SYNTHESIS AND CHARACTERIZATION OF CYCLOMETALATED COMPLEXES OF PALLADIUM(II) AND MANGANESE(I) WITH BIDENTATE SCHIFF-BASES

Treatment of N,N-isophthalylidenebis(cyclohexylamine) 1,3-(CyN=CH)(2)C 6H4(L(2)) (Cy = cyclohexyl) with palladium(II) acetate in glacial acet ic acid gave after column chromatography the monocyclometallated dimer complex [{Pd[3-(CHO)C6H3C(H)=NCy][O(2)CMe)}(2)] (1) with a free formy l group on each phenyl ring, and a mixture of 1 with the doubly cyclom etallated complex [Pd(3-(CyN=CH)C6H3C(H)=NCy)(O(2)CMe)] (2). Treatment of 1 with cyclohexylamine gave the corresponding dimer complex [{Pd[3 -(CyN=CH)C6H3C(H)=NCy](O(2)CMe)}(2)] (17) with an uncoordinated C=N gr oup on each phenyl ring. Treatment of 1 and 2 with aqueous NaX gave th e dimer complexes [{Pd[3-(CHO)C6H3C(H)=NCy]{(X)}(2)] (3: X = Cl; 4: X = Br; 5: X = I) and a mixture of 3, 4 or 5 with the doubly cyclometall ated complex [Pd[3-(CyN=CH)C6H3O(H)=NCy](X)] (6: X = Cl; 7: X = Br; 8: X = I), respectively. The dicydometallated iodo complex 8 was isolate d pure. Treatment of 3, 4 or 5 with cyclohexylamine in a 1:2 or 1:4 mo lar ratio gave the cyclometallated complexes [Pd[3-(CHO)C6H3C(H)=NCy]( X)(NH(2)Cy)] (9: X = Cl; 10: X = Br; 11: x = I) and [Pd[3-(CyN=CH)C6H3 O(H)=NCy](X)(NH(2)Cy)] (12: X = Cl; 13: X = Br; 14: X = I), respective ly; the last three compounds 6 each contain an uncoordinated C=N group . The corresponding bromo and iodo analogues were made similarly. Trea tment of 3, 4 or 5 with thallium cyclopentadienyl or thallium acetylac etonate gave the mononuclear complexes [Pd[3-(CHO)C6H3C(H)=NCy)(C5H5)] (15) and [Pd{3-(CHO)C6H3C(H)=NCy)(H3CCOCHCOCH3)] (16), respectively. Treatment of L(2) with MnMe(CO)(5) in a 1.1 molar ratio gave the monoc yclometallated complex [(OC)(4)Mn{3-(CHO)C6H3C(H)=NCy}] (18) by cleava ge of one C=N bond, whereas treatment of L(2) with MnMe(CO)(5) in a 1: 1.2 molar ratio produced a mixture of the doubly cyclometallated compl ex 19 and the monocyclometallated complex 20 without cleavage of the C =N bond. Treatment of N,N-terephthalylidenebis(cyclohexylamine), 1,4-( CyN=CH)(2)C6H4(L(1)) (Cy = cyclohexyl), with MnMe(CO)(5) in a 1:1.2 mo lar ratio gave a mixture of the monocyclometallated compound [(OC)(4)M n{4-(CHO)C6H3C(H)=NCy}] (22) and the monocyclometallated compound [(OC )(4)Mn{4-(CyN=CH)C6H3C(H)=NCy}] (23); compound 22 was isolated in a pu re state.