Synthesis and antimicrobial activity of new 1,2,4-triazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole,thiopyrane, thiazolidinone,and azepine derivatives

4-oxo-4-phenylbutanehydrazide 3 was reacted with aryl or alkyl isothiocyanates to give the corresponding N-substituted-2-(4-oxo-4-phenylbutanoyl) hydrazine-1-carbothioamide 4a-c . Cyclization of thiosemicarbazides 4a-c with sodium hydroxide led to the formation of 3-(4-sub-5-thioxo-1,2,4-triazol-3-yl)-propanone 5a-c . Desulfurization of thiosemicarbazides 4a-c by mercuric oxide afforded 3-(5-(sub-amino)-1,3,4-oxadiazol-2-yl)-propanone 6a-c . The reaction of 4a-c with phosphorus oxychloride gave 3-(5-(sub-amino)-1,3,4-thiadiazol-2-yl)-propanone 7a-c . Treatment of 4a-c with ethyl-bromoacetate or α-bromopropionic acid gave N′-(3-sub-thiazolidin-2-ylidene)-butanehydrazide 8a-c and (N′-(3-sub-oxothiazolidin-2-ylidene)-butanehydrazide 9a-c . Chlorination of oxothiazolidine-hydrazide 9a-c by phosphorus oxychloride afforded N-(3-sub-4-oxothiazolidine)-butane-hydrazonoyl-chloride 10a-c . The reaction of 10a-c with mercaptoacetyl-chloride yielded 2-((4-benzoyl-thiopyrane) hydrazono)-3-sub-thiazolidinone 11a-c . Also, reacted of 10a-c with hydrazine hydrate afforded N″-(3-sub-oxothiazolidine)-butane-hydrazon-hydrazide 12a-c . The 3-sub-2-((pyridazine) hydrazono) thiazolidinone 13a-c was obtained by cyclization of 12a-c via refluxing in DMF. The reaction and cyclized of 9a-c with chloroacetyl-chloride in ethanolic KOH afforded 1-((3-sub-4-oxothiazolidine) amino)-azepine-dione 14a-c . The chemical structures of the new compounds have been confirmed by diverse spectroscopy analyses such as IR, NMR, MS, and elemental analysis. The synthesized compounds were tested for their antimicrobial activity and these compounds were considered (Pyridazin-hydrazono-thiazolidinone 13a-c , oxothiazolidin-azepinedione 14a-c , N-thiazolidin-hydrazon-hydrazide 12a-c , and thiopyran-hydrazono-thiazolidinone 11a-c ) the most effective as antimicrobial activity.     

Quinoline-Proline,Triazole Hybrids: Design,Synthesis, Antituberculosis,Molecular Docking,and ADMET Studies

A series of novel quinoline-proline hybrids ( 11a-g ) and quinoline-proline-1,2,3-triazole hybrids ( 12-14 ) were synthesized by click chemistry based on molecular hybridization concept and were characterized by NMR, mass spectrometry, and elemental analysis. All the titled target compounds were tested for antitubercular activity by MABA and LORA methods by in vitro. Interestingly, two compounds (2R,4S)-1-((2-cyclopropyl-4-(4-fluorophenyl)-quinolin-3-yl)-methyl)-4-(4-nitrobenzamido)-N-phenylpyrrolidine-2-carboxamide ( 11b ) and (2R,4S)-1-((2-cyclopropyl-4-(4-fluorophenyl)-quinolin-3-yl)-methyl)-4-(4-fluorobenzamido)-N-phenylpyrrolidine-2-carboxamide ( 11c ) exhibited significant activity against the tested Mycobacterium tuberculosis H37Rv strain. Further, the cytotoxicity ( CC ₅₀ ) profile of the titled compounds against the Vero cell was performed and discussed. A molecular docking study of the hit compounds ( 11b and 11c ) was also performed to find their putative binding interaction with the active site of the target proteins. Finally, in silico ADMET properties were also predicted for all the synthesized molecules to evaluate their drug-likeness behavior.     

Synthesis, characterization, crystal structure, and electrochemical, photophysical, and protein-binding properties of luminescent rhenium(I) diimine indole complexes

We report the synthesis, characterization, and photophysical and electrochemical properties of a series of luminescent rhenium(I) diimine indole complexes, [Re(N-N)(CO)3(L)](CF3SO3) (N-N = 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4-phen), L = N-(3-pyridoyl)tryptamine (py-3-CONHC2H4-indole) (1a), N-[N-(3-pyridoyl)-6-aminohexanoyl]tryptamine, (py-3-CONHC5H10CONHC2H4-indole) (1b); N-N = 1,10-phenanthroline (phen), L = py-3-CONHC2H4-indole (2a), py-3-CONHC5H10CONHC2H4-indole (2b); N-N = 2,9-dimethyl-1,10-phenanthroline (Me2-phen), L = py-3-CONHC2H4-indole (3a), py-3-CONHC5H10CONHC2H4-indole (3b); N-N = 4,7-diphenyl-1,10-phenanthroline (Ph2-phen), L = py-3-CONHC2H4-indole (4a), py-3-CONHC5H10CONHC2H4-indole (4b)), and their indole-free counterparts, [Re(N-N)(CO)3(py-3-CONH-Et)](CF3SO3) (py-3-CONH-Et = N-ethyl-(3-pyridyl)formamide; N-N = Me4-phen (1c), phen (2c), Me2-phen (3c), Ph2-phen (4c)). The X-ray crystal structure of complex 3a has also been investigated. Upon irradiation, most of the complexes exhibited triplet metal-to-ligand charge-transfer (3MLCT) (d pi(Re) --> pi*(diimine)) emission in fluid solutions at 298 K and in low-temperature glass. However, the structural features and long emission lifetimes of the Me4-phen complexes in solutions at room temperature suggest that the excited state of these complexes exhibited substantial triplet intraligand (3IL) (pi --> pi*) (Me4-phen) character. The binding interactions of these complexes to indole-binding proteins including bovine serum albumin and tryptophanase have been examined.     

Pyrans,their analogs,and related compounds

Reaction of 4, 4-dichloroflavine (I) with sulfurylchloride affords 2, 3, 3, 4, 4-pentachloroflavan (II). Hydrolysis of II gives 2-hydroxy-3, 3-dichloro-4-flavanone (III), while alcoholysis with aqueous alcohols yields 2-alkoxy-3,3-dichloro-4-flavanones (IVa, b). Treatment of III with SOCl₂ gives 2,3,3-trlchloro-4-flavanone (V), which with caustic alkali or sodium ethoxide is converted into o-(1-phenyl-2, 2-dichlorovinyloxy)benzoic acid (VIc) or its ethyl ester (VIb), respectively.For Part XLII, see [7].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1167–1170, September, 1970.     

Heterobimetallic chalcogenidometallate strands: synthesis, structure, magnetism, and conductivity

Two salts with one-dimensional, SiS(2)-type telluridostannate chain anions {[MSnTe(4)](2-)}(n), Rb(2)[HgSnTe(4)] (2) and (NMe(4))(2)[MnSnTe(4)] (3), were prepared by the reactions of [SnTe](4-) anions with Hg(2+) or Mn(2+) ions in solution. We present the crystal structures of 2 and 3, as well as the magnetic properties of the previously reported Cs(+) analogue Cs(2)[MnSnTe(4)] (1).     

Synthesis, structure, and reactivity of borole-functionalized ferrocenes

Herein, we report on the synthesis of ferrocenylborole [Fc(BC(4) Ph(4) )(2) ] featuring two borole moieties in the 1,1'-positions. The results of NMR and UV/Vis spectroscopy and X-ray diffraction studies provided conclusive evidence for the enhanced Lewis acidity of the boron centers resulting from the conjugation of two borole fragments. This finding was further validated by the reaction of [Fc(BC(4) Ph(4) )(2) ] and the 4-Me-NC(5) H(4) adduct of monoborole [Fc(BC(4) Ph(4) )], which led to quantitative transfer of the Lewis base. The coordination chemistry of ferrocenylboroles was further studied by examining their reactivity towards several pyridine bases. Accordingly, the strong Lewis acidity of boroles in general was nicely demonstrated by the reaction of [Fc(BC(4) Ph(4) )] with 4,4'-bipyridine. Unlike common borane derivatives such as [FcBMe(2) ], which only forms a 2:1 adduct, we also succeeded in the isolation of a 1:1 Lewis acid/base adduct, with one nitrogen donor of 4,4'-bipyridine remaining uncoordinated. In addition, the reduction chemistry of ferrocenylboroles [Fc(BC(4) Ph(4) )] and [Fc(BC(4) Ph(4) )(2) ] has been studied in more detail. Thus, depending on the reducing agent and the reaction stoichiometry, chemical reduction of [Fc(BC(4) Ph(4) )] might lead to the migration of the borolediide fragment towards the iron center, affording dianions with either η(5) -coordinated C(5) H(4) or η(5) -coordinated BC(4) Ph(4) moieties. In contrast, no evidence for borole migration was observed during reduction of bisborole [Fc(BC(4) Ph(4) )(2) ], which readily resulted in the formation of the corresponding tetraanion. Finally, our efforts to further enhance the borole ratio in ferrocenylboroles aiming at the synthesis of [Fc(BC(4) Ph(4) )(4) ] failed and, instead, generated an uncommon ansa-ferrocene containing two borole fragments in the 1,1'-positions and a B(2) C(4) ansa-bridge.     

Design,Synthesis, Characterization,and Antimicrobial Screening of Novel Indazole Bearing Oxadiazole Derivatives

Ethyl 2‐(2,6‐dioxocyclohexyl)‐2‐oxoacetate was prepared by reacting cyclohexane‐1,3‐dione ( 1 ) and diethyl oxalate ( 2 ) with the help of sodium ethoxide in ethanol at 0–5°C. Subsequent treatment of ethyl 2‐(2,6‐dioxocyclohexyl)‐2‐oxoacetate with hydrazine hydrate in ethanol resulted into ethyl 4‐oxo‐4,5,6,7‐tetrahydro‐2H‐indazole‐3‐carboxylate while without solvent in excess hydrazine hydrate on reflux resulted into 4‐oxo‐4,5,6,7‐tetrahydro‐2H‐indazole‐3‐carbohydrazide ( 3 ). The synthesis of novel indazole bearing oxadiazole derivatives (ODZ 01 to 16) has been achieved by the reaction of hydrazide of 2H‐indazole ( 3 ) with acid ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p ) in the presence of POCl₃, and the antimicrobial activity of synthesized novel compounds has been studied.     

High-level ab initio predictions for the ionization energies and heats of formation of five-membered-ring molecules: thiophene, furan, pyrrole, 1,3-cyclopentadiene, and borole, C4H4X/C4H4X+ (X = S, O, NH, CH2, and BH)

The ionization energies (IEs) and heats of formation (ΔH°(f0)/ΔH°(f298)) for thiophene (C(4)H(4)S), furan (C(4)H(4)O), pyrrole (C(4)H(4)NH), 1,3-cyclopentadiene (C(4)H(4)CH(2)), and borole (C(4)H(4)BH) have been calculated by the wave function-based ab initio CCSD(T)/CBS approach, which involves the approximation to the complete basis set (CBS) limit at the coupled-cluster level with single and double excitations plus a quasi-perturbative triple excitation [CCSD(T)]. Where appropriate, the zero-point vibrational energy correction (ZPVE), the core-valence electronic correction (CV), and the scalar relativistic effect (SR) are included in these calculations. The respective CCSD(T)/CBS predictions for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), being 8.888, 8.897, 8.222, and 8.582 eV, are in excellent agreement with the experimental values obtained from previous photoelectron and photoion measurements. The ΔH°(f0)/ΔH°(f298) values for the aforementioned molecules and their corresponding cations have also been predicted by the CCSD(T)/CBS method, and the results are compared with the available experimental data. The comparisons between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2) suggest that the CCSD(T)/CBS procedure is capable of predicting reliable IE values for five-membered-ring molecules with an uncertainty of ±13 meV. In view of the excellent agreements between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), the similar CCSD(T)/CBS IE and ΔH°(f0)/ΔH°(f298) predictions for C(4)H(4)BH, whose thermochemical data are not readily available due to its reactive nature, should constitute a reliable data set. The CCSD(T)/CBS IE(C(4)H(4)BH) value is 8.868 eV, and ΔH°(f0)/ΔH°(f298) values for C(4)H(4)BH and C(4)H(4)BH(+) are 269.5/258.6 and 1125.1/1114.6 kJ/mol, respectively. The highest occupied molecular orbitals (HOMO) of C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, C(4)H(4)CH(2), and C(4)H(4)BH have also been studied by the natural bond orbital (NBO) method, and the extent of π-electron delocalization in these five-membered rings are discussed in correlation with their molecular structures and orbitals.     

Cyclotetraphosphinophosphonium ions: synthesis, structures, and pseudorotation

The first derivatives of catenated cyclotetraphosphinophosphonium cations, [(PhP)4PPhMe]+ (8a), [(MeP)4PMe2]+ (8b), [(CyP)4PPh2]+ (8d), [(CyP)4PMe2]+ (8e), [(PhP)4PPh2]+ (8f), [(PhP)4PMe2]+ (8g), are synthesized as trifluoromethanesulfonate (triflate, OSO2CF3-) salts through the reaction of cyclopentaphosphines (PhP)5 (4a) or (MeP)5 (4b) with methyl triflate (MeOTf) or by a net phosphenium ion [PR2+, R = Ph, Me; from R2PCl and trimethylsilyltriflate (Me3SiOTf)] insertion into the P-P bond of either cyclotetraphosphine (CyP)4 (3c) or cyclopentaphosphines (PhP)5 (4a) or (MeP)5 (4b). Although more conveniently prepared from 4a, compound 8a[OTf] can also be formed from (PhP)4 (3a) and MeOTf, and derivatives 8f[OTf] and 8g[OTf] are also accessible through reactions of 3a and R2PCl/Me3SiOTf with R = Ph or Me, respectively. A tetrachlorogallate salt of [(PhP)4PPhtBu]+ (8c) has been synthesized by alkylation of 4a with tBuCl/GaCl3. 31P[1H] NMR parameters for all derivatives of 8 have been determined by iterative simulation of experimental data. Derivatives 8a[OTf], 8b[OTf], 8c[GaCl4], 8e[OTf], 8f[OTf], and 8g[OTf] and have been characterized by X-ray crystallography, showing the most favorable all-trans configuration of substituents for the phosphine centers, thus minimizing steric interactions. Each derivative adopts a unique envelope or twist conformation of C1 symmetry. The effective C2 symmetry observed for 8b, d, e, f, and g in solution, signified by their 31P[1H] NMR AA'BB'X spin systems, implies a rapid conformational exchange for derivatives of 8. The core frameworks of the cations in the solid state are viewed as snapshots of different conformational isomers within the solution-phase pseudorotation process.     

Synthesis of some nitro and amino derivatives of 1, 2, 4-triazole-5-thiones and 1, 2, 4-triazoles

Isomeric 3-(nitrophenyl)-1, 2, 4-triazole-5-thiones are synthesized by cyclizing 1-nitrobenzoylthiosemicarbazides. 1-(4-Nitrophenyl)-1, 2, 4-triazole-3-thione is prepared by condensing 4-(4-nitrophenyl) thiosemicarbazide with formic acid. Oxidation converts the triazolethiones to nitrophenyltriazoles, and the latter are reduced to aminophenyltriazoles.     

Polarizabilities and hyperpolarizabilities for the atoms Al, Si, P, S, Cl, and Ar: Coupled cluster calculations

Accurate static dipole polarizabilities and hyperpolarizabilities are calculated for the ground states of the Al, Si, P, S, Cl, and Ar atoms. The finite-field computations use energies obtained with various ab initio methods including Moller-Plesset perturbation theory and the coupled cluster approach. Excellent agreement with experiment is found for argon. The experimental alpha for Al is likely to be in error. Only limited comparisons are possible for the other atoms because hyperpolarizabilities have not been reported previously for most of these atoms. Our recommended values of the mean dipole polarizability (in the order Al-Ar) are alpha/e(2)a(0) (2)E(h) (-1)=57.74, 37.17, 24.93, 19.37, 14.57, and 11.085 with an error estimate of +/-0.5%. The recommended values of the mean second dipole hyperpolarizability (in the order Al-Ar) are gamma/e(4)a(0) (4)E(h) (-3)=2.02 x 10(5), 4.31 x 10(4), 1.14 x 10(4), 6.51 x 10(3), 2.73 x 10(3), and 1.18 x 10(3) with an error estimate of +/-2%. Our recommended polarizability anisotropy values are Deltaalpha/e(2)a(0) (2)E(h) (-1)=-25.60, 8.41, -3.63, and 1.71 for Al, Si, S, and Cl respectively, with an error estimate of +/-1%. The recommended hyperpolarizability anisotropies are Deltagamma/e(4)a(0) (4)E(h) (-3)=-3.88 x 10(5), 4.16 x 10(4), -7.00 x 10(3), and 1.65 x 10(3) for Al, Si, S, and Cl, respectively, with an error estimate of +/-4%.     

Synthesis, structure, and electrochemical studies of molybdenum and tungsten dinitrogen, diazenido, and hydrazido complexes that contain aryl-substituted triamidoamine ligands

One-electron reduction of [ArN(3)N]MoCl complexes (Ar = C(6)H(5), 4-FC(6)H(4), 4-t-BuC(6)H(4), 3,5-Me(2)C(6)H(3)) yields complexes of the type [ArN(3)N]Mo-N=N-Mo[ArN(3)N], while two-electron reduction yields ([ArN(3)N]Mo-N=N)(-) derivatives (Ar = C(6)H(5), 4-FC(6)H(4), 4-t-BuC(6)H(4), 3,5-Me(2)C(6)H(3), 3,5-Ph(2)C(6)H(3), and 3,5-(4-t-BuC(6)H(4))(2)C(6)H(3)). Compounds that were crystallographically characterized include ([t-BuC(6)H(4)N(3)N]Mo)(2)(N(2)), Na(THF)(6)([PhN(3)N]Mo-N=N)(2)Na(THF)(3), [t-BuC(6)H(4)N(3)N]Mo-N=N-Na(15-crown-5), and ([Ph(2)C(6)H(3)N(3)N]MoNN)(2)Mg(DME)(2). Compounds of the type [ArN(3)N]Mo-N=N-Mo[ArN(3)N] do not appear to form when Ar = 3,5-Ph(2)C(6)H(3) or 3,5-(4-t-BuC(6)H(4))(2)C(6)H(3), presumably for steric reasons. Treatment of diazenido complexes (e.g., [ArN(3)N]Mo-N=N-Na(THF)(x)) with electrophiles such as Me(3)SiCl or MeOTf yielded [ArN(3)N]Mo-N=NR complexes (R = SiMe(3) or Me). These species react further to yield ([ArN(3)N]Mo-N=NMe(2))(+) species in the presence of methylating agents. Addition of anionic methyl reagents to ([ArN(3)N]Mo-N=NMe(2))(+) species yielded [ArN(3)N]Mo(N=NMe(2))(Me) complexes. Reduction of [4-t-BuC(6)H(4)N(3)N]WCl under dinitrogen leads to a rare ([t-BuC(6)H(4)N(3)N]W)(2)(N(2)) species that can be oxidized by two electrons to give a stable dication (as its BPh(4)(-) salt). Reduction of hydrazido species leads to formation of Mo=N in low yields, and only dimethylamine could be identified among the many products. Electrochemical studies revealed expected trends in oxidation and reduction potentials, but also provided evidence for stable neutral dinitrogen complexes of the type [ArN(3)N]Mo(N(2)) when Ar is a relatively bulky terphenyl substituent.     

Synthesis, reactivities, and magnetostructural properties of FeIII, FeIII-O-FeIII, and ZnIIFeIII-O-FeIIIZnII complexes of a tetraiminodiphenolate macrocycle

The mononuclear iron(III) complexes [Fe(LH2)(H2O)Cl](ClO4)2.2H2O (1) and [Fe(LH2)(H2O)2](ClO4)3.H2O (2) have been prepared by reacting [Pb(LH(2))](ClO4)2 with FeCl3.6H2O and Fe(ClO(4))(3).6H(2)O, respectively. Complex 2 upon treatment with 1 equiv of alkali produces the oxo-bridged dimer [{Fe(LH2)(H2O)}2(mu-O)](ClO4)4.2H2O (3). In these compounds, LH2 refers to the tetraiminodiphenol macrocycle in the zwitterionic form whose two uncoordinated imine nitrogens are protonated and hydrogen-bonded to the metal-bound phenolate oxygens. The aqua ligands of complexes 1-3 get exchanged in acetonitrile. Reaction equilibria involving binding and exchange of the terminal ligands (Cl-/H2O/CH3CN) in these complexes have been studied spectrophotometrically. The equilibrium constant for the aquation reaction (K(aq)) [1]2+ + H2O <==> [2]3+ + Cl- in acetonitrile is 8.65(5) M, and the binding constant (K(Cl)-) for the reaction [1]2+ + Cl- [1Cl]+ + CH3CN is 4.75(5) M. The pK(D) value for the dimerization reaction 2[2]3+ + 2OH- <==> [3]4+ + 3H(2)O in 1:1 acetonitrile-water is 9.38(10). Complexes 1-3 upon reaction with Zn(ClO4)(2).6H(2)O and sodium acetate (OAc), pivalate (OPiv), or bis(4-nitrophenyl)phosphate (BNPP) produce the heterobimetallic complexes [{FeLZn(mu-X)}2(mu-O)](ClO4)2, where X = OAc (4), OPiv (5), and BNPP (6). The pseudo-first-order rate constant (k(obs)) for the formation of 4 at 25 degrees C from either 1 or 3 with an excess of Zn(OAc)2.2H2O in 1:1 acetonitrile-water at pH 6.6 is found to be the same with k(obs) = 1.6(2) x 10(-4) s(-1). The X-ray crystal structures of 3, 4, and 6 have been determined, although the structure determination of 3 was severely affected because of heavy disordering. In 3, the Fe-O-Fe angle is 168.6(6) degrees, while it is exactly 180.0 degrees in 4 and 6. Cyclic and square-wave voltammetric (CV and SWV) measurements have been carried out for complexes 1-4 in acetonitrile. The variation of the solvent composition (acetonitrile-water) has a profound effect on the E(1/2) and DeltaE(p) values. The binding of an additional chloride ion to an iron(III) center in 1-3 is accompanied by a remarkable shift of E(1/2) to more negative values. The observation of quasi-reversible CV for complexes containing a Fe(III)-O-Fe(III) unit (3 and 4) indicates that in the electrochemical time scale unusual Fe(III)-O-Fe(II) is produced. The 1H NMR spectra of complexes 3-6 exhibit hyperfine-shifted signals in the range 0-90 ppm with similar features. The metal-hydrogen distances obtained from T(1) measurements are in good agreement with the crystallographic data. Variable-temperature (2-300 K) magnetic susceptibility measurements carried out for 3 and 4 indicate strong antiferromagnetic exchange interaction (H = -2JS1.S2) between the high-spin iron(III) centers in the Fe-O-Fe unit with J = -114 cm(-1) (3) and -107 cm(-1) (4).     

Synthesis, structure, photophysics, electrochemistry, and ion-binding studies of ruthenium(II) 1,10-phenanthroline complexes containing thia-, selena-, and aza-crown pendants

A series of ruthenium(II) diimine complexes containing thia-, selena- and aza-crowns derived from 1,10-phenanthroline have been synthesized and characterized, and their photophysics and electrochemistry were studied. Their interaction with metal ions was investigated by UV-vis, luminescence, and 1H NMR spectroscopy. The crystal structures of [Ru(bpy)2(L1)](PF6)2, [Ru(bpy)2(L2)](ClO4)2, [Ru(bpy)2(L3)](ClO4)2, and [Ru(bpy)2(L4)](ClO4)2 have been determined. The luminescence properties of [Ru(bpy)2(L1)](ClO4)2 were found to be sensitive and selective toward the presence of Hg2+ ions in an acetonitrile solution. The addition of alkaline-earth metal ions, Zn2+, Cd2+, and Hg2+ ions, to the solution of [Ru(bpy)2(L6)](ClO4)2 in acetonitrile gave rise to large changes in the UV-vis and emission spectra. The binding of metal ions to [Ru(bpy)2(L6)](ClO4)2 was found to cause a strong enhancement in the emission intensities of the complex, with high specificity toward Hg2+ ions.     

Design and synthesis of novel quinoline derivatives bearing oxadiazole,isoxazoline, triazolothiadiazole,triazolothiadiazine, and piperazine moieties

A new series of 2,3-disubstituted quinoline derivatives were synthesized from 2-chloroquinoline-3-carbaldehyde. In the reaction sequence, acetanilide was cyclized to give 2-chloroquinoline-3-carbaldehyde 1 , which was transformed to 2-(4-phenylpiperazin-1-yl)quinolin-3-carbaldehyde 2 by reaction with 4-phenylpiperazine in DMF-containing anhydrous K₂CO₃; then, compound 2 was oxidized by iodine in methanol, and methyl 2-(4-phenylpiperazin-1-yl)quinoline-3-carboxylate 3 was synthesized. The key intermediate 4 , 4-amino-5-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-4H-1,2,4-triazole-3-thiol, was prepared using the ester 3 by a series of step. Reaction of 5 with various aromatic carboxylic acids or phenacyl bromides yielded 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles 5a-c and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 6a-c , respectively. Moreover, compound 2 condensed with o-phenylenediamine to give 2-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-1H-benzimidazole 7 . Interaction of 7 and 2-chloromethyl-5-aryl-1,3,4-oxadiazoles in the presence of K₂CO₃ led to the title compounds 8a-c . Furthermore, 4,5-dihydroisoxazoline derivatives 9a-c were obtained by the reaction of readily accessible starting materials including 2-(4-phenylpiperazin-1-yl)quinolin-3-carbaldehyde 2 , 1-phenyl-2-(triphenylphosphoranylidene)ethanone and hydroximoyl chlorides under mild conditions in the presence of Et₃N. The hydrazone intermediates 10a-c were obtained by the condensation of 2 with aroylhydrazides in ethanol, then, refluxing in acetic anhydride yielded 3-acetyl-5-aryl-2-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-2,3-dihydro-1,3,4-oxadiazoles 11a-c . Structures of these compounds were established by their elemental analysis, IR, ¹H NMR, and mass spectral data.     

Homoleptic organometallic anions of Ti, Zr, Hf, and Nb

Reactions of C(6)H(5)Li and 4-CH(3)C(6)H(4)Li with halides of Ti, Ir, Hf, and Nb lead to the formation of homoleptic organometallic anions of these metals. Owing to their thermal instability and their sensitivity towards H(2) O and O(2) , these compounds are characterized by single-crystal structure determinations at low temperature, whereas other physical data could only be obtained occasionally. Three pentacoordinate complex anions [Ti(C(6)H(5))(5)](-), [Ti(4-CH(3)C(6)H(4))(5)](-), and [Zr(C(6)H(5))(5)](-) have square-pyramidal structures that display only slight deviations from the ideal geometry, in contrast to the already known structures of [Ti(CH(5))(5)](-). The hexacoordinate complex anions [Zr(C(6)H(5))(6)](2-), [Zr(4-CH(3)C(6)H(4))(6)](2-), [Nb(C(6)H(5))(6)](2-), and [Nb(4-CH(3)C(6)H(4))(6)](2-) all have trigonal-prismatic structures, in accord with the known hexamethyl complex dianions. In contrast, the hexacoordinate complex anion [Hf(C(6)H(5))(6)](2)(-) has an octahedral or close to octahedral structure, in contrast to the known trigonal-prismatic structures of [Ta(C(6)H(5))(6)](-) and [Ta(4-CH(3)C(6)H(4))(6) (-). A qualitative explanation for this structural variability is given.     

Synthesis, reactivity, and X-ray crystallographic characterization of mono-, di-, and tetranuclear palladium(II)-metalated species

The reactivity of the tetranuclear metallated palladium compound (Pd[mu 2-(C6H4)PPh2]Br)4 (1) with different ligands has been investigated with the aim of evaluating the influence of the entering ligand on the nature of the reaction products. The results confirmed the ability of the ligand [(C6H4)PPh2]- to expand a bridging [mu 2-] or a chelating [eta 2-] coordination mode, depending on the auxiliary ligands present in the complex. Bulky phosphines stabilize mononuclear species of formula (Pd[eta 2-(C6H4)PPh2]Br[P]), with a four-atom metallocycle, while small phosphines give dinuclear compounds. The molecular structures of three different metalated palladium compounds have been determined by single-crystal X-ray crystallography; the tetranuclear (Pd[mu 2-(C6H4)PPh2]Cl)4 (2), the dinuclear(Pd[mu 2-(C6H4)PPh2]Br[PMe3])2 (3), and the mononuclear (Pd[eta 2-(C6H4)PPh2]Br[PCBr]), (PCBr = P(o-BrC6H4)Ph2) (9) were obtained, the first one by halogen exchange reaction and the others by frame degradation of 1.     

Synthesis, characterisation, crystal structures, reactivity, and electrochemistry of ruthenium-nitrido, ruthenium-cobalt-imido and ruthenapyrrolidone carbonyl clusters containing alkyne ligands

Thermolysis of [Ru3(CO)9(mu3-NOMe)(mu3-eta2-PhC2Ph)] (1) with two equivalents of [Cp*Co(CO)2] in THF afforded four new clusters, brown [Ru5(CO)8(mu-CO)3(eta5-C5Me5)(mu5-N)(mu4-eta2-PhC2Ph)] (2), green [Ru3Co2(CO)7(mu3-CO)(eta5-C5Me5)2(mu3-NH)[mu4-eta8-C6H4-C(H)C(Ph)]] (3), orange [Ru3(CO)7(mu-eta6-C5Me4CH2)[mu-eta3-PhC2(Ph)C(O)N(OMe)]] (4) and pale yellow [Ru2(CO)6[mu-eta3-PhC2(Ph)C(O)N(OMe)]] (5). Cluster 2 is a pentaruthenium mu5-nitrido complex, in which the five metal atoms are arranged in a novel "spiked" square-planar metal skeleton with a quadruply bridging alkyne ligand. The mu5-nitrido N atom exhibits an unusually low frequency chemical shift in its 15N NMR spectrum. Cluster 3 contains a triangular Ru2Co-imido moiety linked to a ruthenium-cobaltocene through the mu4-eta8-C6H4C(H)C(Ph) ligand. Clusters 4 and 5 are both metallapyrrolidone complexes, in which interaction of diphenylacetylene with CO and the NOMe nitrene moiety were observed. In 4, one methyl group of the Cp* ring is activated and interacts with a ruthenium atom. The "distorted" Ru3Co butterfly nitrido complex [Ru3Co(CO)5(eta5-C5Me5)(mu4-N)(mu3-eta2-PhC2Ph)(mu-I)2I] (6) was isolated from the reaction of 1 with [Cp*Co(CO)I2] heated under reflux in THF, in which a Ru-Ru wing edge is missing. Two bridging and one terminal iodides were found to be placed along the two Ru-Ru wing edges and at a hinge Ru atom, respectively. The redox properties of the selected compounds in this study were investigated by using cyclic voltammetry and controlled potential coulometry. 15N magnetic resonance spectroscopy studies were also performed on these clusters.     

Ni, Pd, Pt, and Ru complexes of phosphine-borate ligands

The species Cy(2)PHC(6)F(4)BF(C(6)F(5))(2) reacts with Pt(PPh(3))(4) to yield the new product cis-(PPh(3))(2)PtH(Cy(2)PC(6)F(4)BF(C(6)F(5))(2)) 1 via oxidative addition of the P-H bond of the phosphonium borate to Pt(0). The corresponding reaction with Pd(PPh(3))(4) affords the Pd analogue of 1, namely, cis-(PPh(3))(2)PdH(Cy(2)PC(6)F(4)BF(C(6)F(5))(2)) 3; while modification of the phosphonium borate gave the salt [(PPh(3))(3)PtH][(tBu(2)PC(6)F(4)BF(C(6)F(5))(2))] 2. Alternatively initial deprotonation of the phosphonium borate gave [tBu(3)PH][Cy(2)PC(6)F(4)BF(C(6)F(5))(2)] 4, [SIMesH][Cy(2)PC(6)F(4)BF(C(6)F(5))(2)] 5 which reacted with NiCl(2)(DME) yielding [BaseH](2)[trans-Cl(2)Ni(Cy(2)PC(6)F(4)BF(C(6)F(5))(2))(2)] (Base = tBu(3)P 6, SIMes 7) or with PdCl(2)(PhCN)(2) to give [BaseH](2)[trans-Cl(2)Pd(Cy(2)PC(6)F(4)BF(C(6)F(5))(2))(2)] (Base = tBu(3)P 8, SIMes 9). While [C(10)H(6)N(2)(Me)(4)H][tBu(2)PC(6)F(4)BF(C(6)F(5))(2)] 10 was also prepared. A third strategy for formation of a metal complex of anionic phosphine-borate derivatives was demonstrated in the reaction of (COD)PtMe(2) with the neutral phosphine-borane Mes(2)PC(6)F(4)B(C(6)F(5))(2) affording (COD)PtMe(Mes(2)PC(6)F(4)BMe(C(6)F(5))(2)) 11. Extension of this reactivity to tBu(2)PH(CH(2))(4)OB(C(6)F(5))(3)) was demonstrated in the reaction with Pt(PPh(3))(4) which yielded cis-(PPh(3))(2)PtH(tBu(2)P(CH(2))(4)OB(C(6)F(5))(3)) 12, while the reaction of [SIMesH][tBu(2)P(CH(2))(4)OB(C(6)F(5))(3)] 13 with NiCl(2)(DME) and PdCl(2)(PhCN)(2) afforded the complexes [SIMesH](2)[trans-Cl(2)Ni(tBu(2)PC(4)H(8)OB(C(6)F(5))(3))(2)] 14 and [SIMesH](2)[trans-PdCl(2)(tBu(2)P(CH(2))(4)OB(C(6)F(5))(3))(2)] 15, respectively, analogous to those prepared with 4 and 5. Finally, the reaction of 7 and 13with [(p-cymene)RuCl(2)](2) proceeds to give the new orange products [SIMesH][(p-cymene)RuCl(2)(Cy(2)PC(6)F(4)BF(C(6)F(5))(2))] 16 and [SIMesH][(p-cymene)RuCl(2)(tBu(2)P(CH(2))(4)OB(C(6)F(5))(3))] 17, respectively. Crystal structures of 1, 6, 10, 11, 12, and 16 are reported.     

Synthesis, characterization, and electrochemical and electrochromic properties of sandwich dilutetium tetraphthalocyanine

A new sandwich-tpype dilutetium tetraphthalocyanine 4 has been synthesized by the reaction of dimeric lutetium(III) phthalocyanine 3 with two equiv. of dilithium octakishexylthiophthalocyanine in amyl alcohol. Compound 3 was prepared from 4',5',4",5"-tetraiminoisoindoline(1,4,7,10-tetrathia-12-crown-4) 1, 4,5-bis(hexylthio)-1,2-diiminoisoindoline and lutetium acetate in amyl alcohol. Compounds 3 and 4 were characterized by elemental analysis, UV/visible, IR, (1)H NMR and ESR spectroscopy. The electrochemical and electrochromic properties of 3 and 4 have been examined by cyclic voltammetry. Both 3 and 4 displayed well-defined electrochromic behavior.