Building C(sp(3)) Molecular Complexity on 2,2 '-Bipyridine and 1,10-Phenanthroline in Rhenium Tricarbonyl Complexes

The reactions of [Re(N-N)(CO)(3)(PMe3)]OTf (N-N=2,2 '-bipyridine, bipy; 1,10-phenanthroline, phen) compounds with tBuLi and with LiHBEt3 have been explored. Addition to the N-N chelate took place with different site-selectivity depending on both chelate and nucleophile. Thus, with tBuLi, an unprecedented addition to C5 of bipy, a regiochemistry not accessible for free bipy, was obtained, whereas coordinated phen underwent tBuLi addition to C2 and C4. Remarkably, when LiHBEt3 reacted with [Re(bipy)(CO)(3)(PMe3)]OTf, hydride addition to the 4 and 6 positions of bipy triggered an intermolecular cyclodimerization of two dearomatized pyridyl rings. In contrast, hydride addition to the phen analog resulted in partial reduction of one pyridine ring. The resulting neutral Re-I products showed a varied reactivity with HOTf and with MeOTf to yield cationic complexes. These strategies rendered access to Re-I complexes containing bipy- and phen-derived chelates with several C(sp(3)) centers

Field induced slow magnetic relaxation in a zig-zag chain-like Dy(iii) complex with the ligando-phenylenedioxydiacetato

The new complex [Dy(PDOA)(NO3)(H2O)(2)](n)center dot nH(2)O (1) (H(2)PDOA iso-phenylenedioxydiacetic acid) was isolated from the reaction of dysprosium(iii) nitrate and H(2)PDOA in a 1 : 1 molar ratio. Its crystal structure is formed of neutral zig-zag chains in which the nona-coordinated Dy(iii) atoms (O(9)donor set) are linked by PDOA ligands with a chelating-bridging coordination mode. DC and AC magnetic studies revealed that1behaves as a field-induced SMM with three relaxation channels. The derived values, considering the Orbach relaxation process, of the barrier to spin reversal and the extrapolated relaxation time areU/k(B)= 59.5 K and tau(0)= 6.3 x 10(-10)s, respectively.Ab initiocalculations support the experimental results

Pairwise assembly of organopalladium(II) units with cyanurato(3-) and trithiocyanurato(3-) ligands: formation of chiral Pd12, Pd10 and Pd9 cage-molecules

The o-palladated, chloro-bridged dimers [Pd{2-phenylpyridine(-H)}-μ-Cl]2 and [Pd{N,N-dimethylbenzylamine(-H)}-μ-Cl]2 react with cyanuric acid in the presence of base to afford closed, chiral cage-molecules in which twelve organo-Pd(II) centers, located in pairs at the vertices of an octahedron, are linked by four tetrahedrally-arranged cyanurato(3-) ligands. Incomplete (Pd10) cages, having structures derived from the corresponding Pd12 cages by replacing one pair of organopalladium centers with two protons, have also been isolated. Reaction of [Pd{2-phenylpyridine(-H)}-μ-Cl]2 with trithiocyanuric acid gives an entirely different and more open type of cage-complex, comprising only nine organopalladium centers and three thiocyanurato(3-) ligands: cage-closure in this latter system appears to be inhibited by steric crowding of the thiocarbonyl groups

Regioselective CH Bond Activation on Stabilized Nitrogen Ylides Promoted by Pd(II) Complexes: Scope and Limitations

The orthopalladation of N-ylides [HxCyN–CHC(O)Ar] (HxCyN = pyridine, benzylamine, imidazole, aniline, and phenylpyridine; Ar = aryl) has been studied. The incorporation of the Pd atom to these substrates is regioselective, since the orthopalladation is produced, in most of the cases, only at the aryl ring of the benzoyl group with concomitant C-bonding of the N-ylide. The X-ray structure of one representative example is reported. Factors governing the observed orientation are discussed, because this regioselectivity is worthy of note, considering the deactivating nature of the carbonyl group. Two exceptions to the general trend have been observed. The first one is the double metalation of the ylide [PhMe2NCHC(O)Ph], which incorporates one Pd at each Ph. The second one is the palladation of the phenylpyridine derivative, which occurs at the pyridinic 2-phenyl ring and produces a six-membered palladacycle.Funding by the Ministerio de Ciencia e Innovacion (MICINN) (Spain, Project CTQ2008-01784) and Gobierno de Aragon (Grupo E97) is gratefully acknowledged. L.C. thanks Consejo Superior de Investigaciones Cientificas and MICINN for a Juan de la Cierva contract.Peer reviewe