An unconventional route to [(Me3Si)2HCPCl2W(CO)5] and its conversion to the structurally characterized P-chalcogenides (Me3Si) 2HCP(X)Cl2[X = S, Se]

Heating a solution of 2H-azaphosphirene complex 1 in CCl4 at 75 °C for 2 h yields selectively [(Me3Si)2HCPCl2W(CO)5](6). Attempts to convert this cleanly to the corresponding P-oxide [(Me3Si)2HCP(O)Cl2](7) were unsuccessful and even the reaction of (Me3Si) 2HCPCl2(9) with the urea-H2O2 adduct in toluene led only to the formation of the hydrolysis product [(Me3Si)2HCP(O)(OH)Cl](8). However, 9 could be selectively converted to 7 by the use of DMSO. In contrast, the related chalcogenides [(Me3Si)2HCP(S)Cl2](10) and [(Me3Si)2HCP(Se)Cl2](11) could be synthesized from either 6 or 9 with elemental sulfur and selenium, respectively. All products were characterized by NMR and MS and, additionally 6, 8, 10 and 11 by single crystal X-ray studies. Compound 10 represents the first example of a structurally characterized thiophosphonic dihalide.