Synthesis and single crystal X-ray structures of the first paramagnetic transition metal complexes containing chiral ethylenedithio-tetrathiafulvalene-oxazoline (EDT-TTF-OX) 1a-c and ethylenedithio-tetrathiafulvalene-thiomethyloxazoline 2 (EDT-TTF-(SMe)OX) ligands based on copper (II) and cobalt (II) are described. The racemic [EDT-TTF-OX][Cu(hfac)2] complex 3a crystallizes in the triclinic centrosymmetric space group , whereas the enantiopure counterparts 3b-c crystallize in the triclinic non-centrosymmetric space group P1. Cu(II) adopts a distorted square pyramidal coordination geometry, a much weaker Cu?STTF interaction also being identified. The same coordination pattern around Cu(II) is observed in the complex [(rac)-EDT-TTF-(SMe)OX][Cu(hfac)2] (4) in spite of the bidentate nature of the redox active ligand. DFT theoretical calculations afforded two equilibrium configurations for a corresponding model complex, in which the metal centre establishes secondary coordination either with one STTF or with the SMe group. The same ligand coordinates the cobalt (II) to afford the octahedral complex [(rac)-EDT-TTF-(SMe)OX][Co(hfac)2] (5). In all these novel complexes, the paramagnetic centres are structurally and magnetically isolated. Cyclic voltammetry measurements show the stability of the radical cation species. 相似文献
Interactions of cationic porphyrins bearing five-membered rings at the meso position, meso-tetrakis(1,2-dimethylpyrazolium-4-yl)porphyrin (MPzP; M is H2, CuII or ZnII), with synthetic polynucleotides poly(dG-dC)2 and poly(dA-dT)2 have been characterized by viscometric, visible absorption, circular dichroisim and magnetic circular dichroism spectroscopic and melting temperature measurements. Both H2PzP and CuPzP are intercalated into poly(dG-dC)2 and are outside-bound to the major groove of poly(dA-dT)2, while ZnPzP is outside-bound to the minor groove of poly(dA-dT)2 and surprisingly is intercalated into poly(dG-dC)2. The binding constants of the porphyrin and poly(dG-dC)2 and poly(dA-dT)2 are on the order of 106 M−1 and are comparable to those of other cationic porphyrins so far reported. The process of the binding of the porphyrin to poly(dG-dC)2 and poly(dA-dT)2 is exothermic and enthalpically driven for H2PzP, whereas it is endothermic and entropically driven for CuPzP and ZnPzP. These results have revealed that the kind of the central metal ion of metalloporphyrins influences the characteristics of the binding of the porphyrins to DNA.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
The trinuclear [{RuII(bpy)2(bpy-terpy)}2CoII]6+ complex (16+) in which a Co(II)-bis-terpyridine-like centre is covalently linked to two Ru(II)-tris-bipyridine-like moieties by a bridging bipyridine-terpyridine ligand has been synthesised and characterised. Its electrochemical, photophysical and photochemical properties have been investigated in CH3CN. The cyclic voltammetry exhibits two successive reversible oxidation processes, corresponding to the CoIII/CoII and RuIII/RuII redox couples at E1/2 = −0.06 and 0.91 V vs Ag/Ag+ 10 mM, respectively. The one-electron oxidized form of the complex, [{RuII(bpy)2(bpy-terpy)}2CoIII]7+ (17+) obtained after exhaustive electrolysis carried out at 0.2 V is fully stable. 16+ and 17+ are only poorly luminescent, indicating that the covalent linkage of the Ru(II)-tris-bipyridine centre to the cobalt subunit leads to a strong quenching of the RuII excited state by an intramolecular process. Luminescence lifetime experiments carried out at different temperatures indicate that the transfer is more efficient for 17+ compare to 16+ due to lower activation energy. Continuous irradiation of 17+ performed at 405 nm in the presence of P(Ph)3 acting as sacrificial electron donor leads to its quantitative reduction into 16+, whereas similar experiment starting from 16+ with a sulfonium salt as sacrificial electron acceptor converts 16+ into 17+ with a slower rate and a maximum yield of 80%. These photoinduced electron transfers were followed by UV-Visible spectroscopy and compared with those obtained with a simple mixture of both mononuclear parent complexes i.e. [RuII(bpy)3]2+ and [CoII(tolyl-terpy)2]2+ or [CoIII(tolyl-terpy)2]3+ (tolyl-terpy = 4′-(4-methylphenyl)-2,2′:6′,2′′-terpyridine). 相似文献
Eight specimens of Sericolophus reflexus (Ijima) were compared with the holotype of Hernandeziana ijimae (Hernandez) to assess suspected synonymy of these taxa. An extensive morphometric analysis of the spicules available in these specimens of variable condition show that the H. ijimae holotype exhibits characters near the centre of the range of S. reflexus. It is concluded that H. ijimae is a junior synonym of S. reflexus , and that the family Corythophoridae de Laubenfels is invalid by preoccupation of its base generic name. 相似文献
Lithioamidines {R′N(Li)C(R)NR′, I; R = CH3, R′ = C6H5, p-CH3,C6H4} react with iron(III) chloride in monoglyme to produce navy-blue, high spin Fe{R′NC(R)NR′}3 complexes which are extremely air and moisture sensitive. The corresponding reaction when R = R′ = C6H5 produces a soluble red complex and an air-stable green complex, whereas when R = H, R′ = C6H5 and R = R′ = C6H5 and the reaction is started at ca. ?20°, red and green complexes respectively are formed. Though all the complexes are formulated Fe{R′NC(R)NR′}3, their properties reflect association through bridging amidino-groups. Iron(II) chloride reacts with I(R = CH3, R′ = p-CH3C6H4) to form two complexes, one crimson and soluble in organic solvents, and one brown and insoluble, which are fomulated [Fe{R′NC(R)NR′}2]n. The iron(III) complexes failed to react with, or were decomposed by, a variety of reducing, electrophilic and nucleophilic reagents, though blue Fe{p-CH3C6H4NC(CH3)N-p-CH3C6H4}3 reacts readily with nitric oxide to form a purple addition complex from which the N-nitroso-compound p-CH3C6H4NC(CH3)N(NO)-p-CH3C6H4 was obtained in high yield. Treatment of the corresponding brown iron(II) complex with nitric oxide gave no reaction. 相似文献
Exechia and Bibio have retained several plesiomorphic groundplan features of Diptera and Bibionomorpha, including a fully exposed and sclerotized head capsule, the transverse undivided labrum, the absence of movable premandibles, and undivided mandibles without combs. The fusion of the hypostomal bridge with the head capsule and largely reduced antennae are derived features shared by both taxa. The absence of teeth at the anterior hypostomal margin is a potential autapomorphy of Bibionomorpha. A basal position of Anisopodidae is suggested by a number of plesiomorphies retained in this family. Apomorphies of Bibionomorpha excluding Anisopodidae are the reduction of tentorial elements, the partial fusion of the labrum and clypeus, one-segmented antennae, the absence of a separate submental sclerite, the loss of the labial palpus, and the reduction of the pharyngeal filter apparatus. Head structures of Bibio are largely unmodified. The subprognathous orientation is one of few autapomorphic features. In contrast, the mouthparts of Exechia are highly modified in correlation with the specialized food uptake. The rasping counterrotating movements of maxillae and mandibles with teeth oriented in opposite directions are carried out by strongly developed extensors and flexors of the paired mouthparts. The modified labium mechanically supports the “drill head” formed by the mandibles und maxillae. The necessary stability of the head capsule is provided by the hypostomal bridge which also compensates the far-reaching reduction of the tentorium. 相似文献
