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4), respectively. The alkoxides 1-4 have fluxional structures at room temperature in solution on the 17 O NMR time scale. The trigonal bipyramidal structure of 2, in the crystal, is static in solution only at -90°C. The protic hydrogen of 3 can be abstracted by lithium 2,2,6,6-tetramethylpiperidinate to give the ionic complex Li[ReO 3 (OCMe 2 CMe 2 O)] (5). [ReO 3 (OMe)(MeOH)] 2 (1) crystallizes from dichloromethane in the space group P1 h with unit cell dimensions a ) 6.276(3) Å, b ) 6.720(3) Å, c ) 8.005(4) Å, R ) 109.39(3)°, ) 99.48(3)°, γ ) 110.31(2)°, V ) 238.3 Å 3 , and Z ) 1; the structure was refined to R ) 0.050 and R w ) 0.056. ReO 3 (OCMe 2 -CMe 2 OMe) (2) crystallizes from toluene in the space group Pbca with unit cell dimensions a ) 8.263(2) Å, b ) 10.884(3) Å, c ) 22.963(5) Å, V ) 2065 Å 3 , and Z ) 8; the structure was refined to R ) 0.044 and R w ) 0.028. ReO 3 (OCMe 2 CMe 2 OH) (3) crystallizes from dichloromethane in the space group C2/c with unit cell dimensions a ) 12.327(5) Å, b ) 10.973(3) Å, c ) 14.491(6) Å, ) 90.22(2)°, V ) 1960 Å 3 , and Z ) 8; the structure was refined to R ) 0.047 and R w ) 0.030. (Me 3 SiO)ReO 2 (OCMe 2 CMe 2 O) (4) crystallizes from n-pentane in the space group P2 1 /c with unit cell dimensions a ) 12.042(8) Å, b ) 10.782(2) Å, c ) 12.485(9) Å, ) 117.44-(3)°, V ) 1439 Å 3 , and Z ) 4; the structure was refined to R ) 0.044 and R w ) 0.044. The edge-sharing bioctahedral complex 1 has bridging methoxy and terminal methanol ligands trans to rhenium-oxygen double bonds. The rhenium centers in compounds 2 and 3 are pentacoordinated and located in a distorted trigonal bipyramidal geometry. The alkoxy function of the alkoxy ligand -OCMe 2 CMe 2 OR (R ) H, Me) is located in the equatorial plane, and the Lewis base (-OMe, -OH) is bonded trans to an oxygen atom in an axial coordination site. (Me 3 SiO)ReO 2 (OCMe 2 CMe 2 O) (4) has a similar geometry to 2 and 3 with a trimethylsiloxy ligand trans to an alkoxy function in an axial position.While hardly anything is known about the amides of type C, 4,6 the alkoxides of type D have sporadically appeared in the literature. 7,8 They have been proposed as intermediates in specific organic functional group transformations. 7 To date, only a few compounds of general composition ROReO 3 and † Alexander von Humboldt Foundation Fellow, 1993/94. Current address: ACS Inc., 510 Alder Drive, Milpitas, CA 95035.

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So<. C/IIWI ( '~i t i i m~t i .1992. 789-791. Some phosphate coordination may also hc pre\ciit chiirges on the iiucleotides are ignored in the formulae. Beriiei \-Price. U. Frey, J. D, Ranford. P. J. Sadler, J. Am. Chem SOIC 1993, Xh4Y 8650: 0 = 4 3 -66.4 N /run.\ to CI: c) = 4.09;-69.1 N Iron., to V H , . [I?] S _I Bcrncr\-PI-ice. J. D Ranford. P J. Sadler. / i i~g . Cileiii. 1994. 33. 5842-SXJh [13J The q q m~p i i a i t differential equations were integrated numerically and rate coiistiinth determined by ii iion-linear optimization procedure The errors quotcd repre\eiit one standard deviation. To simplify the kinetic treatment, it was c i \~~i i i e d t h i i t each mmofunctioiial intermediate (3 or 4) gives rise to tlie liame products (5 and 6 ) . To achieve a good fit for complex 2, it was necessary to ;i>\timc that ,I im;ill excess (lo?/,) of strand I over 1 was present in the reaction a o l t i t i~~i i . ahout 20'% of I appeared to he unreacted at equilibrium. We \\ere ;iblc to cxcludc ii model in which each intermediate gives rise to only onc product (c g.. 3 gives 5. and 4 gives 6) since this did tiot fit the data A more clahol-:itc kinetic analysis wII require a more detailed assessment of the errors in iiiciiliurctnenl of concentrations from peak intensities (problems of overlap i t i i d nearne\\ t o the solvent peak) and identification of unknown product,. 1141 S t. Millcr. D A. House. IiiorR. Chi/??. Acru 1989. 161. 131 -137 1151 B! mixing I :itid 11 in an eqiiimolar ratio (1.5m.v: l O m i phosphate buffer.

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