Preparations, Properties, and Crystal Structures of trans-[Rh(CN)2(NH3)4]Cl·H2O and trans-[Rh(CN)2(en)2]Cl

Abstract

Abstract Syntheses of the title new complex compounds of Rh(III) were successful. Single, sharp IR peaks of ν (C≡N) were observed at 2130 cm−1 (trans-[Rh(CH)2(NH3)4]Cl·H2O) and 2170 cm−1 (trans-[RH(CN)2(en)2]Cl), respectively. The values of the ligand field tetragonal parameter Dt were estimated to be −366 and −377 cm−1, respectively, based on the 1Ega (D4h)←1A1g Aig transition (37100 cm−1: trans-[Rh(CN)2(NH3)4]+; 37000 cm−1: trans-[Rh(CN)2(en)2]+). The X-ray crystal data are: for trans-[Rh(CN)2(NH3)4]Cl·H2O, orthorhombic, Cmcm, a=7.961(3), b=17.295(2), c=7.436(3) Å, Dc=1.79, Dm=1.79 g cm−3, Z=4; for trans-[Rh(CN)2(en)2]Cl, monoclinic, P21⁄n, a=9.665(4), b=9.107(3), c=6.779(3) Å, β=109.68(2)°, Dc=1.85, Dm=1.83 g cm−3, Z=2. The N≡C–Rh–C≡N sequence of trans[Rh(CN)2(NH3)4]+ lies in a line of m2m Symmetry in the crystal. The central Rh atom of trans-[Rh(CN)2(en)2]+ occupies the special position of inversion symmetry. The important geometrical data of the complexes are Rh–N=2.07(1), Rh–C=2.02(3) Å, N–Rh–N=88.0(5)° (trans-[Rh(CN)2(NH3)4]+) and Rh–N=2.080(3), 2.072(3), Rh–C=2.047(4) Å, N–Rh–N (within chelate ring)=82.7(1)° (trans-[Rh(CN)2(en)2]+).