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This work reports on synthesis of silica nanoparticles by Stöber method. The synthesis was carried out while varying five parameters: pH, volume of tetraethyl orthosilicate (TEOS), reaction temperature, type of solvent, and time. Dynamic light scattering was used to determine the particle size distribution, and some were analyzed by atomic force microscopy. The result showed that replacing ethanol with a more polar solvent, methanol, led to production of smaller-sized particles with a size as low as 33 nm. Therefore, methanol was chosen as an effective solvent in all experiments. The orange-colored fluorophore, tris(bipyridine)ruthenium (II) chloride, was incorporated into silica nanoparticles using the synthesis that produced the smallest particle size. Fluorimetry in tandem with oxygen and temperature sensing was used to determine the fluorescence, oxygen concentration and temperature using a solution of free tris(bipyridine)ruthenium (II) chloride as control. It was shown that fluorescence of free tris(bipyridine)ruthenium (II) chloride in solution decreases as the O2 concentration and temperature goes up. When the fluorophore was incorporated into silica nanoparticles the fluorescence intensity still decreased with temperature, but the O2 concentration had no effect. These results prove that oxygen could not collide with the fluorophore because it was shielded by silica nanoparticles.

Bipyridinium salts are currently very popular due to their perspective applications in redox flow batteries. Hence, we designed and prepared a series of bipyridiniums based on 2,2 '-, 3,3 '-, and 4,4 '-bipyridine and 2,2 '-bipyrimidine. The straightforward synthesis utilizes commercially or readily available starting compounds and their direct N-alkylation, mostly using 1,3-propanesultone. All eleven target derivatives with systematically evolved structure were investigated by cyclic voltammetry, which allowed elucidating thorough structure-property relationships. The electrochemical behavior depends primarily on the parent scaffold, type of N-alkylation, number of quaternized nitrogen atoms, planarity, counter ion as well as the used media. Two derivatives featuring quasi-reversible redox processes were further tested on rotating disc electrode and in a flow battery half-cell. 4,4 '-Bipyridinium derivative bearing two sultone residues showed better performance and stability in the flow half-cell with small capacity decays of 0.09/0.15% per reduction-oxidation cycle, based on the number of the utilized redox processes (one/two)., Byla připravena série bipyridiniových solí na bázi 2,2'-, 3,3'- a 4,4'-bipyridinu a 2,2'-bipyrimidinu. N-alkylace byly prováděny komerčním 1,3-propansultonem. Vlastnosti všech jedenácti cílových látek byly studovány cyklickou voltametrií a byly tak popsány vztahy struktury-vlastnosti. Elektrochemické vlastnosti závisejí na typu skeletu, typu alkylace, počtu kvarternizovaných atomů dusíku, planaritě, doprovodném iontu a prostředí.

A new generation of confined palladium(II) catalysts covalently attached inside of porous organic polymers (POPs) has been attained. The synthetic approach employed was straightforward, and there was no prerequisite for making any modification of the precursor polymer. First, POP-based catalytic supports were obtained by reacting one symmetric trifunctional aromatic monomer (1,3,5-triphenylbenzene) with two ketones having electron-withdrawing groups (4,5-diazafluoren-9-one, DAFO, and isatin) in superacidic media. The homopolymers and copolymers were made using stoichiometric ratios between the functional groups, and they were obtained with quantitative yields after the optimization of reaction conditions. Moreover, the number of chelating groups (bipyridine moieties) available to bind Pd(II) ions to the catalyst supports was modified using different DAFO/isatin ratios. The resulting amorphous polymers and copolymers showed high thermal stability, above 500 °C, and moderate-high specific surface areas (from 760 to 935 m2 g-1), with high microporosity contribution (from 64 to 77%). Next, POP-supported Pd(II) catalysts were obtained by simple immersion of the catalyst supports in a palladium(II) acetate solution, observing that the metal content was similar to that theoretically expected according to the amount of bipyridine groups present. The catalytic activity of these heterogeneous catalysts was explored for the synthesis of biphenyl and terphenyl compounds, via the Suzuki-Miyaura cross-coupling reaction using a green solvent (ethanol/water), low palladium loads, and aerobic conditions. The findings showed excellent catalytic activity with quantitative product yields. Additionally, the recyclability of the catalysts, by simply washing it with ethanol, was excellent, with a sp2-sp2 coupling yield higher than 95% after five cycles of use. Finally, the feasibility of these catalysts to be employed in tangible organic reactions was assessed. Thus, the synthesis of a bu

The bidentate N-donor ligands 2,2’-bipyridine (bipy) and 1,10-phenanthroline (phen) have attracted considerable attention in the field of coordination chemistry over the last decades because of their remarkable stability towards a wide variety of transition metals1. The coordination chemistry of uranium (U) has been explored with these N-donor ligands as well with a primary focus on its hexavalent state (U(VI) as UO₂2+). To the contrary, much less attention has been paid for the lower oxidation states, such as a tetravalent state (U(IV)). Here we present a systematic study on the coordination chemistry of U(IV) and -(VI) with bipy and phen under different chemical conditions, such as different solvents and changing the metal / ligand ratio. In this study we succeeded to obtain a series of U(IV) complexes with U:ligand ratios of 1:1 and 1:2, all of which show an eight-fold coordinated uranium centre. In addition to the ligand, chloro and methanolato ligands are coordinating to the metal centre for charge compensation. Interestingly, the complexation between U(IV) and the ligand does occur even in protic solvents, in which the ligand is expected to be protonated. We also obtained another series of U(VI) complexes with both bipy and phen, underlining the versatile coordination chemistry of uranyl (UO22+). That is, the coordination between uranyl and the ligand depends strongly on the pH of the solvent used. For instance, in media with lower pH mononuclear complexes are formed, showing the uranyl unit in an unusually bent geometry.3 On the other hand, dinuclear uranyl arrangements with hydroxo-brinding are dominated in the media with higher pH, as shown in the right of Fig. 1. As illustrated in Fig. 1, bipy and phen are forming isostructural complexes both with U(IV) and- (VI).

The bidentate N-donor ligands 2,2’-bipyridine (bipy) and 1,10-phenanthroline (phen) have attracted considerable attention in the field of coordination chemistry over the last decades because of their remarkable stability towards a wide variety of transition metals1. The coordination chemistry of uranium (U) has been explored with these N-donor ligands as well with a primary focus on its hexavalent state (U(VI) as UO₂2+). To the contrary, much less attention has been paid for the lower oxidation states, such as a tetravalent state (U(IV)). Here we present a systematic study on the coordination chemistry of U(IV) and -(VI) with bipy and phen under different chemical conditions, such as different solvents and changing the metal / ligand ratio. In this study we succeeded to obtain a series of U(IV) complexes with U:ligand ratios of 1:1 and 1:2, all of which show an eight-fold coordinated uranium centre. In addition to the ligand, chloro and methanolato ligands are coordinating to the metal centre for charge compensation. Interestingly, the complexation between U(IV) and the ligand does occur even in protic solvents, in which the ligand is expected to be protonated. We also obtained another series of U(VI) complexes with both bipy and phen, underlining the versatile coordination chemistry of uranyl (UO22+). That is, the coordination between uranyl and the ligand depends strongly on the pH of the solvent used. For instance, in media with lower pH mononuclear complexes are formed, showing the uranyl unit in an unusually bent geometry.3 On the other hand, dinuclear uranyl arrangements with hydroxo-brinding are dominated in the media with higher pH, as shown in the right of Fig. 1. As illustrated in Fig. 1, bipy and phen are forming isostructural complexes both with U(IV) and- (VI).

Dye sensitizers are one of the key factors that affects the performance of dye-sensitized solar cells (DSSCs). One of the limitation of ruthenium bipyridyl sensitizer is the limited light absorption in infrared region. Hence, extended cyclic π-conjugated bipyridyl derivative was studied to overcome this limitation. Potential DSSC sensitizers such as 2,2’-bipyridine (bpy), dipyrido[3,2-a:2′,3′-c]-phenazine (dppz) and 11,12-dimethyldipyrido[3,2-a:2′,3′-c]-phenazine (dppx)-based ruthenium complexes were synthesized and characterized in this study. Three heteroleptic ruthenium complexes, namely cis-[Ru(dcbpy)(bpy)(NCS)2] (Rubpy), cis- [Ru(dcbpy)(dppz)(NCS)2] (Rudppz), and cis-[Ru(dcbpy)(dppx)(NCS)2] (Rudppx), where dcbpy = 2,2’-bipyridyl-4,4’-dicarboxylic acid, NCS- = isothiocyanate, were synthesized using a one-pot synthesis method and evaluated for their potential as dyesensitized solar cells (DSSCs) sensitizers. Spectroscopic, electrochemical and electron impedance spectroscopic analysis were performed on the as-synthesized ruthenium complexes. The commercial dye sensitizer, cis-[Ru(dcbpy)2(NCS)2] (N719) was used as a benchmark. The introduction of the dimethyl groups in the Rudppx complex resulted in a bathochromic shift (10 nm) in the intraligand absorption maximum at 384 nm, an enhancement in the molar absorption coefficient of the metal-to-ligand charge transfer band (λ = 500 nm), and the destabilization of both the ground and excited state molecular orbitals of the complex, compared to Rudppz. In terms of photovoltaic performance, Rubpy exhibited higher short circuit current density (2.07 mAcm-2) and power conversion efficiency (ɳ = 0.57%) as compared to Rudppz which had a short circuit current density of 1.52 mAcm-2 and a power conversion efficiency of 0.40%, demonstrating that the lower cyclic π-conjugation of the bipyridine ligand contributed to the lowest unoccupied molecular orbital in Rubpy that favoured electron injection. Rudppx exhibited improved power

An efficient method for the oxidation of aromatic sulfides was developed using aqueous H2O2 catalyzed by in situ-generated chiral Fe/6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) complex. The corresponding sulfoxides were obtained in high enantio-selectivities (up to 98.5:1.5 er) and good yields (up to 61%) when the mono-oxidation of the sulfides was performed in combination with the kinetic resolution of the sulfoxide into the sulfone.

As global anthropogenic carbon dioxide (CO2) emissions continue to rise, there is a need not only to reduce production of CO2, but also an opportunity to use it as a substrate for value-added products. One viable solution is to reduce CO2 in the two proton, two electron coupled process to produce carbon monoxide (CO), which can in turn be utilized to recreate hydrocarbon fuels. One of the most active and selective molecular electrocatalysts for the reduction of CO2 to CO is Re(2,2′-bipyridine)(CO)3Cl (Re-bpy) and derivatives thereof. The best method to study electrocatalysts is cyclic voltammetry (CV), which affords both kinetic and thermodynamic information about catalysis. CV is the main technique used to characterize substituent, labile ligand, and Brønsted acid effects on Re-bpy based catalysts, which show increased activity with electron donating 4,4′-substituents and moderate Brønsted acids such as 2,2,2-trifluoroethanol and phenol. The Re-bpy catalyst motif is also extended to Group 6 Mo and W metals, which are not as active as their Group 7 counterparts due to high overpotentials and product poisoning of the catalyst. To build a fundamental understanding of how molecular catalysts interact with surfaces, Re-bpy derivatives were bound to Au substrates and studied by sum frequency generation spectroscopy (SFG). While cyano substituents deactivated the molecular catalyst, they adsorbed onto Au surfaces, allowing for determination of molecular orientation on the surface as well as characterization of surface-molecule vibratinal communication. Thiol groups were subsequently employed on the bpy ligand for both Re and Mn catalysts to create a covalent attachment to Au surfaces. These groups did not deactivate the molecular catalysts and reproducibly create monolayers on Au surfaces. Further studies are needed in order to fully understand the implications of surface bound Re-bpy based catalysis as well as apply the design principles learned from Re-bpy systems to fu

C2 symmetrical 6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) chiral ligands have been synthesized from readily available 2,2'-bipyridine. Catalytic asymmetric hydrosilylation of ketones was studied using this family of ligands in the presence of iron(II) acetate.

An efficient method for the oxidation of aromatic sulfides was developed using aqueous H2O2 catalyzed by in situ-generated chiral Fe/6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) complex. The corresponding sulfoxides were obtained in high enantio-selectivities (up to 98.5:1.5 er) and good yields (up to 61%) when the mono-oxidation of the sulfides was performed in combination with the kinetic resolution of the sulfoxide into the sulfone.

Póster presentado en: 11th International Symposium on Applied Bioinorganic Chemistry. 2-5 Diciembre 2011. Barcelona, España (ISABC 2011), Supramolecular entities based on self-assembly of metalloporphyrins are paradigmatic examples of the great efficiency of the nanodevices used by natural systems in photosynthesis, oxygen transport, electron transfer and catalysis. Obtaining supramolecular entities may be approached by different strategies of synthetic design. One of them consists on the use of external dipyridyl ligands to assemble the metallated porphyrin units, so the range of compounds that can be used is endless. In this context, our research group is working with different combinations of organic ligands and metalloporphyrins, and the work herein presented corresponds to the compound [CoTPP(bipy)]•[CoTPP]0.22•TPP0.78 (TPP = meso-tetraphenylporphyrin and bipy = 4,4´-bipyridine), obtained by solvothermal synthesis. Its crystal structure consist of chains of alternating [CoTPP(bipy)]•octahedra where bipy molecules are on the axial positions. Within the voids between the parallel chains, isolated [CoTPP]•monomers and TPP units are located. So far, very few compounds with TPP and bipy have been described, just one of them being a real 1D coordination polymer. It is also remarkable that, as far as we know, this is the first structure with these ligands based on Co.

Póster presentado en: 11th International Symposium on Applied Bioinorganic Chemistry. 2-5 Diciembre 2011. Barcelona, España (ISABC 2011), Supramolecular entities based on self-assembly of metalloporphyrins are paradigmatic examples of the great efficiency of the nanodevices used by natural systems in photosynthesis, oxygen transport, electron transfer and catalysis. Obtaining supramolecular entities may be approached by different strategies of synthetic design. One of them consists on the use of external dipyridyl ligands to assemble the metallated porphyrin units, so the range of compounds that can be used is endless. In this context, our research group is working with different combinations of organic ligands and metalloporphyrins, and the work herein presented corresponds to the compound [CoTPP(bipy)]•[CoTPP]0.22•TPP0.78 (TPP = meso-tetraphenylporphyrin and bipy = 4,4´-bipyridine), obtained by solvothermal synthesis. Its crystal structure consist of chains of alternating [CoTPP(bipy)]•octahedra where bipy molecules are on the axial positions. Within the voids between the parallel chains, isolated [CoTPP]•monomers and TPP units are located. So far, very few compounds with TPP and bipy have been described, just one of them being a real 1D coordination polymer. It is also remarkable that, as far as we know, this is the first structure with these ligands based on Co.

C2 symmetrical 6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) chiral ligands have been synthesized from readily available 2,2'-bipyridine. Catalytic asymmetric hydrosilylation of ketones was studied using this family of ligands in the presence of iron(II) acetate.

Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process., QC 20151119

Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process., QC 20151119

Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process., QC 20151119

Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process., QC 20151119

Isotopically pure [D6]-dimethyl-2,2′-bipyridine derivatives were selectively and rapidly formed using microwave-assisted regioselective deuteration of the methyl moieties of the parent bipyridine in a deuterium oxide solution. For instance, [D6]-4,4′-dimethyl-2,2′-bipyridine was formed in quantitative yield within 15 minutes, in a simple and convenient process., QC 20151119

The reaction of fac-[Re(bipy)(CO)3(PMe3)][OTf] (bipy = 2,2′-bipyridine) with KN(SiMe3)2 affords two neutral products: cis,trans-[Re(bipy)(CO)2(CN)(PMe3)], and a thermally unstable compound, which features a new C-C bond between a P-bonded methylene group (from methyl group deprotonation) and the C6 position of bipy. The solid-state structures of more stable 1,2-bis[(2,6-diisopropylphenyl) imino]acenaphthene analogs, resulting from the deprotonation of PMe3, PPhMe2, and PPh2Me ligands, are determined by X-ray diffraction.

Póster presentado en: 11th International Symposium on Applied Bioinorganic Chemistry. 2-5 Diciembre 2011. Barcelona, España (ISABC 2011), Supramolecular entities based on self-assembly of metalloporphyrins are paradigmatic examples of the great efficiency of the nanodevices used by natural systems in photosynthesis, oxygen transport, electron transfer and catalysis. Obtaining supramolecular entities may be approached by different strategies of synthetic design. One of them consists on the use of external dipyridyl ligands to assemble the metallated porphyrin units, so the range of compounds that can be used is endless. In this context, our research group is working with different combinations of organic ligands and metalloporphyrins, and the work herein presented corresponds to the compound [CoTPP(bipy)]•[CoTPP]0.22•TPP0.78 (TPP = meso-tetraphenylporphyrin and bipy = 4,4´-bipyridine), obtained by solvothermal synthesis. Its crystal structure consist of chains of alternating [CoTPP(bipy)]•octahedra where bipy molecules are on the axial positions. Within the voids between the parallel chains, isolated [CoTPP]•monomers and TPP units are located. So far, very few compounds with TPP and bipy have been described, just one of them being a real 1D coordination polymer. It is also remarkable that, as far as we know, this is the first structure with these ligands based on Co.

We demonstrated that 1,3,5-tris([2',2 '']bipyridin-6'-yl) benzene (BpyB) and 1,3,5-tris([ 2',2 '',6 '',2''']terpyridin-6'-yl)benzene (TpyB) are good electron-transport (ET) layer materials for organic light-emitting devices (OLEDs). The new materials exhibit high electron mobilities of around 10 (4) cm(2) V (1) s (1), and OLEDs comprising the materials operate at lower voltage than the OLEDs with tris(8-hydroxyquinolinato) aluminum (Alq) as an ET material. The new materials are also useful for phosphorescent OLEDs in blue-, green-, and red-light-emitting devices, where they function as both electron-transporting and hole-blocking materials. Phosphorescent OLEDs with the new materials operate at lower voltage (while maintaining comparable external quantum efficiencies of electroluminescence) than does the corresponding reference device with bathocuproine/Alq as electron-transporting and hole-blocking layers.

[no abstract]

Bipyridyl thorium metallocenes [5-1,2,4-(Me3C)3C5H2]2Th(bipy) (1) and [5-1,3-(Me3C)2C5H3]2Th(bipy) (2) have been investigated by magnetic susceptibility and computational studies. The magnetic susceptibility data reveal that 1 and 2 are not diamagnetic, but they behave as temperature independent paramagnets (TIPs). To rationalize this observation, density functional theory (DFT) and complete active space SCF (CASSCF) calculations have been undertaken, which indicated that Cp2Th(bipy) has indeed a Th(IV)(bipy2-) ground state (f0d0 2, S = 0), but the open-shell singlet (f0d1 1, S = 0) (almost degenerate with its triplet congener) is lying only 9.2 kcal/mol higher in energy. Complexes 1 and 2 react cleanly with Ph2CS to give [ 5-1,2,4-(Me3C)3C5H2]2Th[(bipy)(SCPh2)] (3) and [ 5-1,3-(Me3C)2C5H3]2Th[(bipy)(SCPh2)] (4), respectively, in quantitative conversions. Since no intermediates were observed experimentally, this reaction was also studied computationally. Coordinationof Ph2CS to 2 in its S = 0 ground state is not possible, but Ph2CS can coordinate to 2 in its triplet state (S = 1) upon which a single electron transfer (SET) from the (bipy2-) fragment to Ph2CS followed by C-C coupling takes place.

Rational design of selective and sensitive 'off-on' fluorescent probes for Zn(II) cations exploiting both PET and ICT mechanisms of sensing is illustrated by the synthesis and application of 5-aryl-2,20-bipyridines modified with a dipicolylaminomethyl fragment. The aryl substituent provides tuning of the properties. © 2012 Elsevier Ltd. All rights reserved.

Tethered osmium bypiridine-pyridine complexes [Os(bpy)2Clpy-R] were prepared from chemically modified non-oxidized silicon (100) electrodes. Pyridinyl groups at the distal end of self-assembled monolayers (SAMs)-modified silicon surfaces were used to coordinatively bind a representative osmium bipyridil complex precursor [Os(bpy)2Cl2]. SAMs presenting the putative osmium ligand were prepared by a step-wise procedure using click reactions of acetylene-terminated alkyl monolayers and isonicotinic acid azide derivatives. The redox properties of the modified Si(100) electrodes were characterized using cyclic voltammetry. 2010 IEEE.

Tethered osmium bypiridine-pyridine complexes [Os(bpy)2Clpy-R] were prepared from chemically modified non-oxidized silicon (100) electrodes. Pyridinyl groups at the distal end of self-assembled monolayers (SAMs)-modified silicon surfaces were used to coordinatively bind a representative osmium bipyridil complex precursor [Os(bpy)2Cl2]. SAMs presenting the putative osmium ligand were prepared by a step-wise procedure using click reactions of acetylene-terminated alkyl monolayers and isonicotinic acid azide derivatives. The redox properties of the modified Si(100) electrodes were characterized using cyclic voltammetry. 2010 IEEE.

Heating [Rh(dtbpy)(CH2CMe2CC6H4)(Rh-CC)(CH2CMe2Ph)] (dtbpy = 4,4’-di-tert-butyl-2,2’-dipyridyl) at 138°C in xylene resulted in intra-molecular C-H activation of the neophyl group and the formation of [Rh(dtbpy)(CH2CMe2CC6H4)(Rh-CC)(C6H4-tBu-2)]. Refluxing [Ir(dtbpy)(CH2CMe2CC6H4)(Ir-CC)(C6H4-tBu-2)] with 2-phenylpyridine in toluene afforded [Ir(dtbpy)(CH2CMe2Ph)Cl(ppy)], which was deportonated by nBuLi to give the bis-cyclometalated compound [Ir(dtbpy)(CH2CMe2CC6H4)(Ir-CC)(ppy)]. Reaction of [Ir(dtbpy)(CH2CMe2CC6H4)(Ir-CC)(C6H4-tBu-2)] with 4-(2-pyridyl)benzaldehyde or benzaldehyde led to decarbonylation of the formyl group and afforded [Ir(dtbpy)(CH2CCMe2Ph)(Ir-C)(CO)(R)] (R = 4-(2’-pyridyl)phenyl, phenyl). Treatment of [M(dtbpy)(CH2CMe2Ph)(OTs)2(H2O)] (M = Rh, Ir) with Na[BArF4] afforded [{M(dtbpy)(CH2CMe2Ph)(OTs)(H2O)}2(μ-OTs)2]2[BArF4]2 (M = Rh, Ir), which can catalyze H/D exchange of THF with D2O. Transmetalation of [Ru(dtbpy)(NO)Cl3] with Me3CCH2Li and Me3SiCH2MgCl afforded the trialkyl compounds [Ru(dtbpy)(NO)(R)3] (R = CH2CMe3, CH2SiMe3). Protonation of [Ru(dtbpy)(NO)(R)3] with HCl afforded [Ru(dtbpy)(NO)(R)2Cl] (R = CH2CMe3, CH2SiMe3). Chloride abstraction of [Ru(dtbpy)(NO)(CH2CMe3)2Cl] with silver triflate (AgOTf) afforded [Ru(dtbpy)(NO)(CH2SiMe3)2(OTf)], which reacted with NH2R to yield amine adducts [Ru(dtbpy)(NO)(CH2SiMe3)2(NH2R)][OTf] (R = tBu, mes, p-tol). [Ru(dtbpy)(NO)(CH2SiMe3)2(OTf)] reacted with sodium phenoxide, siloxides and thiolates to afford [Ru(dtbpy)(NO)(CH2SiMe3)2(OR)] (R = Ph, SiMe3, SiPh3, Si(OtBu)3) and [Ru(dtbpy)(NO)(CH2SiMe3)2(SR)] (R = xyl, SiPh3) (xyl = 2,6-dimethylphenyl), respectively. Treatment of [Ru(dtbpy)(NO)(CH2SiMe3)2(OTf)] with KOAc and K[NOsO3] gave [Ru(dtbpy)(NO)(CH2SiMe3)2(OAc)] and dimetallic [Ru(dtbpy)(NO)(CH2SiMe3)2(NOsO3)] respectively. Treatment of [Ru(dtbpy)(NO)(CH2SiMe3)3] with SBA-15 resulted in elimination of one equivalent of SiMe4. Spectroscopic data suggested that the Ru-grafted species was the alkyl species

N,N-bis(carboxymethyl)-1-adamantylamine acid (H2BCAA) or N-(1-adamantyl)-iminodiacetic acid forms zwitterions that are intra-stabilized by a bifurcated N+-H···O(carboxyl)2 interaction. In the crystal, both half-protonated carboxyl groups of H2BCAA± are involved in linear O-H···O inter-molecular bridges of 2.46Å. In the studied BCAA-CuII derivatives, the iminodiacetate-moiety of the BCAA chelating ligand exhibits a mer-NO2 conformation in [Cu(BCAA)(H2O)2] (1) and [Cu(BCAA)(Him)]2 (2), but a fac-O2+N(apical) conformation in [Cu(BCAA)(bpy)(H2O)]·3.5H2O (3) [Him = imidazole, bpy =2,2-bipyridine]. In clear contrast, dipyridylamine (dpya), as auxiliary ligand, seems to be unable to promote the fac-O2+N(apical) conformation in BCAA, as reveal the structures of two new salts with the trinuclear cation [(dpya)2Cu-2-Cu(BCAA)2-Cu(dpya)2]2+ and the anions [Cu(BCAA)2]2- (4) or NO3- (5), respectively.

Several new symmetrical aromatic hydrocarbon bridged bipyridine ligands and their binuclear Ru (II) complexes have been designed, synthesized and characterized on the basis of H-1 NMR, MS and HRMS. Their absorption and emission properties, electrochemical behaviors and electrochemical luminescence were investigated. All ruthenium complexes show characteristic MLCT absorption and similar redox potential. Among the three complexes reported, 4c has the best electrochemical luminescence property., QC 20100525

This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. Kewords:asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diet, NR 20140805

This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. Kewords:asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diet, NR 20140805

This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. Kewords:asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diet, NR 20140805

This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. Kewords:asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diet, NR 20140805

NR 20140805

NR 20140805

NR 20140805

NR 20140805

Kathleen Shuk Man Poon., Thesis (M.Phil.)--Chinese University of Hong Kong, 1994., Includes bibliographical references (leaves 93-94)., Abbreviations --- p.v, Lists of Figures --- p.vi, Lists of Schemes --- p.vii, Lists of Tables --- p.viii, Part I, Chapter Chapter 1 --- Introduction --- p.2, Chapter 1.1 --- Thermal stability of metallacycles --- p.2, Chapter 1.2 --- General Synthetic methods of Metallacycle --- p.5, Chapter 1.3 --- Objective of this work --- p.6, Chapter 1.4 --- Features of Ligands --- p.6, Chapter 1.5 --- References --- p.10, Chapter Chapter 2 --- Synthesis of Transfer Reagents --- p.11, Chapter 2.1 --- Brief Survey of various Transfer Reagents --- p.11, Chapter 2.2 --- Introduction to metallation reaction --- p.13, Chapter 2.3 --- Result and Discussion --- p.16, Chapter 2.3.1 --- Lithiation and Derivatization of Ligand --- p.16, Chapter 2.3.2 --- Charge Migration --- p.18, Chapter 2.3.3 --- Characterization of compounds --- p.23, Chapter 2.4 --- Experimental --- p.27, Chapter 2.5 --- References --- p.33, Chapter Chapter 3 --- Synthesis of Metallacycles --- p.35, Section I --- p.35, Chapter 3.1 --- Introduction --- p.35, Chapter 3.2 --- Results and Discussion --- p.36, Chapter 3.2.1 --- Synthesis of Metallacycles of Group 14 elements --- p.36, Chapter 3.2.2 --- Characterization of Group 14 metallacycles --- p.42, Chapter 3.2.3 --- Experimental --- p.57, Section II --- p.64, Chapter 3.3 --- Introduction --- p.64, Chapter 3.4 --- Result and Discussion --- p.65, Chapter 3.4.1 --- Synthesis of Metallacycles of Group 4 elements --- p.65, Chapter 3.4.2 --- Experimental --- p.68, Chapter 3.5 --- Attempted synthesis of Group 12 Metallacycles --- p.70, Chapter 3.5.1 --- Results and Discussion --- p.70, Chapter 3.5.2 --- Experimental --- p.71, Chapter 3.6 --- References --- p.73, Part II --- p.75, Chapter Chapter 4 --- Synthesis of Bimetallic Complex --- p.76, Chapter 4.1 --- Brief Review on Bimetallic Complexes --- p.76, Chapter 4.2 --- Results and Discussion --- p.80, Chapter 4.2.1 --- Synthesis of bimetallic complexes --- p.80, Chapter 4.2.2 --- Characterization of bimetallic complexes --- p.87, Chapter 4.2.3 --- Experimental --- p.90, Chapter 4.3 --- References --- p.93, Appendix I General Experimental Procedure --- p.95, http://library.cuhk.edu.hk/record=b5887301, Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Kathleen Shuk Man Poon., Thesis (M.Phil.)--Chinese University of Hong Kong, 1994., Includes bibliographical references (leaves 93-94)., Abbreviations --- p.v, Lists of Figures --- p.vi, Lists of Schemes --- p.vii, Lists of Tables --- p.viii, Part I, Chapter Chapter 1 --- Introduction --- p.2, Chapter 1.1 --- Thermal stability of metallacycles --- p.2, Chapter 1.2 --- General Synthetic methods of Metallacycle --- p.5, Chapter 1.3 --- Objective of this work --- p.6, Chapter 1.4 --- Features of Ligands --- p.6, Chapter 1.5 --- References --- p.10, Chapter Chapter 2 --- Synthesis of Transfer Reagents --- p.11, Chapter 2.1 --- Brief Survey of various Transfer Reagents --- p.11, Chapter 2.2 --- Introduction to metallation reaction --- p.13, Chapter 2.3 --- Result and Discussion --- p.16, Chapter 2.3.1 --- Lithiation and Derivatization of Ligand --- p.16, Chapter 2.3.2 --- Charge Migration --- p.18, Chapter 2.3.3 --- Characterization of compounds --- p.23, Chapter 2.4 --- Experimental --- p.27, Chapter 2.5 --- References --- p.33, Chapter Chapter 3 --- Synthesis of Metallacycles --- p.35, Section I --- p.35, Chapter 3.1 --- Introduction --- p.35, Chapter 3.2 --- Results and Discussion --- p.36, Chapter 3.2.1 --- Synthesis of Metallacycles of Group 14 elements --- p.36, Chapter 3.2.2 --- Characterization of Group 14 metallacycles --- p.42, Chapter 3.2.3 --- Experimental --- p.57, Section II --- p.64, Chapter 3.3 --- Introduction --- p.64, Chapter 3.4 --- Result and Discussion --- p.65, Chapter 3.4.1 --- Synthesis of Metallacycles of Group 4 elements --- p.65, Chapter 3.4.2 --- Experimental --- p.68, Chapter 3.5 --- Attempted synthesis of Group 12 Metallacycles --- p.70, Chapter 3.5.1 --- Results and Discussion --- p.70, Chapter 3.5.2 --- Experimental --- p.71, Chapter 3.6 --- References --- p.73, Part II --- p.75, Chapter Chapter 4 --- Synthesis of Bimetallic Complex --- p.76, Chapter 4.1 --- Brief Review on Bimetallic Complexes --- p.76, Chapter 4.2 --- Results and Discussion --- p.80, Chapter 4.2.1 --- Synthesis of bimetallic complexes --- p.80, Chapter 4.2.2 --- Characterization of bimetallic complexes --- p.87, Chapter 4.2.3 --- Experimental --- p.90, Chapter 4.3 --- References --- p.93, Appendix I General Experimental Procedure --- p.95, http://library.cuhk.edu.hk/record=b5887301, Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Electronic and resonance Raman spectroscopy are used to probe the electronic structures of bipyridine ruthenium complexes of quinone and a series of derivatives in which the oxygen atoms of quinone are successively replaced by NH. The electronic structures of some benzoquinonediimine species are probed by variation of substituent in the benzene ring, and the properties of a diaminophenyl substituted benzoquinonediimine are explored as a function of the twist at the 1,1'-link.

An x-ray crystal structure investigation has revealed that the stable octahedral complex ((O)2Re(2,2'bipyridine)(pyridine)2) . (CLO4) exists in a cis-dioxo ligand configuration. The new complex represents only the second confirmed example of the cis-dioxo structure in hexacoordinate d2 transition-metal chemistry. The cis assignment provides an explanation for the marked electrochemical and spectral differences between the bipyridyl complex and the previously known trans-dioxo rhenium tetrapyridine complex.

QS 201511

Magnetic iron oxide nanoparticles doped with samarium were prepared by solvothermal polyol method. An introduction of 2,2'-bipyridine during the synthesis reduces the particle diameter to about 9 nm in average. The difference in physical and magnetic properties of the samples prepared with and without capping agent was outlined on the basis of complex characterization by a number of experimental techniques. The characteristics of resulted product make it suitable for biomedical applications, for instance, as a contrast agent for MRI

© 2017 Elsevier B.V. Charge state studies of compounds [Mo3S4(tu)8(H2O)]Cl4·4H2O (1), [Mo3S4Cl3(dbbpy)3]Cl·5H2O (2), [Mo3S4(CuCl)Cl3(dbbpy)3][CuCl2] (3), containing {Mo3S4}4+ and {Mo3CuS4}5+ cluster cores bearing terminal thiourea (tu) or 4,4′-di-tert-butyl-2,2′-bipyridine (dbbpy) ligands, have been performed by X-ray photoelectron and X-ray emission spectroscopies combined with quantum chemical calculations. The best agreement between theory and experiments has been obtained using the B3LYP method. According to the experimental and calculated data, the Mo atoms are in the oxidation state 4+ for all compounds. The energies and shapes of the Cu2p lines indicate formal oxidation states of Cu as 1+. The coordination of Сu(I) to the cluster {Mo3S4} in 3 does not lead to significant changes in the charge state of the molybdenum atoms and the {Mo3S4} unit can be considered as a tridentate metallothia crown ether.