Sekundäre Hydroxyalkylphosphane: Synthese und Charakterisierung mono‐, bis‐ und trisalkoxyphosphan‐substituierter Zirconiumkomplexe und des heterobimetallischen Dreikernkomplexes [Cp2Zr{O(CH2)3PHMes(AuCl)}2]

Secondary Hydroxyalkylphosphanes: Synthesis and Characterization of Mono‐, Bis‐ and Trisalkoxyphosphane‐substituted Zirconium Complexes and the Heterobimetallic Trinuclear Complex [Cp₂Zr{O(CH₂)₃PHMes(AuCl)}₂] The secondary hydroxyalkylphosphanes RPHCH₂OH [R = 2,4,6‐Me₃C₆H₂ (Mes) ( 1 ), 2,4,6‐ⁱPr₃C₆H₂ (Tipp) ( 2 )], 1‐AdPH‐2‐OH‐cyclo‐C₆H₁₀ ( 3 ) and RPH(CH₂)₃OH [R = Ph ( 4 ), Mes ( 5 ), Tipp ( 6 ), Cy ( 7 ), ^tBu ( 8 )] were obtained from primary phosphanes RPH₂ and formaldehyde ( 1 , 2 ) or from LiPHR and cyclohexene oxide ( 3 ) or trimethylene oxide ( 4 ‐ 8 ). Starting from 5 or 7 and [Cp^R₂ZrMe₂] [Cp^R = C₅EtMe₄ (Cp°), C₅H₅ (Cp), C₅MeH₄ (Cp′)], the monoalkoxyphosphane‐substituted zirconocene complexes [Cp^R₂Zr(Me){O(CH₂)₃PHMes}] [Cp^R = Cp° ( 9 ), Cp ( 10 )] were prepared. With [Cp^R₂ZrCl₂], the bisalkoxyphosphane‐substituted complexes [Cp′₂Zr{O(CH₂)₃PHMes}₂] ( 11 ) and [Cp₂Zr{O(CH₂)₃PHCy}₂] ( 12 ) are obtained, and with [Tp^RZrCl₃], the trisalkoxyphosphane‐substituted zirconium complexes [Tp^RZr{O(CH₂)₃PHMes}₃] [Tp^R = trispyrazolylborato (Tp) ( 13 ), Tp^R = tris(3,5‐dimethyl)pyrazolylborato (Tp*) ( 14 )] are prepared. The reaction of 5 with [AuCl(tht)] (tht = tetrahydrothiophene) yielded the mononuclear complex [AuCl{PHMes(CH₂)₃OH}] ( 15 ). The trinuclear complex [Cp₂Zr{O(CH₂)₃PHMes(AuCl)}₂] ( 16 ) was obtained from [Cp₂ZrCl₂] and 15 . Compounds 1 ‐ 16 were characterized spectroscopically (¹H‐, ³¹P‐, ¹³C‐NMR; IR; MS) and compound 2 also by crystal structure determination. The bis‐ and trisalkoxyphosphane‐substituted complexes 11‐14 and 16 were obtained as mixtures of two diastereomers which could not be separated.     

Stereospecific styrene polymerization and ethylene–styrene copolymerization with titanocenes containing a pendant amine donor

A series of monocyclopentadienyl titanium complexes containing a pendant amine donor on a Cp group ( A = CpTiCl₃, B = Cp^NTiCl₃, C = Cp^NTiCl₂TEMPO, for Cp = C₅H₅, Cp^N = C₅H₄CH₂CH₂N(CH₃)₂, and TEMPO = 2,2,6,6‐tetramethylpiperidine‐N‐oxyl) are investigated for styrene homopolymerization and ethylene–styrene (ES) copolymerization. When activated by methylaluminoxane at 70 °C, complexes with the amine group ( B and C ) are active for styrene homopolymerization and afford syndiotactic polystyrene (sPS). The copolymerizations of ethylene and styrene with B and C yield high‐molecular weight ES copolymer, whereas complex A yields mixtures of sPS and polyethylene, revealing the critical role that the pendant amine has on the polymerization behavior of the complexes. Fractionation, NMR, and DSC analyses of the ES copolymers generated from B and C suggest that they contain sPS. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1579–1585, 2010     

Heteroleptic Complexes of Zirconium Acetylacetonates: Better Precursors for the Preparation of Zirconia. Structural Characterization of [(acac)2Zr{ONC(Me)py‐2}2]

The reactions of the heteroleptic zirconium diisopropoxide bis(acetylacetonate) in benzene solution with two equivalents of oximes, alkoxyalkanols, triphenylsilanol and trimethylsilyl acetate yield products with the formula [{MeC(O)CHC(O)Me}₂ZrL₂] with L = —ONC(Me)C₅H₄N‐2, —ONC(Me)C₄H₃O‐2, —OCH₂CH₂OR (R = Me, Et, Buⁿ; py = pyridine, fu = furan), —OSiPh₃ and —OSiMe₃. Most of these derivatives are solids, but the [(acac)₂Zr(OSiMe₃)₂] is a viscous oil. They could be purified either by recrystallization or by vacuum distillation; all of these are monomeric in boiling benzene. Their elemental analyses, molecular weight measurements and IR as well as NMR spectra were measured. The oximato complex [(acac)₂Zr{ONC(Me)py‐2}₂] has been shown by single crystal X‐ray crystallography to be monoclinic and mononuclear in the solid state, where zirconium has the coordination number 8; all the ligands are situated in cis‐ position and the oximato ligand binds via N and O in a dihapto (η²‐N, O) manner.     

Stereoselectivity in Diphos Addition to Molybdenum Complex with Pyridine‐2‐thionate (pyS) and η3‐Methallyl Coordinated Ligands

The conformational isomers endo‐ and exo‐[Mo{η³‐C₃H₄(CH₃)}(η²‐pyS)(CO)(η²‐diphos)] (diphos: dppm = {bis(diphenylphosphino)methane}, 2 ; dppe = {1,2‐bis(diphenylphosphino)ethane}, 3 ) are prepared by reacting the double‐bridged pyridine‐2‐thionate (pyS) complex [Mo{η³‐C₃H₄(CH₃)}(CO)₂]₂(η¹:η²:μ‐pyS)₂, 1 with diphos in refluxing acetonitrile. Stereoselectivity of the methallyl, C₃H₄(CH₃), ligand improves the formation of the exo‐conformation of 2 and 3 . Orientations and spectroscopy of these complexes are discussed.     

Ligand‐forced dimerization of copper(I)–olefin complexes bearing a 1,3,4‐thiadiazole core

As an important class of heterocyclic compounds, 1,3,4‐thiadiazoles have a broad range of potential applications in medicine, agriculture and materials chemistry, and were found to be excellent precursors for the crystal engineering of organometallic materials. The coordinating behaviour of allyl derivatives of 1,3,4‐thiadiazoles with respect to transition metal ions has been little studied. Five new crystalline copper(I) π‐complexes have been obtained by means of an alternating current electrochemical technique and have been characterized by single‐crystal X‐ray diffraction and IR spectroscopy. The compounds are bis[μ‐5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine]bis[nitratocopper(I)], [Cu₂(NO₃)₂(C₆H₉N₃S)₂], (1), bis[μ‐5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine]bis[(tetrafluoroborato)copper(I)], [Cu₂(BF₄)₂(C₆H₉N₃S)₂], (2), μ‐aqua‐bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}bis[nitratocopper(I)], [Cu₂(NO₃)₂(C₅H₇N₃S₂)₂(H₂O)], (3), μ‐aqua‐(hexafluorosilicato)bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}dicopper(I)–acetonitrile–water (2/1/4), [Cu₂(SiF₆)(C₅H₇N₃S₂)₂(H₂O)]·0.5CH₃CN·2H₂O, (4), and μ‐benzenesulfonato‐bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}dicopper(I) benzenesulfonate–methanol–water (1/1/1), [Cu₂(C₆H₅O₃S)(C₅H₇N₃S₂)₂](C₆H₅O₃S)·CH₃OH·H₂O, (5). The structure of the ligand 5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine (Mepeta ), C₆H₉N₃S, was also structurally characterized. Both Mepeta and 5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine (Pesta ) (denoted L ) reveal a strong tendency to form dimeric {Cu₂L ₂}²⁺ fragments, being attached to the metal atom in a chelating–bridging mode via two thiadiazole N atoms and an allylic C=C bond. Flexibility of the {Cu₂(Pesta )₂}²⁺ unit allows the Cu^I atom site to be split into two positions with different metal‐coordination environments, thus enabling the competitive participation of different molecules in bonding to the metal centre. The Pesta ligand in (4) allows the Cu^I atom to vary between water O‐atom and hexafluorosilicate F‐atom coordination, resulting in the rare case of a direct Cu^I…FSiF₅²⁻ interaction. Extensive three‐dimensional hydrogen‐bonding patterns are formed in the reported crystal structures. Complex (5) should be considered as the first known example of a Cu^I(C₆H₅SO₃) coordination compound. To determine the hydrogen‐bond interactions in the structures of (1) and (2), a Hirshfeld surface analysis has been performed.     

Synthesis,characterization and soft transformation of some bis(cyclopentadienyl) Ti(IV) and Zr(IV) complexes of Schiff's base ligands to nano‐sized titania or zirconia materials

Some bis(cyclopentadienyl) complexes of Ti(IV)and Zr(IV) have been synthesized by the metathetical reactions of Cp₂MCl₂ with the sodium salt of monofunctional bidentate Schiff's base ligands in 1:1 and 1:2 stoichiometry in anhydrous THF. All the derivatives of the types Cp₂MCl_2?n{O(C₆H₄)CH₆H₅}_n and Cp₂MCl_2?n{OC(CH₃)(R)₆H₅}_n (where R = CH₃ or C₆H₅ and n = 1 or 2) have been characterized by elemental analyses, molecular weight measurements, FT‐IR and ‐NMR [¹H and ¹³C{¹H}] studies. The FAB mass spectra of a few representative complexes and the molecular weight measurements in freezing benzene indicate their monomeric nature in solution. Spectral studies appear to indicate mono‐ and bi‐dentate mode of attachment of the ligand in solution and in the solid state, respectively. Thermogravimetric analyses (TGA) of Cp₂TiCl{O(C₆H₄)CH} ( 1 ) and Cp₂ZrCl{O(C₆H₄)CH} ( 7 ) indicate their low thermal stability. Transformations of some of these complexes to pure titania (TiO₂)/zirconia (ZrO₂) have been observed at relatively low sintering temperatures. Powder X‐ray diffraction (XRD) and scanning electron micrograph (SEM) studies suggest the nanocrystalline nature of these materials. Copyright © 2007 John Wiley & Sons, Ltd.     

[Co(g5‐Me5C5)(g3‐tBu2PPCH–CH3)] aus [Co(g5‐Me5C5)(g2‐C2H4)2] und tBu2P–P=P(Me)tBu2

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XVII [1] [Co(g⁵‐Me₅C₅)(g³‐^tBu₂PPCH–CH₃)] from [Co(g⁵‐Me₅C₅)(g²‐C₂H₄)₂] and ^tBu₂P–P=P(Me)^tBu₂ [Co(η⁵‐Me₅C₅)(η³‐^tBu₂PPCH–CH₃)] 1 is formed in the reaction of [Co(η⁵‐Me₅C₅)(η²‐C₂H₄)₂] 2 with ^tBu₂P–P 4 (generated from ^tBu₂P–P=P(Me)^tBu₂ 3 ) by elimination of one C₂H₄ ligand and coupling of the phosphinophosphinidene with the second one. The structure of 1 is proven by ³¹P, ¹³C, ¹H NMR spectra and the X‐ray structure analysis. Within the ligand ^tBu₂P¹P²C¹H–CH₃ in 1 , the angle P1–P2–C1 amounts to 90°. The Co, P1, P2, C1 atoms in 1 look like a „butterfly”︁. The reaction of 2 with a mixture of ^tBu₂P–P=P(Me)^tBu₂ 3 and ^tBu–C?P 5 yields [Co(η⁵‐Me₅C₅){η⁴‐(^tBuCP)₂}] 6 and 1 . While 6 is spontaneously formed, 1 appears only after complete consumption of 5 .     

Synthese und Insertionsreaktionen von Cp2′HfCl{As(SiMe3)2} (Cp′ = C5H4Me)

Synthesis and Insertion Reactions of Cp₂′HfCl{As(SiMe₃)₂} (Cp′ = C₅H₄Me) The reaction of Cp₂′HfCl₂ (Cp′ = C₅H₄Me) with Li(THF)_2,5As(SiMe₃)₂ (1 : 1) at room temperature gives the terminal hafnocene arsenido complex Cp₂′HfCl{As(SiMe₃)₂} ( 1 ) in high yield. 1 inserts CS₂ and PhNC into the Hf? As bond yielding Cp₂′HfCl{η²-S₂CAs(SiMe₃)₂} ( 2 ) and Cp₂′HfCl{η²-N(Ph)CAs(SiMe₃)₂} ( 3 ). The thermally sensitive complexes 1–3 were characterised spectroscopically and crystal structure determinations were carried out on 1 and 3 which shows the η² bonding mode of the N(Ph)CAs(SiMe₃)₂ ligand in the latter.     

Thiosemicarbazonates of Ruthenium(II): Crystal Structures of [Bis(triphenylphosphine)][bis(N‐phenyl‐pyridine‐2‐carbaldehyde Thiosemicarbazonato)]ruthenium(II) and [Bis(diphenylphosphino)butane][bis(salicylaldehyde Thiosemicarbazonato)]ruthenium(II)

Reaction of RuCl₂(PPh₃)₃ with N‐Phenyl‐pyridine‐2‐carbaldehyde thiosemicarbazone (C₅H₄N–C²(H)=N³‐N²H–C¹(=S)N¹HC₆H₅, Hpytsc‐NPh) in presence of Et₃N base led to loss of ‐N²H‐proton and yielded the complex [Ru(pytsc‐NPh)₂(Ph₃P)₂] ( 1 ). Similar reactions of precursor RuCl₂[(p‐tolyl)₃P]₃ with a series of thiosemicarbazone ligands, viz. pyridine‐2‐carbaldehyde thiosemicarbazone (Hpytsc), salicylaldehyde thiosemicarbazone (H₂stsc), and benzaldehyde thiosemicarbazone (Hbtsc), have yielded the complexes, [Ru(pytsc)₂{(p‐tolyl)₃P}₂] ( 2 ), [Ru(Hstsc)₂{(p‐tolyl)₃P}]₂ ( 3 ), and [Ru(btsc)₂{(p‐tolyl)₃P}₂] ( 4 ), respectively. The reactions of precursor Ru₂Cl₄(dppb)₃ {dppb = Ph₂P–(CH₂)₄–PPh₂} with H₂stsc, Hbtsc, furan‐2‐carbaldehyde thiosemicarbazone (Hftsc) and thiophene‐2‐carbaldehyde thiosemicarbazone (Httsc) have formed complexes of the composition, [Ru(Hstsc)₂(dppb)] ( 5 ), [Ru(btsc)₂(dppb)] ( 6 ), [Ru(ftsc)₂(dppb)] ( 7 ), and [Ru(ttsc)₂(dppb)] ( 8 ). The complexes have been characterized by analytical data, IR, NMR (¹H, ³¹P) spectroscopy and X‐ray crystallography ( 1 and 5 ). The proton NMR confirmed loss of –N²H– proton in all the compounds, and ³¹P NMR spectra reveal the presence of equivalent phosphorus atoms in the complexes. In all the compounds, thiosemicarbazone ligands coordinate to the Ru^II atom via hydrazinic nitrogen (N²) and sulfur atoms. The arrangement around each metal atom is distorted octahedral with cis:cis:trans P, P:N, N:S, S dispositions of donor atoms.     

Olefin polymerization and copolymerization by complexes bearing [ONNO]‐Type salan ligands: Effect of ligand structure and metal type (titanium,zirconium, and vanadium)

A series of novel titanium(IV) complexes bearing tetradentate [ONNO] salan type ligands: [Ti{2,2′‐(OC₆H₃‐5‐t‐Bu)₂‐NHRNH}Cl₂] (Lig¹TiCl₂: R = C₂H₄; Lig²TiCl₂: R = C₄H₈; Lig³TiCl₂: R = C₆H₁₂) and [Ti{2,2′‐(OC₆H₂‐3,5‐di‐t‐Bu)₂‐NHC₆H₁₂NH}Cl₂] (Lig⁴TiCl₂) were synthesized and used in the (co)polymerization of olefins. Vanadium and zirconium complexes: [ M{2,2′‐(OC₆H₃‐3,5‐di‐t‐Bu)₂‐NHC₆H₁₂NH}Cl₂] (Lig⁴VCl₂: M = V; Lig⁴ZrCl₂: M = Zr) were also synthesized for comparative investigations. All the complexes turned out active in 1‐octene polymerization after activation by MAO and/or Al(i‐Bu)₃/[Ph₃C][B(C₆F₅)₄]. The catalytic performance of titanium complexes was strictly dependent on their structures and it improves for the increasing length of the aliphatic linkage between nitrogen atoms (Lig¹TiCl₂ << Lig²TiCl₂ < Lig³TiCl₂) and declines after adding additional tert‐Bu group on the aromatic rings (Lig³TiCl₂ < Lig⁴TiCl₂). The activity of all titanium complexes in ethylene polymerization was moderate and the properties of polyethylene was dependent on the ligand structure, cocatalyst type, and reaction conditions. The Et₂AlCl‐activated complexes gave polymers with lover molecular weights and bimodal distribution, whereas ultra‐high molecular weight PE (up to 3588 kg mol^?1) and narrow MWD was formed for MAO as a cocatalyst. Vanadium complex yielded PE with the highest productivity (1925.3 kg mol_v^?1), with high molecular weight (1986 kg mol^?1) and with very narrow molecular weight distribution (1.5). Copolymerization tests showed that titanium complexes yielded ethylene/1‐octene copolymers, whereas vanadium catalysts produced product mixtures. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2111–2123     

Stabilization of Substituted Triazenide Oxides: Synthesis and X‐ray Structural Features of Polymeric Potassium 3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide‐hydrate, {K[O2C‐C6H4‐N(H)NN(CH3)O]·4H2O}n

3‐(4‐carboxyphenyl)‐1‐methyltriazene N‐oxide reacts with KOH in methanol/pyridine to give {K[O₂C‐C₆H₄‐N(H)NN(CH₃)O]·4H₂O}_n, Potassium‐3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide). The terminal carboxylato group of the anion does not interact with the cation. In the crystal lattice of {K(C₈H₈N₃O₃)·4H₂O}_n each three of the four water molecules interact with two potassium cations, every K⁺ ion being the centre of six bridging K···O interactions. Potassium cations interact further with the terminal N‐oxigen atom of single [C₈H₈N₃O₃]^? anions achieving two parallel {C₈H₈N₃O₃^?K⁺}_n chains, which are linked through water molecules. The resulting polymeric, one‐dimensional chain, is operated by a screw axis 2₁ parallel to the crystallographic direction [010], along and equidistant to the K⁺ centres. The coordination of the K⁺ centres involves a distortion of the boat conformation of elementary sulfur (S₈) with the ideal C_2v symmetry.     

Reaction of Cp2ZrCl2 with Inorganic Amides

The reactions of [η⁵‐Cp₂ZrCl₂] (Cp = η⁵‐C₅H₅) with [K(THF)_n][N(PPh₂)₂] (n = 1.25—1.5) and K[CH(PPh₂NSiMe₃)₂] are reported. The first reaction led to the monoamido complex [η⁵‐Cp₂Zr(Cl)N(PPh₂)₂] in which the {(Ph₂P)₂N}^— ligand — via a phosphorous and the nitrogen atom — is coordinated to the zirconium atom in a chelating (η²) fashion. Reaction of the potassium methanide compound, K{CH(PPh₂NSiMe₃)₂} with zirconocene dichloride yield the carbene‐like mono cyclopentadienyl complex [η⁵‐CpZr(Cl){C(PPh₂NSiMe₃)₂}]. The complex is formed by a salt metathesis and concomitant a cyclopentadiene extrusion.     

Heterobimetallische Komplexe von Lithium,Aluminium und Gold mit dem N‐[2‐N′,N′‐(Dimethylaminoethyl)‐N‐methyl‐aminoethyl]‐ferrocenyl‐Liganden (η5‐C5H5)Fe{η5‐C5H3[CH(CH3)N(CH3)CH2CH2NMe2]‐2}

Heterobimetallic Complexes of Lithium, Aluminum, and Gold with the N ‐[2‐ N ′, N ′‐(dimethylaminoethyl)‐ N ‐methyl‐aminoethyl]‐ferrocenyl Ligand (η⁵‐C₅H₅)Fe{η⁵‐C₅H₃[CH(CH₃)N(CH₃)CH₂CH₂NMe₂]‐2} N‐[2‐N′,N′‐(dimethylaminoethyl)‐N‐methyl‐aminoethyl]ferrocene FcN,NH ( 1 ) reacts with ⁿBuLi under formation of the lithium organyl (FcN,N)Li ( 2 ). At reactions of 2 with AlBr₃ and AuCl · PPh₃ the heterobimetallic organo derivatives (FcN,N)AlBr₂ ( 3 ), (FcN,N)Au · PPh₃ ( 4 ) are formed. A detailed characterization of 2 – 4 was carried out by single crystal x‐ray analyses as well as by NMR and Mößbauer spectroscopy.     

The Nitrogen‐Assisted Triphenylphosphine Displacement of Methylpyridine Ligand in Palladium(II) Complex: Crystal Structures of [Pd(PPh3)2{η1‐C5H3N(CH3)}(Br)] and [Pd(PPh3)Br]2{μ,η2‐C5H3N(CH3)}2

Treatment of Pd(PPh₃)₄ with 2‐bromo‐4‐methylpyridine, C₅H₃N(CH₃)Br, in dichloromethane at ?20 °C causes the oxidative addition reaction to produce the palladium complex [Pd(PPh₃)₂ {η¹‐C₅H₃N(CH₃)}(Br)], 2 , by substituting two triphenylphosphine ligands. In a dichloromethane solution of complex 2 at room temperature for 3 h, it undergoes displacement of the triphenylphosphine ligand to form the dipalladium complex [Pd(PPh₃)Br]₂{μ,η²‐C₅H₃N(CH₃)}₂, 3 , in which the two 4‐methylpyridine ligands coordinated through carbon to one metal center and bridging the other metal through the nitrogen atom. Complexes 2 and 3 are characterized by X‐ray diffraction analyses.     

Syntheses and structures of three macrocyclic supramolecular complexes and one ZnII‐containing coordination polymer generated from a semi‐rigid multidentate N‐containing ligand

Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine ( L ), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, ( I ), the analogous chloroform monosolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·CHCl₃, ( II ), bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn₂I₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, ( III ), and catena‐poly[[[diiodidozinc(II)]‐μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine] chloroform monosolvate], {[ZnI₂(C₁₂H₁₀N₆)]·CHCl₃}_n, ( IV ), by solution reaction with ZnX₂ (X = Cl and I) in a CH₂Cl₂/CH₃OH or CHCl₃/CH₃OH mixed solvent system at room temperature. Complex ( I ) is isomorphic with complex ( III ) and has a bimetallic ring possessing similar coordination environments for both of the Zn^II cations. Although complex ( II ) also contains a bimetallic ring, the two Zn^II cations have different coordination environments. Under the influence of the I^? anion and guest CHCl₃ molecule, complex ( IV ) displays a significantly different structure with respect to complexes ( I )–( III ). C—H…Cl and C—H…N hydrogen bonds, and π–π stacking or C—Cl…π interactions exist in complexes ( I )–( IV ), and these weak interactions play an important role in the three‐dimensional structures of ( I )–( IV ) in the solid state. In addition, the fluorescence properties of L and complexes ( I )–( IV ) were investigated.     

Low‐temperature sol–gel transformation of methyl silicon precursors to silica‐based hybrid materials

Six new methyl silicon (IV) precursors of the type [MeSi{ON?C(R)Ar}₃] [when R = Me, Ar = 2‐C₅H₄N ( 1 ), 2‐C₄H₃O ( 2 ) or 2‐C₄H₃S ( 3 ); and when R = H, Ar = 2‐C₅H₄N ( 4 ), 2‐C₄H₃O ( 5 ) or 2‐C₄H₃S ( 6 )] were prepared and structurally characterized by various spectroscopic techniques. Molecular weight measurements and FAB (Fast Atomic Bombardment) mass spectral studies indicated their monomeric nature. ¹H and ¹³C{¹H} NMR spectral studies suggested the oximate ligands to be monodentate in solution, which was confirmed by ²⁹Si{¹H} NMR signals in the region expected for tetra‐coordinated methylsilicon (IV) derivatives. Thermogravimetric analysis of 1 revealed the complex to be thermally labile, decomposing to a hybrid material of definite composition. Two representative compounds ( 2 and 4 ) were studied as single source molecular precursor for low‐temperature transformation to silica‐based hybrid materials using sol–gel technique. Formation of homogenous methyl‐bonded silica materials (MeSiO_3/2) at low sintering temperature was observed. The thermogravimetric analysis of the methylsilica material indicated that silicon‐methyl bond is thermally stable up to a temperature of 400 °C. Reaction of 2 and Al(OPrⁱ)₃ in equimolar ratio in anhydrous toluene yielded a brown‐colored viscous liquid of the composition [MeSi{ON?C(CH₃)C₄H₃O}₃.Al(OPrⁱ)₃]. Spectroscopic techniques ¹H, ¹³C{¹H}, ²⁷Al{¹H} and ²⁹Si{¹H} NMR spectra of the viscous product indicated the presence of tetracoordination around both silicon and aluminum atoms. On hydrolysis it yielded methylated aluminosilicate material with high specific surface area (464 m²/g). Scanning electron micrography confirmed a regular porous structure with porosity in the nanometric range. Copyright © 2008 John Wiley & Sons, Ltd.     

Polypropylene and poly(ethylene‐co‐1‐octene) effective synthesis with diamine‐bis(phenolate) complexes: Effect of complex structure on catalyst activity and product microstructure

A series of group 4 metal complexes bearing amine‐bis(phenolate) ligands with the amino side‐arm donor: (μ‐O)[Me₂N(CH₂)₂N(CH₂‐2‐O‐3,5‐tBu₂‐C₆H₂)₂ZrCl]₂ ( 1a ), R₂N(CH₂)₂N(CH₂‐2‐O‐3‐R¹‐5‐R²‐C₆H₂)₂TiCl₂ (R = Me, R¹, R² = tBu ( 2a ), R = iPr, R¹, R² = tBu ( 2b ), R = iPr, R¹ = tBu, R² = OMe ( 2c )), and Me₂N(CH₂)₂N(CH₂‐2‐O‐3,5‐tBu₂‐C₆H₂)(CH₂‐2‐O‐C₆H₄)TiCl₂ ( 2d ) are used in ethylene and propylene homopolymerization, and ethylene/1‐octene copolymerization. All complexes, upon their activation with Al(iBu)₃/Ph₃CB(C₆F₅)₄, exhibit reasonable catalytic activity for ethylene homo‐ and copolymerization giving linear polyethylene with high to ultra‐high molecular weight (600·× 10³–3600·× 10³ g/mol). The activity of 1a /Al(iBu)₃/Ph₃CB(C₆F₅)₄ shows a positive comonomer effect, leading to over 400% increase of the polymer yield, while the addition of 1‐octene causes a slight reduction of the activity of the complexes 2a‐2d . The complexes with the NMe₂ donor group ( 2a , 2d , 1a ) display a high ability to incorporate a comonomer (up to 9–22 mol%), and the use of a bulkier donor group, N(iPr)₂ ( 2b , 2c ), results in a lower 1‐octene incorporation. All the produced copolymers reveal a broad chemical composition distribution. In addition, the investigated complexes polymerized propylene with the moderate ( 1a , 2a ) to low ( 2b‐2d ) activity, giving polymers with different microstructures, from purely atactic to isotactically enriched (mmmm = 28%). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2467–2476     

Three AgI,CuI and CdII coordination polymers based on the new asymmetrical ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole: syntheses,characterization and emission properties

The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C₁₇H₁₃N₅O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag^I, Cu^I and Cd^II metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF₆}_n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu₂I₂( L )₂]·C₄H₈O₂}_n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )₂(NO₃)₂]·2CH₄O·0.65H₂O}_n, were obtained. The experimental results show that ligand L coordinates easily with linear Ag^I, tetrahedral Cu^I and octahedral Cd^II metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.     

Judiciously balancing steric and electronic influences on 2,3‐diiminobutane‐based Pd(II) complexes in nourishing polyethylene properties

A new series of palladium complexes ( Pd1–Pd5 ) ligated by symmetrical 2,3‐diiminobutane derivatives, 2,3‐bis[2,6‐bis{bis(4‐FC₆H₄)₂CH}₂‐4‐(alkyl)C₆H₂N]C₄H₆ (alkyl = Me L1 , Et L2 , ⁱ Pr L3 , ^t Bu L4 ) and 2,3‐bis[2,6‐bis{bis(C₆H₅)₂CH}₂‐4‐{(CH₃)₃C}C₆H₂N]C₄H₆ L5 , have been prepared and well characterized, and their catalytic scope toward ethylene polymerization have been investigated. Upon activation with MAO, all palladium complexes ( Pd1–Pd5) exhibited good activities (up to 1.44 × 10⁶ g (PE) mol^?1(Pd) h^?1) and produced higher molecular weight polyethylene in the range of 10⁵ g mol^?1 with precise molecular weight distribution (M _w/M _n = 1.37–1.77). One of the long‐standing limiting features of the Brookhart type α‐diimine Pd(II) catalysts is that they produce highly branched (ca. 100/1000 C atoms) and totally amorphous polymer. Conversely, herein Pd5 produced polymers having dramatically lower branching number (28/1000) as well as improved melting temperature up to 73.1 °C showing well‐controlled linear architecture, and very similar to polyethylene materials generated by early‐transition‐metal based catalysts. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3214–3222     

Synthese und Kristallstruktur des heterobimetallischen Diorganozinndichlorids (FcN,N)2SnCl2 (FcN,N—: (η5‐C5H5)Fe{(η5‐C5H3[CH(CH3)N(CH3)CH2CH2NMe2]‐2}—)

Synthesis and Crystal Structure of the Heterobimetallic Diorganotindichloride (FcN, N)₂SnCl₂ (FcN, N^—: (η⁵‐C₅H₅)Fe{η⁵‐C₅H₃[CH(CH₃)N(CH₃)CH₂CH₂NMe₂]‐2}^—) The heterobimetallic title compound [(FcN, N)₂SnCl₂] ( 1 ) was obtained by the reaction of [LiFcN, N] with SnCl₄ in the molar ratio 1:1 in diethylether as a solvent. The two FcN, N^— ligands in 1 are bound to Sn through a C‐Sn σ‐bond; the amino N atoms of the side‐chain in FcN, N^— remain uncoordinated. The crystals contain monomeric molecules with a pseudo‐tetrahedral coordination at the Sn atom: Space group P2₁/c; Z = 4, lattice dimensions at —90 °C: a = 9.6425(2), b = 21.7974(6), c = 18.4365(4) Å, β = 100.809(2)°, R1_obs· = 0.051, wR2_obs· = 0.136.