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The reaction of a new ligand, ethyl 2,6-diphenylisonicotinate (EtO(2)C-CAN boolean AND C-H(2)), with K(2)PtCl(4) in acetic acid affords the monocyclometalated complex [{(EtO(2)C-CANAC-H)Pt(mu-Cl)}(2)] (1), which transforms to the bis-cyclometalated derivative [Pt(EtO(2)C-C boolean AND N boolean AND C)(DMS0)] (2) when heated in hot DMSO. Complex 2 is the precursor for preparing a new series of neutral mononuclear bis-cyclometalated complexes [Pt(EtO(2)C-CAN boolean AND C)(L)] (L = tht (3), PPh(3) (4), CN-(t)Bu (5), py (6), py-tBu (7), py-NH(2) (8), py-CN (9), py-CONH(2) (10)). These new complexes have been characterized spectroscopically, and structures of 2-10 have been determined crystallographically. Within each crystal structure the individual molecules pack in a head-to-tail arrangement. Noncovalent interactions, including pi center dot center dot center dot pi; C-H center dot center dot center dot O, C-H center dot center dot center dot N, N-H center dot center dot center dot Pt, N-H center dot center dot center dot pi, C-H center dot center dot center dot O, and N-H center dot center dot center dot O, contribute significantly to the supramolecular structures displayed by these complexes in the solid state. All complexes display UV-vis absorptions in dichloromethane solution. Excitation and emission studies as well as lifetime measurements are described and can be correlated to the solid-state structures of the complexes. DFT and TDDFT computational studies have been performed on 5 and 8 which support the conclusions drawn from the photophysical studies.

The reaction between 2- and 3-thienyl-substituted 1,3-butadiynes and the electron-deficient osmium cluster Os3H2(CO)10 yields trinuclear coordination products, associated with transformations of the diacetylene ligands. Depending on the heteroaryl end groups, osmium clusters with both a closed and open Os-triangle core were formed. The reaction between Os3H2(CO)10 and 1,4-bis(2-thienyl)butadiyne yielded [Os3(-H)(CO)10{(-n-(C 4H3S)(C8H4S)}] (1) and [Os 3(-H)(CO)10{(3-n2- n1-n1-(SC7H4)C(SC 4H3)}] (2), whereas in the analogous case of 1,4-bis(3-thienyl)butadiyne the main coordination product was found to be [Os3(-H)(CO)10{(-n-(C4H 3S)(C8H4S)}] (3). Compounds 1-3 were stable in air, but lost carbon monoxide upon prolonged heating. Thermal decarbonylation of 1 under N2 yielded a mixture of [Os3(-H)(CO) 9{(3-n3-(C4H 3S)(C8H4S)}] (4) and [Os3(-H) 2(CO)9{(3-n1- n1-(C4H3S)(C8H3S)}] (5). Thermal decarbonylation of 2 yielded [Os3(-H)(CO) 9{(3-n3-(C4H 3S)(C8H4S)}] (6), while thermal decarbonylation of 3 yielded [Os3(-H)(CO)9{(3- n3-(C4H3S)(C8H4S)}] (7). A reaction involving 3 with CF3COOH affords as the main cluster product the known cluster [Os3(-H)(CO)10(O 2CF3)] (8) and, unusually, permits the isolation and characterization of the novel organic molecule [(C4H 3S)(C8H4S)(OCF3)] (9) cleaved from the parent cluster. The structures of the new compounds were established by single-crystal X-ray studies and spectroscopic methods and supported by density functional theory.

CuCN reacts with RLi and TMPLi (TMP = 2,2,6,6-tetramethylpiperidide) to give Gilman-type cuprates R(TMP)CuLi·nL (R = Ph, n = 3, L = THF 2; R = Me, n = 1, L = TMEDA 3). 3 and 3·LiCN have been tested in directed ortho cupration with data suggesting enhanced efficiency for Lipshutz-type 3·LiCN; competition between Lipshutz- and Gilman-type formulations is rationalized by DFT methods.

The new very-intense vertical-axis Laue diffractometer (VIVALDI) at the Institut Laue-Langevin has been used to probe the single-crystal structure of [(t-Bu2AlMe2)2Li]-[{Ph(2-C5H4N)N}6HLi8]+, with data proving that the molecular main-group-metal cluster cation component incorporates interstitial hydride. Variations in nitrogen coordination mode and distortion of the metal core are in accord with octahedral hydride coordination (H−Li = 1.92(2), 2.04(2), 2.07(2) A), two metal centers being nonbonding with respect to hydride (H···Li = 2.86(2) A).

Reactions of [H2Os3(CO)10] with the substituted diynes R-C2-C2-R' (1, R = Ph, R' = CH2NHPh; 2, R = Ph, R' = CH2NHCH2Ph; 3, R = R' = CH2NHPh) afford the clusters [HOs3(CO)10(L)] (L = {-1:2-PhCH2C(H)=C-C(H)=C-NPh} (4), {-1:2-PhCH2C(H)=C-C(H)=C-NCH2Ph} (5), and {-1:1-CH3CC=C-C(H)=C(H)-NPh} (6), which have been characterized by single-crystal X-ray diffraction analyses as well as by various spectroscopic methods. In clusters 4-6, the starting diynes 1-3 have been rearranged to form substituted pyrrolyl rings which bridge two osmium atoms in 1:2- (4, 5) or 1:1- (6) coordination modes depending on the nature of substituents in 1-3. A possible reaction pathway for the diyne cyclization reactions that yield 4-6 involves initial transfer of a hydride onto a coordinated diyne followed by a series of 1,3-shifts and subsequent nucleophilic attack of the nitrogen on the third carbon atom of the diyne system to afford the five-membered pyrrolyl ring. Cluster 6 and its previously characterized furanyl analogue [HOs3(CO)10{-1:1-(OCHCHCC)-C-CH3)}] (7) undergo facile thermal transformation accompanied by the loss of a CO ligand to give the clusters [HOs3(CO)9{3,3-CH3CC=C-C(H)=C(H)-NPh}] (8) and [HOs3(CO)9{3,3-(OCH=CHC=CCCH3)}] (9). In both 8 and 9, single-crystal X-ray analysis revealed the presence of pentagonal pyramid cluster cores containing three osmium and three carbon atoms. (Less)

Addition of CpM (Cp = C5H5; M = Li, Na, K, Cs) to Cp2E (Cp = C5H5; E = Sn, Pb) produces π-anions of general formula [Cp2x+1Ex]-. Multidecker anions (with x > 1) can be prepared for Pb if crown or c...

The coordination of [(η-Cp)2Pb] and [(η-Cp)2Sn] by bidentate Lewis-base ligands gives the first examples of adducts of neutral p-block metallocenes. Ab initio MO calculations of [(η-Cp)2Pb·TMEDA] (1) (TMEDA = (Me2NCH2)2), [Cp2Pb·4,4‘-Me2bipy] (2) (4,4‘-Me2bipy = 4,4‘-dimethylbipyridine), and the new complex [(η-Cp)2Sn·TMEDA] (3) confirm that despite the presence of longer Pb−N and Sn−N bonds in the solid-state structures of the TMEDA adducts, the association of TMEDA with the metallocenes is more favorable than with 4,4‘-Me2bipy. This finding is a consequence of the greater reorganization energy of 4,4‘-Me2bipy compared to TMEDA. The low association energies of these species can be rationalized in terms of metal lone pair/ligand lone pair repulsion.

A series of dinuclear metal σ-acetylides of the type trans-[Cl(P−P)2MC⋮CRC⋮CM(P−P)2Cl] (M = Fe, Ru, Os; P−P = 1,2-bis(diphenylphosphino)methane (dppm), 1,2-bis(diethylphosphino)ethane (depe), 1,2-bis(dimethylphosphino)ethane (dmpe); R = 1,4-benzenediyl, 1,3-benzenediyl, 2,5-xylenediyl, 2,5-pyridinediyl, 2,5-thiophenediyl) have been formed. Electrochemistry of these complexes shows that there is a metal−metal interaction which is dependent upon the metal and the π-conjugated bridging ligand. Coulometry and optical absorbance spectroscopic studies show the presence of mixed-valence oxidized species which possess a delocalized allenylidene structure and can be classified as Robin and Day “class II” mixed-valence species. Theoretical calculations have been carried out to optimize the geometric structure of the bridging acetylide ligand and indicate that the conjugated system undergoes a structural change upon oxidation to give a quinoid-like geometry. Two mononuclear metal−allenylidene complexes, [Cl(dppm)2MC...

A triosmium cluster with a novel side-on coordinated imine ligand has been synthesized by the reaction between a triosmium carbene complex and ammonia. In the first step of the reaction, an anionic amino complex is formed which reacts upon treatment with [Ph3C]+ to abstract a hydride from the amino group to form the imine complex, the molecular structure of which has been determined.

The methoxycarbene complexes [Fe(C5Me5)(CO)2{C(OMe)C6H4-o-X}][OTf] (2a, X = OMe; 2b, X = Cl) are good precursors of the corresponding (η2-C,X) chelate carbene complexes [Fe(C5Me5)(CO){η2-C(OMe)C6H4-o-X}][OTf] (OTf = CF3SO3) (5a,b). The η2-chloro derivative 5b has been characterized by X-ray diffraction, confirming the formation of a five-membered ring metallacycle. All the new carbene complexes, including the nonheteroatom-stabilized carbene complex [Fe(C5Me5)(CO)2{C(H)C6H4-o-OMe}][OTf] (4a), have been fully characterized by 1H and 13C NMR spectrocopy. The lability of the chelating o-substituent is chemically demonstrated by the formation of the corresponding neutral iodo carbene complexes [Fe(C5Me5)(CO)(I){η1-C(OMe)C6H4-o-X}] (6a,b), the competitive O-demethylation process being thus inhibited. Selective ligand exchange reactions of 5a,b afford various substituted complexes such as [Fe(C5Me5)(CO)n(PMe3){ηx-C(OMe)C6H4-o-OMe}][OTf] (11, n = 1, x = 1; 12, n = 0, x = 2); the mono- and bis(acetonitrile) compl...

Two new cobalt complexes, [Co{PPh2CPhCPhCOC(O)CPhCPh}(CO)2] (4) and [Co{PPh2CPhCPhCC(O)OC(O)CPhCPh}(CO)2] (5), have been synthesized and spectroscopically and structurally characterized. Complex 4 ...

[Ph3PAgC⋮CPh]4·3.5THF (2) can be prepared by the reaction of CpAgPPh3 (1) with lithium phenylacetylide (1:1 equiv). Similarly [Me3PAgC⋮CSiMe3]∞ (4) can be prepared by the reaction of CpAgPMe3 (3) and lithium (trimethylsilyl)acetylide (1:1 equiv). Both complexes have been characterized by elemental analyses, solid-state IR spectroscopy, 1H and 31P NMR spectroscopy, and low-temperature X-ray diffraction studies. The structure of 2 consists of a tetranuclear “flat-butterfly” core, with the two “hinge” silver atoms σ-bonded to two acetylide fragments, which then π-complex the apical Ag(PPh3)2 fragments. In 4, the smaller steric bulk of the phosphine employed allows this complex to crystallize as a polymer. Rather than being constructed from simple [R3PAg(acetylide)] units, both 2 and 4 are formed by the aggregation of (acetylide)2Ag- and Ag(PR3)2+ fragments. The preparation of complexes 2 and 4 demonstrates the synthetic utility of nucleophilic substitution of CpAgPR3 in the synthesis of Ag organometallics. T...

The X-ray structure of the title compound (synthesized by the reaction of 2-lithiobenzoxazole with triphenylborane and subsequent hydrolysis with water) reveals in comparison with the MP2(FC)/6-31G...

The mononuclear complex [(EtO 2C-C ^N ^C)Pt(dmpyz)] (1) (dmpyz = 2,5-dimethylpyrazine) has been synthesized by reaction of [(EtO 2C-C ^N ^C)Pt(dmso)] (A) with dmpyz in a 1:1 molar ratio in dichloromethane. Complex 1 is the precursor for preparing the homodinuclear complex [{(EtO 2C-C ^N ^C)Pt} 2(μ-dmpyz)] (2) and the heterotrinuclear clusters [{(EtO 2C-C ^N ^C)Pt(dmpyz)} 2M]X (M = Cu, X = PF 6 (3); M = Ag, X = BF 4 (4)). Compounds 1, 2, and 4 were studied by X-ray diffraction methods. In the crystal packing of 1 and 2, the molecules display short intermolecular π•••π contacts, which control the solid-state emissive behavior. X-ray study on 4 shows two [Pt 2Ag] sandwich-type clusters in the asymmetric unit, both with the two square-planar >(R-CNC)Pt(dmpyz)> moieties stabilized by two Pt → Ag donor-acceptor bonds as well as by η 1- and η 2-Ag-C interactions. Intramolecular π-π contacts were found between the pyridine rings of the CNC ligands within the same Pt 2Ag cluster. 1H and 195Pt NMR studies confirm that the Pt 2M cluster is also retained in solution at room temperature. 195Pt NMR spectra of 3 and 4 show signals shifted significantly downfield when comparing with that for the monomer (1), which is attributed to the presence of Pt-M dative bonds. At lower temperatures (T = 193 K), the copper derivative definitely falls apart, whereas the silver one still holds up unbroken. In the solid state at 77 K, compounds 1-4 give red emissions arising from 3ππ excited states due to the intra- or intermolecular π-π contacts observed in the crystal structures. As expected, in glassy solutions (77 K), compound 3 displays analogous emissions to those from the starting material (1). Complexes 1 and 2 show structured emission bands that are particularly sensitive to the λ ex (HE and LE). In contrast, 4 displays an unstructured emission at 680 nm with a shoulder at 556 nm; both are not dependent on the λ ex. DFT and TDDFT computational studies have been performed on 1 and 2, which support the conclusions drawn from the photophysical studies. © 2012 American Chemical Society., The authors gratefully acknowledge the European Commission for financial support under the Marie Curie Intra-European Fellowship (PIEF-GA-2009-252883; SFL-PRR) and Prof. Juan Fornies (University of Zaragoza, Project 2008-06669-C02, from the Spanish MICINN) for the use of facilities to do the photophysical studies. The support of the Engineering and Physical Sciences Research Council (U.K.) is also acknowledged and particularly for their award of a Senior Fellowship to P.R.R. and studentships to C.H.W.

Determination de la structure cristalline (triclinique, P1) et etude de spectrometrie RMN a temperature variable

The compound (HRU{sub 3}(CO){sub 10}({mu}-COBH{sub 2}NMe{sub 3})) (1) has been obtained as a minor product from the reaction of Ru{sub 3}(CO){sub 12-x}(NCMe){sub x} (x = 1, 2) either with THF{center dot}BH{sub 3} in the presence of NMe{sub 3} or directly with Me{sub 3}N{center dot}BH{sub 3}. The second boron-containing product is proposed from spectroscopic data to be (Ru{sub 6}(CO){sub 17}B) (HNMe{sub 3}). The structure of 1 has been determined by single-crystal X-ray crystallography: monoclinic, P2{sub 1}/c, a = 14.938 (2) {angstrom}, b = 9.153 (1) {angstrom}, c = 16.872 (1) {angstrom}, {beta} = 100.66 (1){degree}, V = 2267 {angstrom}{sup 3}, Z = 4, R{sub F} = 2.44%. In 1, the (HRu{sub 3}(CO){sub 10}({mu}-CO)){sup {minus}} anion formally functions as a base toward the borane; the observed bond length of the cluster {mu}-CO group (1.262 (4) {angstrom}) in 1 is longer than that of the corresponding bond in (HRu{sub 3}{sup {minus}} (CO){sub 10}({mu}-CO)){sup {minus}}.

Reaction of ((2-(dimethylamino)ethyl)methylamino)lithium (4) with benzonitrile gives a new α-amino lithium imide, 5, which in the solid state is a tetrameric cubane. Aggregation is accompanied by chelation of each metal center using a tertiary amino function, yielding stable seven-membered rings. The stability of 5 limits cyclotrimerization of the benzonitrile moiety to 2,4,6-triphenyl-1,3,5-triazine, thereby suggesting a likely mechanism for the cyclotrimerization process.

The reaction of [2-PyLi] with [Cp2Pb] produces [Pb(2-Py)3Li·THF] (1), containing the first example of a low oxidation state group 14 tris(pyridyl) ligand. The solid-state structure of 1 is that of ...

Reaction of 2,3-dimethylindole in thf with nBuLi and CO2 gives a lithium carbamate complex (2·thf)n, which has a unique tetrameric solid-state structure (n = 4) containing two boat-shaped (−LiOCOLiOCO−) rings joined by four inter-ring Li−O connections. The two-coordinate O atoms of these rings are near to the 2-Me groups of the indolyl residues, suggesting an explanation for second lithiation (and subsequent electrophilic substitution) of 2-alkylindoles and related heterocyclics occurring specifically at the 2-alkyl position.

Preparation des agregats Os 4 (CO) 12 (AuPR 3 ) 2 qui reagissent rapidement avec les nucleophiles. Ils subissent des reductions electrochimiques en [Os 4 (CO) 12 (AuPR 3 ) 4 ] − et [Os 4 (CO) 12 (AuPR 3 ) 2 ] 2− . Structure moleculaire