In chemistry, a transition metal boryl complex is a molecular species with a formally anionic boron center coordinated to a transition metal.[1] They have the formula LnM-BR2 or LnM-(BR2LB) (L = ligand, R = H, organic substituent, LB = Lewis base). One example is (C5Me5)Mn(CO)2(BH2PMe3) (Me = methyl).[2] Such compounds, especially those derived from catecholborane and the related pinacolborane, are intermediates in transition metal-catalyzed borylation reactions.
Structure of (PMe3)4RhB(pinacolate).[3] (color code: pink=B, blue green=Rh, red=O, orange=P).
Synthesis
Oxidative addition is the main route to metal boryl complexes. Both B-H and B-B bonds add to low-valent metal complexes. For example, catecholborane oxidatively adds to Pt(0) to give the boryl hydride.[4]
^Geoffrey J. Irvine; M. J. Gerald Lesley; Todd B. Marder; Nicholas C. Norman; Craig R. Rice; Edward G. Robins; Warren R. Roper; George R. Whittell; L. James Wright (1998). "Transition Metal−Boryl Compounds: Synthesis, Reactivity, and Structure". Chem. Rev. 98 (8): 2685–2722. doi:10.1021/cr9500085. PMID11848976.
^Staubitz, A.; Robertson, A. P. M.; Sloan, M. E.; Manners, I. (2010). "Amine− and Phosphine−Borane Adducts: New Interest in Old Molecules". Chem. Rev. 110 (7): 4023–4078. doi:10.1021/cr100105a. PMID20672859.
