Search results for " complexes"

Homoleptic Pnictogen-Chalcogen Coordination Complexes

2012

The synthesis and structural characterization of dicationic selenium and tellurium analogues of the carbodiphosphorane and triphosphenium families of compounds are reported. These complexes, [Ch(dppe)][OTf]2 [Ch = Se, Te; dppe = 1,2-bis(diphenylphosphino)ethane; OTf = trifluoromethanesulfonate], are formed using [Ch]2+ reagents via a ligand-exchange protocol and represent extremely rare examples of homoleptic pnictogen → chalcogen coordination complexes. The corresponding arsenic compounds were also prepared, [Ch(dpAse)][OTf]2 [Ch = Se, Te; dpAse = 1,2-bis(diphenylarsino)ethane], exhibiting the first instance of an arsenic → chalcogen dative bond. The electronic structures of these unique c…

Ethylene polymerization with FI complexes having novel phenoxy‐imine ligands: Effect of metal type and complex immobilization

2011

A series of bis(phenoxy‐imine) vanadium and zirconium complexes with different types of R3 substituents at the nitrogen atom, where R3 = phenyl, naphthyl, or anthryl, was synthesized and investigated in ethylene polymerization. Moreover, the catalytic performance was verified for three supported catalysts, which had been obtained by immobilization of bis[N‐(salicylidene)‐1‐naphthylaminato]M(IV) dichloride complexes (M = V, Zr, or Ti) on the magnesium carrier MgCl2(THF)2/Et2AlCl. Catalytic performance of both supported and homogeneous catalysts was verified in conjunction with methylaluminoxane (MAO) or with alkylaluminium compounds (EtnAlCl3−n, n = 1–3). The activity of FI vanadium and zirc…

Complex species formation of Cu and Cd metal ions with polyacrylate, polymethacrylate and alginate ligands. Potentiometric investigation by ISE-H+ an…

2008

Diversity of Isomerization Patterns and Protolytic Forms in Aminocarbene PdII and PtII Complexes Formed upon Addition of N,N′-Diphenylguanidine to Me…

2017

Reaction of the palladium(II) and platinum(II) isocyanide complexes cis-[MCl2(CNR)2] [M = Pd, R = C6H3(2,6-Me2) (Xyl), 2-Cl-6-MeC6H3, cyclohexyl (Cy), t-Bu, C(Me)2CH2(Me)3 (1,1,3,3-tetramethylbuth-1-yl abbreviated as tmbu); M = Pt, R = Xyl, 2-Cl-6-MeC6H3, Cy, t-Bu, and tmbu] with N,N′-diphenylguanidine (DPG) leads to DPG-derived metal-bound deprotonated acyclic diaminocarbene (ADC) species. This reaction occurs via a two-step process, involving the initial coupling of the guanidine with one of the isocyanides and leading to deprotonated monocarbene monochelated species, while the next addition grants the deprotonated bis-carbene bis-chelated metal compounds. DPG behaves as nucleophile, depr…

Méthodologie de modélisation et de caractérisation des réseaux spatiaux. Application au réseau viaire de Paris

2016

International audience; Les graphes spatialisés soulèvent différentes questions qui intéressent plusieurs disciplines, depuis la biologie (veinures de feuilles, réseaux neuronaux) ou la géomorphologie (réseaux fluviaux) jusqu’aux études urbaines (réseaux de transports), sans oublier celle des réseaux d’énergie (réseaux électriques, de gaz ou de pétrole) et de télécommunication. Nous nous concentrerons ici sur les exemples apportés par les réseaux viaires. C’est à travers ceux-ci que nous définirons dans cet article d’abord un objet d’étude multi-échelle, la voie, puis cinq indicateurs liés qui permettront une lecture enrichie de la spatialité urbaine. Nous expliciterons ainsi les particular…

Metal salen complexes as ethylene polymerization catalysts - effect of catalytic system composition on its activity and properties of polymerization …

2008

Zsyntetyzowano i zastosowano [po aktywacji metyloaluminoksanem (MAO) lub Et2AlCl] w charakterze katalizatorów niskociśnieniowej polimeryzacji etylenu serię salenowych kompleksów metali przejściowych różniących się rodzajem atomu centralnego (M=Ti, Zr lub V) i budową chemiczną ligandu (schemat A). Stwierdzono, że salenowe kompleksy cyrkonu są aktywne w polimeryzacji jedynie wówczas, gdy aktywator stanowi MAO, natomiast kompleksy tytanu i wanadu są aktywniejsze w przypadku gdy kokatalizatorem jest typowy związek glinoorganiczny - dietylochloroglin. Aktywność kompleksów w układzie z Et2AlCl zmienia się w szeregu V>Ti>>Zr?0, podczas gdy w odniesieniu do kompleksów aktywowanych MAO maleje ona w …

New hydroxyapatite- and selenium-based nanoformulations as potential antimicrobial tools for orthopedic implants

Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state

2019

In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-...

Functional molecular materials: supramolecular networks and coordination polymers with optical and/or magnetic properties

2020

El camp dels materials moleculars atrau l’atenció de molts científics degut al gran potencial de la química molecular en el disseny de materials amb un ajust precís de les seues propietats. Els dos projectes tractats en aquesta tesi representen dos temes que destaquen en aquesta àrea, materials de transició d’espín i polímers de coordinació amb propietats òptiques i/o magnètiques, gràcies al seu significant progrés i ràpid desenvolupament en els últims anys. La primera part d’aquesta tesi es basa en l’ús d’enllaços d’hidrogen en el disseny de xarxes multifuncionals de ferro(II) amb transicions d’espín abruptes. El capítol 1 és una introducció a aquest tema des de la perspectiva dels complex…

Thermodynamic and spectroscopic study of the binding of dimethyltin(IV) by citrate at 25°C

2006

Thermodynamic (potentiometric and calorimetric) and spectroscopic ( 1 H NMR, 119 Sn Mossbauer) studies were performed in aqueous solution in order to characterize the interaction of dimethyltin(IV) cation with citrate ligand. Six species {(CH 3 ) 2 Sn(cit) - ; [(CH 3 ) 2 Sn] 2 (cit) 2 2- ; (CH 3 ) 2 Sn(cit)H 0 ; (CH 3 ) 2 Sn(cit)OH 2- ; [(CH 3 ) 2 Sn] 2 (cit)OH 0 ; [(CH 3 ) 2 Sn] 2 (cit)(OH) 2 - } were found. All the species formed in this system are quite stable and formation percentages are fairly high. For example, at pH = 7.5 and C (CH3)2Sn = C cit = 10 mmol l -1 , E% for [(CH 3 ) 2 Sn] 2 (cit)(OH) 2 - and (CH 3 ) 2 Sn(cit)OH 2- species reaches 65%. Overall thermodynamic parameters obta…