METAL BETAINE INTERACTIONS .10. PREPARATION AND CRYSTAL-STRUCTURES OF BIS(TRIETHYL BETAINE)BIS(NITRATO)DISILVER(I) AND CATENA-BIS(TRIETHYL BETAINE)DISILVER(I) DIPERCHLORATE

Two silver(I) complexes of triethyl betaine (Et3N+CH2COO-, Et3BET) have been prepared and characterized by X-ray crystallography. Both complexes, [Ag2(Et3BET)2 (NO3)2] (1) and [Ag2(Et3BET)2]n(ClO4)2n (2), contain centrosymmetric bis-carboxylato-bridged Ag2(carboxylato-O,O')2 dimers (Ag-O = 2.16-2.23 angstrom). The dimeric unit in 1 is bound to a chelating nitrato group [Ag-O = 2.524(3), 2.619(3) angstrom] at each axial site, resulting in a discrete molecule. In 2 the dimers are extended into a stair-like cationic chain via the coordination of each metal centre by a carboxylato oxygen atom [Ag-O = 2.565(5) angstrom] from an adjacent unit. The intra-dimer Ag...Ag distance is 2.928(1) angstrom for 1 and 2.856(2) angstrom for 2.