| Abstract
| - The phosphinothioylidene-bridged complex Cp2Cr2(CO)5(SPC6H4OCH3) (3) under thermolysis or in reactions with sulfur or Lawesson's reagent (2) yielded the P−P-bonded complex (CpCr(CO)2(SPC6H4OCH3))2 (cis-7) and its isomer trans-7; each of the two isomers is found to interconvert at elevated temperatures to give an equilibrium mixture of 4 (cis):1 (trans); both isomers react with [CpCr(CO)3]2 (1) to re-form 3.
- At ambient temperature the reaction of [CpCr(CO)3]2 (1; Cp = η5-C5H5) with 1 mol equivof Lawesson's reagent, Ar2P2S4 (2; Ar = C6H4OCH3), for 3 h led to the isolation of browncrystals of Cp2Cr2(CO)5(SPAr) (3), dark red solids of Cp2Cr2(CO)5(S2PAr) (4), deep blue solidsof Cp2Cr2(S2P(O)Ar)2 (5), greenish yellow solids of CpCr(CO)3H (9), and deep green crystalsof Cp2Cr2(CO)4S (10) with yields of 5, 11, 20, 7, and 8%, respectively; a similar reaction at90 °C for 2 h gave 5 (36%), CpCr(CO)2(SP(H)Ar) (6) as red crystals (9%), [CpCr(CO)2(SPAr)]2(cis-7) as dark brown crystalline solids (14%), and its isomer trans-7 as dark red crystals(5%), together with 9 (4%) and 10 (11%). The ambient-temperature reaction of [Cp*Cr(CO)3]2(1*; Cp* = η5-C5Me5) yielded the Cp* analogues of 4, 5, 9, and 10, i.e., 4*, 5*, 9*, and 10*with yields of 51, 17, 6, and 8%, respectively. The thermolysis of Cp*2Cr2(CO)5(S2PAr) (4*)resulted in the isolation of Cp*Cr(CO)2(SP(H)Ar) (6*), Cp*2Cr2(CO)4(SPAr) (8*), and Cp*2Cr2(S2P(O)Ar)2 (5*) with yields of 7, 14, and 13%, respectively. A NMR spectral studydemonstrated that thermolytic degradation of complex 3 or its reaction with sulfur orLawesson's reagent (2) led to the formation of cis-7; cis- and trans-7 were found to interconvertunder elevated temperatures, giving 4:1 equilibrium mixtures at 80 °C; both isomers reactwith 1 to re-form 3. The solid-state structures of all the above-mentioned complexes havebeen characterized by single-crystal X-ray diffraction analysis. Complexes 3 and 8* containthe phosphinothioylidene ligand in different coordination modes. The analogous structuresof complexes 4/4* reveal a bridging dithiophosphorane ligand, being η2(S,S‘) coordinated toa Cp/Cp*Cr(CO)2 moiety and η1(P) coordinated to a Cp/Cp*Cr(CO)3 moiety. The similarmolecular structures of 5 and 5* contain an eight-membered ring, comprising two CpCr/Cp*Cr units and two [S2P(O)Ar] moieties. Complexes 6/6* contain a rare η2-arylthioxophosphane ligand. The complexes cis- and trans-7 are conformers of a P−P-bonded dimer.
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