The X-ray crystal structure and reactivity of trans-[RuCl2(P(OC2H5)(3))(4)]

The X-ray structure of trans-[RuCl2(P(OC2H5)(3))(4)] indicates that the mol ecule has the C-2 symmetry with the Ru(II) and the two Cl ions lying on the two-fold axis. The E-Ru(III)/Ru(II)(O) in the trans-[RuCl2(P(OC2H5)(3))(4) ] complex is 0.61+/-0.01 vs. SCE, (mu=0.10 M NaCF3COO/CF3COOH, ethanol/wate r 2:1, 25 degrees C, C-H(+)=1.0X10(-2) M). In the same experimental conditi ons the electronic spectrum of this complex exhibit two bands: 254 nm (epsi lon congruent to 6.7X10(3) M-1 cm(-1)) and 410 nm (epsilon=8X10 M-1 cm(-1)) and a shoulder at 290 nm (epsilon congruent to 6X10(2) M-1 cm(-1)). Only o ne signal (128 ppm) is observed in the P-31 NMR spectrum of trans-[RuCl2(P( OC2H5)(3))(4)] in ethanol (130 ppm) or ethanol/water buffered solutions at pH = 7.0 (128 ppm), In ethanol or ethanol/water buffered solutions, the com plex trans-[RuCl2(P(OC2H5)(3)](4), exhibits dissociation of two chloride li gands (k(-Cl)=(3.2+/-0.2)X10(-5) s(-1); 25 degrees C, mu=0.10 (NaCF3COO), y ielding as a product the [Ru(P(OC2H5)(3))(4)S-2](2+) ion in which the two a xial positions are occupied by solvent molecules (S). In the presence of ac id, the final product is the cis-[Ru(P(OC2H5)(3))(2)S-4](2+) ion. (C) 1999 Elsevier Science Ltd. All rights reserved.