Showing papers by "Christopher C. Cummins published in 2003"
TL;DR: A multistep synthetic strategy enables the isolation of the niobaziridine-hydride complex Nb(H)(eta2-tBu(H)C=NAr)(N[Np]Ar)2, demonstrating that dual pathways of reactivity are available to the niOBazIRidine-Hydride functional group.
Abstract: A multistep synthetic strategy enables the isolation of the niobaziridine−hydride complex Nb(H)(η2-tBu(H)CNAr)(N[Np]Ar)2 (1, Np = neopentyl, Ar = 3,5-C6H3Me2), which functions as a reactive synthon for its tautomer, the three-coordinate, trisamide species Nb(N[Np]Ar)3 (2). Treatment of 1 with various small molecules has demonstrated its capacity to effect two-electron reduction chemistry. Most noteworthy is the reaction between 1 and elemental phosphorus (P4), providing in high yield the bridging diphosphide complex (μ2:η2,η2-P2)[Nb(N[Np]Ar)3]2. However, unsaturated organic functionality including nitriles and aldehydes can insert into the Nb−H bond of 1, leaving the niobaziridine ring intact, thus demonstrating that dual pathways of reactivity are available to the niobaziridine−hydride functional group.
107 citations
TL;DR: In this article, a new synthetic route utilizes the reductive coupling of molybdenum(IV) acetylides toward the construction of both enediyne molecules and trialkoxymolybDENum alkylidynes, the latter being useful as alkyne metathesis initiators.
72 citations
TL;DR: In this article, the sterically hindered RCN with Me2NCN was used to give the diiminato product analogous to the one mentioned for the tert-butyl system, where molybdaziridine-hydride 2 has provided access to the threecoordinate Mo(N[i-Pr]Ar)3 (3) moiety.
53 citations
TL;DR: In this article, the catalytic effect of adding stoichiometric amounts of N-heterocyclic bases such as 2,6-dimethylpyrazine, 1-methylimidazole, 4-dimethylaminopyridine (DMAP), and pyridine itself was investigated.
30 citations
TL;DR: Using alcoholysis, terminal phosphide PMo(N[i-Pr]Ar)3 is converted into a new, monomeric terminal phosphides PMo (OR)3, where R = 1-methylcyclohexyl or 1-adamantyl.
Abstract: Using alcoholysis, we converted terminal phosphide PMo(N[i-Pr]Ar)3 into a new, monomeric terminal phosphide PMo(OR)3, where R = 1-methylcyclohexyl or 1-adamantyl. Dimerization of the PMo unit was observed upon alcoholysis with 2,6-dimethylphenol, and the dimer [PMo(N[i-Pr]Ar)(O-2,6-C6H3Me2)2]2 was isolated and characterized by X-ray crystallography.
28 citations
TL;DR: It is concluded that this diamagnetic formal scandium(I) system enjoys stabilization of its Sc-based filled d(yz)() orbital by a delta-acceptor linear combination of BrMgL ring orbitals.
Abstract: Sc(BrMgL)2Br (L = (R2NCH2CH2NCMe)2CH, R = H) was studied by DFT methods leading to the conclusion that this diamagnetic formal scandium(I) system enjoys stabilization of its Sc-based filled dyz orbital by a δ-acceptor linear combination of BrMgL ring orbitals. Investigation of the reactivity of Sc(BrMgL)2Br (L = (R2NCH2CH2NCMe)2CH, R = Et) with H2O·B(C6F5)3 and (HOCH2)2CMe2, respectively, led to decomposition, with LMgBr being isolated in the latter case.
21 citations
TL;DR: Molybdenum chalcogenobenzimidates of formula (Ph[PhE]C=N)Mo(N[t-Bu]Ar)(3) (Ar = 3,5-C(6)H(3)Me(2)
Abstract: Molybdenum chalcogenobenzimidates of formula (Ph[PhE]CN)Mo(N[t-Bu]Ar)3 (Ar = 3,5-C6H3Me2) have been obtained by treatment of Mo(N[t-Bu]Ar)3 sequentially with benzonitrile and 0.5 equiv of PhEEPh (E = S, Se, and Te). Molecular structure determinations have been carried out for the S and Se variants. The Te variant extrudes PhCN forming structurally characterized (PhTe)Mo(N[t-Bu]Ar)3 with facility assessed via stopped-flow kinetic measurements, while the Se and S analogues exhibit increasing stability. Quantum chemical calculations and solution calorimetry have been employed as an aid to interpretation of the PhCN extrusion reaction.
16 citations
TL;DR: The reaction of closo-exo-5,6-Na(THF)2,1-Na (THF), 2,3-(SiMe3)2-2,3-C2B4H4 with HoCl3 and H2O in a molar ratio of 5:4:1 produces the new holmacarborane cluster as mentioned in this paper.
13 citations
Patent•
19 Sep 2003TL;DR: One aspect of the present invention relates to methods of preparing enedialkylidyne complexes, enediynes, and alkyne metathesis catalysts, as well as methods of catalyzing alkynes reactions as discussed by the authors.
Abstract: One aspect of the present invention relates to methods of preparing enedialkylidyne complexes, enediynes, and alkyne metathesis catalysts, as well as methods of catalyzing alkyne metathesis reactions The present invention also relates to methods of activating enedialkylidyne complexes for metathesis The present invention also relates to enedialkylidyne complexes
2 citations