Bridge-Dependent Donor-Metal-Acceptor-Metal-Donor (D-M-A-M-D) Systems: From Charge Transfer to Electron Transfer in Dioxolene-Ge-Diimine Complexes.

Synthesis and structural characterization of a family of germanium-dioxolene complexes with ditopic N-donor ligands (L-L) (L=1,2-bis(pyridin-2-ylmethylene)hydrazine L=1,6-bis-(pyridin-2-yl)-2,5-diaza-1,5-hexadiene, L=N,N-bis(pyridin-2-ylmethylene)-1,4-benzenediamine, L=N,N-bis(pyridin-2-ylmethylene)-(biphenyl)-4,4-diamine, L=2,2'-azopyridine) is reported. The reaction of germanium bis-catecholate with bridging ligands L - L, differing by the nature of the linker between pyridine sites gives rise to dinuclear digermanium complexes (36CatGe)L (36Cat=dianion of 3,6-di-tert-butylcatechol) 1-4 of DMAMD type (donor-metal-acceptor-metal-donor) with a charge transfer in the UV-Vis region. In opposite, the interaction of the 36CatGe with 2,2'-azopyridine (L) results in the two-electron transfer from the donor 36Cat ligands to the azopyridine bridge forming stable open-shell complex 5 [(36SQ)(36CatGe)](L) (36SQ=radical-anionic semiquinonate ligand).

Porogen Concentration Effect on the Pore Structure and Properties Evolution of Polymer Monolith Based on Oligocarbonate Dimethacrylate OCM-2.

Porous polymer monolith materials of 2-mm thickness were obtained by visible light-induced radical polymerization of oligocarbonate dimethacrylate (OCM-2) in the presence of 1-butanol (10 to 70 wt %) as a porogenic additive. The pore characteristics and morphology of polymers were studied by mercury intrusion porosimetry and scanning electron microscopy. Monolithic polymers with both open and closed pores up to 100 nm in size are formed when the alcohol content in the initial composition is up to 20 wt %.

Novel Rigidochromic and Anti-Kasha Dual Emission Fluorophores Based on D-π-A Dyads as the Promising Materials for Potential Applications Ranging from Optoelectronics and Optical Sensing to Biophotonics and Medicine.

Today we see an increasing demand for new fluorescent materials exhibiting various sensory abilities due to their broad applicability ranging from the construction of flexible devices to bioimaging. In this paper, we report on the new fluorescent pigments AntTCNE, PyrTCNE, and PerTCNE which consist of 3-5 fused aromatic rings substituted with tricyanoethylene fragments forming D-π-A diad. Our studies reveal that all three compounds exhibit pronounced rigidochromic properties, i.

Charge Transfer Chromophores Derived from 3d-Row Transition Metal Complexes.

A series of new charge transfer (CT) chromophores of "α-diimine-M-catecholate" type (where M is 3d-row transition metals-Cu, Ni, Co) were derived from 4,4'-di--butyl-2,2'-bipyridyl and 3,6-di--butyl--benzoquinone () in accordance with three modified synthetic approaches, which provide high yields of products. A square-planar molecular structure is inherent for monomeric () and () chromophores, while dimeric complex () units two substantially distorted heteroleptic D-M-A (where D, M, A are donor, metal and acceptor, respectively) parts through a donation of oxygen atoms from catecholate dianions. Chromophores - undergo an effective photoinduced intramolecular charge transfer (λ = 500-715 nm, extinction coefficient up to 10 M·cm) with a concomitant generation of a less polar excited species, the energy of which is a finely sensitive towards solvent polarity, ensuring a pronounced negative solvatochromic effect.

Novel Antireflection Coatings Obtained by Low-Temperature Annealing in the Presence of Tetrabutylammonium Bromide and Gold Nanoparticles.

In this work, nanoporous antireflective coatings on silicate glass were obtained from silicon dioxide sol compositions by the sol-gel method in the presence of quaternary ammonium salt (tetrabutylammonium bromide) at different annealing temperatures (200-250 °C). Varying the salt concentration from 3 to 5 wt.%, we achieved the transmittance of the coatings of about 97% at 250 °C in comparison with 91% for clean glass in the wavelength range from 400 to 1100 nm.

Magnetically bistable cobalt-dioxolene complexes with a tetradentate N-donor base.

Synthesis and magnetic characterization of a family of cobalt-dioxolene complexes [(MeTPA)Co(36-DBCat)] (1), [(MeTPA)Co(36-DBCat)](PF) (2) and [(MeTPA)Co(diox-(OMe))](BPh) (3) (MeTPA = bis(6-methyl-2-pyridyl)methyl-(2-pyridylmethyl)amine; 36-DBCat = dianion of 3,6-di--butylcatechol; diox-(OMe) - 2,5-di--butyl-3,3,4-trimethoxy-6-oxocyclohexa-1,4-dienolate) is reported. The neutral complex 1 is found to form hexa- (CoON, 1a) and pentacoordinated (CoON, 1b) isomers. Variable temperature single crystal X-ray diffraction analysis of 1a and 1b clearly indicates the presence of the high-spin divalent metal ion and the dianionic catecholate form of the dioxolene ligand.

Towards Asymmetrical Methylene Blue Analogues: Synthesis and Reactivity of 3-'-Arylaminophenothiazines.

The search for new ways to obtain analogues of the well-known Methylene Blue dye is an important synthetic task. Herein, we proposed and developed an approach to the synthesis of 3-'-arylaminophenothiazines and asymmetrical 3,7-di('-arylamino)phenothiazines. This approach included the optimization of synthetic strategy by quantification analysis of the positive charge distribution in the cation of 3-'-arylaminophenothiazine derivative.

Square-Planar Heteroleptic Complexes of α-Diimine-Ni-Catecholate Type: Intramolecular Ligand-to-Ligand Charge Transfer.

Two heteroleptic Ni complexes combined the redox-active catecholate and 2,2'- bipyridine ligand platforms were synthesized to observe a photoinduced intramolecular ligand-to-ligand charge transfer (LL'CT, HOMO → LUMO). A molecular design of compound [Ni(3,6-Cat)(bipy)]∙CHCN () on the base of bulky 3,6-di--butyl--benzoquinone () was an annelation of the ligand with an electron donor glycol fragment, producing derivative [Ni(3,6-Cat)(bipy)]∙CHCl (), in order to influence the energy of LL'CT transition. A substantial longwave shift of the absorption peak was observed in the UV-Vis-NIR spectra of compared with those in .

Complexes of Metal Halides with Unreduced -(Imino)quinones.

A series of complexes of metal halides with unreduced quinone-type ligands have been synthesized and characterized in detail. The 3,6-di--butyl--benzoquinone () and 4,6-di--butyl--aryl-substituted -iminobenzoquinones (-) (aryl is 2,6-dimethylphenyl in , 2-methyl-6-ethylphenyl in , 2,6-diethylphenyl in , and 2,6-diisopropylphenyl in ) were used to obtain the molecular complexes with metal 12 group halides as well as with indium(III) iodide. The molecular structures of five complexes, bearing an unreduced form of redox-active ligand, have been established by single-crystal X-ray analysis.

Heteroleptic La Anilate/Dicarboxylate Based Neutral 3D-Coordination Polymers.

Three new 3D metal-organic frameworks of lanthanum based on mixed anionic ligands, [(La(pQ)(BDC))·4DMF], [(La(pQ)(DHBDC))·4DMF], [(La(CA)(BDC))·4DMF] (pQ-dianion of 2,5-dihydroxy-3,6-di-tert-butyl-para-quinone, CA-dianion of chloranilic acid, BDC-1,4-benzenedicarboxylate, DHBDC-2,5-dihydroxy-1,4-benzenedicarboxylate and DMF-N,N'-dimethylformamide), were synthesized using solvothermal methodology. Coordination polymers demonstrate the rare or topology of a 3D framework. The homoleptic 2D-coordination polymer [(La(pQ))·4DMF] was obtained as a by-product in the course of synthetic procedure optimization.

The (Dioximate)Ni/I System: Ligand Oxidation and Binding Modes of Triiodide Species.

Reinvestigation of (-benzoquinonedioximate)Ni/I systems demonstrated that the reaction itself and also the crystallization conditions dramatically affect the identity of generated species. Crystallization (CHCl, 20-25 °C) of the nickel(II) dioximate complex [Ni(bqoxH)] (bqoxH = -benzoquinonedioxime) with I in the 1:(1-10) molar ratios of the reactants led to several (-benzoquinonedioximate)Ni derivatives and/or iodine adducts [Ni(I)(bqoxH)(bqoxH)]·/I, [Ni(I)(bqoxH)(bqoxH)]·[Ni(bqoxH)], and [Ni(I)(bqox)(bqoxH)]·I; the latter one, featuring the anion-radical bqox ligand, is derived from the formal (-2H/1)-oxidation of bqoxH. In these three adducts, various types of noncovalent interactions were identified experimentally and their existence was supported theoretically.

Tetrahedral nickel(ii) and cobalt(ii) bis-o-iminobenzosemiquinonates.

The new bis-o-iminobenzosemiquinonate nickel and cobalt complexes (imSQt-Bu)2M (M = Ni (1), Co (2)), where imSQ is a radical anion of 4,6-di-tert-butyl-N-(tert-butyl)-o-iminobenzoquinone, were synthesized and characterized in detail. The molecular structures of 1 and 2 have been established by single-crystal X-ray analysis. The metal atoms in 1 and 2 have a distorted tetrahedral environment, and the dihedral angles between the planes of two radical imSQ ligands are approximately 80° in both complexes.

Cobalt complexes with hemilabile o-iminobenzoquinonate ligands: a novel example of redox-induced electron transfer.

The tetracoordinated square-planar CoIII complex (imSQC(O)Ph)CoIII(APC(O)Ph) (1) bearing a radical anion and the closed-shell o-amidophenolate forms of the functionalized o-aminophenol H2LC(O)Ph were synthesized. The intermediate spin state (SCo = 1) CoIII center was found for compound 1. The cyclic voltammogram of derivative 1 contains two oxidative processes and one reductive redox process as well as an additional multi-electron wave at high negative potentials above -2 V, which can involve both the ligand and metal center.

The new C-C bond formation in the reaction of o-amidophenolate indium(III) complex with alkyl iodides.

The reaction of bis(4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-amidophenolato)indium(III) anion with alkyl iodides is reported. This process includes oxidative addition of two RI (R = Me, Et) molecules to the non-transition metal complex and results in an alkyl transfer to ring carbon atoms with the formation of two new C-C bonds. The interaction proceeds at mild conditions and gives new indium(III) derivatives containing iminocyclohexa-1,4-dienolate type ligands.

Tin(IV) and lead(IV) complexes with a tetradentate redox-active ligand.

The coordination chemistry of a tetradentate redox-active ligand, glyoxal-bis(2-hydroxy-3,5-di-tert-butylanil) (H(2)L), was investigated with the diorganotin(IV) and diphenyllead(IV) moieties. Complexes R(2)SnL (R = Me (1), Et (2), (t)Bu (3), Ph (4)) and Ph(2)PbL (5) have been prepared and characterized. The molecular structures of compounds 1, 3, and 5 have been determined by single crystal X-ray diffraction.

Synthesis and molecular structure of indium complexes based on 3,6-di-tert-butyl-o-benzoquinone. Looking for indium(I) o-semiquinolate.

The interaction of 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) with indium in toluene leads to the tris-o-semiquinolate derivative (3,6-SQ)(3)In (3,6-SQ - radical-anion of 3,6-Q). According to single-crystal X-ray diffraction analysis, this complex has a trigonal prismatic structure. Magnetic measurements revealed that the exchange interactions between odd electrons of the paramagnetic ligands in (3,6-SQ)(3)In are antiferromagnetic in character.

Oxidation by oxygen and sulfur of Tin(IV) derivatives containing a redox-active o-amidophenolate ligand.

Oxidation of tin(IV) o-amidophenolate complexes [Sn(ap)Ph(2)] (1) and [Sn(ap)Et(2)(thf)] (2) (ap=dianion of 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone (ImQ)) with molecular oxygen and sulfur in toluene solutions was investigated. The reaction of oxygen with 1 at room temperature forms a paramagnetic derivative [Sn(isq)(2)Ph(2)] (3) (isq=radical anion of ImQ) and diphenyltin(IV) oxide [{Ph(2)SnO}(n)]. Interaction of 1 with sulfur gives another monophenyl-substituted paramagnetic tin(IV) complex, [Sn(ap)(isq)Ph] (4), and the sulfide, [Ph(3)Sn](2)S.