Preparation and structural characterization of Rh 2(O 2CCPh 3) 4(EtOH) 2, Ru 2(O 2CCPh 3) 4(H 2O)(EtOH)·2EtOH and Mo 2(O 2CCPh 3) 4·3CH 2Cl 2

Abstract

Triphenylacetic acid and its sodium salt were used in the preparation of three dimetal tetracarboxylates. The reaction of RhCl 3 with NaO 2CCPh 3 in ethanol gives Rh 2(O 2CCPh 3) 4(EtOH) 2 ( 1). The exchange reaction of Mo 2(O 2CCH 3) 4 with NaO 2CCPh 3 in dichloromethane yields Mo 2(O 2CCPh 3) 4·3CH 2Cl 2 ( 2). The reaction of Ru 2[ l-O 2CCH(OH)Ph] 4(H 2O) 2 with HO 2CCPh 3 in ethanol results in Ru 2(O 2CCPh 3) 4(H 2O)(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 I4 with unit cell dimensions a= b=18.340(2), c=10.646(1) Å, V=3581.1(6) Å 3, Z=2. The structure was refined to R=0.053 ( R w=0.059) with 1431 reflections having I>3σ( I). The RhRh distance is 2.365(1) Å, RhO(1)=1.967(6) Å, RhO(2)=2.047(6) Å, RhO(axial)=2.31(2) Å. 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) Å, V=7624(5) Å 3, Z=4. The structure was refined to R=0.048 ( R w=0.064) with 1269 reflections having I>3σ( I). The MoMo distance is 2.076(1) Å, MoO(1)=2.098(5) Å, MoO(2)=2.095(6) Å. 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) Å, β=94.24(3)°, V=7864(5) Å 3, Z=4. The structure was refined to R=0.063 ( R w=0.094) with 2893 reflections having I>3σ( I). The RuRu distance is 2.252(2) Å; the RuO distances are 2.079(7), 2.061(8), 2.073(7) and 2.064(7) Å; the RuO(axial) distances are both 2.35(1) Å. The Mo atoms of 2 do not experience any axial interactions, and there is a resulting decrease of 0.016 Å in the MoMo quadruple bond distance compared to Mo 2(O 2CR) 4 molecules having axial coordination.