PREPARATION AND STRUCTURAL CHARACTERIZATION OF RH-2(O(2)CCPH(3))(4)(ETOH)(2), RU-2(O(2)CCPH(3))(4)(H2O)(ETOH)CENTER-DOT-2ETOH AND MO-2(O(2)CCPH(3))(4)CENTER-DOT-3CH(2)CL(2)

Triphenylacetic acid and its sodium salt were used in the preparation of three dimetal tetracarboxylates. The reaction of RhCl3 with NaO(2)CCPh(3) in ethanol gives Rh-2(O(2)CCPh(3))(4)(EtOH)(2) (1). The exchange reaction of Mo-2(O2CCH3)(4) With NaO(2)CCPh(3) in dichloromethane yields Mo-2(O(2)CCPh(3))(4).3CH(2)Cl(2) (2). The reaction of Ru-2[l-O2CCH(OH)Ph](4)(H2O)(2) with HO(2)CCPh(3) in ethanol results in Ru-2(O(2)CCPh(3))(4)(H2O)(EtOH).2EtOH (3). The structures of these compounds were determined by single crystal X-ray crystallography. The crystallographic data for 1 are as follows: tetragonal, space group I ($) over bar 4 with unit cell dimensions a = b = 18.340(2), c = 10.646(1) Angstrom, V = 3581.1(6) Angstrom(3), Z = 2. The structure was refined to R = 0.053 (R(w) = 0.059) with 1431 reflections having I>3 sigma(I). The Rh-Rb distance is 2.365(1) Angstrom, Rh-O(1) = 1.967(6) Angstrom, Rh-O(2) = 2.047(6) Angstrom, Rh-O(axial) = 2.31(2) Angstrom. The pertinent crystallographic data for 2 are as follows: tetragonal, space group P4/ncc with unit cell dimensions a = b = 20.930(4), c = 17.404(4) Angstrom, V = 7624(5) Angstrom 3, Z = 4. The structure was refined to R = 0.048 (R(w) = 0.064) with 1269 reflections having I>3 sigma(I). The Mo-Mo distance is 2.076(1) Angstrom, Mo-O(1) = 2.098(5) Angstrom, Mo-O(2) = 2.095(6) Angstrom. The crystallographic data for 3 are as follows: monoclinic, space group C2/c with unit cell dimensions a = 19.872(7), b = 16.985(6), c = 23.36(1) Angstrom, beta = 94.24(3)degrees, V = 7864(5) Angstrom(3), 2 = 4. The structure was refined to R = 0.063 (R(w) = 0.094) with 2893 reflections having I > 3 sigma(1). The Ru-Ru distance is 2.252(2) Angstrom; the Ru-O distances are 2.079(7), 2.061(8), 2.073(7) and 2.064(7) Angstrom; the Ru-O(axial) distances are both 2.35(1) Angstrom. The Mo atoms of 2 do not experience any axial interactions, and there is a resulting decrease of 0.016 Angstrom in the Mo-Mo quadruple bond distance compared to Mo-2(O(2)CR)(4) molecules having axial coordination.