Abstract
The synthesis and characterization of rare 1,3-diphosphacyclobutene transition-metal complexes is described. Reactions of the cobalt-hydride complex [Co(P(2)C(2)tBu(2))(2)H] (G) with nBuLi, tBuLi, or PhLi afforded [Li(solv)(x){Co(eta(3)-P(2)C(2)tBu(2)HR)(eta(4)-P(2)C(2)tBu(2))}] (1: R=nBu, (solv)(x)=(Et2O)(2); 2: R=tBu, (solv)(x)=(thf)(2); 3: R=Ph, (solv)(x)=(Et2O)(thf)(2)), with an ...
Abstract
The synthesis and characterization of rare 1,3-diphosphacyclobutene transition-metal complexes is described. Reactions of the cobalt-hydride complex [Co(P(2)C(2)tBu(2))(2)H] (G) with nBuLi, tBuLi, or PhLi afforded [Li(solv)(x){Co(eta(3)-P(2)C(2)tBu(2)HR)(eta(4)-P(2)C(2)tBu(2))}] (1: R=nBu, (solv)(x)=(Et2O)(2); 2: R=tBu, (solv)(x)=(thf)(2); 3: R=Ph, (solv)(x)=(Et2O)(thf)(2)), with an eta(3)-coordinated 1,3-diphosphacyclobutene ligand as a result of organyl-anion attack at one of the phosphorus atoms of the bis(1,3-diphosphacyclobutadiene) backbone. In contrast to the reactions with PhLi, the aryl-magnesium compounds p-tolyl magnesium chloride and p-fluorophenyl magnesium bromide deprotonate [Co(P(2)C(2)tBu(2))(2)H] to give the magnesium salt [Mg(MeCN)(6)][Co(eta(4)-P(2)C(2)tBu(2))(2)](2) (4), which contains a bis(1,3-diphosphacyclobutadiene)-cobaltate anion. The [Co(eta(4)-P(2)C(2)tBu(2))(2)](-) anions are well separated from the octahedral [Mg(MeCN)(6)](2+) cation in the molecular structure of 4. Compound 1 reacts with Me3SiCl to give neutral [Co(eta(3)-P(2)C(2)tBu(2)HnBu)(eta(4)-P(2)C(2)tBu(2)SiMe(3))] (5, 52 % yield) with an SiMe3 group attached to one of the P atoms of the previously unfunctionalized backbone.
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