New inorganic metallacycles and the first six-membered covalent "true" heterocycle - oxidation of RC(E)NHPPh₂ (E = O or S; R = H₂N, Ph or Py) with O, S, or Se to give RC(E)NHP(E')Ph₂ (E' = O, S, Se) and their coordination chemistry

Direct oxidation of PhC(O)NHPPh2, H2NC(S)NHPPh2, (CSH4N)C(S)NHPPh2 with O-2, S-8, or Se gives [PhC(O)NHP(O)Ph-2] (1), [H2NC(S)NHP(S)Ph-2] (2), [H2NC(O)NHP(S)Ph-2] (3), [PhC(O)NHP(S)Ph-2] (4), [(C5H4N)C(S)NHP(S)Ph-2] (5), and [H2NC(S)NHP(Se)Ph-2] (6). Deprotonation of 1, 2, 4-6 with potassium tert-butoxide gives K[PhC(O)NP(O)Ph-2] (7), K[H2NC(S)NP(S)Ph-2] (8), K[PhC(O)NP(S)Ph-2] (9), K[(C5H4N)C(S)NP(S)Ph-2] (10), and K[H2NC(S)NP(Se)Ph-2] (11). Reaction of 4 with KOBu and [Cu(Ph3P)(2)][NO3] gives [Cu(Ph3P)(PhC(O)NP(S)Ph-2)] (12) which is the first crystallographically characterised example of a non-ionic six-membered "true" heterocycle (i.e. a ring in which every heterocatom is different). 9 and 10 were treated with [PdCl2(COD)] to give [Pd{PhC(O)NP(S)Ph-2}(2)] (13) and [Pd{(C5H4N)C(O)NP(S)Ph-2}(2)] (14), respectively The anion of 8 coordinates to zinc forming [Zn{H2NC(S)NP(S)Ph-2}(2)] (15). Treatment of 2 or 8 with [PtCl2(COD)] gives [Pt{H2NC(S)NP(S)Ph-2}{H2NC(S)NHP(S)Ph-2}]Cl-+(-) (16) and [Pt{H2NC(S)NP(S)Ph-2}(2)] (17), respectively. The X-ray structures of 12, 15-17 are reported.