Synthesis, Structure, and Reactivity of a Rhenium Oxo-Vinylalkylidene Complex

The reaction of 3 equiv of KOC(CF_3)_2Me with ReOCl_3(PPh_3)_2 in dichloromethane, followed by recrystallization from hexanes/THF, gives ReO[OC(CF_3)_2Me]_3(THF)_2( 1) in 35 7% yield. An X-ray diffraction study of 1 (monoclinic, P2_1/n, a = 10.010(3) Å, b = 29.247(6) Å, c = 10.800(3) Å, β = 117.09(1)', Z = 4) reveals a facial arrangement of the three alkoxide ligands around the metal center in a distorted octahedron. The ligand environment in 1 is quite crowded, as evidenced by an elongated Re-O bond between rhenium and one of the THF ligands. The reaction of 3,3-diphenylcyclopropene with 1 in dichloromethane gives initially a mixture of two isomeric rhenium oxo-vinylalkylidene complexes, of which the isomer syn,mer-ReO[C(H)-CH=CPh_2] [OC(CF3)2Me]3(THF) (2b) was isolated in 87% yield. An X-ray diffraction study of 2b (triclinic, P1^(bar), a = 10.459(3) Å, b = 10.913(3) Å, c = 21.308(6) Å, α = 91.16(3)°,β = 102.05-(2)°, γ = 117.98(2)°, 2 = 2) supports a pseudooctahedral structure with mutually trans vinylalkylidene and THF ligands. Complex 2b does not react readily with internal or terminal olefins; however, the addition of GaBr_3 (1 equiv) to 2b yields moderately active catalyst(s) that metathesize cis-2-pentene at ~6.7 turnovers min^(-1). No propagating alkylidene species are observed during the metathesis reaction

An Iridium-based Catalyst System for Metathesis/lsomerization of Acyclic Olefins, including Methyl Oleate

Reaction between [Ir(coe)_2Cl]_2(coe = cyclooctene) and AgO_2CCF_3(4 equiv.) produces a highly active system for metathesis/isomerization of acyclic olefins, including methyl oleate

Synthesis, Structure, and Reactivity of a Rhenium Oxo-Vinylalkylidene Complex

The reaction of 3 equiv of KOC(CF_3)_2Me with ReOCl_3(PPh_3)_2 in dichloromethane, followed by recrystallization from hexanes/THF, gives ReO[OC(CF_3)_2Me]_3(THF)_2( 1) in 35 7% yield. An X-ray diffraction study of 1 (monoclinic, P2_1/n, a = 10.010(3) Å, b = 29.247(6) Å, c = 10.800(3) Å, β = 117.09(1)', Z = 4) reveals a facial arrangement of the three alkoxide ligands around the metal center in a distorted octahedron. The ligand environment in 1 is quite crowded, as evidenced by an elongated Re-O bond between rhenium and one of the THF ligands. The reaction of 3,3-diphenylcyclopropene with 1 in dichloromethane gives initially a mixture of two isomeric rhenium oxo-vinylalkylidene complexes, of which the isomer syn,mer-ReO[C(H)-CH=CPh_2] [OC(CF3)2Me]3(THF) (2b) was isolated in 87% yield. An X-ray diffraction study of 2b (triclinic, P1^(bar), a = 10.459(3) Å, b = 10.913(3) Å, c = 21.308(6) Å, α = 91.16(3)°,β = 102.05-(2)°, γ = 117.98(2)°, 2 = 2) supports a pseudooctahedral structure with mutually trans vinylalkylidene and THF ligands. Complex 2b does not react readily with internal or terminal olefins; however, the addition of GaBr_3 (1 equiv) to 2b yields moderately active catalyst(s) that metathesize cis-2-pentene at ~6.7 turnovers min^(-1). No propagating alkylidene species are observed during the metathesis reaction

Social comparison processes in organizations

We systematically analyze the role of social comparison processes in organizations. Specifically, we describe how social comparison processes have been used to explain six key areas of organizational inquiry: (1) organizational justice, (2) performance appraisal, (3) virtual work environments, (4) affective behavior in the workplace, (5) stress, and (6) leadership. Additionally, we describe how unique contextual factors in organizations offer new insight into two widely studied sub-processes of social comparison, acquiring social information and thinking about that information. Our analyses underscore the merit of integrating organizational phenomena and social comparison processes in future research and theory

Phosphorescent Iridium(III) Complexes of Cyclometalated 5‑Aryl‑1<i>H</i>‑1,2,4-Triazole Ligands: Structural, Computational, Spectroscopic, and Device Studies

Ir­(III) complexes of cyclometalated 5-aryl-1<i>H</i>-1,2,4-triazole ligands are highly efficient, phosphorescent emitters. We describe herein a series of <i>fac</i>-IrL₃ complexes, in which the nature of aryl substituents are shown to strongly affect emission wavelength over the range 453–499 nm. Computational and structural studies indicate that for aryl groups the point of attachment and dihedral angle with respect to the cyclometalated ring influence emission color. Significantly, this degree of color tuning may be achieved without resorting to electron-withdrawing or -donating groups. Photo- and electroluminescence device studies of the different emitters indicate that they are generally highly efficient: photoluminescent efficiencies >90% and external quantum efficiencies of up to 22% are observed

Highly Quantum Efficient Phosphorescent Sky Blue Emitters Based on Diastereomeric Iridium(III) Complexes of Atropisomeric 5‑Aryl‑4<i>H</i>‑1,2,4-triazole Ligands

Homoleptic <i>fac</i>-Ir^IIIL₃ complexes of 5-aryl-4<i>H</i>-1,2,4-triazole ligands are sky blue emitters. When unsymmetrically substituted, the triazole ligands exhibit atropisomerism, and upon cyclometalation to Ir­(III) a mixture of diastereomers is formed. We have isolated and structurally characterized all four possible diastereomers of the <i>fac</i>-Ir^IIIL₃ complex formed upon cyclometalation of an atropisomeric 5-aryl-4<i>H</i>-1,2,4-triazole ligand onto Ir­(III). The phosphorescent blue emitting materials reported herein are among the most efficient to date, with quantum efficiencies above 95%