SYNTHESIS AND PROPERTIES OF DIAMINEPLATINUM(II) AND DIAMINEPLATINUM(IV) COMPLEXES INVOLVING CYCLOHEXYLIDENEMALONATE LIGAND

New diamineplatinum(II) complexes of cyclohexylidenemalonate (chm) lig and, A(2)Pt(OOC)(2)C=C(CH2)(4)CH2 (1, A(2)=ethylenediamine (en); 2, A( 2)=propylenediamine (pn); 3, A=NH3; 4, A=isopropylamine (ipa)) have be en prepared. Their oxidation with H2O2 has led to the corresponding di hydroxoplatinum(IV) complexes: cis, cis, trans-A(2)Pt((OOC)2C=C (CH2)( 4)CH2)(OH)(2) (5, A(2)=en; 6, A(2)=pn; 7, A=NH3; 8, A=ipa). The title complexes have been characterized by means of various spectroscopies a nd X-ray crystallography. 5 crystallizes in the monoclinic space group P2(1)/a (Z 4) with a=12.098(7) Angstrom, b=9.552(2) Angstrom, c 16.25 8(4) Angstrom, beta=98.03(5)degrees and V=1860(1) Angstrom.(3) The str ucture was refined to R=0.074. The local geometry around platinum atom is approximately octahedral with each hydroxide group in trans positi on. These platinum complexes are stable in aqueous solution. Pt(IV) co mplexes are readily reduced to the corresponding Pt(II) complexes by a scorbic acid.