Reactions of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with zinc reagents Zn(SS) and Zn(OS) (SS = 3,4-toluenedithiolate, OS = 2-mercaptophenolate) produced 5-coordinated d
2 Re(V) alkylidyne complexes Re(≡CCH
2Ph)(SS)(PMePh
2)
2 (Re21) and Re(≡CCH
2Ph)(OS)(PMePh
2)
2 (Re22), respectively. Ligand substitution reaction of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with pyridine (py) gave the pyridine-substituted complex Re(≡CCH
2Ph)Cl
2(PMePh
2)
2(py) (Re23). Treatment of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with the phosphino-phenolate ligand (2-hydroxyphenyl)diphenylphosphine (PO1) and the phosphino-anilide ligand (2-aminophenyl)diphenylphosphine (PN1) led the formation of the complexes Re(≡CCH
2Ph)(
PhPO)
2(PMePh
2) (Re24) and Re(≡CCH
2Ph)(
PhPN)
2(PMePh
2) (Re25), respectively. The complex Re24 could slowly catalyze homo-metathesis of...[
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Reactions of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with zinc reagents Zn(SS) and Zn(OS) (SS = 3,4-toluenedithiolate, OS = 2-mercaptophenolate) produced 5-coordinated d
2 Re(V) alkylidyne complexes Re(≡CCH
2Ph)(SS)(PMePh
2)
2 (Re21) and Re(≡CCH
2Ph)(OS)(PMePh
2)
2 (Re22), respectively. Ligand substitution reaction of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with pyridine (py) gave the pyridine-substituted complex Re(≡CCH
2Ph)Cl
2(PMePh
2)
2(py) (Re23). Treatment of Re(≡CCH
2Ph)Cl
2(PMePh
2)
3 (Re5) with the phosphino-phenolate ligand (2-hydroxyphenyl)diphenylphosphine (PO1) and the phosphino-anilide ligand (2-aminophenyl)diphenylphosphine (PN1) led the formation of the complexes Re(≡CCH
2Ph)(
PhPO)
2(PMePh
2) (Re24) and Re(≡CCH
2Ph)(
PhPN)
2(PMePh
2) (Re25), respectively. The complex Re24 could slowly catalyze homo-metathesis of p-tolyl-1-propyne in toluene solution at 100
oC with the presence of 5 Å MS.
A series of modified phosphino-phenolate (PO) ligands have been synthesized and used to prepare analogous complexes Re31 – Re36 with the structure formula Re(≡CCH
2Ph)(
ArPO)
2(PMePh
2) [Ar = 4-F-Ph (Re31), 4-CF
3-Ph (Re32), 4-MeO-Ph (Re33), 3,5-Me-Ph (Re34), 3,5-CF
3-Ph (Re35), 2,4-F-Ph (Re36)]. In addition, the complexes Re(≡CCH
2Ph)(
PhP
pyO)
2(PMePh
2) (Re37) and Re(≡CCH
2Ph)(
PhP
4-CF3-PhO)
2(PMePh
2) (Re38) with PO ligands bearing an electron withdrawing group on the phenolate ring were prepared. The complexes Re24 and Re31 – Re38 displayed similar catalytic activity for homo-metathesis of p-tolyl-1-propyne.
The pyridine-coordinated complex Re(≡CCH
2Ph)(
FxylPO)
2(py) (Re42) was prepared by substitution of the PMePh
2 ligand of Re(≡CCH
2Ph)(
FxylPO)
2(PMePh
2) (Re35) with pyridine in the presence of CuI as the phosphine sponge. Re42 was found to be more active for alkyne metathesis than the PMePh
2 analog Re35 and the homo-metathesis of p-tolyl-1-propyne could be finished with 2 mol% of Re42 at 100
oC within 8 hours. The d
2 Re(V) alkylidyne complex Re42 is robust enough to be stored in air and used in wet or protic solvents. Moreover, Re42 could catalyze homo-metathesis of internal alkynes with a broad substrate scope, including alcohols, amines and even carboxylic acids.
Analogous pyridine-coordinated complexes Re(≡CCH
2Ph)(
PhPO)
2(py) (Re41), Re(≡CCH
2Ph)(
4-MeO-PhPO)
2(py) (Re51), Re(≡CCH
2Ph)(
4-CF3-PhPO)
2(py) (Re52), Re(≡CCH
2Ph)(
2,4-F2-PhPO)
2(py) (Re53) and Re(≡CCH
2Ph)(
PhP
4-CF3-PhO)
2(py) (Re55) were synthesized. All of the pyridine-coordinated complexes showed significantly improved activities than their PMePh
2 analogs. Catalytic experiments indicated that electron donating ancillary ligands could help pyridine dissociation but slow cycloaddition down while electron withdrawing ancillary ligands could promote cycloaddition but slow pyridine dissociation. Re41, the catalyst with no CF
3 group and Re52, the catalyst with four CF
3 groups, were found to be the state-of-the-art catalysts and could efficiently promote alkyne metathesis reactions at 80
oC in 0.1 M toluene solution.
The reactions of OsCl
2(PPh
3)
3 with diazoindenes produced the η
1-N
2-coordinated binuclear complex [(PPh
3)
2(N
2)Os(μ-Cl
3)OsCl(PPh
3)
2] (Os5). Treatment of [(p-cymene)OsX
2]
2 (X = Br, I) with 3-tert-butyl diazoindene (1e) produced the indenylidene complexes (η
6-p-cymene)OsI
2(=C
9H
5-3-
tBu) (Os12) and (η
6-p-cymene)OsBr
2(=C
9H
5-3-
tBu) (Os13), while the reaction of [(p-cymene)OsCl
2]
2 with 1e produced the sandwich complex {(η
6-p-cymene)Os[η
5-C
9H
5(
tBu)Cl]}Cl (Os11). The osmium indenylidene complexes Os12 and Os13 represent the first well-characterized mononuclear indenylidene complexes synthesized from diazoindene precursors.
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