Palladium(II) ortho -cyano-aminothiophenolate (ocap) complexes.

A series of Pd(II) complexes containing ortho -cyano-aminothiophenolate (ocap) ligands have been prepared and their molecular structures elucidated. Hg(II) ocap complexes, [Hg{SC 6 H 3 XN(CN)}] n (X = H, Me) (1), react with Na 2 S to afford HgS and Na 2 [ocap] which reacts in situ with K 2 [PdCl 4 ] to afford palladium ocap complexes [Pd{SC 6 H 3 XN(CN)}] n (2). A second route to these coordination polymers has also been developed from reactions of 2-aminobenzothiazole (abt) complexes, trans -PdCl 2 (abt) 2 (3), with NaOH. We have not been able to crystallographically characterise coordination polymers 2, but addition of PPh 3 , a range of phosphines and cyclic diamines affords mono and binuclear complexes in which the ocap ligand adopts different coordination geometries. With PPh 3 , binuclear [Pd(μ-κ 2 ,κ 1 -ocap)(PPh 3 )] 2 (4) results, in which the ocap bridges the Pd 2 centre acting as an S,N-chelate to one metal centre and binding the second via coordination of the cyanide nitrogen. In contrast, with diphosphines, Ph 2 P(CH 2 ) n PPh 2 ( n = 1-4), mononuclear species predominate as shown in the molecular structures of Pd(κ 2 -ocap){κ 2 -Ph 2 P(CH 2 ) n PPh 2 } (5-7; n = 1-3). With 2,2'-bipy and 1,10-phen we propose that related monomeric chelates Pd(κ 2 -ocap)(κ 2 -bipy) (9) and Pd(κ 2 -ocap)(κ 2 -phen) (10) result but we have been unable to substantiate this crystallographically. Addition of HgCl 2 (phen) to 9a (generated in situ ) affords heterobimetallic Pd(κ 2 -phen)(μ-κ 2 ,κ 1 -ocap)HgCl 2 (κ 2 -phen) (11), in which Hg(II) is coordinated through the ring sulfur.