Rödl C, Schwedtmann K, Weigand JJ, Wolf R. 1,3-Diphosphacyclobutene Cobalt Complexes.
Chemistry 2019;
25:6180-6188. [PMID:
30840328 DOI:
10.1002/chem.201900170]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/05/2019] [Indexed: 11/10/2022]
Abstract
The synthesis and characterization of rare 1,3-diphosphacyclobutene transition-metal complexes is described. Reactions of the cobalt-hydride complex [Co(P2 C2 tBu2 )2 H] (G) with nBuLi, tBuLi, or PhLi afforded [Li(solv)x {Co(η3 -P2 C2 tBu2 HR)(η4 -P2 C2 tBu2 )}] (1: R=nBu, (solv)x =(Et2 O)2 ; 2: R=tBu, (solv)x =(thf)2 ; 3: R=Ph, (solv)x =(Et2 O)(thf)2 ), with an η3 -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(P2 C2 tBu2 )2 H] to give the magnesium salt [Mg(MeCN)6 ][Co(η4 -P2 C2 tBu2 )2 ]2 (4), which contains a bis(1,3-diphosphacyclobutadiene)-cobaltate anion. The [Co(η4 -P2 C2 tBu2 )2 ]- anions are well separated from the octahedral [Mg(MeCN)6 ]2+ cation in the molecular structure of 4. Compound 1 reacts with Me3 SiCl to give neutral [Co(η3 -P2 C2 tBu2 HnBu)(η4 -P2 C2 tBu2 SiMe3 )] (5, 52 % yield) with an SiMe3 group attached to one of the P atoms of the previously unfunctionalized backbone.
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