Reaction of the N‐heterocyclic carbene, 1,3‐dimesityl‐ imidazol‐2‐ylidene,with a uranyl triflate complex,UO2(OTf)2(thf)3

The N‐heterocyclic carbene, 1,3‐dimesityl‐imidazol‐2‐ylidene (IMes) reacts with tetrahydrofuran (THF) in the presence of an oxidizing uranyl triflate complex, UO₂(OTf)₂(thf)₃ (^?OTf = ^?OSO₂CF₃), to give 1,4‐bis(1,3‐dimesityl‐2‐imidazolium)‐1,3‐butadiene bis(trifluoromethanesulfonate), formally understood as the coupling product of two equivalents of IMes with [CH?CH? CH?CH](OTf)₂. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallographic report: [N,N‐Methylethylaminopropylalane]2

Dimeric and centrosymmetric [MeEtN(CH₂)₃AlH₂]₂ comprises aluminum centers, coordinated in a distorted trigonal bipyramidal fashion by three hydrogen atoms, one nitrogen atom and one carbon atom. The aluminum atoms are bridged by hydrogen atoms, creating a planar, four‐membered Al₂H₂ ring. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallographic report: Di(p‐chlorobenzyl)tin bis(N‐methylpiperazinyldithiocarbamate)

The tin atom in (4‐Cl‐C₆H₄CH₂)₂Sn[S₂CN(CH₂CH₂)₂NCH₃]₂ is in a C₂S₄ skew‐trapezoidal bipyramidal geometry with the two carbon atoms being disposed over the weaker Sn? S bonds. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and antimicrobial activity of Ag(I)‐N‐heterocyclic carbene complexes derived from benzimidazol‐2‐ylidene

Novel benzimidazol‐2‐ylidene carbene complexes of Ag(I) were prepared by interaction of the corresponding benzimidazolium salt with Ag₂O in dichloromethane. Their structures were characterized by elemental analyses, ¹H‐NMR, ¹³C‐NMR and IR spectroscopy techniques. All compounds studied in this work were screened for their in vitro antimicrobial activities against the standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and the fungi Candida albicans and Candida tropicalis. The new complexes were found to be effective antimicrobial activity against a series of bacteria and fungi. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,characterization and catalytic activity of Pd(II) complexes with N‐allyl functionalized imidazol‐2‐ylidenes in Suzuki–Miyaura reaction

A series of Pd–N‐heterocyclic carbene (Pd–NHC) complexes were synthesized and characterized by elemental analysis and spectroscopic methods. In addition, the molecular structures of 3c and 4c were determined by X‐ray diffraction studies. Finally, the performance of complexes 3 and 5 were studied on Suzuki–Miyaura reactions of phenylboronic acid with aryl bromides. Copyright © 2014 John Wiley & Sons, Ltd.     

New palladium(II)–N‐heterocyclic carbene complexes containing benzimidazole‐2‐ylidene ligand derived from menthol: synthesis,characterization and catalytic activities

A new series of sterically hindered ligands containing (1R,2S,4R)‐(+)‐menthoxymethyl group attached to benzimidazole‐based N‐heterocyclic carbene (NHC), palladium–bis‐NHC complexes and (κ²‐C,N)‐palladacyclic NHC complexes have been synthesized and characterized using appropriate spectroscopic techniques. Catalytic performance of the palladium complexes has been investigated for allylic alkylation, Suzuki and Heck carbon–carbon coupling reactions. These complexes smoothly catalyse the carbon–carbon bond formation reactions. Copyright © 2016 John Wiley & Sons, Ltd.     

Crystallographic report: Bis[tris(2‐methyl‐2‐phenylpropyl)tin] piperazinyldithiocarbamate

The centrosymmetric structure of bis[tris(2‐methyl‐2‐phenylpropyl)tin]piperazinyldithiocarbamate contains four‐coordinated tin and monodentate dithiocarbamate ligands. Copyright © 2004 John Wiley & Sons, Ltd.     

Crystallographic report: 2,4‐Diphenyl‐1,3‐bis(4,4,5,5‐tetramethyl[1,3,2] dioxaborolan‐2‐yl)‐buta‐1Z,3E‐diene

The compound comprises a 1Z,3E‐butadiene moiety substituted by two pinacol boronate functional groups. Copyright © 2005 John Wiley & Sons, Ltd.     

[1,3‐Bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]chloridogold(I)

The molecule of the title compound, [AuCl(C₂₇H₃₆N₂)], which belongs to a class of potentially catalytically active N‐heterocyclic carbene complexes, has crystallographic C₂ symmetry and approximate C_2v symmetry. The structure is isostructural with the Cu^I and Ag^I analogues. A previous report of the structure of the title compound as its toluene solvate [Fructos et al. (2005). Angew. Chem. Int. Ed. 44 , 5284–5288] has inaccurate geometry for the complex molecule as a consequence of probable incorrect refinement in the space group Cc, instead of C2/c [Marsh (2009). Acta Cryst. B 65 , 782–783]. The Au—C bond length of 1.998 (4) Å in the title compound is more consistent with the mean distance of 1.979 (14) Å found in 52 other reported [AuCl(carbene)] complexes than with the shorter distance of 1.942 (3) Å given for the refinement in the space group Cc for the toluene solvate and the value of 1.939 Å obtained from the recalculation of that structure in C2/c.     

Crystallographic report: Diisopropylammonium [3‐(2‐thienyl)‐2‐sulfanylpropenoato]triphenylstannate

The title compound comprises trigonal bipyramidal SnPh₃(tspa) anions and ⁱPr₂NH₂ cations linked into centrosymmetric dimers by N? H·O hydrogen bonds. Copyright © 2004 John Wiley & Sons, Ltd.     

A New Class of Remote N‐Heterocyclic Carbenes with Exceptionally Strong σ‐Donor Properties: Introducing Benzo[c]quinolin‐6‐ylidene

We make the case for benzo[c]quinolin‐6‐ylidene ( 1 ) as a strongly electron‐donating carbene ligand. The facile synthesis of 6‐trifluoromethanesulfonylbenzo[c]quinolizinium trifluoromethanesulfonate ( 2 ) gives straightforward access to a useful precursor for oxidative addition to low‐valent metals, to yield the desired carbene complexes. This concept has been achieved in the case of [Mn(benzo[c]quinolin‐6‐ylidene)(CO)₅]⁺ ( 15 ) and [Pd(benzo[c]quinolin‐6‐ylidene)(PPh₃)₂(L)]²⁺ L=THF ( 21 ), OTf ( 22 ) or pyridine ( 23 ). Attempts to coordinate to nickel result in coupling products from two carbene precursor fragments. The CO IR‐stretching‐frequency data for the manganese compound suggests benzo[c]quinolin‐6‐ylidene is at least as strong a donor as any heteroatom‐stabilised carbene ligand reported.     

Synthesis of palladium complexes derived from imidazolidin‐2‐ylidene ligands and used for catalytic amination reactions

N‐Aryl amination and the Buchwald–Hartwig reaction are of great synthetic and industrial interest and scientists accept their usefulness and versatility for obtaining arylamines. In this study Ag–N‐heterocyclic carbene complexes were used as transmetallation reagents for the synthesis of Pd–N‐heterocyclic carbene complexes. The new Pd–N‐heterocyclic carbene complexes were characterized using elemental analysis and ¹H NMR, ¹³C NMR and infrared spectroscopies. The crystal structure of one, namely dichlorobis[1,3‐bis(2‐methylbenzyl)imidazolidin‐2‐yliden]palladium(II), is presented. The activity of the Pd(II) complexes in the coupling reaction of anilines or amines with bromobenzene was investigated. These complexes exhibited high catalytic activities in the direct synthesis of triarylamines and secondary amines in a single step. Copyright © 2016 John Wiley & Sons, Ltd.     

Crystallographic report: Tri(p‐fluorobenzyl)tin N‐methylpiperazinyldithiocarbamate

The tin atom is a distorted trigonal bipyramid geometry defined by sulfur donors derived from the asymmetrically binding dithiocarbamate ligand and three ipso‐carbon atoms from the p‐fluorobenzyl substituents. Copyright © 2004 John Wiley & Sons, Ltd.     

Structure and spectroscopic properties of the dimeric copper(I) N‐heterocyclic carbene complex [Cu2(CNCt‐Bu)2](PF6)2

In recent years, the use of copper N‐heterocyclic carbene (NHC) complexes has expanded to fields besides catalysis, namely medicinal chemistry and luminescence applications. In the latter case, multinuclear copper NHC compounds have attracted interest, however, the number of these complexes in the literature is still quite limited. Bis[μ‐1,3‐bis(3‐tert‐butylimidazolin‐2‐yliden‐1‐yl)pyridine]‐1κ⁴C²,N:N,C^2′;2κ⁴C²,N:N,C^2′‐dicopper(I) bis(hexafluoridophosphate), [Cu₂(C₁₉H₂₅N₅)₂](PF₆)₂, is a dimeric copper(I) complex bridged by two CNC, i.e. bis(N‐heterocyclic carbene)pyridine, ligands. Each Cu^I atom is almost linearly coordinated by two NHC ligands and interactions are observed between the pyridine N atoms and the metal centres, while no cuprophilic interactions were observed. Very strong absorption bands are evident in the UV–Vis spectrum at 236 and 274 nm, and an emission band is observed at 450 nm. The reported complex is a new example of a multinuclear copper NHC complex and a member of a compound class which has only rarely been reported.     

Crystallographic report: Dichloro[bis(1‐methylimidazole‐2)disulfide]zinc(II)

The Zn center in [ZnCl₂(L‐S‐S‐L)], where L‐S‐S‐L = bis(1‐methylimidazole‐2)disulfide, adopts a tetrahedral configuration defined by two Cl atoms and two N atoms from L‐S‐S‐L, which was obtained by in situ oxidation of 1‐methylimidazole‐2‐thione. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallographic report: Chloro[1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol]zinc(II) chloride hydrate, [(C23H36N4O3)ZnCl]Cl·H2O

The zinc(II) center in the molecule of [(C₂₃H₃₆N₄O₃)ZnCl]Cl·H₂O is coordinated by four nitrogen atoms of HL (1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol) and one chloro anion. The coordination moieties are connected by hydrogen bonds to form a one‐dimensional structure. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallographic report: Diaquabis(1,10‐phenanthroline)zinc(II) 4,5‐dihydroxy‐1,3‐benzenedisulfonate trihydrate

The zinc atom has a distorted octahedral geometry defined by two 1,10‐phenanthroline and two cis water molecules. A three‐dimensional network structure arises owing to extensive hydrogen bonds involving all the components of [Zn(phen)₂(H₂O)₂][C₆H₂(OH)₂(SO₃)₂]·3H₂O. Copyright © 2005 John Wiley & Sons, Ltd.     

Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3‐(pyridin‐2‐yl)‐1H‐imidazol‐1‐yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II)

Iron is of interest as a catalyst because of its established use in the Haber–Bosch process and because of its high abundance and low toxicity. Nitrogen‐heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron–NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1′‐bis(pyridin‐2‐yl)‐2,2‐bi(1H‐imidazole)‐κN³][3,3′‐bis(pyridin‐2‐yl‐κN)‐1,1′‐methanediylbi(1H‐imidazol‐2‐yl‐κC²)](trimethylphosphane‐κP)iron(II) bis(hexafluoridophosphate), [Fe(C₁₇H₁₄N₆)(C₁₆H₁₂N₆)(C₃H₉P)](PF₆)₂, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C—C‐coupled biimidazole, is trapped by coordination to still‐intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.     

Crystallographic report: Dibenzyltin(IV) bis(N,N‐dibenzyldithiocarbamate)

A distorted octahedron C₂S₄ geometry is found for the tin atom in the title compound; C? Sn? C is 136.61(19)°. Copyright © 2004 John Wiley & Sons, Ltd.     

Crystallographic report: Bis{4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine} dichlorozinc(II)

In (C₁₁H₁₂N₄)₂ZnCl₂, the zinc(II) center is coordinated by the pyridine nitrogen atoms of two 4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine ligands and two chlorine atoms in a tetrahedral geometry. Copyright © 2004 John Wiley & Sons, Ltd.