(eta~5-C_5Me_5)Fe(CO)_2(BOCH_2CH_2CH_20):an organoiron complex containing the(trimethyleneglycolato)boryl ligand

摘要

The structure of the pentamethylcyclopentadienyliron boryl complex(eta~5-C_5Me_5)Fe(CO)_2B(tmg)(tmg = trimethylene glycolato,-OCH_2CH_2Ct_2O-),reveals a planar three-coordinate boryl ligand and an Fe-B distance significantly in excess of that reported for related catecholboryl complexes.The title complex,(eta~5-C_5Me_5)Fe(CO)_2B(tmg)(I;Fig.1),represents only the second reported example of a complex containing the B(tmg)ligand.Of interest are(i)the near orthogonal alignment of BO_2 and centroid(eta~5-C_5Me_5)-Fe-B planes(Zcentroid-Fe-B-O_3 = 92.9(4)deg)presumably adopted on steric grounds and(ii)the Fe-B distance(2.024(4)A),which is essentially identical to that found in the related dinuclear complex(eta~5-C_5H_5)Fe(CO)_2BO_2C_5H_8O_2BFe(CO)_2(eta~5-C_5H_5)(2.030(5)A),but significantly greater than that found in the corresponding catecholboryl complex(eta~5-C_5Me_5)Fe(CO)_2BO_2C_6H_4(1.980(2)A).This observation is consistent with weaker pi acceptor properties for alkoxoboryl ligands compared with aryloxo analogues,as reported previously.