Synthesis and Spectroscopic Characteriration of Transition MetalComplexes of Maleionitriledithiolene and 1,10-Phenanthroline

Thedithiolenesanddiiminesandtheirmetalcomplexesareanimportantresearchfieldintheorganicandcoordinationchemistry'-'.Metalcomplexesofadithioleneandadiiminehaveexcellentelectronicfullctionsduetotheintramolecularchargetransferfromaligandtootherligand(LL'C...     

Interactions and influence of α-cyclodextrin on the aggregation and interfacial properties of mixtures of nonionic and zwitterionic surfactants

The interactions of α-cyclodextrin (α-CD) with the nonionic surfactant decanoyl-N-methyl-glucamide (Mega-10) and the zwitterionic surfactant dimethyldodecylammoniopropanesulfonate (DPS) in their mixed system have been studied using interfacial tension, fluorescence, and nuclear magnetic resonance measurements. From the plots of interfacial tension vs. log of total surfactant concentration, we have obtained values of the surface excess of surfactant, the critical micellar concentration (cmc), the standard free energy of micelle formation, and association constant of surfactant/α-CD inclusion complexes (assuming a 1:1 stoichiometry). A comparison of the K _a values obtained for the interaction between α-CD and DPS and Mega-10, respectively, shows that DPS interacts stronger with α-CD than Mega-10. The experimental mixed cmc was analyzed by the pseudophase separation model and regular solution theory for the evaluation of ideality or nonideality of the mixed micelle formation. The interaction parameters in the mixed micelle and the micelle composition at different mole fractions of DPS were also computed. The fluorescence anisotropy (r) values of rhodamine B decreases with the increase of α-CD concentrations.     

Fluorometric Investigation of the Acid-Base and Complexation Behaviour of Tetracycline and Oxytetracycline

The widely used antibiotics tetracyclines have been effectively used for ailing heart attack, ulcer cure and gene therapy. The actual mechanism of their activity has been proposed to link with the complexes with many metal ions.However, the sites at which complex formation takes place are not well established. In the present work, the deprotonation sequence of tetracycline (TC) and oxytetracycline (OTC), and their specific group used to bind europium ion were investigated by examining the character of fluorescence of TC and OTC as well as that of their complexes.It was concluded that the site of complexation is coordinated with the deprotonation sequence changing with the acidity/basicity of the solution. And it was inferred that five hydrogens in TC and OTC could be dissociated. The deprotonation sequence is as follows: C(3) hydroxy, C(10) phenol, C(4) dimethylamine, C(12) hydroxy and C(12a) hydroxy. The corresponding complexation site changed with pH increase in solution as follows: C(2) acylamino and C(3) hydroxy moiety, C(10)-C(11) ketophenol moiety, C(4) dimethylamine and C(3) hydroxy moiety,C(11)-C(12)β-diketone moiety, C(12) hydroxy and C(12a) hydroxy moiety, and C(12) hydroxy and C(1) ketonemoiety respectively.     

Spectral and Electrochemical Investigation of Intercalations of Adrenaline and CT－DNA

A strong interaction between double stranded calf-thymus DNA (ds-DNA) and adrenaline in solution, but no interaction between single stranded calf-thymus DNA (ss-DNA) and adrenaline was observed by the use of UV-visible spectroscopy and voltammetric techniques. It is suggested that the interaction leads to an intercalation of adrenaline molecules into the groove of ds-DNA and the formation of ds-DNA (adrenallne)n complex. The binding site size of the interaction of adrenaline with CT-DNA in nucleotide phosphate [ NP] has been determined as 25. The interaction of different concentration adrenaline with DNA modified GCE shows that the DNA modified GCE can be a good tool to detect lower concentration adrenaline.     

Synthesis and study of the cyclization pathways and reactivities of α-diazoimidolates

The reaction of unsymmetrical N,N-disubstituted malonamides with benzenesulfonyl azide in the presence of sodium ethoxide gives individual sodium 1,2,3-triazol-5-olates or mixtures of their isomers, from the relative amounts of which the effect of substituents in the amido groups on the cyclization pathways and reactivities of -diazoimidolates was ascertained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1521–1527, November, 1991.     

Synthesis and Characterization of ABBA Block Copolymer of Glycolide and ε-Caprolactone

A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.     

Synthesis and Characterization of ABBA Block Copolymer of Glycolide and ε-Caprolactone

A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ε-Scaprolactone (CL, B) and glycolide (A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL prepolymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide (A) to PCL pre-polymer(BB). The block copolymers were characterized by ^1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.     

Synthesis and Structure of Lanthanide Sandwich Complexes with Mixed Cyclooctatetraenyl and Chelating Substituted‐indenyl Ligands

Two types of sandwich complexes (η⁵‐MeOCH₂CH₂C₉H₆) Ln (η⁸‐C₈H₈) (THF)_n [Ln=La (1), Nd(2), n=0; Sm(3), Dy (4) and Er (5). n = l] and (η⁵‐C₄H₇OCH₂C₉H₆)Ln(η⁸‐C₈H₈) (THF) [Ln = La (6), Nd(7). Sm(8). Dy (9) and Er (10)] were synthesized by the reactions of LnCl₃ with equivalent mole of K₂C₈H₈, followed by treatment with corresponding potassium salt of ether‐substituted indenide. The molecular structures of 3 and 8 were determined by single crystal X‐ray diffraction. (η⁵ ‐MeOCH₂CH₂C₉H₆) Sm (η⁸‐C₈H₈) (THF) (3) monoclinic. Pt₁/c, a = 1.4793(3) nm, b = 0.8716 (2) nm, c = 1.6149 (3) nm, β = 98. 17(3), V = 2.0612(7) nm³, Z = 4, R(F)=0.0362. (η⁵‐C₄H₇OCH₂C₉H₆)Sm(η⁸‐C₈H₈)(THF) (8) orthorhombic. p2₁2₁2₁. a = 0.8754(2) nm, b = 1.1000(2) nm, c = 2.3117 (5) nm, V = 2.2260(8) nm³, Z=4, R(F) =0.0497.     

Synthesis,Structure, and Lanthanide Derivatives of an Unusual Hexameric Alcohol: [2,4,6-(CF3)3C6H2CH2OH]6

Hitherto unknown 2,4,6-tris(trifluoromethyl)benzyl alcohol ( 3 ) was synthesized in 41 % yield by treatment of freshly prepared R_FLi ( 2 ) with paraformaldehyde (R_F = 2,4,6-tris(trifluoromethyl)phenyl). According to an X-ray diffraction study the crystal structure of 3 consists of S₆ symmetric cyclic hexamers [2,4,6-(CF₃)₃C₆H₂CH₂OH]₆. Deprotonation of 3 with NaN(SiMe₃)₂ in toluene afforded the unsolvated sodium alkoxide derivative R_FCH₂ONa ( 4 ). Homoleptic lanthanide alkoxides of the type Ln(OCH₂R_F)₃ (Ln = Nd ( 5 ), Sm ( 6 ), Yb ( 7 )) were made by treatment of Ln(C₅H₅)₃ with three equivalents of 3 . Similar reactions in a 1:1 molar ratio afforded the bis(cyclopentadienyl)lanthanide alkoxide derivatives (C₅H₅)₂Ln(OCH₂R_F) (Ln = Nd ( 8 ), Sm ( 9 ), Yb ( 10 )).     

Lanthanocene Diolate Complexes: Synthesis,Structures and Catalytic Property for ε-Caprolactone Polymerization

Reaction of LnCl₃ first with three equivalent of C₅H₅Na in THF, then with one equivalent of N‐phenyldiethanolamine in THF‐DME afforded complexes of {[(C₅H₅)Ln((‐OCH₂CH₂)₂N(C₆H₅)]₄((₄‐Cl)}[Na(DME)₄] (Ln=Sm ( 1 ), Yb ( 2 )), being characterized by infrared spectra, elemental analyses and X‐ray crystallography. They are ionic pair compounds. The anionic part is a cluster, which can be viewed as a cyclic tetramer with four (C₅H₅)Ln units bridged by four pairs of OR groups, forming a pinwheel structure. Both the complexes can catalyze the ring‐opening polymerization of ε‐caprolactone under mild conditions, and complex 1 is more active than complex 2 . The polymerization accords with one order reaction kinetics for monomer concentration. The molecular weight increases with the yield increasing, and the molecular weight distribution is rather narrow (1.19相似文献   

Bis(β‐diketiminato) lanthanide amides: synthesis,structure and catalysis for the polymerization of l‐lactide and ε‐caprolactone

Treatment of the chlorides (L^2,6‐iPr2_Ph)₂LnCl (L^2,6‐iPr2_Ph = [(2,6‐ⁱPr₂C₆H₃)NC(Me)CHC(Me)N(C₆H₅)]^?) with 1 equiv. of NaNH(2,6‐ⁱPr₂C₆H₃) afforded the monoamides (L^2,6‐iPr2_Ph)₂LnNH(2,6‐ⁱPr₂C₆H₃) (Ln = Y ( 1 ), Yb ( 2 )) in good yields. Anhydrous LnCl₃ reacted with 2 equiv. of NaL^2,6‐iPr2_Ph in THF, followed by treatment with 1 equiv. of NaNH(2,6‐ⁱPr₂C₆H₃), giving the analogues (L^2,6‐iPr2_Ph)₂LnNH(2,6‐ⁱPr₂C₆H₃) (Ln = Sm ( 3 ), Nd ( 4 )). Two monoamido complexes stabilized by two L^2‐Me ligands, (L^2‐Me)₂LnNH(2,6‐ⁱPr₂C₆H₃) (L^2‐Me = [N(2‐MeC₆H₄)C(Me)]₂CH)^?; Ln = Y ( 5 ), Yb ( 6 )), were also synthesized by the latter route. Complexes 1 , 2 , 3 , 4 , 5 , 6 were fully characterized, including X‐ray crystal structure analyses. Complexes 1 , 2 , 3 , 4 , 5 , 6 are isostructural. The central metal in each complex is ligated by two β‐diketiminato ligands and one amido group in a distorted trigonal bipyramid. All the complexes were found to be highly active in the ring‐opening polymerization of L‐lactide (L‐LA) and ε‐caprolactone (ε‐CL) to give polymers with relatively narrow molar mass distributions. The activity depends on both the central metal and the ligand (Yb < Y < Sm ≈ Nd and L^2‐Me < L^2,6‐iPr2_Ph). Remarkably, the binary 3/benzyl alcohol (BnOH) system exhibited a striking ‘immortal’ nature and proved able to quantitatively convert 5000 equiv. of L‐LA with up to 100 equiv. of BnOH per metal initiator. All the resulting PLAs showed monomodal, narrow distributions (M_w/M_n = 1.06 ? 1.08), with molar mass (M_n) decreasing proportionally with an increasing amount of BnOH. The binary 4/BnOH system also exhibited an ‘immortal’ nature in the polymerization of ε‐CL in toluene. Copyright © 2014 John Wiley & Sons, Ltd.     

Gemischte Sandwichkomplexe der 4 f‐Elemente: Enantiomerenreine Cyclooctatetraenyl‐Cyclopentadienyl‐Komplexe des Samariums und Lutetiums mit donorfunktionalisierten Cyclopentadienylliganden

Organometallic Compounds of the Lanthanides. 139 Mixed Sandwich Complexes of the 4 f Elements: Enantiomerically Pure Cyclooctatetraenyl Cyclopentadienyl Complexes of Samarium and Lutetium with Donor‐Functionalized Cyclopentadienyl Ligands The reactions of [K{(S)‐C₅H₄CH₂CH(Me)OMe}], [K{(S)‐C₅H₄CH₂CH(Me)NMe₂}] and [K{(S)‐C₅H₄CH(Ph)CH₂NMe₂}] with the cyclooctatetraenyl lanthanide chlorides [(η⁸‐C₈H₈)Ln(μ‐Cl)(THF)]₂ (Ln = Sm, Lu) yield the mixed cyclooctatetraenyl cyclopentadienyl lanthanide complexes [(η⁸‐C₈H₈)Sm{(S)‐η⁵ : η¹‐C₅H₄CH₂CH(Me)OMe}] ( 1 a ), [(η⁸‐C₈H₈)Ln{(S)‐η⁵ : η¹‐C₅H₄CH₂CH(Me)NMe₂}] (Ln = Sm ( 2 a ), Lu ( 2 b )) and [(η⁸‐C₈H₈)Ln{(S)‐η⁵ : η¹‐C₅H₄CH(Ph)CH₂NMe₂}] (Ln = Sm ( 3 a ), Lu ( 3 b )). For comparison, the achiral compounds [(η⁸‐C₈H₈)Ln{η⁵ : η¹‐C₅H₄CH₂CH₂NMe₂}] (Ln = Sm ( 4 a ), Lu ( 4 b )) are synthesized in an analogous manner. ¹H‐, ¹³C‐NMR‐, and mass spectra of all new compounds as well as the X‐ray crystal structures of 3 b and 4 b are discussed.     

2,2′‐Bipyrimidine as Efficient Sensitizer of the Solid‐State Luminescence of Lanthanide and Uranyl Ions from Visible to Near‐Infrared

Treatment of Ln(NO₃)₃?nH₂O with 1 or 2 equiv 2,2′‐bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [Ln(NO₃)₃(bpm)₂] (Ln=Eu, Gd, Dy, Tm) or [Ln(NO₃)₃(bpm)₂]?THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [Ln(NO₃)₃(bpm)₂]?THF (Ln=Nd, Sm) from THF, or [Ln(NO₃)₃(bpm)(MeOH)₂]?MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO₂(NO₃)₂?6H₂O with 1 equiv BPM in THF afforded the monoadduct [UO₂(NO₃)₂(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid‐state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the Yb^III ion emitting in the near‐IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8 %, respectively. All these complexes in the solid state were stable in air.     

Synthesis of ferrocene‐containing N‐aryloxo β‐ketoiminate lanthanide complexes and polymerization of ε‐caprolactone

The synthesis, characterization and ε‐caprolactone polymerization behavior of lanthanide amido complexes stabilized by ferrocene‐containing N‐aryloxo functionalized β‐ketoiminate ligand FcCOCH₂C(Me)N(2‐HO‐5‐Bu^t‐C₆H₃) (LH₂, Fc = ferrocenyl) are described. The lanthanide amido complexes [LLnN(SiMe₃)₂(THF)]₂ [Ln = Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] were synthesized in good yields by the amine elimination reactions of LH₂ with Ln[N(SiMe₃)₂]₃(µ‐Cl)Li(THF)₃ in a 1:1 molar ratio in THF. These complexes were characterized by IR spectroscopy and elemental analysis, and ¹H NMR spectroscopy was added for the analysis of complex 4 . The definitive molecular structures of complexes 1 and 3 were determined by X‐ray diffraction studies. Complexes 1 – 4 can initiate the ring‐opening polymerization of ε‐caprolactone with moderate activity. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Characterization of donor‐functionalized ansa‐Cyclopentadienyl‐Indenyl and ansa‐Indenyl‐Indenyl Complexes of Yttrium,Samarium, Thulium,and Lutetium

The stepwise reaction of Me₂SiCl₂ with K[C₅H₃ ^tBuMe‐3] or Li[C₉H₇] and then with K[C₉H₆CH₂CH₂‐ NMe₂‐1] followed by double deprotonation with NaH or LiBu, yields the two dimethylsilicon bridged cyclopentadienyl‐indenyl and indenyl‐indenyl donor‐functionalized ligand systems K₂[(C₅H₂ ^tBu‐3‐Me‐5)SiMe₂(1‐C₉H₅CH₂CH₂NMe₂‐3)] ( 1 ), and Li₂[(1‐C₉H₆)SiMe₂(1‐C₉H₅CH₂CH₂NMe₂‐3)] ( 2 ), respectively. Treatment of 1 with YCl₃(THF)₃, SmCl₃(THF)_1.77, TmI₃(DME)₃, and LuCl₃(THF)₃ gives the mixed ansa‐metallocenes [(C₅H₂ ^tBu‐3‐Me‐5)SiMe₂(1‐C₉H₅CH₂CH₂NMe₂‐3)]LnX (X = Cl, Ln = Y ( 3 ), Sm ( 4 ), Lu ( 5 ); X = I, Ln = Tm ( 6 )), respectively. The reaction of 2 with LuCl₃(THF)₃ yields [(1‐C₉H₆)SiMe₂(1‐C₉H₅CH₂CH₂NMe₂‐3)]LuCl ( 7 ). Compound 4 reacts with LiMe to give the corresponding alkyl derivative [(C₅H₂ ^tBu‐3‐Me‐5)SiMe₂(1‐C₉H₅CH₂CH₂NMe₂‐3)]Sm(CH₃) ( 8 ). The new complexes were characterized by elemental analyses, MS spectrometry, and NMR spectroscopy. The molecular structures of 5 and 6 were determined by single crystal X‐ray diffraction.     

Synthese,Struktur und Reaktivität von Tris‐, Bis‐ und Mono(2,4‐dimethylpentadienyl)‐Komplexen des Neodyms,Lanthans und des Yttriums

The tris(2,4‐dimethylpentadienyl) complexes [Ln(η⁵‐Me₂C₅H₅)₃] (Ln = Nd, La, Y) are obtained analytically pure by reaction of the tribromides LnBr₃·nTHF with the potassium compound K(Me₂C₅H₅)(thf)_n in THF in good yields. The structural characterization is carried out by X‐ray crystal structure analysis and NMR‐spectroscopically. The tris complexes can be transformed into the dimeric bis(2,4‐dimethylpentadienyl) complexes [Ln₂(η⁵‐Me₂C₅H₅)₄X₂] (Ln, X: Nd, Cl, Br, I; La, Br, I; Y, Br) by reaction with the trihalides THF solvates in the molar ratio 2:1 in toluene. Structure and bonding conditions are determined for selected compounds by X‐ray crystal structure analysis and NMR‐spectroscopically in general. The dimer‐monomer equilibrium existing in solution was investigated NMR‐spectroscopically in dependence of the donor strength of the solvent and could be established also by preparation of the corresponding monomer neutral ligand complexes [Ln(η⁵‐Me₂C₅H₅)₂X(L)] (Ln, X, L: Nd, Br, py; La, Cl, thf; Br, py; Y, Br, thf). Finally the possibilities for preparation of mono(2,4‐dimethylpentadienyl)lanthanoid(III)‐dibromid complexes are shown and the hexameric structure of the lanthanum complex [La₆(η⁵‐Me₂C₅H₅)₆Br₁₂(thf)₄] is proved by X‐ray crystal structure analysis.     

Rare-earth metal allyl and hydrido complexes supported by an (NNNN)-type macrocyclic ligand: synthesis, structure, and reactivity toward biomass-derived furanics

The preparation and characterization of a series of neutral rare‐earth metal complexes [Ln(Me₃TACD)(η³‐C₃H₅)₂] (Ln=Y, La, Ce, Pr, Nd, Sm) supported by the 1,4,7‐trimethyl‐1,4,7,10‐tetraazacyclododecane anion (Me₃TACD^?) are reported. Upon treatment of the neutral allyl complexes [Ln(Me₃TACD)(η³‐C₃H₅)₂] with Brønsted acids, monocationic allyl complexes [Ln(Me₃TACD)(η³‐C₃H₅)(thf)₂][B(C₆X₅)₄] (Ln=La, Ce, Nd, X=H, F) were isolated and characterized. Hydrogenolysis gave the hydride complexes [Ln(Me₃TACD)H₂]_n (Ln=Y, n=3; La, n=4; Sm). X‐ray crystallography showed the lanthanum hydride to be tetranuclear. Reactivity studies of [Ln(Me₃TACD)R₂]_n (R=η³‐C₃H₅, n=0; R=H, n=3,4) towards furan derivatives includes hydrosilylation and deoxygenation under ring‐opening conditions.