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The bifunctional ligands of isonicotinic acid (Py-4-COOH) and 4-pyrid-4-ylbenzoic acid (Pybz-4-COOH) instead of polypyridines were therefore reacted with (Re(CO)4)3(C3N3S3) (C3N3S3 = cyanurate trianion), resulting in the formation of two trinuclear [(Re(CO)3)3(C3N3S3)(Py-4-COOH)3] (1) and [(Re(CO)3)3(C3N3S3)(Pybz-4-COOH)3] (2), respectively. In the meantime, both complexes 1 and 2 are connected by three bifurcated hydrogen bonds between their carboxylic acid moieties Py-4-COOH and Pybz-4-COOH to form the supramolecular trigonal-prismatic and -antiprismatic structures, respectively. It is noted that complex 1 can further react with copper(II) nitrate upon deprotonation to give nonanuclear [(Re(CO)3)3(C3N3S3)(Py-4-COO)3]2Cu3(H2O)9 (3), where two trinuclear [(Re(CO)3)3(C3N3S3)(Py-4-COO)3] moieties are connected by three penta-coordinate copper(II) ions, each coordinating to two carboxylates and three water molecules, to form the trigonal-prismatic structure. Surprisingly, addition of pyrazine (pz) in the synthetic process of complex 3 resulted in serendipitous isolation of a rare example of octadecanuclear {[(Re(CO)3)3(C3N3S3)(Py-4-COO)3]2Cu3(H2O)6(pz)2}2 (4), which can be regarded as a dimer of complex 3, connected by two bridging pz ligands. Interestingly, both complexes 3 and 4 are heteronuclear molecular Re(I)-Cu(II) boxes, constructed by a complex-as-a-ligand strategy. Furthermore, complexes 1 and 2 can exhibit respective low-energy luminescence at ca. 561 and 534 nm at room temperature upon photoexcitation, and complex 3 is found to display antiferromagnetic coupling of −127.68 and −134.70 cm–1, possibly due to multiple hydrogen bonds inducing significant Cu(II)···Cu(II) coupling.

The organocatalytic α-alkylation of vinylogous carbonyl compounds to hydroxynitroolefins for the synthesis of hemiacetals was realized with excellent enantioselectivities and in high yields. High diastereoselectivity (up to >20:1) has been accomplished with the addition of Et3N. The α- and γ-alkylation of vinylogous ketone against nitroolefins displayed high but opposite facial selectivities. Transformation of the hemiacetal products to other polycyclic compounds, including the euroticin B analog, has been demonstrated.

The reaction of AuCl(SMe2) with equimolar NaO5NCS2 [O5NCS2 = (aza-18-crown-6)dithiocarbamate] in CH3CN gave [Au2(O5NCS2)2]·2CH3CN (2·2CH3CN), where six other 2·solvates (solvates = 2DMF, 2DMSO, 2THF, 2acetone, 1.5toluene, and 1.5anisole) can be successfully isolated from different crystal-growing processes (i.e., ether diffusion, layer method, or evaporation in air) by dissolving the dry powder samples of 2·2CH3CN in the respective solvents, and their crystal structures are all determined by X-ray diffraction as well. It is noted that there are different intermolecular Au(I)···Au(I) contacts in combination with various luminescences for 2·solvates and indeed there is a close relationship between intermolecular Au(I)···Au(I) contacts [i.e., 2.8254(7)-2.9420(5) A] and luminescence energies (i.e., 554-604 nm), including three examples of 2·2CH3CN, 2·0.5m-xylene, and 2·tert-butylbenzene·H2O reported in our previous work. In 2·solvates, the toluene and tert-butylbenzene solvates have the shortest [2.8254(7)-2.8289(7) A] and longest [2.9420(5) A] intermolecular Au(I)···Au(I) contacts, respectively, and consequently they show the respective lowest (604 nm) and highest (554 nm) luminescence energies. Indeed, 2·solvates exhibit different types of time-dependent luminescence upon solvate loss in air. Furthermore, B3LYP/LanL2DZ calculation results can help to clarify the relationship between intermolecular Au(I)···Au(I) contacts and luminescence energies for 2·solvates.

Grafting of organic groups on the surface of metal-oxide clusters greatly enhances the Li+ ion capacity. Triply organo-substituted polyoxometalates (RN-POMs) display an excellent Li+ ion capacity (...

Reaction of tert-butyl 3,5-diaminobenzoate with cyanuric chloride gave triazine-based macrocycle 1 in 44.3% yield, which was characterized by 1H and 13C NMR spectroscopy, mass spectrometry, and ele...

Two supramolecular architectures, [Mn(Hdpe)(C4O4)0.5(H2O)3][Mn(C4O4)2(H2O)2] (1) and [Mn(Hdpe)2(H2O)4][Mn(C4O4)2(H2O)2]2·8H2O (2) (C4O42– = dianion of squaric acid (H2C4O4); dpe = 1,2-bis(4-pyridyl...

A new organic small-molecule family comprising tetracyanoquinodimethane-substituted quinoidal dithioalky(SR)terthiophenes (DSTQs) (DSTQ-6 (1); SR = SC6H13, DSTQ-10 (2); SR = SC10H21, DSTQ-14 (3); S...

Light triggers the formation of HNO from a metal-nitrosyl species, facilitated by an intramolecular pendant thiol proton. Two {FeNO}6 complexes (the Enemark-Felthan notation), [Fe(NO)(TMSPS2)(TMSPS2H)] (1, TMSPS2H2 = 2,2'-dimercapto-3,3'-bis(trimethylsilyl)diphenyl)phenylphosphine; H is a dissociable proton) with a pendant thiol and [Fe(NO)(TMSPS2)(TMSPS2CH3)] (2) bearing a pendant thioether, are spectroscopically and structurally characterized. Both complexes are highly sensitive to visible light. Upon photolysis, complex 2 undergoes NO dissociation to yield a mononuclear Fe(III) complex, [Fe(TMSPS2)(TMSPS2CH3)] (3). In contrast, the pendant SH of 1 can act as a trap for the departing NO radical upon irradiation, resulting in the formation of an intermediate A with an intramolecular [SH···ON-Fe] interaction. As suggested by computational results (density functional theory), the NO stretching frequency (νNO) is sensitive to the intramolecular interaction between the pendant ligand and the iron-bound NO, and a shift of νNO from 1833 (1) to 1823 cm-1 (A) is observed experimentally. Subsequent photolysis of the intermediate A results in HNO production and a thiyl group that then coordinates to the Fe center for the formation of [Fe(TMSPS2)2] (4). In contrast with the common acid-base coupling pathway, the HNO is not voluntarily yielded from 1 but rather is generated by the photopromoted pathway. The photogenerated HNO can further react with [MnIII(TMSPS3)(DABCO)] (TMSPS3H3 = (2,2'2''-trimercapto-3,3',3''-tris(trimethylsilyl)triphenylphosphine; DABCO = 1,4-diazabicyclo[2.2.2]octane) in organic media to yield anionic [Mn(NO)(TMSPS3)]- (5-) with a {MnNO}6 electronic configuration, whereas [MnIII(TMSPS3)(DABCO)] reacts with NO gas for the formation of a {MnNO}5 species, [Mn(NO)(TMSPS3)] (6). Effective differentiation of the formation of HNO from complex 1 with the pendant SH versus NO from 2 with the pendant SMe is achieved by the employment of [MnIII(TMSPS3)(DABCO)].

Two tetrathioalkyl-substituted bithiophene-based small molecule quinoids (TSBTQs) having different chain lengths (thio-hexyl and -decyl) are synthesized and applied as an n-type active component in organic field effect transistors (OFETs). The resulting two TSBTQs exhibit good solubility in various organic solvents and LUMO levels below −4.0 eV. The theoretical DFT calculation supported by single crystal structures confirms the π-conjugated backbone planarity due to the S(thiophene)⋯S(alkyl) non-covalent interaction. Optimized TSBQT-10 OFETs exhibit an electron mobility of 0.18 cm2 V−1 s−1, which is higher than that of TSBTQ-6 (0.09 cm2 V−1 s−1). The reliability of the OFETs under representative environmental and operational conditions is also determined. The effects of side chains including their lengths and contribution to the main chain π-system coplanarity presented here demonstrate an efficient method to manipulate the charge carrier mobility of the quinoidal organic semiconductors.

This paper proposes a novel μ-hydroxo-bridged dinuclear macrocyclic zinc complex, {[Zn(C10H20N8)]2(OH)}(BF4)3. The structure was determined by X-ray crystallography: Monoclinic, C2/c, a = 25.4632(6), b = 10.9818(3), c = 15.7522(4) A, Z = 8, R1 = 0.0233, wR2 = 0.0557, based on reflections I > 2σ(I). The complex was successfully reacted with graphene oxide to form a μ-hydroxo-bridged dinuclear macrocyclic Zn complex/reduced graphene oxide composite. To evenly disperse the Zn- and N-rich complex onto the surface of the reduced graphene oxide, and to enhance the electrocatalytic property of the graphene composites, a soluble molecular grafting method was used here. The graphene-based composites were applied as the counter electrodes (CEs) of dye-sensitized solar cells. Current density–voltage measurements revealed that the conversion efficiency of the GO/Zn (1 : 10) sample was 7.78%, which was better than that of Pt CE (7.49%). GO/Zn (1 : 10) CE exhibited the lowest impedance (RCE = 9.90 Ω), which was better than that of Pt CE (RCE = 66.1 Ω), showing that GO/Zn CEs can reduce the impedance at the CE/electrolyte interface. The proposed method is simple, and the composite materials can potentially replace conventional Pt, optimizing efficiency and reducing production cost.

A series of new metal-free organic dyes based on 3,3′-dithioalkyl-2,2′-bithiophene (SBT) organic chromophores was synthesized for use in dye-sensitized solar cells (DSSCs). Because S(alkyl)⋯S(thiophene) intermolecular interlocking renders the twist angle in the structure as

A V(iii) complex bearing a tris(thiolato)phoshine derivative mediates the reduction of nitrite without the assistance of external protons or oxophilic substrates. The metal site plays dual roles for nitrite binding and deoxygenation. The reaction is monitored by spectroscopy combined with isotopic labeling experiments. The formed product, a {VNO}4 species, is isolated and characterized.

Synthesis of the multidentate coordinated chelate N3C–H2, composed of a linked functional pyridyl pyrazole fragment plus a peripheral phenyl and pyridyl unit, was obtained using a multistep protoco...

Sponge-derived scalaranes are remarkable sesterterpenoids previously found to exhibit profound inhibitory effects against neutrophilic inflammation. In our current work, we constructed the metabolomic profile of marine sponge Lendenfeldia sp. for the first time using a tandem mass spectrometry (MS/MS) molecular networking approach. The results highlighted the rich chemical diversity of these scalaranes, motivating us to conduct further research to discover novel scalaranes targeting neutrophilic inflammation. MS- and NMR-assisted isolation and elucidation led to the discovery of seven new homoscalaranes, lendenfeldaranes K–Q (1–7), characterized by methylation at C-24, together with five known derivatives, lendenfeldarane B (8), 25-nor-24-methyl-12,24-dioxoscalar-16-en-22-oic acid (9), 24-methyl-12,24,25-trioxoscalar-16-en-22-oic acid (10), felixin B (11), and 23-hydroxy-20-methyldeoxoscalarin (12). Scalaranes 1–4 and 6–12 were assayed against superoxide anion generation and elastase release, which represented the neutrophilic inflammatory responses of respiratory burst and degranulation, respectively. The results indicated that 1–3 and 6–12 exhibited potential anti-inflammatory activities (IC50 for superoxide anion scavenging: 0.87~6.57 μM, IC50 for elastase release: 1.12~6.97 μM).

Three complexes [Fe(L)2](ClO4)2 (1)、[Ni(L)2](ClO4)2 (2) and [Co(L)2](ClO4)2 (3) were synthesized by the reaction of N,N’-(4-methylpyridin-2-yl)pyrazine-2,6-diamine (L) with Fe(ClO4)2·6H2O, (Ni(ClO4)2·6H2O or Co(ClO4)2·6H2O) at room temperature, respectively. They were characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The catalytic behavior of the complexes for the synthesis of propylene carbonate from propylene oxide and carbon dioxide were studied. The results show that all of them showed excellent catalytic activities with TOF as high as 2104 h-1, 2824 h-1 and 2605 h-1, respectively. Complex 2 that exhibit higher catalytic activity was taken to explore the influence of time, pressure and temperature to optimize the reaction condition in detail.

The [3 + 2] cycloaddition reactions of a series of ynoate esters with a ruthenium azido complex [Ru]−N 3 ( 1 , [Ru] = ( η 5 -C 5 H 5 )(dppe)Ru, dppe = Ph 2 PCH 2 CH 2 PPh 2 ) were investigated. The reaction products, metal-bound heterocyclic complexes such as the triazolato complexes [Ru]N 3 C 2 (CO 2 Et) 2 ( 2 ), [Ru]N 3 C 2 (CO 2 Et)(CF 3 ) ( 3 ), [Ru]N 3 C 2 (CO 2 Me)(Ph) ( 4 ) and [Ru]N 3 C 2 (CO 2 Et)(CH 3 ) ( 5 ) were produced from diethyl acetylene dicarboxylate, ethyl 4,4,4-trifluoro-2-butynoate, methyl phenylpropiolate and ethyl 2-butynoate, respectively. The complexes were all structurally characterized as being N(2)-bound. The alkylation of 2 with organic halides resulted in the cleavage of the Ru−N bond and the formation of a series of 1-alkylated-4,5-bis(ethoxycarbonyl)-1,2,3-triazoles N 3 (CH 2 R)C 2 (CO 2 Et) 2 ( 6a , R = H; 6b , R = C 6 F 5 ; 6c , R = Ph; 6d , R = 4-CH 2 Br-C 6 H 4 ; 6e , R = 4-CN-C 6 H 4 ). The high regioselective alkylation of 4 with organic halides gave a 1-alkylated-4-phenyl-5-methoxycarbonyl-1,2,3-triazoles N 3 (CH 2 C 6 F 5 )C 2 (Ph)(CO 2 Me) ( N 3 - 7a ). The structures of complexes 2 , 3 , 4 , 5 and N 3 - 7a were confirmed by single-crystal X-ray diffraction analysis.

Anionic nitrogen heterocyclic carbene complexes of C,N-bound mercuramacrocycles {Hg4Cl4(R-Bim)4} (BimH = benzimidazole; R = Ph, Py) were prepared either from the simple reaction of N-substituted benzimidazoles with HgCl2 or from the reaction of N-substituted benzimidazoles with Hg(OAc)2 and NaCl. The former reaction is unique as no additional base is required, although in low reaction yield. Under similar reaction conditions, only N-bound benzimidazole complexes were obtained when HgBr2 or HgI2 instead of HgCl2 was employed. The different reactivity could be due to the hard-soft acid-base property of mercury(II) and halides, that facilitates the cleavage of Hg-Cl bond and promotes the C-metallation of HgCl2 and benzimidazole. Upon protonation of {Hg4Cl4(R-Bim)4} with HBF4⋅OEt2, NH,NR-NHC complexes of [HgCl(R-Bim-H)][BF4] (R = Ph, Py) were obtained. Preliminary study on the transmetallation reaction of {Hg4Cl4(Ph-Bim)4} with PdCl2(CH3CN)2 and LiCl did provide a C,N-bound NHC palladium complex.

A known briarane, brianthein W (1), along with four new hydroperoxybriaranes, briaviolides R–U (2–5), have been obtained from the octocoral Briareum violaceum. The absolute configuration of 1 was determined by X-ray analysis for the first time and the structures of briaranes 2–5 were established by spectroscopic methods. Bioactivity study showed that briarane 3 decreased the production of superoxide anions from human neutrophils.

We report the syntheses, characterization, electronic structures and magnetic properties of four redox pairs of novel nickel-extended metal-atom chain (EMAC) complexes containing pyridine-, naphthyridine- and sulfonyl-containing ligands (H2Tspnda and H2Mspnda) (1–2 and 5–6). We further study the corresponding phenyl-substituted ligands (H2Tsphpnda and H2Msphpnda) (3–4 and 7–8) to examine the details of ligand effects. The X-ray structure of one-electron-reduced [Ni5]9+ complexes shows shorter Ni–Ni bond distances (2.2646(6) for 1, 2.2943(7) for 3, 2.2436(11) for 5 and 2.2322(8) A for 7) in comparison with an average Ni–Ni distance of 2.3187(8) A for these complexes, indicative of a partial metal–metal bond interaction in the mixed-valence [Ni2]3+ (S = 3/2) unit. The most striking result is that the [Ni2]3+ site migrates from Ni(1)–Ni(2) to Ni(2)–Ni(3) when we replace the p-tolyl-sulfonyl group with methyl-sulfonyl group. These complexes present a rare example of the effect of crystal packing on the symmetric molecular structure yielding unsymmetric electronic distribution. Cyclic voltammetry measurements show four reversible redox waves and display the lower potentials of the [Ni5]9+ complexes. These unusual lower potentials facilitate one-electron oxidation of these four complexes to [Ni5]10+-core forms. We applied the magnetic susceptibility and EPR measurements to examine the magnetic properties of these four [Ni5]9+-core pentanickel complexes and study the bonding nature of these mixed-valence [Ni2]3+ units. Indeed, the results of EPR measurements reflect the migration of the mixed-valence site and the change of symmetry. Surprisingly, the oxidized [Ni5]10+ counterparts behave differently: complex 2 exhibits an antiferromagnetic interaction with J = −13.59 cm−1 between the two terminal Ni ions, while the others (4, 6 and 8) display diamagnetic properties as all of the Ni2+ ions are in low-spin (S = 0) states. These three complexes, to the best of our knowledge, are the first examples of all Ni2+ ions in a null spin configuration for pentanickel chains. Even though the structures of these complexes are similar to each other, their corresponding electronic structure and oxidized products show drastic changes in their magnetic properties and bonding nature. These differences of the properties and bonding nature of these pentanickel complexes are attributed to the ligand effects.

This paper reports on the synthesis, structure and magnetic properties of a new type of rod like Mn₁₂ metal cluster, [Mn₁₂O₇(OH)₂(OMe)₂(dmhmp)₄(O₂CPh)₁₁(H₂O)] (6) where the ligand (dmhmpH) is 2-(pyridine-2-yl) propan-2-ol. Compound (6) was obtained by reacting MnCl₂•4H₂O with dmhmpH in the presence of benzoic salt and Et₃N. The resulting crystalline material is assigned to the triclinic space group P1̄. Although compound (6) displays ferromagnetic and antiferromagnetic competition behavior, this does not prevent the molecule from functioning as a single-molecule magnet (SMM). The SMM behavior is evidenced by observing frequency dependent out-of-phase ac signals as well as magnetization hysteresis loops at low temperatures in a micro-SQUID study. A brief comparison between all rod-like Mn₁₂ materials is also given in the manuscript.

The alkylation of the N(2)-bound ruthenium triazolate [Ru]N3C2HCO2Et (2, [Ru] = (η5-C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with benzylbromides is reported. The regiospecific alkylation of 2, which results from the [3 + 2] cycloaddition of ethyl propiolate with [Ru]-N3 (1), gives a series of cationic N(1)-bound N(3)-alkylated-4-ethoxycarbonyl triazolato complexes {[Ru]N3(CH2R)C2HCO2Et}[Br] (3a, R = 4-CH2Br-C6H4; 3b, R = 3,5-(CH2Br)2-C6H3; 3c, R = 2,6-F2-C6H3; 3d, R = 4-CN-C6H4) and the subsequent cleavage of the Ru-N bond of 3a-3d gives N(1)-alkylated-5-ethoxycarbonyl triazoles N3(CH2R)C2HCO2Et (4a-4d) and [Ru]-Br, which, on reacting with sodium azide, would afford [Ru]-N3 (1) thus forming a reaction cycle. The treatment of {[Ru]N3(CH2C6F5)C2HCO2Et}[Br] (3e) with sodium azide in refluxing ethanol gives the free triazole N3(CH2C6F5)C2HCO2Et (4e) and 1. The treatment of 2 with an equivalent of 3a affords a dinuclear bis(triazolato) complex {α,α'-bis([Ru]N3C2HCO2Et)-p-xylene}[Br]2 (5) and an organic bis(triazole) complex α,α'-bis(N3C2HCO2Et)-p-xylene (6). The treatment of 2 with CF3COOH in CHCl3 at room temperature affords a mixture of N(2)-bound 1H- and 3H-4-ethoxycarbonyl triazolato complexes {[Ru]N3HC2HCO2Et}[CF3COO] (1H-7) and (3H-7) in a ratio of 5 : 2. The structures of 4e, 5 and 1H-7 were confirmed by single-crystal X-ray diffraction analysis.

Two tetrapyridyl ligands of 1,2,4,5-tetraethynyl(4-pyridyl)benzene (tpeb) and tetra(4-pyridyl)-tetrathiafulvalene (TTF(py)4) were used to react with trinuclear (Re(CO)4)3(C3N3S3) (C3N3S3 = cyanurate trianion) moieties to afford hexanuclear [(Re(CO)3)6(tpeb)2(C3N3S3)2]·4CH3CN·toluene (1) and dodecanuclear [(Re(CO)3)12(TTF(py)4)3(C3N3S3)4]·8CH3CN·12DMF (2) boxes, respectively, under solvothermal conditions. Surprisingly, similar tetrapyridyl ligands with different core units (i.e., benzene and tetrathiafulvalene moieties) led to dramatically different structural motifs (i.e., hexanuclear and dodecanuclear boxes). Complex 1 forms a slightly bent trigonal-prismatic structure, containing two μ3-tpeb ligands and two Re3C3N3S3 moieties as well as a π⋯π interaction distance of 3.86 A. It is noted that complex 2 features a novel four-star structure, and three crossed tetrathiafulvalene moieties from three μ4-TTF(py)4 ligands to form a triple-decker arrangement with a π⋯π interaction distance of 3.70 A. Moreover, 1 and 2 display luminescence properties in the solid state along with electrochemical properties for complex 2 arising from the electroactive TTF core.

A novel trinuclear complex [Ni3(μ3-dbay)4Cl2]I3 (1) with a mixed-valence state was prepared by reacting the tridentate ligand 1,13,14-triaza-dibenz[a,j]anthracene (dibenzanthyridine = dbay) with anhydrous NiCl2 and sodium tetraphenylborate. The title compound provides the first example of a trinuclear nickel-anthyridine-based string complex in which the metal framework of complex 1 consists of NiII-NiI-NiII. X-ray crystallography, magnetic susceptibility and detailed EPR measurements were performed to characterize the structure and magnetic properties of this unique complex.

The first regioselective, diastereoselective, and enantioselective organocatalyzed Michael-Michael cascade of vinylogous ketone enolates and nitroalkenes for the construction of fully substituted cyclobutanes is achieved by the deployment of the appropriate chiral squaramide catalyst and the pertinent substituent on the substrate. The domino reaction provided cyclobutanes with four contiguous stereocenters, including a quaternary center in good yields with diastereomeric ratio of >20:1 and with enantioselectivities of mostly up to 98% enantiomeric excess (ee). The structures and the absolute configurations of the adducts were confirmed by single-crystal X-ray crystallographic analyses of the appropriate products.

A three-dimensional (3D) polycatenation supramolecular network with chemical formulas, [Zn(bpp)(BDC)]·1.5H2O (1), (bpp = 1,3-bis(4-pyridyl)propane, BDC2- = dianion of terephthalic acid), was synthesized and structurally determined. In compound 1, the coordination geometry of Zn(II) ion is distorted tetrahedral, where its 2D undulated layered framework is constructed via the bridges of Zn(II) ions with bpp and BDC2− ligands. Adjacent 2D layers are arranged in a combined parallel and interpenetrated manner to complete its 3D polycatenation supramolecular architecture. Compound 1 shows a one-step dehydration process with the weight losses of 6.1 %, approximately equal to the weight percentage of losing 1.5 guest water molecules. The cyclic thermogravimetric analysis reveals that compound 1 shows reversible, sponge-like water de-/adsorption behavior during de-/rehydration processes. Compound 1 also exhibits significant water vapor hysteresis isotherm.

A new class of bis-tridentate Ir(III) complexes (Dap-1-4) was synthesized using carbene pincer pro-chelates PC1·H3(PF6)2 or PC2·H3(PF6)2 with either imidazolylidene or imidazo[4,5-b]pyridin-2-ylidene appendages, together with a second cyclometalating 2,6-diaryoxypyridine chelate, L1H2 and L2H2, differed by a NMe2 donor at the central pyridinyl fragment. The respective emission tuning between the ultraviolet and blue region was rationalized using time-dependent density functional theory (TD-DFT) approaches. Next, a highly efficient blue emitter (Dap-5) was synthesized by concomitant addition of two methyl groups and a single CF3 substituent at the central phenyl and peripheral imidazo[4,5-b]pyridin-2-ylidene entities of the carbene pincer chelate, respectively. The organic light-emitting diode (OLED) device with 15 wt % Dap-5 in DPEPO shows electroluminescence at 468 nm and with CIE (0.14, 0.15) and a max external quantum efficiency (max EQE) of 16.8% with low efficiency roll-off (EQE of 14.4% at 1000 cd m-2); the latter is attributed to the relatively shortened triplet excited-state radiative lifetime. These results highlight the adequateness of bis-tridentate Ir(III) phosphors in fabrication of practical blue-emitting OLEDs.

This paper describes a tetrahedral mononuclear Co(ii) complex [CoL2](ClO4)2 (1) in which L = 2,9-diphenyl-1,10-phenanthroline. The structure of 1, which was determined by single crystal X-ray diffraction, indicates that it exists in the triclinic space group P1[combining macron]. Magnetic property studies were conducted by reduced magnetization measurements, ab initio calculations and X-band EPR experiments, the results of which revealed a large zero-field splitting, with D ∼ -45.9 cm-1. The Arrhenius equation indicates that the kinetic energy barrier of 1 is Ueff = 46.9 cm-1. This study describes a very rare case of a Co(ii) single ion magnet (SIM) that is purely tetrahedrally coordinated by pyridine like ligands.

A two-dimensional (2D) coordination polymer, [Co(4-dpds)(bdc)(H2O)2]&middot, 4-dpds (1) (4-dpds = 4,4&prime, dipyridyldusulfide and bdc2&minus, = dianion of benzenedicarboxylic acid), has been synthesized and structurally determined by single-crystal X-ray diffractometer. In 1, the bdc2&minus, and 4-dpds both act as bridging ligands connecting the Co(II) ions to form a 2D wrinkled-like layered coordination polymer. Two wrinkled-like layered coordination polymers are mutually penetrated to generate a doubly interpenetrated framework, and then extended to its 3D architecture via the supramolecular forces between doubly interpenetrated 2D frameworks and free 4-dpds ligands by intermolecular O&ndash, H&sdot, &sdot, N hydrogen bonding interaction. Crystal packing arrangements were characterized by fingerprint plots, which were derived from the Hirshfeld Surfaces analysis, and showed that intermolecular hydrogen bonding interactions are the most important interactions on the construction of the crystal 1.

In a refluxing chloroform solution, the &eta, 1-pyrimidinyl {pyrimidinyl = C4H3N2} palladium complex [Pd(PPh3)2(&eta, 1-C4H3N2)(Br)], 1 exhibited intermolecular displacement of two triphenylphosphine ligands to form the doubly bridged &eta, 2-pyrimidinyl Dipalladium complex [Pd(PPh3)(Br)]2(&mu, &eta, 2-C4H3N2)2, 3. The treatment of 1 with Hdppa {Hdppa = N,N-bisdiphenyl phosphinoamine} in refluxing dichloromethane yielded the doubly bridged Hdppa dipalladium complex [Pd(Br)]2(&mu, 2-Hdppa)2, 4. Complex 1 reacted with the bidentate ligand, NH4S2CNC4H8 and, NaS2COEt, and the tridentate ligand, KTp {Tp = tris(pyrazoyl-1-yl)borate}, to form the &eta, 2-dithio &eta, 1-pyrimidinyl complex [Pd(PPh3)(&eta, 1-C4H3N2)(&eta, 2-SS)], (5: SS = S2CNC4H8, 6: SS = S2COEt) and &eta, 2-Tp &eta, 2-Tp)], 7, respectively. Treatment of 1 with AgBF4 in acetonitrile at room temperature resulted in the formation of the doubly bridged &eta, 2-pyrimidinyl dipalladium complex [{Pd(PPh3)(CH3CN)}2(&mu, 2-C4H3N2)2][BF4]2, 8. All of the complexes were identified using spectroscopic methods, and complexes 3, 4, and 8 were determined using single-crystal X-ray diffraction analyses.

Three homoleptic Pt(II) metal complexes [Pt(imPz)2] (1), [Pt(imiz)2] (2), and [Pt(imMz)2] (3) were synthesized from the treatment of Pt(DMSO)2Cl2 and functional imidazolyl pyrazole in refluxing tetrahydrofuran (THF). Alternatively, the heteroleptic Pt(II) complexes [Pt(imPz)(fppz)] (4), [Pt(imiz)(fppz)] (5), and [Pt(imMz)(fppz)] (6) were obtained from the treatment of a common intermediate [Pt(fppzH)Cl2] with a corresponding imidazolyl chelate. Pt(II) complexes 1, 2, and 5 were studied by single-crystal X-ray diffraction to reveal the corresponding packing arrangement in their crystal lattices, among which both homoleptic complexes 1 and 2 formed monomeric species, while heteroleptic 5 aligned as a dimer with a nonbonding Pt···Pt contact of 3.574 A. Subsequent photophysical examinations showed that the homoleptic 1-3 and heteroleptic 4-6 exhibited the structured sky-blue ππ* emission and structureless light-green-emitting metal-metal-to-ligand charge transfer (MMLCT) emission in the solid state, respectively. A shortened Pt···Pt interaction of approximately 0.34-0.35 nm was confirmed in thin films of all heteroleptic Pt(II) complexes 4-6 by grazing-incidence X-ray diffraction (GIXD) analyses. Finally, Pt(II) complex 6 was employed as a dopant in the fabrication of organic light-emitting diode (OLED) devices with varied doping ratios, among which OLEDs with only 1 wt % 6 in the SimCP host exhibited a maximum external quantum efficiency (EQE) of 5.8% and CIEx,y values of 0.20, 0.31. In contrast, OLEDs using a nondoped architecture (i.e., 100% of 6 in the emitting layer (EML)) achieved a maximum EQE of 26.8%, current efficiency (CE) of 91.7 cd A-1, and power efficiency (PE) of 80.1 lm·W-1 and CIEx,y values of 0.41, 0.55, manifesting their versatility in various degrees of stacking assemblies and hence facile color-tuning capability on OLEDs.

A series of 3,3'-dithioalkyl-2,2'-bithiophene (SBT)-based organic chromophores were designed and developed for the use in dye-sensitized solar cells (DSSCs). By appropriate structural modification of the SBT π-linkers with different alkyl chains and conjugated thiophene units, chromophore aggregation and interfacial charge recombination could be suppressed to a remarkable degree. Single-crystal and optical/electrochemical data clearly show that the SBT core is nearly planar with the torsional angle

Two 11,20-epoxybriaranes, including a known compound, juncenolide K (1), as well as a new metabolite, fragilide X (2), have been isolated from gorgonian Junceella fragilis collected off the waters of Taiwan. The absolute configuration of juncenolide K (1) was determined by single-crystal X-ray diffraction analysis for the first time in this study and the structure, including the absolute configuration of briarane 2 was established on the basis of spectroscopic analysis and compared with that of model compound 1. One aspect of the stereochemistry of the known compound 1 was revised. Briarane 2 was found to enhance the generation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) release from RAW 264.7 cells.

By using tripyridyldiamine ligand, N , N’ -di(pyrazin-2-yl)pyridine-2,6-diamine (H 2 dpzpda), linear pentanuclear nickel(II) [Ni 5 (µ 5 -dpzpda) 4 Cl 2 ] (1) and tetranuclear copper(II) [Cu 4 (Hdpzpda) 2 (CH 3 COO) 6 ] (2) complexes were first synthesized and structurally characterized. This pentanickel linear metal chain is helically wrapped by four syn-syn-syn-syn type dpzpda 2- ligands. There are two types of Ni Ni distances existing in the complex. The terminal Ni Ni distances bonded to the axial ligand are longer (2.3877(8) A) affected by the axial ligands. The inner Ni Ni distances are very short and remain constant (2.3071(6) A). Two terminal Ni(II) ions bonded to the axial ligands are in a square-pyramidal (NiN 4 Cl) environment and exhibit long Ni N bonds (2.097(4) A), which are consistent with a high-spin Ni(II) configuration. The inner three Ni(II) ions display short Ni N (1.8915(8)–1.903(4) A) bond distances, which are consistent with a square planar (NiN 4 ), the diamagnetic arrangement of a low-spin Ni(II) configuration. Temperature-dependent magnetic research revealed an antiferromagnetic interaction between the two terminal atoms through a superexchange pathway along metal cores with a parameter of about −51.0 cm –1 . Observation of the first oxidation peak in the cyclic voltammograms of 1 at +1.206 V revealed that this complex is the most resistant to oxidation among all known pentanuclear nickel strings with unmodulated and modulated oligo-α-pyridylamido ligands. The structure of 2 consists of four copper atoms linearly placed with a copper(II) acetate dimer in the centre. In complex 2 ligand H 2 dpzpda coordinates to the Cu(II) atoms as a tetradentate ligand in an all anti conformation. Copper complex 2 is built to a 1-D supramolecular chain structure through intermolecular hydrogen bond and strong π-π interaction (3.19 A) between the pyridine and pyrazine rings. From the magnetic susceptibility data, 2 shows strong antiferromagnetic coupling, which was satisfactorily fitted using Hamiltonian H = J 1 ( S 1 S 2 + S 3 S 4 ) + J 2 S 2 S 3 . The best fitting result were obtained with the parameters J 1 = 10.64 cm −1 , J 2 = −175.36 cm −1 , g = 2.11.

Multiple-stimuli-responsive photoluminescence films based on a ZnII -organic framework, {[Zn2 (Htpim)(3,4-pydc)2 ]⋅4 DMF⋅4 H2 O}n (1, Htpim=2,4,5-tri(4-pyridyl)imidazole, 3,4-H2 pydc=3,4-pyridinedicarboxylic acid), were fabricated. This compound consisted of a 2D corrugated layer, {Zn(3,4-pydc)}n , which was further pillared using a Y-shaped pillar N-donor ligand (Htpim) to form a 3D-pillared-layer framework with 1D open channels. The rectangular channels in the as-synthesized compound are fully occupied by guest DMF and H2 O molecules. The framework exhibits instant and reversible thermochromic properties corresponding to the removal of different H2 O and DMF guest molecules as temperature increases. The pale-yellow crystal undergoes significant redshifting to a greenish emission centered at 530 nm. Compound 1 also showed remarkable solvatochromic effects in the presence of various organic solvents without affecting its structural integrity. In addition, polycrystalline MOF films were grown on an α-Al2 O3 support for switchable and fast-response thermochromic and solvatochromic sensors.

New types of organocatalytic 1,2-rearrangements, which resemble the Smiles-like or semi-pinacol-like rearrangement, of Michael adducts of 1,3-dicarbonyl-2-alkyl compounds and nitroalkenes have been realized. Unlike the well-known conjugate addition, the reaction affords the 1-phenyl-1-nitroalkanes via unprecedented rearrangement and cascade reactions. Structures of the appropriate products were unambiguously characterized by X-ray crystallography.

We report the unprecedented dual properties of excited-state structural planarization and thermally activated delayed fluorescence (TADF) of 10-dimesitylboryl phenoxazine, i.e., PXZBM. Bearing a nonplanar phenoxazine moiety, PXZBM shows the lowest lying absorption onset at ∼390 nm in nonpolar solvents such as cyclohexane but reveals an anomalously large Stokes-shifted (∼14 500 cm–1) emission maximized at 595 nm. In sharp contrast, when a phenylene spacer is added between phenoxazine and dimesitylboryl moieties of PXZBM, the 10-(4-dimesitylborylphenyl)phenoxazine PXZPBM in cyclohexane reveals a much blue-shifted emission at 470 nm despite its red-shifted absorption maximized at 420 nm (cf. PXZBM). The emission of PXZBM further reveals solvent polarity dependence, being red-shifted from 595 nm in cyclohexane to 645 nm in CH2Cl2. For rationalization, the steric hindrance between phenoxazine and the dimesitylboryl unit in PXZBM caused a puckered arrangement of phenoxazine at the ground state. Upon electronic ...

A new 3D coordination polymer {[Co2(μ-OH2)(TTPA)(DTDN)2·DMF]·H2O}n (1, TTPA = tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine, DTDN = 6,6'-dithiodinicotinate) was synthesised and characterised. The redox properties of this framework were elucidated by solid state electrochemical and spectroelectrochemical data. This is the first investigation of the redox behaviour of TTPA in coordination polymers. Furthermore, the incorporation of a paramagnetic Co(ii) metal ion into the framework caused 1 to show spin-flop behaviour as the result of a field-induced magnetic transition. The incorporation of two flexible ligands and Co(ii) metal ions represents a feasible approach for the advancement of multifunctional materials.

The CoRu2(dpa)4Cl2 (1) (dpa: 2,2′-dipyridylamide) is synthesized by the reaction of Ru2(OAc)4Cl and Co3(dpa)4Cl2. By mixing 1 with NH3, Co2+ can be removed and result in the formation of unique binuclear complex 4,0-Ru2(dpa)4Cl (2) featuring one coordination pocket supported by free pyridine groups. Hence, this complex can act as an outstanding precursor for the formation of heterotrimetallic chains with MRu2 cores. A series of M–Ru25+ complexes (M = Co2+ (3), Ag+ (4), Mn2+ (5), Fe2+ (6), Zn2+ (7), Cd2+ (8), Pd2+ (9), Rh2+ (10), and Ir2+ (11)) were prepared and isolated, representing the most complete series of heterotrimetallic chains to date. All these metal string complexes are in a linear trimetallic framework helically wrapped by four dpa− ligands, characterized by X-ray diffraction measurements. The bending of the trinuclear metal cores in RhRu2 (10) and IrRu2 (11) (∠Ru–Ru–Rh: 167.58° and ∠Ru–Ru–Ir: 167.61°) indicates that a heterometallic metal–metal bonds (Ru–Rh; Ru–Ir) are generated. The studies from DFT calculation of 10 and 11 coincide with the experimental results. Furthermore, the M⋯Ru25+ distances are regulated by the factors including the bonding force of M–pyridyl and the static repulsion between M and Ru25+ unit. Interestingly, the trend for these distances is in line with that observed in trans-M(py)4Cl2 complexes.

TADF molecules with a higher horizontal–dipole ratio have recently been realized to show a large conversion efficiency in organic light-emitting diodes (OLEDs) and hence great promise for their application in display and solid state lighting sources. The current work focuses on fine-tuning the structure of the parent 2,6-diphenylpyrimidinyl compound PhPMAF and its derivatives with a series of 2,6-dipyridylpyrimidine acceptors; namely: 2NPMAF, 3NPMAF and 4NPMAF, among which the intramolecular CH⋯N bonding interaction was confirmed for 2NPMAF, showing good agreement with the NMR results. The solvatochromism and TADF behaviors, together with TD-DFT computations, of the titled compounds were explored to gain insights into the structure–photophysics relationship. Eventually, these functional 2,6-dipyridylpyrimidine acceptor based TADF compounds exhibit electroluminescence ranging from deep-blue to sky-blue, among which an external quantum efficiency (EQE) of 24.9% was achieved for the derivative 3NPMAF. The high horizontal–dipole ratios (∼0.86–0.91) obtained for this class of compounds elucidates the superior OLED performance. Moreover, the non-doped OLED architecture achieves an EQE of 14.1% for 3NPMAF, which is superior to that of PhPMAF with an EQE of 5.1%, demonstrating the significance of dipyridylpyrimidine as an acceptor for the future structural design of TADF emitters.

The synthesis, characterization by X-ray analysis and magnetic properties of a one dimensional coordination polymer {[Mn7(OH)2(dhap)2(N3)3(MeCN)4(ClO4)2]·2(MeCN)·2(ClO4)}∞ (1) are reported. The ligand dhapH4 in the complex is 2,6-bis[N,N-di(hydroxyethyl)aminomethyl]pyridine. This compound crystallizes in the monoclinic space group C2/c. Each [Mn7(OH)2(dhap)2(N3)3(MeCN)4(ClO4)2] unit (abbreviated by Mn7) is linked end-to-end by azido ligands to its neighboring units to form a one dimensional polymer. Magnetic susceptibility measurements indicate that the polymer is composed of S = 8 units with inter-Mn7-unit antiferromagnetic coupling. The Jahn–Teller axes of the Mn7 units are arranged in a zigzag manner along the polymer chain which induces spin canting at low temperatures. The slow magnetization relaxation at low temperatures was evidenced by observing out-of-phase signals in ac magnetic susceptibility measurements that give Ueff = 47.5 K and Δ0 = 2.7 × 10−13 s. This phenomenon also indicates that this one dimensional coordination polymer functions as a single-chain magnet (SCM).

Two series of ionic liquid crystals (ILCs) derived from N-phenylpyridinium 1–2 were prepared and their mesomorphic properties were investigated. A versatile and effective method was developed to prepare these ionic compounds 2-X from their precursor chloride 2-Cl. X-ray crystal structure analyses of three single crystals revealed that a sandwiched head-to-head or bilayer lamellar structure induced by H-bonds in the solid state was observed. The anion was proximally intercalated near the head group. Weak H-bonds were induced and attributed to the formation of mesophases. The type of counter anions has a significant influence on the stability of the mesophase, ΔTSmA = 221.3 (2-Cl) > 213.1 (2-SCN) > 173.9 (2-BF4) > 85.4 (2-RSO3) > 63.8 (2-PF6) > 41.4 °C (2-OTf) for all derivatives with n = 12. The compound 2-BF4 (n = 16) has the widest temperature range of the smectic-A (SmA) phase (i.e., ΔTSmA = 234.3 °C), significantly broader than those of other reported ILCs. Also compound 2-NTf2 (n = 14) was the first phenylpyridinium-based ILC and compound 2-SCN (n = 16) was the room temperature ILC. The X-ray diffraction experiments confirmed the structure of the SmA phase and it showed a strong dependence of bilayer structure with various anions. A linear correlation plot (R2 = 0.9643) of the clearing temperatures of compounds 2-X with the calculated effective radius (Reff) of the anions was obtained.

Two series of ionic liquid crystals derived from diphenylviologens, 1 and 2, were prepared and their photophysical and electrochemical properties were also investigated. The crystallographic data of two single crystals, 1-RSO3 (n = 10) and 2-BF4 (n = 12), showed that a mono- or bilayer-lamellar structure was induced by intermolecular H-bonds. All mesophases were identified as smectic A phases by POM textures and powder XRD data. A linear correlation plot (R2 = 0.8885) of the d-spacings vs. the calculated effective radius (Reff) in compounds 2-X was obtained. The aggregation-induced emission (AIE) ranging from ca. 463 to 529 nm observed in compounds 2-X (e.g., X = BF4, PF6, RSO3, OTf and NTf2) was also anion dependent. Also, compounds 2-X exhibited thermal switching, with an On/Off-emission mode between the Cr and SmA phases. In its cyclic voltammogram, compound 1-RSO3 (n = 12) exhibited two distinct reversible redox couples; in contrast, compound 2-RSO3 (n = 12) formed spike-like voltammetric peak potentials without redox couples.

A mixed-ligands Cd(II) coordination polymer, [Cd(2,2’-bpe)(C4O4)(H2O)2] (1) (2,2’-bpe = 1,2-bis(2-pyridyl)ethylene; C4O42− = dianion of squaric acid), has been synthesized and structurally characterized by single-crystal X-ray diffraction method. The coordination environment of Cd(II) ions in compound 1 is six-coordinate bonded to four oxygen atoms from two μ1,3-squarate (C4O42−) and two water molecules, and two nitrogen atoms from two 2,2’-bpe ligands. The squarate and 2,2’-bpe both act as bridging ligands with bis-monodentate coordination modes, connecting the Cd(II) ions to form a two-dimensional (2D) layered metal-organic framework (MOF). Adjacent 2D layers are then arranged in an ABAB parallel non-interpenetrating manner to construct its three dimensional (3D) supramolecular network. Intra- and inter-layers hydrogen bonding interactions between the C4O42− and water molecules in 1 provide an extra-stabilization energy on the construction of its 3D supramolecular network. The thermal stability of 1 is studied and discussed in details by TG analysis and in-situ PXRD measurement.

As a new synthetic approach, a versatile building block of [(Re(CO)4)3(N3S3)] (1a) can be used to react with linear dipyridyl ligands (i.e., pyrazine (pz), 4,4'-bipyridine (bpy), 1,2-di(4-pyridyl)ethylene (dpe), bis(4-pyridyl)acetylene (bpa), and 1,4-bis(pyridyl-4-ylethynyl)benzene (bpb)) and a tripyridyl one (1,3,5-tris(4-pyridylethynyl)benzene (tpb)) to afford a series of molecular cages, [(Re(CO)3)6(L)3(N3S3)2] (L = pz 2; bpy 3; bpe 4; bpa 5; bpb 6) and [(Re(CO)3)9(tpb)3(N3S3)3] (7) by solvothermal methods. Interestingly, various structural dimensions and motifs can be systematically tuned and obtained depending on different dipyridyl and tripyridyl ligands used in the reaction condition. In this regard, molecular cages of hexanuclear complexes of 2-6 containing dipyridyl ligands feature interesting trigonal-prism structures with different dimensionalities. Furthermore, the nonanuclear complex of 7 shows a novel trianglular-star structure, and three benzene rings of tpb ligands form a triple-decker arrangement with significant pi...pi interactions of 3.490(1) and 3.528(1) A. In addition, molecular cages of 1-3 and 5-7 exhibit luminescence in the solid state, and their luminescent properties are also studied.

An organocatalyzed enantioselective Michael–Michael–Michael–aldol cascade reaction for the construction of cyclopentane fused spirooxindoles was achieved. The domino reaction provided the spirooxindoles with six contiguous stereocenters including a quaternary center in good yields (55–64%) with excellent enantioselectivities (up to >99% ee). Enantioselective Michael–Michael–Michael–aldol condensation–aromatization reactions of an isomeric product were observed.

In an attempt to prepare the heavier analogue of NHC-stabilized borenium cation, we have prepared a silylene-coordinated borenium equivalent (1a), which can be viewed as a contact ion pair of borenium and triflate. The triflate anion coordinates to the oxophilic silicon center, leaving the boron center existing in a trigonal-planar geometry in the solid state and in solution. Nucleophilic substitution reactions of 1a all result in the release of free silylene ligand, demonstrating the borenium-ion-like reactivity of 1a. Chemical reduction of 1a leads to a neutral radical possessing a partial Si–B double bond.