Search results for "Zen"
showing 10 items of 3479 documents
Solid-state cis–trans isomerism in bis(oxamato)palladate(ii) complexes: synthesis, structural studies and catalytic activity
2014
A new generation of bis(oxamato)palladate(II) monomeric complexes has been prepared by using N-2,6-dimethylphenyloxamate (2,6-Me2pma) as the ligand. Four alkaline salts of the complex, namely {[Na(H2O)]2trans-[PdII(2,6-Me2pma)2]}n (1a), {[Na4(H2O)2]cis-[PdII(2,6-Me2pma)2]2}n (1b), {[K4(H2O)3]cis-[PdII(2,6-Me2pma)2]2}n (2), {[Rb4(H2O)3]cis-[PdII(2,6-Me2pma)2]2}n (3) and {[Cs6(H2O)7]trans-[PdII(2,6-Me2pma)2]2cis-[PdII(2,6-Me2pma)2]}n·3nH2O (4), were obtained and structurally characterized by single crystal X-ray diffraction. Both the cis and trans stereoisomers of the [PdII(2,6-Me2pma)2]2− complex anion were isolated in the solid state, in a cation-dependent manner. The trans-isomer as the so…
Two- and one-step cooperative spin transitions in Hofmann-like clathrates with enhanced loading capacity
2014
Structural, magnetic, calorimetric and Mo¨ssbauer studies of the cooperative spin crossover naphthalene and nitrobenzene clathrates of the novel FeII Hofmann-like porous metal–organic framework {Fe(bpb)[Pt(CN)4]}2Guest are described (bpb = bis(4-pyridyl)butadiyne).
Synthesis and biological evaluation of 4-nitro-substituted 1, 3-diaryltriazenes as a novel class of potent antitumor agents
2011
Abstract We describe the synthesis and biological activity of a new class of 1,3-diaryltriazenes, namely 4-nitro-substituted 1,3-diaryltriazenes. Structure–activity relationship analysis reveals that 1,3-diaryltriazenes can be modified from inactive to highly cytotoxic compounds by the introduction of two nitro groups at the para positions of benzene rings and two additional electron-withdrawing groups (bromo, chloro, trifluoromethyl or fluoro substituents) at their ortho position. In order to increase the solubility of the modified compounds, we introduced various acyl groups to their triazene nitrogen. The results of LC-MS/MS analysis showed that N -acyltriazenes can be considered as prod…
Mononuclear heterocyclic rearrangements—vi
1974
Publisher Summary This chapter discusses the mononuclear heterocyclic rearrangements. The chapter discusses the ring conversion of type 1→2 characterized by nucleophilic attack from a Z atom on a sp 2 -nitrogen atom with displacement of an atom. On this basis, the known ring conversions are tabulated. Taking into account the reactivities observed in the rearrangements, results are presented for 1,2,4-oxadiazole, isoxazole, and 1,2,5-oxadiazole. The sequence involving an oxime group in the side chain is discussed. The chapter presents several attempts for inducing rearrangements in which the reaction center of the starting ring is an atom other than nitrogen. Rearrangement of arylhydrazones …
Design, synthesis and spectral studies of novel bile acid-arene conjugates: Trans to cis isomerization of azobenzene core controlled by bile acid hyd…
2008
Abstract Four bile acid-arene conjugates, 1,4-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]benzene dibromide ( 1 ), 1,3,5-tris[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]benzene tribromide ( 2 ), bis{4-[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]phenyl}diazene dibromide ( 3 ), and bis{4-[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]phenyl}diazene dibromide ( 4 ), have been synthesized in good yields, and their structures have been characterized by 1 H, 13 C, 13 C DEPT-135, PFG 1 H, 13 C HMQC, PFG 1 H, 13 C HMBC, and PFG 1 H, 15 N HMBC NMR spectra. Their molecular weights and elemental compositions have…
NMR studies on [Rh(η6-arene)(P(OPH)3)2]ClO4 in the presence of acetone-d6. Arene dissociation and dynamic behaviour of the solvent complex
1985
Abstract Dissociation of the complexes [Rh(η 6 -arene)L 2 ]ClO 4 (arene = mesitylene (Ia), toluene (Ib) and benzene (Ic); L = P(OPh) 3 ) with loss of the arene ligand in CD 2 Cl 2 / acetone- d 6 (95/5 mol/mol) has been studied by 31 P NMR spectroscopy; for initial 0.025 M concentrations of degrees of dissociation were 0.23, 0.33 and 0.85, respectively. The dissociations were first-order, with half-lifes of 31 (Ia), 1.2 (Ib) and 0.7 (Ic) h. The solvent complex [Rh(acetone) m L 2 ]ClO 4 produced by these dissociation reactions showed unusual dynamic structural behaviour. In dry acetone the two phosphorus nuclei were magnetically equivalent (species II-A 2 ), whereas in acetone solutions conta…
Dinuclear Ortho-Metalated Palladium(II) Compounds with N,N- and N,O-Donor Bridging Ligands. Synthesis of New Palladium(III) Complexes
2011
New dinuclear ortho-metalated palladium(II) compounds with N,N′-diarylformamidinates, Pd2[(C6H4)PPh2]2[R′NC(H)NR′]2 (R′ = C6H5, 3a; R′ = p-CH3C6H4, 3b; R′ = p-CH3OC6H4, 3c) and N,O-donor ligands, Pd2[(C6H4)PPh2]2[N,O]2 (N,O = succinimidate (5), phtalimidate (6), 2-hydroxypyridinate (7), acetanilidate (8)) have been synthesized and characterized by NMR spectroscopy and X-ray diffraction methods. The oxidation with iodobenzene dichloride gave new and rare Pd26+ compounds, Pd2[(C6H4)PPh2]2[R′NC(H)NR′]2Cl2 (R′ = C6H5, 4a; R′ = p-CH3C6H4, 4b). DFT calculations on the Pd24+ → Pd26+ oxidation reaction show that the substituents on the amidinate N atoms have a greater effect on the reaction energy …
Investigations on organotin, organolead, lead(IV), and lead(II) dithiolates
1985
Abstract Bis(triorganometal) 1,2-dithiolates (R3M)2S2R′ [(HS)2R′ = C7H8S2 for toluene-dithiol-3,4 (H2TDT); M = Sn, Pb; R = Ph; or (HS)2R′ = C10H14S2 for 1,2-dimethyl-4,5-bis(mercaptomethyl)benzene (H2DBB); M = Sn, R = CH3, C6H5; M = Pb, R = C6H5], diorganometal 1,2-dithiolates R2MS2R′ [(HS)2R′ = C6H6S2 for 1,2-dimercaptobenzene (H2DMB); M = Pb, R = CH3, C2H5, C6H5; or (HS)2R′ = H2TDT; M = Sn, R = CH3, C6H5; M = Pb, R = C6H5; or (HS)2R′ = H2DBB; M = Sn, R = CH3, C6H5; M = Pb, R = CH3, C2H2, C6H5; or (HS)2R′ = C8H6N2S2 for 2,3-dimercaptoquinoxaline (H2QDT); M = Pb, R = C6H5] and some lead(IV) and lead(II) dithiolates Pb(S2R′)n [(HS)2R′ = H2DMB, n = 2; (HS)2R′ = H2TDT, n = 2; (HS)2R′ = H2DBB, …
Antibodies directed to drug epitopes to investigate the structure of drug-protein photoadducts. Recognition of a common photobound substructure in ti…
2001
Drug-induced photoallergy is an immune adverse reaction to the combined effect of drugs and light. From the mechanistic point of view, it first involves covalent binding of drug to protein resulting in the formation of a photoantigen. Hence, determination of the structures of drug-protein photoadducts is of great relevance to understand the molecular basis of photoallergy and cross-immunoreactivity among drugs. Looking for new strategies to investigate the covalent photobinding of drugs to proteins, we generated highly specific antibodies to drug chemical substructures. The availability of such antibodies has allowed us to discriminate between the different modes by which tiaprofenic acid (…
Synthesis and characterization of cyclometallated palladium(II) complexes with 2-(diphenylphosphino)benzaldehyde
2013
New palladium(II) complexes containing 2-(diphenylphosphino)benzaldehyde a (Ph2P(o-C6H4CHO), displaying different coordination modes, have been synthesized in moderate to good yields (62–91%). The cyclometallated palladium(II) complexes [Pd(C^N)(Ph2 P(o-C6H4CHO)(Cl)] (1–4) in which a is P-monodentate have been prepared by reacting it with selected cyclometallated precursors containing bridging chlorides [Pd(C^N)(μ-Cl)]2 [C^N=2-phenylpyridine (Phpy), 7,8-benzoquinoline (Bzq), azobenzene (Phazo), and 2-phenyloxazoline (Phox), respectively]. A rigid P,O-chelating behavior of a, confirmed by the crystal structure determination of [Pd(Phox)(Ph2 P (o-C6H4CHO)][CF3SO3] (8), is observed in complexe…