emissions were found depending on the isolation conditions. Slow crystallization favors formation of the thermodynamically more stable yellow form (2-y), which exhibits a high-energy (HE) structured emission band, whereas fast crystallization gives rise to the orange form (2-o), with a remarkably lower energy structureless emission. Complexes 1 and 3 exhibit dual luminescence in the solid state at 298 K: an unstructured low-energy band associated with (3)ππ* excimeric emission due to π···π (C^N) interactions and a more structured HE band, assigned, with support of density functional theory calculations, to an intraligand (3)LC (C^N) excited state mixed with some ligand (SPy)/platinum-to-ligand (C^N)(3)[(L' + M)LCT] charge transfer. Chain 4 only shows a HE band at 298 K, attributed to a (3)L'LCT (SpyCF3 → bzq) excited state mixed with a minor (3)MLCT/(3)MM'CT (M = Pt; M' = Tl) contribution. At 77 K, the ππ*-stacking emission is predominant in all complexes, except in the form 2-y. Interestingly, 2-4 exhibit reversible mechanochromic color and luminescence changes, with remarkable red shift and increased quantum yields, and upon exposure to solvents, they are restored to their original color and emission. On the basis of powder X-ray diffraction studies, a plausible mechanism of the mechanochromic processes is proposed, involving reversible crystalline-to-amorphous phase transitions.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Bis(cyclometalated) diiridium complexes [Ir(ppy)(2)(mu-kappa C-alpha:eta(2)-C CR)](2) (R = Tol 1, C6H4OMe-4 2, 1-Np 3, SiMe3 4, Bu-t 5), stabilized by a double alkynyl bridging system, have been synthesized by alkynylation of [Ir(ppy)(2)(mu-Cl)](2) with excess of the appropriate LiC CR (1:6 or 1:10 molar ratio). Complexes 1-3 were alternatively generated by treatment of [Ir(ppy)(2)(MeCN)(2)](OTf) with 2.5 equiv of LiC CR. However, the related reaction with LiC=(CBu)-Bu-t evolves with the formation of mixtures from which the unexpected dinuclear complex [Ir(ppy)(2)(mu-CH2CN)](2) 6 was crystallized, as confirmed by X-ray diffraction studies. Complexes 1-5 have been characterized by NMR, IR, absorption and emission spectroscopies, cyclic voltammetry, and mass spectrometric methods. Characterization indicates that 1-3 and 5 are obtained as a unique diastereoisomer (Lambda Lambda/Delta Delta), whereas 4 gives the two diastereoisomers (Lambda Lambda and Lambda Lambda/Delta Delta). Single crystals of [Ir(ppy)(2)(mu-C=CTol)](2) 1 contains the inversion related Lambda Lambda/Delta Delta isomers, and crystals of 4 (chosen from a mixture of two different types of crystals) consist of the meso-Delta Lambda isomer. Electrochemical studies showed the presence in 1-3 and 5 of two consecutive one-electron-oxidation Ir-III/Ir-IV processes, whereas 4 displayed only one irreversible oxidation peak. In degassed fluid solutions, complexes 1-5 are emissive in the 505-515 nm region with quantum yields higher (phi = 0.007-0.024) than that of the dichloro bridged precursor (0.0037). The influence of the alkynyl substituent in the emissive state at room and at low temperatures has been investigated. For the naphthylacetylide derivative 3, a clear switch from a mixed charge transfer (MLCT)-M-3/L-3'LCT excited state at 298 K (515 nm) to a characteristic long-lived low lying naphthalene emission at low temperature (77 K) is observed. DFT and TD-DFT calculations were performed on complexes 1 and 3 in the ground and triplet states to gain insight into the structural, electronic, and photophysical properties.

New blue or blue-green emitting iridium complexes have been synthesised with cyclometalating ligands derived from the 1-methyl-3-(2'-pyridyl)pyridinium cation. Efficient luminescence is observed in MeCN or aqueous solutions, with a large range of lifetimes in the μs region and relatively high quantum yields.

Dipyrrolidylmethane, CH2(pyr)(2), and dipiperidylmethane, CH2(pip)(2), are synthesized via the condensation of their respective secondary amine precursors and dichloromethane at room temperature in the absence of light. Their use as chelating ligands is shown by the isolation and complete characterization of [CH2(pyr)(2)]Mo(CO)(4) and [CH2(pip)(2)]Mo(CO)(4) complexes. X-ray analysis reveals the methylene bis(cycloamines) to possess a sharp bite angle between 61 degrees and 63 degrees and a strong steric impact on the surrounding carbonyl ligands as a result of their ring conformations.

Correction for 'Study of the one-photon and two-photon properties of two water-soluble terpyridines and their zinc complexes' by Pengfei Shi et al., Dalton Trans., 2015, 44, 8041-8048.

The compounds 4,4′-bis[(E)-2-R-vinyl]-2,2′-bipyridyl {R = ferrocenyl [(Fcv)2bpy], octamethylferrocenyl [(Me8Fcv)2bpy] or 4-(diphenylamino)phenyl [(Dapv)2bpy]} are used to prepare eight new complexes with ZnIICl2, ZnII(OAc)2, or fac-ReICl(CO)3 centers. The recently reported complex fac-ReICl(CO)3[(Dapv)2bpy] (Horvath, R. et al. Inorg. Chem. 2013, 52, 1304) is also studied. Electronic absorption spectra show intense d → π* metal-to-ligand charge-transfer (MLCT) and π → π* intraligand charge-transfer (ILCT) absorption bands, the relative energies of which correlate logically with the molecular structure. Cyclic voltammetry reveals a reversible oxidation wave for the Fc/Me8Fc complexes, accompanied by quasireversible or irreversible ligand-based reductions. The Re complexes also show irreversible ReII/I waves. Single-crystal X-ray structures are reported for (Me8Fcv)2bpy, ZnIICl2[(Me8Fcv)2bpy], ZnII(OAc)2[(Fcv)2bpy]·CHCl3, and fac-ReICl(CO)3[(Me8Fcv)2bpy]·0.5CHCl3. Molecular first hyperpolarizabilities β are measured in DCM solutions via the hyper-Rayleigh scattering (HRS) technique at 1300 nm. Stark (electroabsorption) spectroscopic studies on only the MLCT bands in frozen butyronitrile allow the indirect estimation of lower limits for the overall static first hyperpolarizabilities β0. Time-dependent density functional theory (TD-DFT) calculations on selected complexes confirm the expected assignments of their low energy absorption bands, with the best results obtained by using the M06 functional and Def2-TZVP/SVP/TZVPP mixed basis set. DFT predicts that the total static first hyperpolarizability βtot increases in the ZnIICl2 series in the order R = Fc < Me8Fc < Dap, consistent with the HRS and Stark data. The computed β values increase substantially on moving from the gas phase to a DCM or MeCN solvent medium, and the essentially 2D nature of the chromophores leads to dominant βxxy tensor components.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.