Cyclometalation of 2-p-tolylbenzthiazole and 2-p-tolylbenzoxazole with palladium(II) acetate. Synthesis and crystal structures of the acetate-bridged dimers (MeC6H3C7H4NS)Pd2(.mu.-O2CMe)2 and (MeC6H3C7H4NO)Pd2(.mu.-O2CMe)2

The reaction of palladium(II) acetate with 2-arylbenzthiazoles or 2-arylbenzoxazoles leads to dimeric cyclometalated products. The 2-p-tolyl derivatives (MeC6H3C7H4NS)Pd2(μ-O2CMe)2 (1) and (MeC6H3C7H4NO)Pd2(μ-O2CMe)2 (2) have each been characterized via an X-ray diffraction study. These complexes are isomorphous and crystallize in the centrosymmetric monoclinic space group P21/n with Z = 4. Unit cell parameters are as follows: 1, a = 9.980 (2) Å, b = 22.802 (6) Å, c = 13.438 (3) Å, β = 104.46 (2)°, V= 2961.3 (11) Å3, p(calcd) = 1.75 g cm-3 for mol wt 778.8; 2, a = 9.908 (1) Å, b = 22.387 (4) Å, c = 13.350 (2) Å, β = 104.53 (1)°, V= 2866.5 (7) Å3, p(calcd) = 1.73 g cm-3 for mol wt 747.7. Diffraction data (Mo Kα) were collected with a Syntex P21, automated diffractometer, and the structures were solved by conventional Patterson, Fourier, and full-matrix least-squares refinement techniques. The resulting discrepancy indices are as follows: 1, Rf = 4.0% and = 4.1% for all 3876 reflections 2θ(max) = 45°; 2, RF = 4.6% and RwF = 4.1% for all 2687 independent reflections 2θ(max) = 40° two forms averaged. In each molecule the palladium(II) ion is bonded to a nitrogen atom of the thiazole or oxazole ring (rather than sulfur in I or oxygen in 2) and to an ortho carbon atom of the p-tolyl group. In addition, the resulting (MeC6H3C7H4NX)Pd systems (X = S (1) or O (2)) are linked together by two mutually cis acetate bridges to form dimeric (MeC6H3C7H4NX)Pd2(μ-O2CMe)2 molecules.