Novel sydnone derivatives carrying azidomethyl-1,2, 4-oxadiazole unit and their 1,3-dipolar cycloadditions

A series of 1,2,4-oxadiazolymethyl sydnones carrying azido group were synthesized and subjected to react with a variety of alkenic and acetylenic dipolarophilic reagents; N-phenyl maleimide, phenyl vinyl sulfone, and phenyl propiolic acid. All the new products are identified by spectral/physical data including high-resolution mass measure-ments and X-ray diffraction data

N2S2 and N4S4 precursors to PS2 macrocycles and cyclic amidinium salts

A PS2macrocycle and cyclic amidinium salts have been prepared from novel, asymmetric N2S2and N4S4macrocycles.</p

Complexes of Thiourea with alkali metal bromides and iodides: Structural properties, mixed-halide and mixed-metal materials, and halide exchange processes

We report the preparation and structural properties of complexes of metal halides and thiourea with composition MX[thiourea]4 (MX = KBr, KI, RbI, CsI), together with the mixed-halide materials KBrnI1–n[thiourea]4 (0 < n < 1) and the mixed-metal materials KnCs1–nI[thiourea]4 (0 < n < 1). These materials are isostructural, with a tetragonal structure (space group P4/mnc) characterized by M+[thiourea]4 coordination columns along the 4-fold axis and halide anions located in channels in the region of space between adjacent columns and running parallel to the columns. For the mixed-halide materials, the stoichiometry KBrnI1–n[thiourea]4 depends on the bromide/iodide ratio in the crystallization solution; the crystalline complexes have a higher bromide/iodide ratio than the crystallization solution, indicating preferential incorporation of bromide within the complex. Soaking crystals of KBr0.61I0.39[thiourea]4 in iodide containing solutions leads to halide exchange, with the iodide to bromide ratio increasing relative to the parent crystal. Further experiments produced no evidence that these thiourea complexes can accommodate extended polyiodide networks

Co-ordination behaviour of a novel tristhiourea tripodal ligand; structural variations in a series of transition metal complexes

The co-ordination chemistry of a tristhiourea tris(2-pyridylmethyl)amine ligand (L1) with a series of transition metal ions has been investigated. Crystallographic data show that large metal ions, with no geometrical preferences , such as Mn(II) and Cd(II), will form seven co-ordinate monocapped octahedral complexes, while smaller metal ions such as Zn(II) favour five co-ordinate trigonal bipyramidal structures. In a similar manner to the related bisthiourea complexes, the Ni(II) complex shows a strong preference for octahedral geometries resulting in the ligand binding asymmetrically. Spectroscopic (IR and NMR), spectrometric (MS) as well as electrochemical data for these complexes are reported

Crystal structure of 7,7-dimethyl-6-methylidenetricyclo[6.2.1.01,5]undecane-2-carboxylic acid

In the title compound, C15H22O2, both five-membered rings display an envelope conformation whereas the six-membered ring displays a chair conformation. In the crystal, pairs of O-H...O hydrogen bonds between carb­oxy­lic groups link mol­ecules, related by a twofold rotation axis, into supra­molecular dimers

Crystal structure of pseudoguainolide

The lactone ring in the title mol­ecule, C15H22O3 (systematic name: 3,4a,8-tri­methyl­dodeca­hydro­azuleno[6,5-b]furan-2,5-dione), assumes an envelope conformation with the methine C atom adjacent to the the methine C atom carrying the methyl substituent being the flap atom. The other five-membered ring adopts a twisted conformation with the twist being about the methine-methyl­ene C-C bond. The seven-membered ring is based on a twisted boat conformation. No specific inter­actions are noted in the the crystal packing

Di-μ3-chlorido-tetra-μ2-chlorido-di­chloridotetra­kis­(N,N-di­ethyl­ethane-1,2-di­amine-κ2N,N′)tetra­cadmium(II)

In the title compound, [Cd4Cl8(C6H16N2)4], the Cd2+ cations and Cl− anions form M4Cl8 clusters with six of the Cl− ions bridging Cd2+ cations and two being pendant. Each Cd2+ cation has distorted octa­hedral coordination completed by four Cl− ions and two N atoms of the asymmetrical bidentate amino ligand. The cluster consists of pairs of face-sharing hexa­hedra linked by a shared edge

Rapid assembly of highly-functionalised difluorinated cyclooctenones via ring-closing metathesis

Building block methodology from trifluoroethanol and ringclosing metathesis using a Fürstner modification of Grubbs’ conditions allows the rapid synthesis of novel difluorinated cyclooctenones

Asymmetric cationic phosphines: synthesis, coordination chemistry, and reactivity

A single enantiomer of a cationic phosphine, [α-CgPAmHMe]BF4 has been synthesized and coordinated to Rh(I), Au(I), Ag(I), Cu(I), and Pt(0). Analysis of pertinent empirical data reveals the ligand to be highly electron-withdrawing due to the cationic amidinium group directly bound to the phosphorus. The N−P bond connecting the amidinium and the phosphacycle is susceptible to attack by nucleophiles (H2O, OH−) when coordinated leading to bond rupture and release of the neutral amidine group. These fortuitous observations suggest that [α-CgPAmHMe]BF4 may be a very useful synthon for the production of novel asymmetric phosphines

Mono- and dimeric complexes of an asymmetric heterotopic P,CNHC,pyr ligand

An asymmetric heterotopic ligand (S-NMeCP) containing a central bicyclic, expanded-ring NHC with one pyridyl and one phosphine exo-substituent has been synthesised and its coordination chemistry with selected late transition metals investigated. The amidinium precursor [S-NMeCHP]PF6 shows variable coordination modes with Ag(I), Cu(I) and Au(I) depending on the L:M ratio. The reaction of two mols of [S-NMeCHP]PF6 with [Cu(MeCN)4]BF4, AgBF4 or Au(THT)Cl gives the bis-ligand complexes [Cu(κ-P-NMeCHP)2(CH3CN)2]BF4·(PF6)2, 1, and [M(κ-P-NMeCHP)2]X·(PF6)2 (3: M = Ag, X = BF4; 6: M = Au, X = Cl) respectively. The 1:1 reaction of [S-NMeCHP]PF6 with AgOTf gave the head-to-tail dimer H,T-[Ag2(μ-N,P-NMeCHP)2(μ-OTf)2](PF6)2, 2, whereas the analogous reaction with Au(THT)Cl gave monomeric [Au(κ-P-NMeCHP)Cl]PF6, 5. Complex 2 was converted to H,T-[Ag2(μ-C,P-NMeCP)2](PF6)2, 4, upon addition of base, while 6 gave [Au(κ-C-NMeCP)2]Cl, 8, when treated likewise. Reaction of [S-NMeCHP]PF6 with Ni(1,5-COD)2 gave the oxidative addition/insertion product [Ni(κ3-N,C,P-NMeCP)(η3-C8H13)]PF6, 9, which converted to [Ni(κ3-N,C,P-NMeCP)Cl]PF6, 10, upon exposure of a CHCl3 solution to air. Complex 10 showed conformational isomerism that was also present in [Rh(κ3-N,C,P-NMeCP)(CO)]PF6, 14, prepared from the precursor complex [Rh(κ-P-NMeCHP)(acac)(CO)]PF6, 13, upon heating in C6H5Cl. [Pt(κ3-N,C,P-NMeCP)(Cl)]PF6, 12, derived from trans-[Pt(κ-P-NMeCHP)2(Cl)2](PF6)2, 11, was isolated as a single conformer