Dichlorostannylene complexes of group 10 metals, a unique bonding mode stabilized by bridging 2-pyridyldiphenylphosphine ligands.

The reaction of tin dichloride with catalytically-relevant group 10 metal precursors [M(Cl)(X)(2-PyPPh(2))(2)] (M = Ni, Pd, Pt; 2-PyPPh(2) = 2-pyridyldiphenylphosphine; X = Cl, Me) provides easy access to unprecedented cationic dichlorostannylene complexes [M(X)(2-PyPPh(2))(2)(SnCl(2))](+) where the M-Sn bond is bridged by two head-to-head coordinated 2-PyPPh(2) ligands. The formation of such species instead of the classical neutral trichlorostannyl derivatives [M(X)(SnCl(3))(2-PyPPh(2))(2)] offers a new insight on the specific effect of the SnCl(2) cocatalyst in group 10 metal catalyzed transformations.

IPr* an easily accessible highly hindered N-heterocyclic carbene.

Herein, we wish to describe the efficient three-step synthesis of a novel highly hindered, but flexible, N-heterocyclic carbene and its coordination chemistry to Ag(i) and Rh(i).

Copper(I)/O2 chemistry with imidazole containing tripodal tetradentate ligands leading to mu-1,2-peroxo-dicopper(II) species.

Cuprous and cupric complexes with the new imidazolyl containing tripodal tetradentate ligands {L(MIm), (1H-imidazol-4-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine, and L(EIm), 2-(1H-imidazol-4-yl)-N,N-bis((pyridin-2-yl)methyl)ethanamine}, have been investigated to probe differences in their chemistry, especially in copper(I)-dioxygen chemistry, compared to that already known for the pyridyl analogue TMPA, tris(2-pyridyl)methyl)amine. Infrared (IR) stretching frequencies obtained from carbon monoxide adducts of [(L(MIm))Cu(I)](+) (1a) and [(L(EIm))Cu(I)](+) (2a) show that the imidazolyl donor is stronger than its pyridyl analogue. Electrochemical data suggest differences in the binding constant of Cu(II) to L(EIm) compared to TMPA and L(MIm), reflecting geometric changes.

Supramolecular NHC ligands: on the influence of Zn(II)-templates on the activity of Rh(I)(cod) complexes in 'carbene polymerization'.

New Rh(I)(cod) complexes of N-heterocyclic carbene ligands containing a pending pyridyl moiety for subsequent binding of Zn(II)-templates were designed for supramolecular catalyst control in 'carbene polymerization' reactions. Zn(II)-templates indeed have an influence on the yields and the polymer molecular weights (and weight distributions) produced by these 'supramolecular assemblies'. However, control experiments reveal that the effect of the Zn(II)-template on the polymerization results is general and not due to the assembly formation.

A molecular cage of nickel(II) and copper(I): a [{Ni(L)2}2(CuI)6] cluster resembling the active site of nickel-containing enzymes.

A new mononuclear low-spin nickel(II) dithiolato complex, [NiL(2)] (1), reacts with copper iodide to form the hetero-octanuclear cluster [{Ni(L)(2)}(2)(CuI)(6)] (2) with four trigonal-planar CuI(2)S and two tetrahedral CuI(2)S(2) sites; anagostic interactions between the nickel(II) ions and aromatic protons have been demonstrated by variable-temperature NMR studies to pertain in solution.

Sulfonamido-phosphoramidite ligands in cooperative dinuclear hydrogenation catalysis.

Sulfonamido-phosphoramidite ligands lead to the formation of Rh-Rh dinuclear complexes through the anionic P-N(-) bridging character. The resulting "boat-shaped" dinuclear catalysts activate molecular H(2) through a cooperative dinuclear endocyclic mechanism, resulting in one bridging and one classical hydride on the dinuclear complex. These new complexes are very active hydrogenation catalysts that operate via a new cooperative hydrogenation activation mechanism, as calculated with density functional theory, and they display unequaled high selectivities in the hydrogenation of hindered cyclic acetamidoalkenes.

Synthesis and resolution of planar-chiral ruthenium-palladium complexes with ECE' pincer ligands.

Feel the pinch! Planar-chiral, cationic, ruthenium-palladium complexes based on eta(6),eta(1)-coordinated ECE' pincer ligands are synthesized as racemic mixtures by reacting ECE'-palladium complexes and [Ru(C(5)R(5))(MeCN)(3)](+) arenophiles (R=H or Me). Chiral resolution of the cationic complexes was achieved by using the chiral counterion [Delta-TRISPHAT](-), and solving the X-ray crystal structure of one diastereoisomer (shown here).

Five more phases of the structural family [M(H2O)2(15-crown-5)](NO3)2.

The structures of five more phases of the structural family of compounds [M(H2O)2(15-crown-5)](NO3)2 have been determined. All of these phases are stable at room temperature or above, but transform to other phases if cooled slowly. All five phase transitions take place without significant damage to the single crystal.

The elusive [Ni(H2O)2(15-crown-5)]2+ cation and related co-crystals of nickel(II) hydrates and 15-crown-5.

Initial attempts to make [Ni(H2O)2(15-crown-5)](NO3)2, i.e. to insert the Ni2+ ion into the 15-crown-5 macrocycle, gave the mono- (two polymorphs) and dihydrate of a co-crystal of[Ni(H2O)6](NO3)2 and 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane=15C5).

A two-step spin crossover mononuclear iron(II) complex with a [HS-LS-LS] intermediate phase.

The two-step spin crossover of a new mononuclear iron(ii) complex is studied by magnetic, crystallographic and calorimetric methods revealing two successive first-order phase transitions and an ordered intermediate phase built by the repetition of the unprecedented [HS-LS-LS] motif.

(S)-6-Methyl-∊-caprolactone.

The chiral title compound, C(7)H(12)O(2), a lactone derivative, features a seven-membered ring that adopts a chair conformation. The crystal structure is stabilized by weak C-H⋯O inter-actions occurring in the (100) plane. The absolute configuration was assigned on the basis of the enantioselective synthesis.

An unexpected co-crystal with a variable degree of order: 1:1 rac-1,2-cyclohexanediol/triphenylphosphine oxide.

A 1:1 co-crystal of rac-trans-1,2-C(6)H(10)(OH)(2) and (C(6)H(5))(3)PO has been found that is unusual because there are no strong interactions between the two kinds of molecules, which are segregated into layers. Furthermore, neither pure rac-1,2-cyclohexanediol (CHD) nor pure triphenylphosphine oxide (TPPO) has any obvious packing problem that would make the formation of inclusion complexes likely. The TPPO layers are very much like those found in two of the four known polymorphs of pure TPPO.

(4aS,5R,7R,8S,8aR)-8-(1,3-Dioxolan-2-yl)-7,8-dimethyl-5-(1-methyl-ethen-yl)perhydro-naphthalen-2-one.

In the chiral title compound, C(18)H(28)O(3), the two six-membered rings of the perhydronaphthalenone adopt a rigid chair-chair conformation and the five-membered dioxolanyl ring adopts an envelope conformation. The crystal structure is stabilized only by weak inter-actions.