Conformational analysis of some 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones by 1H NMR spectroscopy and molecular simulation

Based on ¹H NMR spectral analysis combined with molecular simulation, conformational states of the cyclohexanone ring were studied for some 1R,4S‐2‐(4‐X‐benzylidene)‐p‐menthan‐3‐ones (X = COOCH₃ or C₆H₅) in CDCl₃ and C₆D₆. The co‐existence of chair conformers with an axial orientation of both alkyl substituents and twist‐boat forms was established for the compounds studied at room temperature (22–23° C). The substituent X does not influence appreciably the ratio of these conformers, but the fraction of twist‐boat forms increases noticeably in benzene solutions as compared with CDCl₃ solutions. Rotameric states of the isopropyl fragment were also characterised for the compounds studied. Distinctions in conformational states for the 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones and (?)‐menthone were revealed and are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Molecular structures of regioisomeric 7‐arylidene hexahydroindazoles from 1H NMR spectra

The structural characterization of two regioisomeric products of the interaction of 2,6‐bis‐(4‐methoxybenzylidene)‐3R‐methylcyclohexanone with methyl hydrazine was achieved using ¹H NMR spectral data, including chemical shifts, coupling constants and results of COSY and nuclear overhauser effect (NOE) experiments. Configurations of the new chiral centers in the (3S,3aR,6R,7E)‐7‐(4‐methoxybenzylidene)‐3,4,5,7‐hexahydro‐3‐(4‐methoxyphenyl)‐2,6‐dimethyl‐ and 2,4‐dimethyl‐2H‐indazoles were assigned on the basis of experimental data combined with molecular modeling by the density functional theory (DFT) method. The distinction in the helical twisting power of studied compounds under addition to a nematic liquid crystal is discussed on the basis of peculiarities of the molecular structures. Copyright © 2009 John Wiley & Sons, Ltd.     

Efficient asymmetric addition of diethylzinc to aldehydes using C2‐novel chiral pyridine β‐amino alcohols as chiral ligands

A series of novel C₂‐symmetric chiral pyridine β‐amino alcohol ligands have been synthesized from 2,6‐pyridine dicarboxaldehyde, m‐phthalaldehyde and chiral β‐amino alcohols through a two‐step reaction. All their structures were characterized by ¹H NMR, ¹³C NMR and IR. Their enantioselective induction behaviors were examined under different conditions such as the structure of the ligands, reaction temperature, solvent, reaction time and catalytic amount. The results show that the corresponding chiral secondary alcohols can be obtained with high yields and moderate to good enantiomeric excess. The best result, up to 89% ee, was obtained when the ligand 3c (2S,2′R)‐2,2′‐((pyridine‐2,6‐diylbis(methylene))bisazanediyl))bis(4‐methyl‐1,1‐diphenylpentan‐1‐ol) was used in toluene at room temperature. The ligand 3g (2S,2′R)‐2,2′‐((1,3‐phenylenebis(methylene))bis(azanediyl))bis(4‐methyl‐1,1‐diphenylpentan‐1‐ol) was prepared in which the pyridine ring was replaced by the benzene ring compared to 3c in order to illustrate the unique role of the N atom in the pyridine ring in the inductive reaction. The results indicate that the coordination of the N atom of the pyridine ring is essential in the asymmetric induction reaction. Copyright © 2014 John Wiley & Sons, Ltd.     

Structure and in vitro antifungal activity of [2,6‐bis(dimethylaminomethyl)phenyl]diphenyltin(IV) compounds

A set of seven [2,6‐bis(dimethylaminomethyl)phenyl]diphenyltin(IV) ({[(CH₃)₂NCH₂]₂(C₆H₃)}­(C₆H₅)₂Sn⁺X^?) ionic organotin(IV) compounds (X = Br, NO₃, CN, SCN, SeCN, BF₄ and PF₆) has been prepared and characterized by electrospray ionization mass spectrometry, ¹H NMR spectroscopy in CDCl₃,¹¹⁹Sn NMR in CDCl₃ and DMSO‐d₆ solution, as well as by ¹³C and ¹¹⁹Sn CP/MAS NMR spectroscopy and X‐ray diffraction techniques in the solid state. The in vitro antifungal activity of these water‐soluble ionic organotin(IV) compounds was compared with starting compounds and the antifungal drugs currently in clinical use. Copyright © 2002 John Wiley & Sons, Ltd.     

The influence of comonomer (2‐hydroxyethyl acrylate) and keto group on photocrosslinking property of arylidene polymers

Two types of arylidene compounds were synthesized by reacting p‐hydroxybenzaldehyde with acetone [1,5‐bis(4‐hydroxyphenyl)penta‐1,4‐dien‐3‐one] (PBHP) and cyclohexanone [2,6‐bis(4‐hydroxybenzylidene)cyclohexanone] (HBC). 1,4‐Pentadien‐3‐one‐1‐p‐hydroxyphenyl‐5‐p‐phenyl methacrylate (PHPPMA) and 4‐{[‐3‐(4‐hydroxybenzylidene)‐2‐oxocyclohexylidene]methyl}phenyl acrylate (HBA) were prepared by reacting PBHP and HBC with methacryloyl chloride and acryloyl chloride in the presence of triethylamine, respectively. Copolymerization of different feed compositions of PHPPMA and HBA with 2‐hydroxyethyl acrylate (HEA) was carried out using a free‐radical solution polymerization technique in ethyl methyl ketone (MEK) using benzoyl peroxide (BPO). All the monomer and polymers were characterized by IR and NMR (¹H/¹³C) spectroscopic techniques. The reactivity ratio of the monomers were obtained using Fineman–Ross (FR), Kelen–Tudos (KT), and extended Kelen–Tudos (exKT) methods. The photocrosslinking properties of the polymers were done using a UV absorption spectroscopy technique. Homopolymers of both the arylidene polymers shows similar trend towards the rate of photocrosslinking. The rate of photocrosslinking was enhanced when the cyclohexanone based arylidene monomer was copolymerized with HEA. Thermal stability and molecular weights (M_w and M_n) of the polymers were determined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3433–3444, 2004     

Two ZnII mononuclear coordination compounds with pyridinedicarboxylate and auxiliary N‐(pyridin‐4‐ylmethylidene)hydroxylamine ligands

Two new mononuclear coordination compounds, bis{4‐[(hydroxyimino)methyl]pyridinium} diaquabis(pyridine‐2,5‐dicarboxylato‐κ²N,O²)zincate(II), (C₆H₇N₂O)₂[Zn(C₇H₃NO₄)₂(H₂O)₂], (1), and (pyridine‐2,6‐dicarboxylato‐κ³O²,N,O⁶)bis[N‐(pyridin‐4‐ylmethylidene‐κN)hydroxylamine]zinc(II), [Zn(C₇H₃NO₄)(C₆H₆N₂O)₂], (2), have been synthesized and characterized by single‐crystal X‐ray diffractometry. The centrosymmetric Zn^II cation in (1) is octahedrally coordinated by two chelating pyridine‐2,5‐dicarboxylate ligands and by two water molecules in a distorted octahedral geometry. In (2), the Zn^II cation is coordinated by a tridentate pyridine‐2,6‐dicarboxylate dianion and by two N‐(pyridin‐4‐ylmethylidene)hydroxylamine molecules in a distorted C₂‐symmetric trigonal bipyramidal coordination geometry.     

Moderately branched ultra‐high molecular weight polyethylene by using N,N′‐nickel catalysts adorned with sterically hindered dibenzocycloheptyl groups

Five examples of unsymmetrical 1,2‐bis (arylimino) acenaphthene ( L1 – L5 ), each containing one N‐2,4‐bis (dibenzocycloheptyl)‐6‐methylphenyl group and one sterically and electronically variable N‐aryl group, have been used to prepare the N,N′‐nickel (II) halide complexes, [1‐[2,4‐{(C₁₅H₁₃}₂–6‐MeC₆H₂N]‐2‐(ArN)C₂C₁₀H₆]NiX₂ (X = Br: Ar = 2,6‐Me₂C₆H₃ Ni1 , 2,6‐Et₂C₆H₃ Ni2 , 2,6‐i‐Pr₂C₆H₃ Ni3 , 2,4,6‐Me₃C₆H₂ Ni4 , 2,6‐Et₂–4‐MeC₆H₂ Ni5 ) and (X = Cl: Ar = 2,6‐Me₂C₆H₃ Ni6 , 2,6‐Et₂C₆H₃ Ni7 , 2,6‐i‐Pr₂C₆H₃ Ni8 , 2,4,6‐Me₃C₆H₂ Ni9 , 2,6‐Et₂–4‐MeC₆H₂ Ni10 ), in high yield. The molecular structures Ni3 and Ni7 highlight the extensive steric protection imparted by the ortho‐dibenzocycloheptyl group and the distorted tetrahedral geometry conferred to the nickel center. On activation with either Et₂AlCl or MAO, Ni1 – Ni10 exhibited very high activities for ethylene polymerization with the least bulky Ni1 the most active (up to 1.06  ×  10⁷ g PE mol^?1(Ni) h^?1 with MAO). Notably, these sterically bulky catalysts have a propensity towards generating very high molecular weight polyethylene with moderate levels of branching and narrow dispersities with the most hindered Ni3 and Ni8 affording ultra‐high molecular weight material (up to 1.5  ×  10⁶ g mol^?1). Indeed, both the activity and molecular weights of the resulting polyethylene are among the highest to be reported for this class of unsymmetrical 1,2‐bis (imino)acenaphthene‐nickel catalyst.     

Crystal structure and DFT analyses of a pentacoordinated PCP pincer nickel(II) complex

The reaction of NiCl₂ with 1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidine in the presence of 2,6‐dimethylphenyl isocyanide and KPF₆ afforded a new pentacoordinated PCP pincer Ni^II complex, namely {1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidin‐2‐yl‐κN²}(2,6‐dimethylphenyl isocyanide‐κC)nickel(II) hexafluoridophosphate 0.70‐hydrate, [Ni(C₉H₉N)(C₃₀H₃₀ClN₂P₂)]PF₆·0.7H₂O or [NiCl{C(NCH₂PPh₂)₂(CH₂)₃‐κ³P,C,P′}(Xylyl‐NC)]PF₆·0.7H₂O, in very good yield. Its X‐ray structure showed a distorted square‐pyramidal geometry and the compound does not undergo dissociation in solution, as shown by variable‐temperature NMR and UV–Vis studies. Density functional theory (DFT) calculations provided an insight into the bonding; the nickel dsp²‐hybridized orbitals form the basal plane and the nearly pure p orbital forms the axial bond. This is consistent with the NBO (natural bond orbital) analysis of analogous nickel(II) complexes.     

The crystal structure,luminescence and nitrobenzene‐sensing properties of a two‐dimensional MnII coordination polymer based on 2,6‐bis(imidazol‐1‐yl)pyridine

A two‐dimensional Mn^II coordination polymer (CP), poly[bis[μ₂‐2,6‐bis(imidazol‐1‐yl)pyridine‐κ²N³:N^3′]bis(thiocyanato‐κN)manganese] [Mn(NCS)₂(C₁₁H₉N₅)₂]_n, (I), has been obtained by the self‐assembly reaction of Mn(ClO₄)₂·6H₂O, NH₄SCN and bent 2,6‐bis(imidazol‐1‐yl)pyridine (2,6‐bip). CP (I) was characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The crystal structure features a unique two‐dimensional (4,4) network with one‐dimensional channels. The luminescence and nitrobenzene‐sensing properties were explored in a DMF suspension, revealing that CP (I) shows a strong luminescence emission and is highly sensitive for nitrobenzene detection.     

Structural characterization of the derivatives of bis{[2,6‐(dimethylamino)methyl]phenyl} selenide with palladium(II) and mercury(II)

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6‐bis[(dimethylamino)methyl]phenyl} selenide, C₂₄H₃₈N₄Se or R₂Se, where R is 2,6‐(Me₂NCH₂)₂C₆H₃, 14 , was synthesized and its ligation reactions with Pd^II and Hg^II precursors were explored. The reaction of 14 with SO₂Cl₂ and K₂PdCl₄ resulted in the formation of the meta C—H‐activated dipalladated complex {μ‐2,2′‐bis[(dimethylamino)methyl]‐4,4′‐bis[(dimethylazaniumyl)methyl]‐3,3′‐selanediyldiphenyl‐κ⁴C¹,N²:C^1′,N^2′}bis[dichloridopalladium(II)], [Pd₂Cl₄(C₂₄H₃₈N₄Se)] or [{R(H)PdCl₂}₂Se], 15 . On the other hand, when ligand 14 was reacted with HgCl₂, the reaction afforded a dimercurated selenolate complex, {μ‐bis{2,6‐bis[(dimethylamino)methyl]benzeneselanolato‐κ⁴N²,Se:Se,N⁶}‐μ‐chlorido‐bis[chloridomercury(II)], [Hg₂(C₁₂H₁₉N₂Se)Cl₃] or RSeHg₂Cl₃, 16 , where two Hg^II ions are bridged by selenolate and chloride ligands. In palladium complex 15 , there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se—C bonds to form a bifurcated SeHg₂ moiety with the formal charge on the Se atom being ?1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg—Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T‐shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°.     

Two cobalt(II) supramolecular isomers based on N,N′‐bis(pyridin‐3‐yl)oxalamide induced by the molecular orientation of lattice DMF molecules

Supramolecular isomerism for coordination networks refers to the existence of different architectures having the same building blocks and identical stoichiometries. For a given building block, different arrangements can lead to the formation of a series of supramolecular isomers. Two one‐dimensional Co^II coordination polymers based on N,N′‐bis(pyridin‐3‐yl)oxalamide (BPO), both catena‐poly[[[dichloridocobalt(II)]‐bis[μ‐N,N′‐bis(pyridin‐3‐yl)oxalamide‐κ²N:N′]] dimethylformamide disolvate], {[CoCl₂(C₁₂H₁₀N₄O₂)₂]·2C₃H₇NO}_n, have been assembled by the solvothermal method. Single‐crystal X‐ray diffraction analyses reveal that the two compounds are supramolecular isomers, the isomerism being induced by the orientation of the dimethylformamide (DMF) molecules in the crystal lattice.     

The synthesis,NMR (1H, 13C, 119Sn) and IR spectral studies of some di‐ and tri‐organotin(IV) sulfonates: X‐ray crystal structure of [(n‐C4H9)2Sn(OSO2C6H4CH3‐4)2·2H2O]

A number of alkyltin(IV) paratoluenesulfonates, R_nSn(OSO₂C₆H₄CH₃‐4)_4?n (n = 2, 3; R = C₂H₅, n‐C₃H₇, n‐C₄H₉), have been prepared and IR spectra and solution NMR (¹H, ¹³C, ¹¹⁹Sn) are reported for these compounds, including (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), the NMR spectra of which have not been reported previously. From the chemical shift δ(¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn) and ²J(¹H, ¹¹⁹Sn), the coordination of the tin atom and the geometry of its coordination sphere in solutions of these compounds is suggested. IR spectra of the compounds are very similar to that observed for the paratoluenesulfonate anion in its sodium salt. The studies indicate that diorganotin(IV) paratoluenesulfonates, and the previously reported compounds (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), contain bridging SO₃X groups that yield polymeric structures with hexacoordination around tin and contain non‐linear C? Sn? C bonds. In triorganotin(IV) sulfonates, pentacoordination for tin with a planar SnC₃ skeleton and bidentate bridging paratoluenesulfonate anionic groups are suggested by IR and NMR spectral studies. The X‐ray structure shows [(n‐C₄H₉)₂Sn(OSO₂C₆H₄CH₃‐4)₂·2H₂O] to be monomeric containing six‐coordinate tin and crystallizes from methanol–chloroform in monoclinic space group C2/c. The Sn? O (paratoluenesulfonate) bond distance (2.26(2) Å) is indicative of a relatively high degree of ionic character in the metal–anion bonds. Copyright © 2003 John Wiley & Sons, Ltd.     

Primary Studies on Variation in Position of Trifluoromethyl Groups in Several Aromatic Group‐14 Derivatives by 19F‐NMR Spectroscopy

Variation in the position of CF₃ groups in several aromatic Group‐14 compounds was studied by ¹⁹F‐NMR spectroscopy. In these compounds R_nECl_4?n (n=1 or 2; E=Si, Ge, or Sn; R=2,4,6‐(CF₃)₃C₆H₂ (=Ar), 2,6‐(CF₃)₂C₆H₃ (=Ar′), or 2,4‐(CF₃)₂C₆H₃ (=Ar″)), Ar, Ar′, and Ar″ are all bulky, strongly electron‐withdrawing ligands. The ¹⁹F‐NMR studies of the variation in position of the CF₃ substituents in these compounds as revealed by chemical shifts could be correlated with the electronegativities of the central elements E, and with intramolecular E–F interactions derived from single‐crystal X‐ray diffraction data. These interactions are considered to play an important role in the stabilization of these compounds.     

Synthesis and Characterization of m‐Terphenyl (1,3‐Diphenylbenzene) Compounds Containing Trifluoromethyl Groups

The bis(silyl)triazene compound 2,6‐(Me₃Si)₂‐4‐Me‐1‐(N?N? NC₄H₈)C₆H₂ ( 4 ) was synthesized by double lithiation/silylation of 2,6‐Br₂‐4‐Me‐1‐(N?N? NC₄H₈)C₆H₂ ( 1 ). Furthermore, 2,6‐bis[3,5‐(CF₃)₂‐C₆H₃]‐4‐Me‐C₆H₂‐1‐(N?N? NC₄H₈)C₆H₂ derivative 6 can be easily synthesized by a C,C‐bond formation reaction of 1 with the corresponding aryl‐Grignard reagent, i.e., 3,5‐bis[(trifluoromethyl)phenyl]magnesium bromide. Reactions of compound 4 with KI and 6 with I₂ afforded in good yields novel phenyl derivatives, 2,6‐(Me₃Si)₂‐4‐MeC₆H₂? I and 2,6‐bis[3,5‐(CF₃)₂? C₆H₃]‐4‐MeC₆H₂? I ( 5 and 7 , resp.). On the other hand, the analogous m‐terphenyl 1,3‐diphenylbenzene compound 2,6‐bis[3,5‐(CF₃)₂? C₆H₃]C₆H₃? I ( 8 ) could be obtained in moderate yield from the reaction of (2,6‐dichlorophenyl)lithium and 2 equiv. of aryl‐Grignard reagent, followed by the reaction with I₂. Different attempts to introduce the ^tBu (Me₃C) or neophyl (PhC(Me)₂CH₂) substituents in the central ring were unsuccessful. All the compounds were fully characterized by elemental analysis, melting point, IR and NMR spectroscopy. The structure of compound 6 was corroborated by single‐crystal X‐ray diffraction measurements.     

Hypervalent Organoselenium(II) Compounds with Organophosphorus Ligands. Crystal and Molecular Structure of [2‐(iPr2NCH2)C6H4]Se[S2PR′2] (R′ = Ph,OiPr)

Redistribution reactions between diorganodiselenides of type [2‐(R₂NCH₂)C₆H₄]₂Se₂ [R = Et, iPr] and bis(diorganophosphinothioyl disulfanes of type [R′₂P(S)S]₂ (R = Ph, OiPr) resulted in the hypervalent [2‐(R₂NCH₂)C₆H₄]SeSP(S)R′₂ [R = Et, R′ = Ph ( 1 ), OiPr ( 2 ); R = iPr, R′ = Ph ( 3 ), OiPr ( 4 )] species. All new compounds were characterized by solution multinuclear NMR spectroscopy (¹H, ¹³C, ³¹P, ⁷⁷Se) and the solid compounds 1 , 3 , and 4 also by FT‐IR spectroscopy. The crystal and molecular structures of 3 and 4 were determined by single‐crystal X‐ray diffraction. In both compounds the N(1) atom is intramolecularly coordinated to the selenium atom, resulting in T‐shaped coordination arrangements of type (C,N)SeS. The dithio organophosphorus ligands act monodentate in both complexes, which can be described as essentially monomeric species. Weak intermolecular S ··· H contacts could be considered in the crystal of 3 , thus resulting in polymeric zig‐zag chains of R and S isomers, respectively.     

Syntheses and Structures of Zinc Bis(phosphinimino)methanide Complexes

Reactions of bis(phosphinimino)methanes H₂C(PPh₂NR)₂ [R = SiMe₃ (L¹H), Ph (L²H), 2,6‐iPr₂‐C₆H₃ (DIPP) (L³H)] with ZnR₂ (R = Me, Et) yielded the corresponding bis(phosphinimino)methanide zinc complexes LZnMe [L² ( 1 ), L³ ( 2 )] and LZnEt [L¹ ( 3 ), L² ( 4 ), and L³ ( 5 )]. Complexes 1 – 5 were characterized by heteronuclear NMR (¹H, ¹³C, ³¹P) and IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction.     

Cycloheptyl‐fused NNO‐ligands as electronically modifiable supports for M(II) (M = Co,Fe) chloride precatalysts; probing performance in ethylene oligo‐/polymerization

The N,N,O‐cobalt(II), [2,3‐{C₄H₈C(NAr)}:5,6‐{C₄H₈C(O)}C₅HN]CoCl₂ (Ar = 2,6‐(CHPh₂)₂‐4‐MeC₆H₂ Co1 , 2,6‐(CHPh₂)₂‐4‐EtC₆H₂ Co2 , 2,6‐(CHPh₂)₂‐4‐ClC₆H₂ Co3 , 2,6‐(CHPh₂)₂‐4‐FC₆H₂ Co4 ) and N,N,O‐iron(II) complexes, [2,3‐{C₄H₈C(NAr)}:5,6‐{C₄H₈C(O)}C₅HN]FeCl₂ (Ar = 2,6‐(CHPh₂)₂‐4‐MeC₆H₂ Fe1 , 2,6‐(CHPh₂)₂‐4‐EtC₆H₂ Fe2 , 2,6‐(CHPh₂)₂‐4‐ClC₆H₂ Fe3 , 2,6‐(CHPh₂)₂‐4‐FC₆H₂ Fe4 ), each containing one sterically enhanced but electronically modifiable N‐2,6‐dibenzhydryl‐4‐R²‐phenyl group, have been prepared by a one‐pot template approach using α,α′‐dioxo‐2,3:5,6‐bis(pentamethylene)pyridine, the corresponding aniline along with the respective cobalt or iron salt in acetic acid. Distorted square pyramidal geometries are a feature of the molecular structures of Co1 – Co4 . Upon activation with MAO or MMAO, Co1 – Co4 show good activities (up to 2.2 × 10⁵ g mol^?1(Co) h^?1) affording short chain oligomers (C₄–C₃₀) with good α‐olefin selectivity. By contrast, Fe1 – Fe4 , in the presence of MMAO, displayed moderate activities (up 10.9 × 10⁴ g(PE) mol^?1(Fe) h^?1) for ethylene polymerization forming low‐molecular‐weight linear polymers (up to 13.0 kg mol^?1) incorporating saturated n‐propyl and i‐butyl chain ends. For both cobalt and iron, the precatalysts incorporating the more electron withdrawing 4‐R²‐substituents [Cl ( Co3 / Fe3 ), F ( Co4 / Fe4 )] deliver the best catalytic activities, while with cobalt, these types of substituents additionally broaden the oligomeric distribution. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3980–3989     

The first example of a two‐coordinated AuI atom bonded to an FeII atom and an N‐heterocyclic carbene (NHC) ligand

The aurophilicity exhibited by Au^I complexes depends strongly on the nature of the supporting ligands present and the length of the Au–element (Au—E) bond may be used as a measure of the donor–acceptor properties of the coordinated ligands. A binuclear iron–gold complex, [1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene‐2κC²]dicarbonyl‐1κ²C‐(1η⁵‐cyclopentadienyl)gold(I)iron(II)(Au—Fe) benzene trisolvate, [AuFe(C₅H₅)(C₂₇H₃₆N₂)(CO)₂]·3C₆H₆, was prepared by reaction of K[CpFe(CO)₂] (Cp is cyclopentadienyl) with (NHC)AuCl [NHC = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]. In addition to the binuclear complex, the asymmetric unit contains three benzene solvent molecules. This is the first example of a two‐coordinated Au atom bonded to an Fe and a C atom of an N‐heterocyclic carbene.     

Synthesen und Eigenschaften von Bis(perfluoralkyl)zink‐Verbindungen

Syntheses and Properties of Bis(perfluoroalkyl)zinc Compounds The conditions for the syntheses of bis(perfluoroalkyl)zinc compounds Zn(R_f)₂ · 2 D (R_f = C₂F₅, n‐C₃F₇, i‐C₃F₇, n‐C₄F₉, n‐C₆F₁₃, n‐C₇F₁₅, and n‐C₈F₁₇; D = CH₃CN, tetrahydrofurane, dimethylsulfoxide) are described. Mass spectra, thermal decompositions, ¹⁹F‐ and ¹³C‐NMR spectra are discussed.     

Vinyl homo/copolymerization of norbornene and ethylene using sterically enhanced 1,2‐bis(arylimino)acenaphthene–palladium precatalysts

A family of unsymmetrical 1,2‐bis(imino)acenaphthene‐palladium methyl chloride complexes [1‐[2,6‐{(C₆H₅)₂CH}₂‐ 4‐{C(CH₃)₃}‐C₆H₂N]‐2‐(ArN)C₂C₁₀H₆]PdMeCl (Ar = 2,6‐Me₂Ph Pd1 , 2,6‐Et₂Ph Pd2 , 2,6‐ⁱPr₂Ph Pd3 , 2,4,6‐Me₃Ph Pd4 , 2,6‐Et₂‐4‐MePh Pd5 ) have been prepared and fully characterized by ¹H/¹³C NMR, FTIR spectroscopies, and elemental analysis. X‐ray diffraction analysis of Pd2 complex revealed a square planar geometry. Upon activation with methylaluminoxane, all the palladium complexes displayed high activities for norbornene (NBE) homo‐polymerization producing insoluble polymer. For the copolymerization of NBE with ethylene, Pd4 complex exhibited good activities with high incorporation of ethylene (up to 59.2–77.4%) and the resultant copolymer showed high molecular weights as maximum as 150.5 kg mol⁻¹. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 922–930