2 NOVEL COMPLEXES OF GLUTARIMIDE WITH PALLADIUM(II) TRANS-K-2[PD(C5H6NO2)(2)CL-2]CENTER-DOT-4.5H(2)O AND TRANS-KNA[PD(C5H6NO2)(2)CL-2]CENTER-DOT-6H(2)O - CRYSTAL-STRUCTURES AND VIBRATIONAL-SPECTRA

Two novel complexes of glutarimide anion with Pd(II) have been prepare d and their structures determined by single crystal X-ray diffraction and vibrational (IR and Raman) spectroscopic investigations. These are the first synthesized and structurally characterized Pd(II) complexes with glutarimide. Both trans-K-2[Pd(C5H6NO2)(2)Cl-2]. 4.5H(2)O (i) an d trans-KNa[Pd(C5H6NO2)(2)Cl-2]. 6H(2)O (2) belong to the monoclinic s pace group P2(1)/c and have four formula units in the unit cell. The c ell dimensions for 1: a = 17.438(3), b = 16.225(3), c = 7.932(2) Angst rom, beta = 117.03(3)degrees; for 2: a = 8.098(2), b = 16.447(3), c = 16.031(3) Angstrom, beta = 101.65(3)degrees. The structures were solve d by heavy atom methods, and refined to R = 0.034 for 2715 reflections (1) and R = 0.037 for 3384 reflections (2). In 1 there are two crysta llographically independent molecules in the unit cell. Palladium atoms are located at the inversion centers. Two glutarimide ligands are coo rdinated with Pd via the deprotonated ring nitrogen. The two chloride and two nitrogen atoms form a trans square-planar environment around t he palladium atom and the Cl-Pd-Cl and N-Pd-N bonds are linear. The co ordination geometry of 2 is very similar to that of 1, but there is on e molecule in the asymmetric unit and the N-Pd-N bond in 2 shows a sma ll deviation from linearity (175.4(2)degrees). The potassium cation fo rms an additional bridge between the carbonyl groups of the two ligand s. Crystals of both the 1 and 2 complexes are held together by an exte nsive hydrogen bonding network involving the carbonyl groups of glutar imides, water molecules and chloride ions. Assignment of the metal-lig and and other vibrations in the IR and Raman spectra has provided furt her evidence for the nature of the bonding in these compounds. The N-P d-N antisymmetric and symmetric stretching vibrations in Pd(II) comple xes with the N-deprotonated glutarimide molecules have been assigned t o the bands at 543 (IR) and 478 (Raman) cm(-1), respectively. The Pd(g lutarimidato)(2) unit reveals a remarkable similarity in its structura l and electronic features to Pd(II) and Pt(II) complexes with pyrimidi ne bases, which suggests that the biological activity of glutarimide d erivatives may be related to their resemblance to pyrimidine bases.