Bis(4′-phenyl-2,2′:6′,2″-terpyridine)ruthenium(II): Holding the {Ru(tpy)2} embraces at bay

The solid state structure of [Ru(Phtpy)₂][PF₆]₂ · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)₂]²⁺ cations pack into sheets by virtue of {M(tpy)₂}₂ embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)₂]²⁺ or [M(pytpy)₂]²⁺ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine).     

Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

DNA binding of mixed-metal supramolecular Ru, Pt complexes

The mixed-metal supramolecular complexes [(tpy)Ru(PEt₂Ph)(dpp)PtCl₂](PF₆)₂ and [(tpy)Ru(PEt₂Ph)(bpm)PtCl₂](PF₆)₂ are of interest in that they couple light absorbing ruthenium centers to a reactive metal site through a communicative bridge (tpy=2,2^′:6^′,2^′′-terpyridine, BPM=2,2^′-bipyrimidine and DPP=2,3-bis(2-pyridyl)pyrazine). These systems have been studied and shown to avidly bind to DNA, greatly reducing its mobility through an agarose gel.     

Two-dimensional assembly of the type Cd10Te4 thiolate cluster with 4,4′-trimethylenedipyridine

Cadmium tellurium cluster molecule [Cd₁₀Te₄(SC₆H₄Me-p)₁₂] and bifunctioanal organic ligand 4,4′-trimethylenedipyridine (tmdp) are joined together through metal–ligand coordination bonds, forming a new inorganic–organic hybrid polymeric cluster {Cd₁₀Te₄(SC₆H₄Me-p)₁₂(tmdp)₂}_n (1) with a unique two-dimensional super-structure. The room temperature absorption and the diffuse reflectance UV–Vis spectra along with the photo-luminescence behavior were determined in the solid state. The thermal stability of the polymeric cluster was studied by thermal gravimetric analysis.     

A new binuclear potassium (І) complex with a novel 1D infinite water chain containing (H2O)12 clusters

A novel 1D infinite water chain made of (H₂O)₁₂ clusters containing two different chair water hexamers is found in the binuclear coordination compound, [K₂(L)₂(phen)₄]·6H₂O (1) (where L = 2,2′-azanediyldibenzoic dianion, phen = 1,10′-phenanthroline), which has been synthesized and structurally characterized by single-crystal X-ray diffraction. The fluorescence spectrum and thermogravimetric analysis (TGA) of the title complex 1 have been also discussed.     

A novel stair-like lithium coordination polymer constructed from 4,4′-bipyridine

A novel stair-like lithium coordination polymer Li₂(4,4′-bpy)₂(NO₃)₂, 1, has been synthesized by using standard Schlenk techniques. X-ray diffraction shows the 2D stair-like framework contains an approximately perpendicular 1D “Z” type Li-4,4′-bpy chain and an unprecedented Li–NO₃ chain.     

Anion-directed assembly of two novel cadmium(II) complexes constructed by 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) ligand

Depending on the different coordinated anions used, reaction of Cd(II) salt with 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) results in the formation of two coordination polymers: a 1D chain {[Cd(H₂C4BIm)Cl₂] · (H₂C4BIm)}_n (1), and a 2D sheet [Cd(HC4BIm)(NCS)]_n (2) which features distorted 4.8² topology (H₂C4BIm = 2,2′-(1,4-butanediyl)bis(1H-benzimidazole)). The fluorescence properties for both the complexes have been studied.     

The electrocatalytic cascade assembling of isatins, malononitrile and N-alkyl barbiturates: An efficient multicomponent approach to the spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] framework

Electrochemically induced catalytic multicomponent transformation of isatins, barbituric acid or N-alkyl barbiturates and malononitrile in alcohols in an undivided cell results in the formation of substituted 7′-amino-2,2′,4′-trioxo-1,1′,2,2′,3′,4′-hexahydrospiro[indole-3,5′-pyrano[2,3-d]pyrimidine]-6′-carbonitriles in 80–95% yields. The developed efficient electrocatalytic approach to corresponding spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] system is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a new example of the ecologically pure synthetic concept for electrocatalytic multicomponent reactions strategy.     

Synthesis and X-ray crystal structure determination of monomeric cis-Pd(2,2′-bipyridine)(NO3)2

Complex cis-Pd(2,2′-bipyridine)(NO₃)₂ was synthesized by the reaction of cis-Pd(2,2′-bipyridine)Cl₂ with AgNO₃ in water and crystallized by vapor diffusion of diethyl ether into an acetonitrile solution of the complex. The crystal structure obtained shows that each of the two nitrate ligands are coordinated through oxygen atoms to the Pd(2,2′-bipyridine)²⁺ center in unidentate fashion. IR and ¹H NMR spectral data were also obtained.     

Ferromagnetic mixed tribridged dinuclear copper(II) complex [Cu2(OAc)2(OH)(dpa)2]PF6 · H2O (dpa = 2,2′-dipyridylamine): 3D superstructure based on hydrogen bond and π…π interaction

A new dinuclear complex [Cu₂(OAc)₂(OH)(dpa)₂] PF₆ · H₂O (1) is prepared and structurally and magneto-structurally characterized. The monocationic core contains one acetate in familiar bidentate η¹:η¹:μ₂-bridge and another in the rare monoatomic bridge along with one hydroxo intermediary. 1 packs through N–H…O and O–H…O hydrogen bonds and π…π interaction resulting a 3D supramolecular continuum and displays high-energy intraligand ¹(π − π^*) fluorescence and intraligand ³(π − π^*) phosphorescence in glassy solution.     

Oxidation of catechol and l-ascorbic acid by [Ru(tpy)(pic)(OH)] (tpy = 2,2′6′,2″-terpyridine; pic = picolinate): Kinetic and mechanistic studies

Kinetics of oxidation of catechol (H₂cat) to benzoquinone (BQ) and, ascorbate (HA⁻) to dehydroascorbic acid (A) by [Ru^III(tpy)(pic)(OH)]⁺ (1) (tpy = 2,2’6’,2”-terpyridine; pic⁻ = picolinate) have been studied as function of [H₂cat] (or [HA⁻]), ionic strength (0.01 − 0.25 M), temperature (10–30 °C) at a constant pH = 3.2, using stopped-flow and rapid-scan diode array spetrophotometric techniques. The rate of reaction of 1 with HA⁻ was found to be very fast as compared to that of with H₂cat. The kinetic data and activation parameters are interpreted in terms of an associative interchange mechanism. Analysis of spectral and kinetic data revealed that the reaction of 1 with catechol proceeds by a straightforward outer-sphere electron transfer pathway, whereas, reduction of 1 with HA⁻ involves ion-pair formation.     

Photoinduced linkage isomerism of binuclear bis(pyrazole-3,5-dicarboxylato)-bridged {RuNO} centres

The two novel binuclear pyrazole-3,5-dicarboxylato-bridged {RuNO}⁶ complexes K₂[{Ru(NO)Cl}₂(μ-pzdc)₂] (1) and [{Ru(NO)(H₂O)}₂(μ-pzdc)₂]·4H₂O (2) (pzdc = pyrazole-3,5-dicarboxylate) were synthesized and characterized by elemental analysis, mass spectrometry and spectroscopic methods (NMR, UV–vis, IR). 2 was investigated by means of single-crystal X-ray diffraction analysis. On irradiation, in both 1 and 2 the existence of photoinduced long-lived metastable isonitrosyl states SI were detected by low-temperature infrared spectroscopy.     

A novel infinite 1D covalent chain of end-to-end thiocyanato bridged heptacoordinated cadmium(II)Schiff base: π…π interaction and weak C–H…S hydrogen bonded supramolecule

A new Schiff base, N,N′-(bis(pyridin-2-yl)formylidene)ethane-1,2-diamine (bpfd) is prepared and used to synthesize a novel end-to-end thiocyanato bridged infinite 1D polymeric heptacoordinated cadmium(II) chain [Cd(bpfd)(μ_1,3-NCS)(NCS)]_n (1) which forms a 3D supramolecule through weak C–H…S hydrogen bonding and π…π interaction.     

Cu(II) bipyridine and phenantroline complexes: Tailor-made catalysts for the selective oxidation of tetralin

Mononuclear Cu(II) complexes have been synthesized, and their structure thoroughly characterized by electrospray ionization mass spectrometry (ESI-MS). These 2,2′-bipyridine and 1,10-phenantroline mononuclear Cu(II) complexes have been tested as catalysts in the partial oxidation of tetralin (1,2,3,4-tetrahydronaphthalene), using hydrogen peroxide as oxidant in acetonitrile/water as solvent.The complexes [Cu(bipy)₃]Cl₂·6H₂O (1), [Cu(bipy)₂Cl]Cl·5H₂O (2), [Cu(bipy)Cl₂] (3), [Cu(phen)₃]Cl₂·6H₂O (4), [Cu(phen)₂Cl]Cl·5H₂O (5), [Cu(phen)Cl₂] (6) were able to oxidize tetralin at room temperature, at high degrees of conversion (62.1% with 2) into α-tetralol and α-tetralon at 91% selectivity (81% in 1-tetralon).Depending on nature and number of ligands (bipyridine or phenantroline) surrounding Cu²⁺ cation, one was able to tailor both the activity toward tetralin oxidation, and the selectivity toward 1-tetralol and 1-tetralone products, but also to raise the yield in valuable α-tetralone.     

tert-butylaluminium complex of 2,2-di(hydroxymethyl)biphenyl: intra-molecular hydrogen bonding

The reaction of 2,2^′-di(hydroxymethyl)biphenyl with (t-Bu)₃Al leads to the formation of the bimetallic compound [(t-Bu)₄Al₂(HOCH₂C₁₂H₈CH₂O)₂] (1) with two hydroxyl groups. The compound 1 has been characterized by ¹H and ¹³C NMR spectroscopy, cryoscopic molecular weight measurements and elemental analysis and molecular structure has been confirmed by X-ray crystallography. The 18 membered cycle (Al₂O₄C₁₂) of 1 adopts a configuration with endocyclic oxygen atoms that allow for the intra-molecular hydrogen bonding formation.     

Aldehyde-decorated 2,2′-bipyridine and 2,2′:6′,2″-terpyridine ruthenium(II) complexes: Convenient scaffolds for supramolecular chemistry

Two new aldehyde-decorated tpy and bpy-containing ruthenium(II) complexes, [Ru(1)(bpy)₂][PF₆]₂ and [Ru(1)(tpy)Cl][PF₆] in which 1 is 5,5′-bis(4-formylphenyl)-2,2′-bipyridine, have been prepared and fully characterized. The packing in both solid state structures involves extensive O_aldehyde···HC_pyridine contacts, but π-stacking interactions are important only between [Ru(1)(tpy)Cl]⁺ cations.     

Catalytic properties of Ru-η-C6H6-diphosphine complexes for hydrogenation of benzene in aqueous-organic biphasic system

The influences of pH on the catalytic properties of Ru-η⁶-C₆H₆-diphosphine complex [RuCl(η⁶-C₆H₆)(BISBI)]Cl (1) (BISBI = 2,2′-bis(diphenylphosphinomethyl)-1,1′-biphenyl), [RuCl(η⁶-C₆H₆)(BDPX)]Cl (2) (BDPX = 1,2-bis(diphenylphosphinomethyl)benzene), Ru₂Cl₄(η⁶-C₆H₆)₂(μ₂-BDNA) (3) (BDNA = 1,8-bis(diphenylphosphinomethyl)naphthalene), [RuCl(η⁶-C₆H₆)(BISBI)]BF₄ (4), [RuCl(η⁶-C₆H₆)(BDPX)]BF₄ (5), and [(η⁶-C₆H₆)₂Ru₂Cl₂(μ₂-Cl)(μ₂-BDNA)]BF₄ (6) for the hydrogenation of benzene were investigated in aqueous-organic biphasic system. The hydrogenation of benzene catalyzed by all complexes yielded only cyclohexane. The catalytic results revealed that the stabilities of these complexes were not only closely relative with their compositions or molecular structures but also the pH value of aqueous solution. Complexes 1 and 2 were homogeneous catalysts at pH <5, but complexes 3, 4, 5 and 6 were partly decomposed in the same reaction conditions and played simultaneously the roles of homogeneous and heterogeneous catalysts. When the pH was up to 12, all of six complexes were gradually decomposed to Ru(0) particles. The addition of extra phosphine ligand was favorable to prevent these complexes from decomposing in the catalytic process. The experiment of mercury poisoning and the curve of conversion vs time strongly supported above conclusions.     

Crystallography and Structure–Property Relationships in 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐Dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐ Quaterphenyl (DODECA)

X‐ray crystallographic study of 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐quaterphenyl (DODECA) has been carried out. Nonbonding interatomic distances of oxygen atoms inside of all the nitro groups are shorter than those corresponding to the intermolecular contact radii for oxygen. By means of the DFT B3LYP/6‐31(d, p) method a difference of 136 kJ mol⁻¹ between the X‐ray and DFT structures of DODECA was found. The bearer of the highest initiation reactivity in its molecule in solid phase should be the nitro group at 4′′′‐position, in contrast to those at 2′‐ or 2″‐positions in its isolated molecule. The most reactive nitro group in the DODECA molecule can be well specified by the relationship between net charges on nitro groups and charges on their nitrogen atoms, both of them for the X‐ray structure. The ¹⁵N chemical shift, corresponding to this nitro group for the initiation by impact and shock, correlates very well with these shifts of the reaction centers of the other six “genuine” polynitro arenes.     

The synthesis and optical characterization of quinoxalines bearing 2,2′:6′,2″-terpyridine

4′-(4-{2-[6,7-Bis-dodecyloxy-3-(2-p-substituted phenyl-vinyl)-quinoxalin-2-yl]-vinyl}-phenyl)-[2,2′:6′,2″] terpyridine was prepared by the Horner–Wadsworth–Emmons (HWE) reaction of 4-[2,2′:6′,2″]terpyridin-4′-yl-benzaldehyde and quinoxaline derivatives. The absorption and fluorescence maximum of these compounds were observed at 398–443 nm and 484–586 nm, respectively. The compounds were characterized by ¹H NMR spectroscopy and MALDI-TOF-MS, and their recognition properties for metal ions were evaluated using both absorption and emission spectroscopy.     

Extraction Equilibria of Trimellitic and [ 1,1′-Biphenyl]-2,2′-dicarboxylic Acid with 1-Octanol, 50%TBP,and 10%TRPO in Kerosene

To explore the feasibility of extracting aromatic acid products from oxidizing coal, two aromatic acids, trimellitic and [1,1′-biphenyl]-2,2′-dicarboxylic acid, were selected as the solutes, and the extraction equilibrium of the acids were studied with 1-octanol, 50% tributyl phosphate （TBP） in kerosene, and 10% trialkylphosphine oxide （TRPO） in kerosene. The results showed that the degree of extraction of [1,1′-biphenyl]-2,2′-dicarboxylic acid was larger than that of trimellitic acid for all of the solvent, and the extraction capacity with TRPO is more effective than the one with TBP. The extraction behavior of aromatic polyacid is different from that of carboxylic acid, and the reactive extraction function of aromatic acids with TBP and TRPO is not as effective as that of carboxylic acid. 1-octanol could be used to remove [1,1′-biphenyl]-2,2′-dicarboxylic acid from the mixture of trimellitic acid and [1,1′-biphenyl]-2,2′-dicarboxylic acid. Because the weak hydrogen bond association exists between -OH in 1-octanol and -COOH in aromatic acid, the extractive selectivity of [ 1, 1′-biphenyl]-2,2′-dicarboxylic to trimellitic acid depends on the stoichiometric ratio.