The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic "ate" complex [Fe(mes)3 ](-) (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)3 ](-) and the related complex [Fe(Bn)3 ](-) (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2 (TMEDA)] complexes. Fe(I) species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X-ray structures of [Fe(Bn)3 ](-) and [Fe(Bn)4 ](-) were determined; [Fe(Bn)4 ](-) is the first homoleptic σ-hydrocarbyl Fe(III) complex that has been structurally characterized.

A series of platinum(II) boryl complexes of general formula trans-[(Cy(3)P)2Pt(Br)(BX2)], including the rare dibromoboryl species trans-[(Cy(3)P)2Pt(Br)(BBr2)], were synthesized by oxidative addition of the B-Br bond of a number of bromoboranes to [Pt(PCy3)2]. X-ray diffraction studies were performed on several such compounds. Comparison of the Pt--Br bond lengths allowed an empirical assessment of the trans-influence of different boryl ligands. A trans-influence scale was thus deduced and the results were compared with those previously computed for compounds of the type trans-[(Me(3)P)2Pt(Cl)(BX2)].

Activation of B2pin2 with tBuLi facilitates the Fe-catalyzed borylation of alkyl, allyl, benzyl, and aryl halides via the formation of Li[B2pin2(tBu)] (1). The reaction of 1 with a representative iron phosphine precatalyst generates the unique iron(I) boryl complex [Fe(Bpin)(dpbz)2] (2).

While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates.

Syntheses of the first heteroleptic N-heterocyclic carbene (NHC)-phosphane platinum(0) complexes and formation of the corresponding Lewis acid-base adducts with aluminum chloride is reported. The influence of N-heterocyclic carbenes on tuning the Lewis basic properties of the metal complexes was judged from spectroscopic, structural, and computational data. Conclusive experimental evidence for the enhanced Lewis basicity of NHC-containing complexes was provided by a transfer reaction.