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The selective photoreactions under mild conditions play an important role in synthetic chemistry. Herein, efficient and mild protocols for switching the photoreactions of Ir(III)-diamine complexes between the interligand C-N coupling and dehydrogenation are developed in the presence of O

Bioinformatics and machine learning tools have made it possible to integrate data across different -omics platforms for novel multiomic insights into diseases. To synergistically process -omics data in an integrative manner, analyte extractions for each -omics type need to be done on the same set of clinical samples. Therefore, we introduce a simultaneous dual extraction method for generating both metabolomic (polar metabolites only) and glycomic (protein-derived N-glycans only) profiles from one sample with good extraction efficiency and reproducibility. As proof of the usefulness of the extraction and joint-omics workflow, we applied it on platelet samples obtained from a cohort study comprising 66 coronary heart disease (CHD) patients and 34 matched healthy community-dwelling controls. The metabolomics and N-glycomics data sets were subjected to block partial least-squares-discriminant analysis (block-PLS-DA) based on sparse generalized canonical correlation analysis (CCA) for identifying relevant mechanistic interactions between metabolites and glycans. This joint-omics investigation revealed intermodulative roles that protein-bound carbohydrates or glycoproteins and amino acids have in metabolic pathways and through intermediate protein dysregulations. It also suggested a protective role of the glyco-redox network in CHD, demonstrating proof-of-principle for a joint-omics analysis in providing new insights into disease mechanisms, as enabled by a simultaneous polar metabolite and protein-derived N-glycan extraction workflow.

Aerobic photo-oxidation of sulfide into sulfoxide in water is of great interest in green chemistry. In this study, three highly stable Ir(III)–Zr(IV) metal–organic frameworks (Ir–Zr MOFs), namely Z...

Enantiopure Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) (where dfppy is (4,6-difluoropheny)pyridine) were demonstrated to preferentially react with (S,S)-1,2-bis(arylsulfinyl)ethane and (R,R)-1,2-bis(arylsulfinyl)ethane, respectively, under thermodynamic equilibrium. Sequential treatment of Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) with C2-symmetric bis-sulfoxides led to diastereoselective formation of the corresponding diastereomers Λ-[Ir(dfppy)2(R,R)-bis-sulfoxide)](PF6) in 90-92% and Δ-[Ir(dfppy)2(S,S)-bis-sulfoxide)](PF6) in 88-90%, respectively. The uncoordinated (R,S)-bis-sulfoxides were afforded in 45% with >97% de values. Enantiopure (S,S)-bis-sulfoxides and (R,R)-bis-sulfoxides were respectively obtained by the release of sulfoxide ligands from the corresponding complexes in the presence of glycine in yields of 20-21% with 97-99% ee values. The enantioreceptors Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) can be recycled and reused in the next reaction cycle. Moreover, a protocol for asymmetric oxidation of prochiral bis-sulfide into enantiopure C2 symmetric bis-sulfoxide was also developed in a high enantioselectivity. The absolute configurations at the metal centers and sulfur atoms were determined by X-ray crystallography.

The assembly of mixed [1,1';3',1'']terphenyl-4,5',4''-tricarboxylic acid (H3TPTC) and [1,1'-biphenyl]-4,4'-dicarboxylic acid (H2BPDC), 2,2'-diamino-[1,1'-biphenyl]-4,4'-dicarboxylic acid (H2BPDC-NH2), or 6-oxo-6,7-dihydro-5H-dibenzo[ d, f][1,3]diazepine-3,9-dicarboxylic acid (H2BPDC-Urea) with Cu2+ ion generated the corresponding copper-paddlewheel-based metal-organic framework (MOF) [Cu5(TPTC)3(BPDC)0.5(H2O)5] (1), [Cu5(TPTC)3(BPDC-NH2)0.5(H2O)5] (1-NH2), or [Cu5(TPTC)3(BPDC-Urea)0.5(H2O)5] (1-Urea). They are isostructural with hierarchical porosity, consisting of zero-dimensional cage (19.2 A × 18.9 A) and one-dimensional pillar channel (29.7 A × 15.1 A) in a manner of face sharing. Platon analyses revealed the porous volume ratios are 80.2%, 80.0%, and 77.8% for 1, 1-NH2, and for 1-Urea, respectively. Thermogravimetric measurements suggested 53, 51, and 48 wt % guest molecules in 1, 1-NH2, and 1-Urea, respectively. 1-NH2 and 1-Urea were precisely functionalized via the introduction of amino and urea functional groups into the pillar channels. The constructed MOF 1-Urea, incorporating both exposed copper active sites and accessible urea functional groups to substrates, presents high efficiency on catalytic CO2 cycloaddition with propene oxide to produce cyclic carbonate in the yield of 98% with a TOF value of 136 h-1 at 1 atm and room temperature. This synergic effect provides a new strategy for designing high-efficient catalysts for CO2 chemical conversion under ambient conditions.

A diastereoselective photooxidation of α-amino acid (AA) complexes into imino acid complexes using a chiral iridium(III) complex as a photosensitizer and stereo-controller under visible light irradiation and oxygen was developed. It was found that the oxidative rate of Δ-[Ir(pq)2(L-AA)] (pq is 2-phenylquinoline) diastereomer is significantly higher than that of the corresponding Δ-[Ir(pq)2(D-AA)] diastereomer, providing a new protocol for kinetic resolution of AAs via a nonenzymatic pathway. Moreover, the thermodynamic controlled strategy offered a complemental method for the diastereoselective hydrogenation of imine bonds using NaBH4 as a reductant under the chiral Ir(III) complex as a stereo-controller. The combination of diastereoselective photooxidation and reduction processes results in a new protocol for deracemization of α-amino acids under mild conditions. Mechanism study strongly indicates that singlet oxygen is a key participant in the reaction and the α-C–H bond cleavage of AAs is the rate-dete...

Dysiarenone (1), a dimeric C21 meroterpenoid featuring an unprecedented 2-oxaspiro[bicyclo[3.3.1]nonane-9,1′-cyclopentane] carbon skeleton, was isolated from the marine sponge Dysidea arenaria. The structure of 1 was determined by HRMS and NMR spectroscopic analyses coupled with ECD calculations. Dysiarenone showed inhibitory activities against COX-2 expression and the production of prostaglandin E2 with an IC50 value of 6.4 μM in LPS-stimulated RAW264.7 macrophages.

Diastereoselective synthesis of bis-cyclometalated Ir(III) stereoisomers Δ/Λ-[Ir(C∧N)2(d-pro)] and Δ/Λ-[Ir(C∧N)2(l-pro)] (where C∧N is 2-phenylpyridine (Hppy), (4,6-difluorophenyl)pyridine (Hdfppy), and 2-phenylquinoline (Hpq) and pro is proline) with dual stereogenic centers at the metal and auxiliary ligand has been developed. The diastereomers Λ-l and Λ-d, and Δ-l and Δ-d exhibit distinguishable photophysical properties in both solution and the solid state. The thermodynamically stable diastereomers Λ-[Ir(ppy)2(l-pro)], Λ-[Ir(dfppy)2(l-pro)], and Λ-[Ir(pq)2(l-pro)] emit a green emission at 524 nm (Φ = 3.5% and τ = 35 ns), a blue-green emission at 480 nm (Φ = 4.5% and τ = 59 ns), and a red emission at 588 nm (Φ = 6.5% and τ = 200 ns) in DCM solution, respectively, which are blue-shifted accompanied by a large quantum yield and long lifetime relative to the corresponding unstable diastereomers Δ-[Ir(ppy)2(l-pro)] at 537 nm (Φ = 2.3% and τ = 29 ns), Δ-[Ir(dfppy)2(l-pro)] at 489 nm (Φ = 2.8% and τ = 43 ns)...

The optically active Ir(III) complex Λ-[Ir(ppy)2(MeCN)2](PF6) (ppy is 2-phenylpyridine) with a chiral-at-metal was first demonstrated to preferentially react with (R)-configuration sulfoxides 2-(alkylsulfinyl)phenol (HLO-R, R = Me, Et, iPr, and Bn) rather than (S)-configuration sulfoxides under thermodynamic equilibrium due to the hydrogen-bonding interaction and the differences in the steric interference, and thus act as a highly efficient enantioreceptor for resolution of sulfoxide enatiomers. Treatment of Λ-[Ir(ppy)2(MeCN)2](PF6) with 2 equiv of rac-HLO-R offered (S)-HLO-R in yields of 46–47% with 97–99% enantiomeric excess (ee) values and Λ-[Ir(ppy)2{(S)-LO-R}] complex in yields of 89–93% with 98% diastereomeric excess (de). The (R)-HLO-R chiral sulfoxides were obtained by the acidolysis of Λ-[Ir(ppy)2{(S)-LO-R}] complexes with trifluoroacetic acid (TFA) in the presence of coordinated solvent MeCN in yields of 45–47% with 98–99% ee values. Moreover, the enantioreceptor Λ-[Ir(ppy)2(MeCN)2](PF6) can be ...

Chiral precursors Λ-[Ir(ppy)2(l-pro)] (Λ-L, where ppy is 2-phenylpyridine; pro is proline), Λ-[Ir(ppy)2(MeCN)2](PF6) (Λ-1), Δ-[Ir(ppy)2(d-pro)] (Δ-D), and Δ-[Ir(ppy)2(MeCN)2](PF6) (Δ-1) were synthesized from rac-[(Ir(ppy)2)2Cl2] and l-pro or d-pro by means of the auxiliary ligand strategy with 99% de values. The enantiopure mono complexes Λ/Δ-[Ir(ppy)2(L)](PF6) (L is 2,2'-bipyridine, Λ/Δ-2; L is 2,2'-dipyrimidine (dpm), Λ/Δ-3; L is 2,2'-bibenzimidazole (H2bbim), Λ/Δ-4) with 99% ee values and binuclear complexes ΛΛ/ΔΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (ΛΛ-5 and ΔΔ-5) and ΛΛ/ΔΔ-[(Ir(ppy)2)2(bbim)] (ΛΛ-6 and ΔΔ-6) with 99% de values were synthesized in one step using the corresponding chiral precursors. The absolute configurations at Ir(III) centers of precursor Δ-1, mononuclear Λ-3, and binuclear ΔΔ-6 were confirmed by single-crystal structural analysis and characterized by circular dichroism (CD) spectroscopy. The correlation between the absolute configuration at Ir(III) center and CD spectra was established. The configurations at Ir(III) centers are stable during the reactions, and the chiral precursors can be used for the asymmetric synthesis of enantiomerically pure mono- and polynuclear Ir(III) complexes. Moreover, meso ΛΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (meso-5) and ΛΔ-[(Ir(ppy)2)2(bbim)] (meso-6) were also synthesized using these precursors.

An efficient approach for direct carbamoylation of terminal alkynes with formamides affording propiolamides has been developed by copper-catalyzed oxidative cross coupling of C(sp)-H and C(sp2)-H bonds in the presence of a pincer ligand with two imidazolyl groups. The catalytic reaction is compatible with diverse functional groups but sensitive to the electronic effect of terminal alkyne and the steric effect of formamides. KIE study indicates the cleavage of the carbamoyl C–H bond affording formamide radical is the rate-determining step.

Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF.

A novel method for the synthesis of high-performanced titanium silicalite-1 (TS-1) zeolite at a very low usage of tetrapropylammonium hydroxide (TPAOH) was developed in this work. The method involved a temperature-programmed hydrothermal crystallization (TPHC) of a batch with a TPAOH/SiO2 molar ratio of as low as 0.05, being 5 times smaller than that employed in the conventional synthesis, in which the TPAOH was entirely provided by a TS-1 precursor sol. The characterizations of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet–visible spectroscopy (DR UV–vis), and scanning electron microscopy (SEM) indicated that the TS-1 synthesized via the novel method possessed a uniform crystal size of ∼0.3 μm, a very high crystallinity and a considerably large content of framework Ti (2.33 mol %). The TS-1 had been employed as the catalyst for the ammoximation of cyclohexanone, of which the influencing factors were systematically investigated. It was shown that...

Pt/MWCNT and Pd/MWCNT nanocatalysts were prepared via a liquid reduction method. The selective hydrogenation of cinnamaldehyde (CAL) was investigated over 5.0 wt.% Pt/MWCNT and 5.0 wt.% Pd/MWCNT catalysts in a CO2-expanded alcoholic medium at different reaction conditions. The hydrogenation selectivities over these two catalyst types were shown to be entirely different. It was found that the Pt/MWCNT catalysts are highly selective for C=O bonds, giving the unsaturated alcohol a selectivity for cinnamyl alcohol (COL) of 97.3% and a conversion rate for cinnamaldehyde of 99.3%. Conversely, the Pd/MWCNT catalyst is highly selective for C=C bonds, producing a saturated aldehyde with a selectivity for hydrocinnamaldehyde (HCAL) of 91.3% and a conversion rate for cinnamaldehyde of 98.6%. The small diameter of the Pt or Pd granules over the multiwalled carbon nanotubes (MWCNTs) leads to a high catalyst activity, and an increase of CO2 pressure results in a better hydrogenation performance for C=O bonds than that for C=C bonds.

Six new complexes [Zn2(L1)4]·2H2O·DMF (1), [Zn2(L2)4]3·13H2O (2), [Zn1.5(L3)3]2 (3), Zn(L4)2·2H2O (4), Zn(L5)2·2CHCl3 (5), and [Zn(L6)2]2 (6) (where HL1 = 1-(4-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL2 = 1-(4-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione, HL3 = 1-(4-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione, HL4 = 1-(3-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL5 = 1-(3-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione and HL6 = 1-(3-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione) have been synthesized by the reaction of the bifunctional ligands and Zn(II) salts under similar experimental conditions. Structural analyses show that the ligands act as a tridentate and bind to two Zn(II) ions as a two-connected linker, generating a variety of geometries from discrete binuclear [2 + 2] metallomacrocycles (3 and 6) to a one-dimensional looped-chain coordination polymer (4) and two-dimensional (4,4) network (5) as well as three-dimensional frameworks with lvt (1) and NbO (2) topologies. The results demonstrate that ...

We report a theoretical study on a series of heteroleptic cyclometalated Ir(III) complexes for OLED application. The geometries, electronic structures, and the lowest-lying singlet absorptions and triplet emissions of [(fppy)(2)Ir(III)(PPh(2)Np)] (1), and theoretically designed models [(fppy)(2)Ir(III)(PH(2)Np)] (2) and [(fppy)(2)Ir(III)Np](-)(3) were investigated with density functional theory (DFT)-based approaches, where, fppyH = 4-fluorophenyl-pyridine and NpH = naphthalene. The ground and excited states were, respectively, optimized at the M062X/LanL2DZ;6-31G* and CIS/LanL2DZ:6-31G* level of theory within CH(2)Cl(2) solution provided by PCM. The lowest absorptions and emissions were evaluated at M062X/Stuttgart;cc-pVTZ;cc-pVDZ level of theory. Though the lowest absorptions and emissions were all attributed as the ligand-based charge-transfer transition with slight metal-to-ligand charge-transfer transition character, the subtle differences in geometries and electronic structures result in the different quantum yields and versatile emission color. The newly designed molecular 3 is expected to be highly emissive in deep blue region.

Seven complexes based on the ligands 4,6-bis(4-pyridyl)-1,3,5-triazin-2-ol (4-HOBPT) and 4,6-bis(3-pyridyl)-1,3,5-triazin-2-ol (3-HOBPT), namely, [Fe(4-OBPT)2(H2O)2]·6H2O (2), M(4-OBPT)(INA)(H2O) (M = Co(II) (3a), Fe(II) (3b), Zn(II) (3c), HINA = isonicotinic acid), [Co(3-OBPT)2(H2O)2]·H2O (4), and [M(3-OBPT)(NA)(H2O)]·0.5CH3OH (M = Co(II) (5a), Ni(II) (5b), HNA = nicotinic acid), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The thermal stability and coordination model of the ligands are extremely dependent on the reaction temperature and the presence of metal ions. In the range of 90−120 °C, unique complexes 2 and 4 were obtained and the ligands are a N,O-bimonodentate coordination model. At 130 °C, complexes 3 and 5 were afforded in yields of 12−48% depending on the metal ions, in which both of the ligands act as a N,N,O-trimonodentate triangular ligand and the INA and NA anions are generated in situ by hydrolysis of the corresponding parents...

We describe the first observation of the quantitative and rapid synthesis ofa (10,3)-b three-dimensional hydrogen bonded network {[Ru(H 2 biim) 3 ](TMA)}·5H 2 O(1·H 2 O)(H 2 biim = 2,2'-biimidazole; H3TMA = trimesic acid) via a "liquid-assisted" solid-state reaction approach. The reaction occurs within minutes of grinding together [Ru(H 2 biim) 3 ](PF 6 ) 2 and Na 2 HTMA with a few drops of H 2 O 2 as an oxidant and solvent, concomitant with a color change from yellow (Ru(II) ion) to blue-green (Ru(III) ion). The characterization of the solid-state product was achieved by a combination of a single crystal obtained via seeding and powder diffraction experiments. To compare with the solid-state reaction, similar reactions were also carried out in an EtOH solution. Two complexes {[Ru(H 2 biim) 3 ](TMA)}·10H 2 O(2·H 2 O) and [Ru(H 2 biim) 3 ](HTMA) (3) were isolated in the presence of a polypyridine base, such as 2,2-dipyridylamine or 2,2':6',2"-terpyridine or 1,10-phenanthroline. Complex 2 is a (6,3) honeycomb two-dimensional hydrogen-bonded network. Complexes 1 and 2 are topological isomers. The formation of multiple robust hydrogen bonds between [Ru(H 2 biim) 3 ] 3+ and TMA may trigger the proton transfer from H 2 biim to TMA, then electron transfer, resulting in Ru(III) status. This may provide an effective approach for the generation of high status metal complexes via supramolecular interactions. Importantly, our experiments suggest that solution crystallization may at times offer more product diversity than grinding.

A nanocage complex [Co(H2O)6⊂Co8L12](NO3)6·12H2O (1) (HL = 2-amino-4,6-bis(2-pyridyl)-1,3,5-triazin) has been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction. A [Co(H2O)6]2+ ion as a guest is included in the central cavity of the cubelike nanocage [Co(H2O)6⊂Co8L12]6+ cation, assembled by 8 cobalt ions at the corners and 12 bis-bidentate ligands L at the edges, via the formation of 12-fold strong hydrogen bonds between the six coordinated water molecules and the nitrogen atoms of 12 L ligands. When compound 1 cocrystalizes with KHCO3 and trimesic acid (H3TMA), complexes [Co(H2O)6⊂Co8L12](HCO3)6·24H2O (2) and [Co(H2O)6⊂Co8L12](H2TMA)6·6EtOH·3H2O (3) are obtained, respectively. In 2, a planar [(HCO3)2]2− dimer motif R22(8) synthon plus six lattice water molecules constitute a planar supramolecular synthon R88(20), which acts as a 4-connector, generating a three-dimensional (3D) hydrogen-bonded NbO net with an approximately 20 A diameter cavity. In 3, the R44(24...

Five different cobalt complexes were synthesized by the combination of the multidentate ligand 2,2′-bibenzimidazole (H2bbim) and the coordination plasticity of cobalt ion in the presence of 4-cyanopyridine under hydrothermal conditions using temperature as the only independent variable. The structural features of theses complexes, which ranged from zero-dimensional (0D) in [Co(Hbbim)3]·3H2O (1) and [Co(ina)2(H2O)4] (5) to two-dimensional (2D) layer in {[Co4(Hbbim)4(bbim)2]·2H2O}n (2) or three-dimensional (3D) networks in [Co2(Hbbim)(bbim)2(H2O)]n (3) and [Co5(Hbbim)(bbim)3(ina)2(μ3-OH)]n (4), were extremely dependent on the reaction temperature. At 130 °C, discrete 1 was the unique product. However, 4 was the main product when the reaction temperatures were set in the range of 160−200 °C. 2 and 3 yielded at 140 °C as main products. In spite of the structural diversity of this system, crystallographic studies reveal that the H2bbim ligand typically displays tridentate (Hbbim−) and/or tetradentate (bbim2−) ...

The geometries, electronic structures, and spectroscopic properties of Ir(ppy)2(N^N)+ (1) (N^N = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, ppy = 2-phenylpyridine), Ir(ppy)2(N^N)+·F− (2), Ir(p...

Six complexes containing the 2,2′-biimidazole-like ligand and chloride, namely, trans-[Ni(H2biim)2(H2O)2]Cl2 (1), trans-[Co1.5(H2biim)3(H2O)3]Cl3 (2), [Zn(H2biim)2Cl]Cl (3), [Ni2(H2bbim)4(bbim)]Cl2 (4), [Co(H2bbim)3]Cl2·2H2O (5), and [Zn2(Hbbim)2(bbim)0.5Cl] (6) (where H2biim = 2,2′-biimidazole, H2bbim = 2,2′-bibenzimidazole) have been synthesized by the reactions of the H2biim or H2bbim ligand with the metal chloride salts. The structures of the complexes were determined by single-crystal X-ray diffraction analyses, and the results revealed that the distances of N···Cl varied from 3.10 to 3.29 A and the angles of N−H···Cl varied from 148 to 169°, O···Cl varied from 3.09 to 3.16 A, O−H···Cl varied from 151 to 178°, C···Cl varied from 3.49 to 3.69 A, and C−H···Cl varied from 122 to 167°. The chloride may act as a multi hydrogen bonded acceptor varying from 3 to 6, resulting in an important collective contribution to cohesion. The data observed in this study seem to suggest that a variety of X−H···Cl (X = N...

A series of ruthenium(II) complexes, [Ru(tcterpy)(NCS)3](4-) (0H), [Ru(Htcterpy)(NCS)3](3-) (1H), [Ru(H2tcterpy)(NCS)3](2-) (2H), and [Ru(H3tcterpy)(NCS)3](-) (3H) (tcterpy = 4,4',4''-tricarboxy-2,2':6',2''-terpyridine), are investigated theoretically to explore their electronic structures and spectroscopic properties. The geometry structures of the complexes in the ground and excited states are optimized by the density functional theory and single-excitation configuration interaction methods, respectively. The absorption and emission spectra of the complexes in gas phase and solutions (ethanol and water) are predicted at the TDDFT(B3LYP) level. The calculations indicate that the protonation effect slightly affects the geometry structures of the complexes in the ground and excited states but leads to significant change in the electronic structures. In cases of both absorptions and emissions, the energy levels of HOMOs and LUMOs for 0H-3H decrease dramatically as a result of the introduction of the COOH groups. The protonation much stabilizes the unoccupied orbitals with respect to the occupied orbitals. Thus, both the absorptions and emissions are red-shifted from 0H to 3H. The phosphorescence of 0H-3H are attributed to tcterpyridine --d(Ru)/NCS ((3)MLCT/(3)LLCT) transitions. The solvent media can influence the molecular orbital distribution of the complexes; as a consequence, the spectra calculated in the presence of the solvent are in good agreement with the experimental results. The MLCT/LLCT absorptions of 0H in ethanol and water are red-shifted relative to that in the gas phase. However, the MLCT/LLCT absorptions of the protonated complexes (1H-3H) are blue-shifted in ethanol and water with respect to the gas phase. Similarly, the solvent effect causes a blue-shift of the phosphorescent emission for 0H-3H.

The geometries, electronic structures, and spectroscopic properties of a series of novel cationic iridium(III) complexes [trans-(C/N)(2)Ir(PH(3))(2)]+ (C/N = 2-phenylpyridine, 1; benzoquinoline, 2; 1-phenylpytazolato, 3; 2-(4,6-difluorophenyl)pyridimato, 4) were investigated theoretically. The ground- and excited-state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The optimized geometry structural parameters agree well with the corresponding experimental results. The unoccupied molecular orbitals are dominantly localized on the C/N ligand, while the occupied molecular orbitals are composed of Ir atom and C/N ligand. Under the time-dependent density functional theory (TDDFT) level with the polarized continuum model (PCM) model, the absorption and phosphorescence in acetonitrile (MeCN) media were calculated based on the optimized ground- and excited-state geometries, respectively. The calculated results showed that the lowest-lying absorptions at 364 nm (1), 389 nm (2), 317 nm (3), and 344 nm (4) are all attributed to a {[d(yz)(Ir) + pi(C/N)] --> [pi*(C/N)]} transition with metal-to-ligand and intraligand charge transfer (MLCT/ILCT) characters; moreover, the phosphorescence at 460 (1) and 442 nm (4) originates from the 3{[d(yz)(Ir) + pi(C/N)] [pi*(C/N)]} (3)MLCT/(3)ILCT excited state, while that at 505 (2) and 399 nm (3) can be described as originating from different types of (3)MLCT/(3)ILCT excited state (3){[d(xy)(Ir) + pi(C/N)] [pi*(C/N)]}. The calculated results also revealed that the absorption and emission transition character can be altered by adjusting the pi electron-withdrawing groups and, furthermore, suggested that the phosphorescent color can be tuned by changing the pi-conjugation effect of the C/N ligand.

A new anion sensor [Ru(bpy)2(H2biim)](PF6)2 (1) (bpy = 2,2'-bipyridine and H2biim = 2,2'-biimidazole) has been developed, in which the Ru(II)-bpy moiety acts as a chromophore and the H2biim ligand as an anion receptor via hydrogen bonding. A systematic investigation shows that 1 is an eligible sensor for various anions. It donates protons for hydrogen bonding to Cl-, Br-, I-, NO3-, HSO4-, H2PO4-, and OAc- anions and further actualizes monoproton transfer to the OAc- anion, changing color from yellow to orange brown. The fluoride ion has a high affinity toward the N-H group of the H2biim ligand for proton transfer, rather than hydrogen bonding, because of the formation of the highly stable HF2- anion, resulting in stepwise deprotonation of the two N-H fragments. These processes are signaled by vivid color changes from yellow to orange brown and then to violet because of second-sphere donor-acceptor interactions between Ru(II)-H2biim and the anions. The significant color changes can be distinguished visually. The processes are not only determined by the basicity of anion but also by the strength of hydrogen bonding and the stability of the anion-receptor complexes. The design strategy and remarkable photophysical properties of sensor 1 help to extend the development of anion sensors.

The electronic structures and spectroscopic properties of the three tridentate cyclometalated Pt(II) complexes Pt(N/\N/\C)C(triple bond)CPh (N/\N/\CH = 6-phenyl-2,2'-bipyridine) (1), Pt(N/\N/\S)C(triple bond)CPh (N/\N/\SH = 6-thienyl-2,2'-bipyridine) (2), and Pt(N/\N/\O)C(triple bond)CPh (N/\N/\OH = 6-furyl-2,2'-bipyridine) (3) were investigated theoretically using the density functional theory (DFT) method. The geometric structures of the complexes in the ground and excited states were explored at the B3LYP and UB3LYP levels, respectively. The absorption and emission spectra of the complexes in CH2Cl2 and CH3CN solutions were calculated by time-dependent density functional theory (TD-DFT) with the PCM solvent model. The calculated energies of the lowest singlet state and lowest triplet state in the three complexes are in good agreement with the results of experimental absorption and luminescence studies. All of the lowest-lying transitions were categorized as LLCT combined with MLCT transitions. The 623-nm emission of 1 from the 3A' --1A' transition was assigned as 3LLCT and 3MLCT transitions, whereas the 657- and 681-nm emissions of 2 and 3, respectively, were attributed to 3ILCT perturbed by 3MLCT transitions. NLO response calculations revealed that the nonzero values of the static first hyperpolarizability (beta0) for 1-3 are greatly enhanced through the introduction of the metal Pt(II) into the cyclometalated ligands, an effect that is determined by MLCT and LLCT transitions.

The facile and effective one-pot solvothermal syntheses of 3,5-disubstituted 1,2,4-triazole and its derivatives (substituted group = alkyl, aryl, and pyridyl) through cyclocondensations of organonitriles and hydrazine hydrate in the absence/presence of metal salts have been established. By control of the solvothermal conditions and/or the addition of counteranions, different intermediates and final products were derived from various organonitriles, in which an intermediate N,N'-bis(picolinamide)azine (H4bpa) has been successfully trapped in its neutral manganese(II) complexes. A systematical study shows that, after the initial formation of 2-pyridylamidrazone from 2-cyanopyridine and hydrazine, two reaction paths are involved in the formation of 1,2,4-triazoles: via the formation of 3,6-bis(2-pyridyl)-1,2-dihydro-1,2,4,5-tetrazine and H4bpa as intermediates. The tetrazine and H4bpa paths are preferred in the absence and presence of metal ions, respectively. In the presence of metal ions, metal ion binding can stabilize the tautomers, enhance the nucleophilic reactivity of the imino C atom, and inhibit the tautomerization of H4bpa, hence leading to the formation of 1,2,4-triazolates or H4bpa in complexed forms. The in situ cyclocondensation reactions of 2-pyridylamidrazone and carboxylate into asymmetric 3,5-disubstituted 1,2,4-triazolates under solvothermal conditions have also been observed for the first time. Crystal structures of the crystalline metal complexes have been obtained, including dinuclear [Mn2(bpt)2Cl2(H2O)2] (1) and [Mn2(bpt)2(SCN)2(H2O)2] (3; Hbpt = 3,5-bis(2-pyridyl)-4H-1,2,4-triazole), tetranuclear [Mn4(H3bpa)2(mpt)4(N3)2].2H2O (5; Hmpt = 3-methyl-5-(2-pyridyl)-1H-1,2,4-triazole), [Mn4(H3bpa)2(pt)4(N3)2].2C2H5OH (6; Hpt = 5-(2-pyridyl)-1H-1,2,4-triazole), and [Mn4(H3bpa)4(SCN)4].2C2H5OH (7), as well as helical [Cu(bpt)] (2). Among them, 7 is the first example of a neutral tetranuclear [2 x 2] grid manganese(II) complex. Both 5 and 7 exhibit antiferromagnetic interactions.

The series of iridium(III) complexes Ir(C^N) 2 LX (C^N = bzq, LX = acac, 1; CAN = thp, LX = acac, 2; C^N = tpy, LX = acac, 3; C^N = bzq, LX = dbm, 4; acac = acetoylacetonate, bzq = benzoquinoline, tpy = 2-(4-tolyl)pyridine, thp = 2-(2'-thienyl)pyridine and dbm = dibenzoylmethanate) have been investigated theoretically to explore their electronic structures and spectroscopic properties. Their structures in the ground and excited states have been optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The calculated bond lengths of Ir-N, Ir-C, and Ir-O in the ground state agree well with the corresponding experimental results. Upon excitation, the bond lengths of Ir-N and Ir-C lengthen by 0.03 A and that of Ir-O shortens by 0.01 A compared with those in the X 1 A ground states. This is consistent with the variation trend of corresponding vibration mode in the ground and excited states. At the TD-DFT and PCM levels, 1-4 give rise to absorptions at 484, 462, 452, and 536 nm and phosphorescent emissions at 541, 589, 499, and 540 nm, respectively. The transitions of 1-3 are attributed to [d(Ir) + π(C^N)] →[π*(C^N)] charge transfer, whereas those of 4 are related to [d(Ir) + π(C^N)] → [π*(LX) + π*(CAN)]. It is shown that the emissions are significantly dominated by the metal participating in the frontier molecular orbitals and affected by the C^N ligands but are hardly perturbed by the LX ligands.

Four new complexes [Cd4(bpa)2(MeCO2)8]·9H2O (1), {[Cd4(bpa)4(suc)2(H2O)4](suc)2·17H2O}n (2), {[Cd2(bpa)2(glu)2]·9H2O}n (3), and {[Cd2(bpa)2(adi)2]·11H2O}n (4) (where bpa = N,N‘-bis(picolinamide)azine, H2suc = succinic acid, H2glu = glutaric acid, and H2adi = adipic acid) have been synthesized by the reactions of the bpa ligand and different Cd(II) carboxylates in similar conditions. Their structures consist of double-stranded helical [Cd2(bpa)2] structural units and various carboxylates. Each of the [Cd2(bpa)2] structural units in 1 is capped at its both ends by acetate-chelated Cd(II) fragments through acetate bridges into discrete tetranuclear species, which are self-assembled into two-dimensional (2D) hydrogen-bonded sheets with cavities. The 2D hydrogen-bonded sheets in 1 are threaded by one-dimensional (1D) water tapes featuring (H2O)4 clusters to generate an unprecedented three-dimensional (3D) hydrogen-bonded polypseudo-rotaxane architecture. The [Cd2(bpa)2] structural units as secondary building b...