| Abstract
| - The nucleophilicity of the {Pt2S2} core in [{Ph2P(CH2)nPPh2}Pt(μ-S)2Pt{Ph2P(CH2)nPPh2}] (n = 3, dppp (1); n =2, dppe (2)) metalloligands toward the CH2Cl2 solvent has been thoroughly studied. Complex 1, which has beenobtained and characterized by X-ray diffraction, is structurally related to 2 and consists of dinuclear molecules witha hinged {Pt2S2} central ring. The reaction of 1 and 2 with CH2Cl2 has been followed by means of 31P, 1H, and13C NMR, electrospray ionization mass spectrometry, and X-ray data. Although both reactions proceed at differentrates, the first steps are common and lead to a mixture of the corresponding mononuclear complexes [Pt{Ph2P(CH2)nPPh2}(S2CH2)], n = 3 (7), 2 (8), and [Pt{Ph2P(CH2)nPPh2}Cl2], n = 3 (9), 2 (10). Theoretical calculationsgive support to the proposed pathway for the disintegration process of the {Pt2S2} ring. Only in the case of 1, thereaction proceeds further yielding [Pt2(dppp)2{μ-(SCH2SCH2S)-S,S‘}]Cl2 (11). To confirm the sequence of the reactionsleading from 1 and 2 to the final products 9 and 11 or 8 and 10, respectively, complexes 7, 8, and 11 have beensynthesized and structurally characterized. Additional experiments have allowed elucidation of the reaction mechanisminvolved from 7 to 11, and thus, the origin of the CH2 groups that participate in the expansion of the (SCH2S)2-ligand in 7 to afford the bridging (SCH2SCH2S)2- ligand in 11 has been established. The X-ray structure of 11 istotally unprecedented and consists of a hinged {(dppp)Pt(μ-S)2Pt(dppp)} core capped by a CH2SCH2 fragment.
- The reaction of [{Ph2P(CH2)nPPh2}Pt(μ-S)2Pt{Ph2P(CH2)nPPh2}] (n = 3, dppp; n = 2, dppe) metalloligands with CH2Cl2 proceeds at different rates and yields different products depending on the diphosphine nature. The first steps, which are common for both reactions and involve the disintegration of the {Pt2S2} core, lead to a mixture of the corresponding [Pt{Ph2P(CH2)nPPh2}(S2CH2)] and [Pt{Ph2P(CH2)nPPh2}Cl2], n = 2, 3, complexes. Then, only [Pt{Ph2P(CH2)3PPh2}(S2CH2)] is further attacked by CH2Cl2, thus affording the unprecedented [Pt2(dppp)2{μ-(SCH2SCH2S)-S,S‘}]Cl2 complex.
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