Novel oxazine, oxazoline and carboxamide cluster complexes were prepared when different nucleophilic oxygen species reacted with nitriles coordinated to the Lewis acidic [Re6Se8]2+ cluster core. Reaction of ICH2CH2O- (generated in situ) with [Re6Se8(PEt3)5(NCR)]A2 (1A2 (R = Me) and 2A2 (R = Ph) where A = BF4-), leads to the formation of [Re6Se8(PEt3)5(2-methyloxazoline)]2+ (32+) and [Re6Se8(PEt3)5(2-phenyloxazoline)]2+ (42+). Similarly, reaction of BrCH2CH2CH2O- with the same nitrile complexes, 1A2 and 2A2 (where A = BF4- or SbF6-) leads to the corresponding oxazine complexes, [Re6Se8(PEt3)5(2-methyloxazine)]2+ (52+) and [Re6Se8(PEt3)5(2-phenyloxazine)]2+ (62+). In addition, reaction of 2(BF4)2 with KOH leads to the formation of the carboxamide complex, [Re6Se8(PEt3)5(phenylcarboxamide)](BF4) (7(BF4)). The neutral oxazine and oxazoline ligands can be removed using either heat or UV irradiation; UV irradiation was found to be more efficient at ligand removal as indicated by the shorter reaction times. The relative coordination strength of the neutral N-donor ligands was determined by these reaction times. X-ray structure determinations of 5(BF4)2 and 7(BF4) are also reported.

Three organometallic rhenium-based clusters containing phenylacetylide ligands, [Re 6 Se 8 (PEt 3 ) 5 (C�C−Ph)]-(SbF 6 ) (1) and cis-and trans-[Re 6 Se 8 (PEt 3 ) 4 (C�C−Ph) 2 ] (2 and 3), were synthesized and fully characterized including singlecrystal X-ray diffraction analyses. Reactivity studies of 1 show that reaction with electrophilic reagents does not result in the formation of the vinylidene species as predicted; instead, elimination of the acetylide moiety is observed. Products isolated from these r e a c t i o n s , i n c l u d i n g t h e m e t h y l s u l f a t e c o m p l e x , [Re 6 Se 8 (PEt 3 ) 5 (OSO 3 Me)](SbF 6 ) (4), have been characterized along with those obtained from the [2 + 2] cycloadditions of 1 with tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane. The relative reactivities of the electrophilic agents utilized are compared. Preliminary computational studies reveal useful information about the nature of the [Re 6 Se 8 ] 2+ −acetylide bond and aid in our understanding of the reactivity associated with this cluster complex.