Characteristic Features of the Synthesis of 2,1,3-Benzothiadiazole-Substituted 1,3-Iminophosphine and Platinum Complex of This Compound

Abstract

In an attempt to synthesize a new iminomethylphosphine, ^tBuC(Ph₂P)=N-Btd (Btd = 2,1,3-benzothiadiazole) by a three-step procedure including (1) NH₂-Btd + ^tBuC(=O)Cl → ^tBuC(=O)NH-Btd, (2) ^tBuC(=O)NH-Btd + SOCl₂ → ^tBuC(Cl)=N-Btd, and (3) ^tBuC(Cl)=N-Btd + Ph₂PSiMe₃ → ^tBuC(Ph₂P)=N-Btd, it was found that the second step is accompanied by the chlorination of the carbocycle in the benzothiadiazole moiety. The reaction of the imidoyl chloride ^tBuC(Cl)=N-(7-Cl-Btd) formed in this reaction with Ph₂PSiMe₃ gave 1,3-iminomethylphosphine ^tBuC(Ph₂P)=N-(7-Cl-Btd) (PC=N). The by-products formed in this step include 1,3-aminomethylphosphine oxide ^tBuC{Ph₂P(O)}NH-(7-Cl-Btd) (POCN) and (Ph₂PO_x)₂, resulting from partial oxidation and hydrolysis. The reactions of PC=N and POCN with [Pt(COD)Cl₂] (COD = 1.3-cyclooctadiene) were studied. In the case of PC=N, the reaction affords the [Pt(PC=N)₂Cl₂] complex. In the latter case, cleavage of the P–C bond in POCN takes place, and [PtCl₂(Ph₂POH)₂](POCN) and [Pt(CH₃CN){^tBuC-NH-(7-Cl-Btd)}Cl] are isolated from the reaction mixture. The structures of the new compounds were established by single-crystal X-ray diffraction (CCDC nos 2335150 (^tBuC(Cl)N-(7-Cl-Btd)), 2335152 (POCN·Et₂O), 2335149 (Ph₂PO_x)₂, 2335153 ([Pt(PC=N)₂Cl₂]), 2335154 ([PtCl₂(Ph₂POH)₂](POCN)), and 2335151 ([Pt(CH₃CN)(^tBuC-NH-(7-Cl-Bbtd))Cl]).