LIGAND-EXCHANGE REACTIONS BETWEEN METAL(II) CHELATES OF DIFFERENT SULFUR AND SELENIUM-CONTAINING LIGANDS .10. EXCHANGE BEHAVIOR OF CHELATESOF 1,3-DITHIOLE-2-THIONE-4,5-DISELENOLATE (DSIT) AND 1,1-DICHALCOGENOLATES - X-RAY STRUCTURE OF BU(4)N[PD(DSIT)(ET(2)DSC)]

Copper, nickel and palladium bis-chelates of 1,3-dithiole-2-thione-4,5 -diselenolate (dsit) react with geminal dichalcogenolates (L) of these metals in acetone (M = Pd: acetonitrile) forming the mixed-ligand com plexes [M(dsit)L](n-) exclusively when n = 1 and L = Et(2)NCXY(-): X = Y = S (Et(2)dtc), X = S, Y = Se (Et(2)tsc), X = Y = Se (Et(2)dsc) or n = 2 and L = (CN)(2)C double bond CXY(2-): X = Y = S (i-mnt), X = S, Y = Se (i-mnts), X = S = Se (i-mns), which can be isolated as salts of suitable cations. EPR measurements on the copper, UV-Vis spectroscopy on the nickel, and C-13/Se-77 NMR measurements on the palladium compl exes are used for characterizing the complexes. The mixed-ligand compo und Bu(4)N[Pd(dsit)(Et(2)dsc)] crystallized orthorhombic, space group Fdd2 with 16 molecules in the unit cell; a = 36,585(4), b = 29,219(3), c = 12,0708(2) Angstrom.