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Synthesis of reduced tungsten and rhenium complexes with multiple bonds to carbon and nitrogen

Thesis/Dissertation ·
OSTI ID:7179338

Reduction of W(NAr)[sub 2]Cl[sub 2](DME) with sodium amalgam in the presence of phosphine produces W(NAr)[sub 2](PR[sub 3])[sub 2]. This compound reacts readily with [pi]-acceptor ligands to give four-coordinate complexes or five-coordinate complexes. Extensive comparisons between the 14 electron M(NAr)[sub 2] core and the 14 electron Cp[sub 2]M core are drawn. The cores are isobal and the structural analogy is borne out in the two systems. Re(C[sup t]Bu) (NAr)Cl[sub 2](PR[sub 3]) is obtained in high yield by deprotonation of [Et[sub 4]N][Re(C[sup t]Bu)(NHAr)CL[sub 4]] in the presence of phosphine. [Re(NAr)[sub 3]][sup [minus]] ion can be alkylated to give RE(NAr)[sub 3]R and protonated to give RE(NAr)[sub 3]H. Reactions of Re(NAr)[sub 3]H with [pi]-acceptor ligands yield Re(NAr)[sub 2] (NHAr) ([eta][sup 2]-L). Reduction of Re(NAr)[sub 2]Cl[sub 3] (py) with sodium amalgam in THF in the presence of NpC[triple bond]CNp (NP = neopentyl) yields Re(NAr)[sub 2]([eta][sup 2]-C[sub 2]R[sub 2])Cl. Reduction of Re(NAr)[sub 2]([eta][sup 2]-C[sub 2]Np[sub 2])Cl yields pentane-soluble Na(THF)[sub 2]Re (NAr)[sub 2]([eta][sup 2]-C[sub 2]Np[sub 2]). Re(NAr)Cl[sub 3](py)[sub 2] is reduced in refluxing THF to afford Re(NAr) ([eta][sup 2]-C[sub 2]Np[sub 2])[sub 2]Cl. Reduction of Re(NAr) ([eta][sup 2]-C[sub 2]Np[sub 2])[sub 2]Cl by one or two equivalents of sodium amalgam in THF yields Na(THF)[sub 2]Re(NAr)([eta][sup 2]-C[sub 2]Np[sub 2]). Cyclic voltammograms were obtained for the chloride derivatives and sodium salts of the tris, bis, and mono imido complexes in a solution of 0.5 M [NBu[sub 4]][PF[sub 6]] in THF. Reduction of Re[sub 2] (CO)[sub 10] in a mixture of ether and THF and subsequent acylation with aryl acid chlorides affords the compounds (OC)[sub 5]ReC(O)R [R = Ar', Ar[sup *]]. Reaction of these compounds with triflic anhydride in dichloromethane quantitatively affords [Re(CR)(CO)[sub 4]](OTf)[sub 2].

Research Organization:
Massachusetts Inst. of Tech., Cambridge, MA (United States)
OSTI ID:
7179338
Country of Publication:
United States
Language:
English