Coordination reactions of 2-pyridinecarboxaldehyde-phenylhydrazonatolithium with selected transition metal (Zn, Sn, Fe, Co, Ni and Zr) chlorides and its coupling reaction with dichloromethane.

The reactions of 2-pyridinecarboxaldehyde-phenylhydrazonatolithium C5H4Npy-CH[double bond, length as m-dash]Ni-NaLi(Ph) (abbreviated as Li) with a 1/2 equivalent of anhydrous metal (Zn, Sn, Fe and Co) chlorides or NiCl2(DME) (DME = 1, 2-dimethoxyethane) produced the corresponding mononuclear metal(ii) complexes ( and ), in which each ligand acts as a bidentate ligand and the coordination geometries around the metals are shown to be tetrahedral within the complexes , , and , respectively, and a tetragonal pyramid in the complex . The reaction of Li successively with sodium tert-butoxide and anhydrous ZrCl4 afforded the unanticipated bizirconium complex , in which each monoanionic ligand behaves as a tridentate bridge. Whereas treatment of Li with NiCl2 and then CH2Cl2 led to an interesting methylene-bridged bis(2-pyridyl-phenylhydrazone) compound in moderate yield; a comparative experiment showed that when the Li reacted with CH2Cl2, the coupling compound was also obtained but in very low yield.

A moderate distortion of the `picket-fence' porphyrin (cryptand-222)potassium chlorido[meso-α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrinato]ferrate(II) n-hexane monosolvate.

As representative porphyrin model compounds, the structures of `picket-fence' porphyrins have been studied intensively. The title solvated complex salt {systematic name: (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.

Structural study of a manganese(II) 'picket-fence' porphyrin complex.

'Picket-fence' porphyrin compounds are used in the investigation of interactions of hemes with dioxygen, carbon monoxide, nitric monoxide and imidazole ligands. (Cryptand-222)potassium chlorido[meso-tetra(α,α,α,α-o-pivalamidophenyl)porphyrinato]manganese tetrahydrofuran monosolvate (cryptand-222 is 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.

Geometric and electronic structures of five-coordinate manganese(ii) "picket fence" porphyrin complexes.

Three five-coordinate, high spin manganese(ii) "picket fence" porphyrin complexes, [Mn(TpivPP)(L)] (TpivPP = α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrinato; L = 1-MeIm (1-methylimidazole), 1-EtIm (1-ethylimidazole) and 2-MeHIm (2-methylimidazole)), are synthesized and studied by single-crystal X-ray, UV-vis and electronic paramagnetic resonance (EPR) spectroscopy. Structural parameters are investigated and compared with analogues. Low temperature (90 K), high field EPR studies of [Mn(TpivPP)(1-MeIm)] and [Mn(TpivPP)(2-MeHIm)] showed five resonances including characteristic signals at ∼5.

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine.

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n=4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH=3.05, 6.50, 8.

Spectroscopic study of the recognition of 2-quinolinone derivative on mercury ion.

A new compound based on 2-quinolinone derivative with very little side effects on organisms, 3-(1H-benzo[d]imidazol-2-yl)-6,7-difluoroquinolin-2(1H)-one, has been designed, synthesized and characterized. And its recognition ability was firstly studied by spectroscopy. The result indicated that the compound shows high selectivity for Hg2+ over other metal ions with detectable fluorescent signals in aqueous-methanol media.

Thiol-chromene click chemistry: a coumarin-based derivative and its use as regenerable thiol probe and in bioimaging applications.

The synthesis and characterization of a coumarin-chromene (8, 9-dihydro-2H-cyclopenta[b]pyrano[2,3-f]chromene-2,10(7aH)-dione) (1) derivative and its use for thiol chemosensing in water was reported. Experimental details showed 1 acts as a probe for the detection of thiols including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), whereas amino acids which do not contain thiols induced no changes in UV-vis spectra and fluorescence emission properties of 1. A possible detection mechanism is a nucleophilic attack of thiols to the α,β-unsaturated ketone in 1 that resulted in a fluorescent coumarin derivative.

On the reliability of DNA sequences of Ophiocordyceps sinensis in public databases.

Some DNA sequences in the International Nucleotide Sequence Databases (INSD) are erroneously annotated, which has lead to misleading conclusions in publications. Ophiocordyceps sinensis (syn. Cordyceps sinensis) is a fungus endemic to the Tibetan Plateau, and more than 100 populations covering almost its distribution area have been examined by us over recent years.

Metal (Mg, Fe, Co, Zr and Ti) complexes derived from aminosilyl substituted aminopyridinato ligand: synthesis, structures and ethylene polymerization behaviors of the group 4 complexes.

Lithium N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamidate (2) was prepared from the reaction of new compound N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamine (1) and LiBu(n). Treatment of the lithium salt (2) with an equal equivalent of MgBr(2)(THF)(2), FeCl(2) and CoCl(2) afforded the corresponding dinuclear complexes , , and , in which metal atoms possess similar trigonal bipyramidal geometries and each ligand functions as a bimetallic bridging binding aminopyridinato moiety with N-donation from the dimethylamino group. While the stoichiometric reaction of with ZrCl(4) gave the mononuclear zirconium complex (6); the seven coordinated zirconium atom adopts a distorted pentagonal bipyramid geometry and the ligand acts as monoanionic η(2)-aminopyridinato moiety with the pendant arm coordinated via N(CH(3))(2).

meso-Bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}iron(II) and the cobalt(II) analogue.

The two title crystalline compounds, viz. meso-bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}iron(II), [Fe(C(12)H(20)NSi)(2)], (II), and meso-bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}cobalt(II), [Co(C(12)H(20)NSi)(2)], (III), were obtained by the reaction of lithium 1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienide with FeCl(2) and CoCl(2), respectively. For (II), the trimethylsilyl- and dimethylaminoethenyl-substituted cyclopentadienyl (Cp) rings present a nearly eclipsed conformation, and the two pairs of trimethylsilyl and dimethylaminoethenyl substituents on the Cp rings are arranged in an interlocked fashion.

From lithium bis(trimethylsilyl)amide with cyanoamine into triazine compounds: synthesis and structures of lithium 6-((trimethylsilyl)amido)-2,4-bis(dimethylamino)[1,3,5]triazines and their manganese and cobalt complexes.

Addition reactions of lithium bis(trimethylsilyl)amide with dimethylcyanamide lead to novel lithium salts of 6-((trimethylsilyl)amido)-2,4-bis(dimethylamino)[1,3,5]triazines [LLi(D)](2) (L = NC(NMe(2))NC(NMe(2))NC(NSiMe(3)); D = Me(2)NCN (1), Et(2)O (2)) and to the Mn and Co complexes [LL'M] (L' = N{N(SiMe(3))C(NMe(2))}(2); M = Mn (3), Co (4)); the structures of crystalline 1, 3, and 4 are reported. Their formation involves trimethylsilyl shifts, ring formation, and unusual Me(2)NSiMe(3) elimination.

Ultraviolet-visible light (UV-Vis)-reversible but fluorescence-irreversible chemosensor for copper in water and its application in living cells.

An ultraviolet-visible light (UV-Vis)-reversible but fluorescence-irreversible chemosensor was developed for the detection of copper. Coordination between the probe, 2-pyridylaldehyde fluorescein hydrazone (FHP), and Cu(2+) gave a reversible UV-Vis response, Storage of the probe-Cu complex resulted in hydrolytic cleavage of the N═C bond, which released the fluorophore (ring-opened fluorescein hydrazine) and gave irreversible fluorescence. Thus, FHP becomes a multifunctional chemosensor, and its reversibility can be controlled by the reaction time.

Cloning and analysis of the MAT1-2-1 gene from the traditional Chinese medicinal fungus Ophiocordyceps sinensis.

The entomopathogenic fungus Ophiocordyceps sinensis has been important in traditional Chinese medicine but has yet to be commercially cultivated. One bottleneck is the very low frequency of stromata formation from artificially infected moth larvae. The mating system of fungi is the determining factor for sexual reproduction, but mating-type genes of O.

Mononuclear titanium compounds based on the silyl-linked bis(amidinate) ligand: synthesis, characterization and ethylene polymerization.

The mononuclear silyl-linked bis(amidinate) titanium compound 2 was prepared by salt metathesis of 1 and TiCl(4)(thf)(2). Alkylation of 2 with methyllithium gave analogue 3. Both 2 and 3 exhibited a configuration similar to ansa-metallocene and showed good activity towards ethylene polymerization after activation with MAO.

A bulky silyl shift-directed synthesis of a silyl-linked amidinate-amidine and its Zr(IV) complex.

A novel silyl-linked amidinate-amidine monoanionic ligand 3 was synthesized by double additions of PhCN starting from silyl-linked bis(amino) monoanion 2, which underwent an intramolecular Li/H metathesis and double silyl shift. The related Zr(IV) complex 4 was prepared and confirmed by X-ray diffraction revealing a structural rearrangement from its precursor. The mechanisms for the reaction processes have been proposed.

Magnesium(II) complexes of 2,4-N,N'-disubstituted 1,3,5-triazapentadienyl ligands: synthesis and characterization of [N(Dipp)C(NMe2)NC(NMe(2))N(SiMe3)MgBr]2 and [N(R)C(R')NC(R')N(SiMe3)]2Mg (Dipp = 2,6-iPr2-C6H3, R = Ph, SiMe(3); R' = NMe2, 1-piperidino).

Treatment of the appropriate lithium or sodium 2,4-N,N'-disubstituted 1,3,5-triazapentadienate [RNC(R')NC(R')N(SiMe(3))M](2) (R = Ph, 2,6-(i)Pr(2)-C(6)H(3)(Dipp) or SiMe(3); R' = NMe(2) or 1-piperidino; M = Li or Na) with one or half equivalent portion of MgBr(2)(THF)(2) in Et(2)O under mild conditions furnishes in good yield the first structurally characterized molecular magnesium 2,4-N,N'-disubstituted 1,3,5-triazapentadienates [DippNC(NMe(2))NC(NMe(2))N(SiMe(3))MgBr](2) (1), [{RNC(R')NC(R')N(SiMe(3))}(2)Mg] (R = Ph, R' = NMe(2) 2; R = Ph, R' = 1-piperidino 3; R = SiMe(3), R' = 1-piperidino 4). The solid-state structure of 1 is dimeric and those of 2, 3, and 4 are monomeric. The ligand backbone NCNCN in 1 adopts a W-shaped configuration, while in 2, 3 and 4 adopts a U-shaped configuration.

Experimental and theoretical study of 10-methoxy-2-phenylbenzo[h]quinoline.

10-Methoxy-2-phenylbenzo[h]quinoline (MPBQ) has been synthesized and characterized by NMR and X-ray single crystal diffraction. Both the ground and the lowest singlet excited-state geometries of MPBQ were optimized by B3LYP and ab initio CIS methods at 6-31G (d,p) level, respectively. The absorption and emission spectra of the compound were experimentally determined in CH(3)CN solution and were simultaneously computed using density functional theory (DFT) and time-dependent density functional theory (TDDFT) in CH(3)CN solution.

Investigation of the association behaviors between biliverdin and bovine serum albumin by fluorescence spectroscopy.

The interaction between biliverdin and bovine serum albumin (BSA) has been studied by steady fluorescence spectroscopy, synchronous fluorescence and resonance light scanning spectra. The binding of biliverdin to BSA quenches the tryptophan residue fluorescence and the results show that both static and dynamic quenching occur together with complex formation. The binding constant and binding sites of biliverdin to BSA at pH 7.

Synthesis and structures of selected triazapentadienate of Li, Mn, Fe, Co, Ni, Cu(I), and Cu(II) using 2,4-N,N'-disubstituted 1,3,5-triazapentadienate anions as ancillary ligands: [N(Ar)C(NMe2)NC(NMe2)N(R)](-) (Ar = Ph, 2,6-(i)Pr2-C6H3; R = H, SiMe3).

Addition reaction of ArN(SiMe 3)M (Ar = Ph or 2,6 - (i) Pr 2-C 6H 3 (Dipp); M = Li or Na) to 2 equivalents of alpha-hydrogen-free nitrile RCN (R = dimethylamido) gave the dimeric [M{N(Ar)C(NMe 2)NC(NMe 2)N(SiMe 3)}] 2 ( 1a, Ar = Ph, M = Li; 1b, Ar = Ph, M = Na; 1c, Ar = Dipp, M = Li). 1d was obtained by hydrolysis of 1c at ambient temperature. Treatment of a double ratio of 1a or 1b with anhydrous MCl 2 (M = Mn, Fe, Co) yielded the 1,3,5-triazapentadienato complexes [M{N(Ph)C(NMe 2)NC(NMe 2)N(SiMe 3)} 2] (M = Mn, 2; Fe, 3; Co, 4) and with NiCl 2.

Syntheses of 2,4-disubstituted 1,3,5-triazapentadienyl ligands having two guanidinato moieties and their use in the isolation of copper(I) complexes.

2,4-N,N'-Disubstituted 1,3,5-triazapentadienyl ligands as their lithium salts [Li{(N(R)C(R'))2N}]2 [where R = SiMe3 here and hereafter and R' = dimethylamino (1) or 1-piperidino (2)] were synthesized via the reactions of LiN(SiMe3)2 with 2 equiv of the alpha-hydrogen-free carbonitrile dimethylcyanamide or 1-piperdinecarbonitrile and used in the isolation of the two-coordinate copper(I) complexes [Cu{(N(R)C(R'))2N}]2 [R' = dimethylamino (3) and 1-piperidino (4)]. Complex 2 features a twisted W-shaped ligand backbone in the solid state. Complexes 3 and 4 show an unusual 12-membered ring dinuclear copper( I) triazapentadienyl and a less expressed ability to form a stable delocalized triazapentadienyl system.

Enantioselective quenching of room-temperature phosphorescence lifetimes of proteins: bovine and human serum albumins.

Enantioselective quenching of the room-temperature phosphorescence (RTP) lifetime of proteins was demonstrated due to the effects of various external chiral quenching agents. In the absence of quenchers, the RTP lifetimes for bovine serum albumin (BSA) and human serum albumin (HSA) were found to be 5.0 +/- 0.

Acceptor or donor (diaryl B or N) substituted octupolar truxene: synthesis, structure, and charge-transfer-enhanced fluorescence.

Two diaryl B- and N-substituted truxene charge-transfer compounds B3 and N3 have been synthesized. The fluorescence intensities of several nonfunctionalized truxene compounds are 1 order of magnitude weaker than that of B3 and N3. To reveal the structure-property correlations, the X-ray structures of B3 and N3 and their precursors 3 and 4 have been determined.

A convenient route to silyl linked bis(amidinate) ligands and synthesis of group(I) metal derivatives.

A novel type of linked bis(amidinate) ligands (D) were developed successfully. Their lithium derivatives 1-4 were synthesized by treating the silyl-bridged diamines I-IV with two equivalents of LiBu(n) and PhCN in sequence, which underwent a silyl-bridge migration process. In addition, the linked bis(amidinate) configuration proved to be the thermodynamically stable form rather than the mono(amidinate) type by contrasting reaction of I with one equivalent of LiBu(n) and PhCN in sequence.

Effect of temperature on dynamic rheological behavior of discontinuous cubic liquid crystal.

The dynamic rheological properties of discontinuous cubic liquid crystal, formed by nonionic surfactant C(12-14)E(12), were investigated in the discrete and continuous patterns of raising temperature. In the discrete pattern, the discontinuous cubic phase appears in two types of viscoelastic behaviors under the melting points of cubic phase: elastic gel and viscoelastic liquid. When the discontinuous cubic phase begins to melt, it has the weak polymer-like viscoelasticity.