Studies on selenocyanatocarbonyl complexes. The synthesis and characterization of selenocyanato-Se and -N linkage isomers of C 5H 5Fe(CO)[P(C 6H 5) 3l(SeCN)

Abstract

The reaction of C 5H 5Fe(CO)[P(C 6H 5) 3]CH 2C 6H 5 with Se(SeCN) 2 yields the selenocyanato linkage isomers C 5H 5Fe(CO)[P(C 6H 5) 3]SeCN and C 5H 5Fe(CO)[P(C 6H 5) 3]NCSe. Both compounds are stable with respect to interconversion at room temperature; at higher temperatures, deselenation to C 5H 5Fe(CO)[P(C 6H 5) 3]CN takes place in preference to isomerization. This reaction is slow with the Se-bonded isomer and much faster with the N-bonded isomer, which also deselenates rapidly at 27° in the presence of triphenyl-phosphine. The interaction between C 5H 5Fe(CO) 2SeCN and PR 3(R = C 6H 5 or C 6H 11) at room temperature yields almost exclusively the ionic [C 5H 5Fe(CO) 2−(PR 3)] +SeCN −; C 5H 5Fe(CO) 2[P(C 6H 5) 3] +SeCN − affords the Se-bonded C 5H 5Fe(CO)[P(C 6H 5) 3]SeCN in refluxing benzene, but a similar thermal treatment of C 5H 5Fe(CO) 2[P(C 6H 11) 3] +SeCN − gives several products. Triphenyl phosphite does not react with C 5H 5Fe(CO) 2SeCN at room temperature; under reflux conditions in benzene it yields only the selecyanato-Se-monocarbonyl C 5H 5Fe(CO)[P(OC 6H 5) 3]SeCN.