Annie L. Colebatch

Secondary phosphinocarbyne and phosphaisonitrile complexes.

The palladium-mediated reaction of [W(≡CBr)(CO)2(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with primary phosphines PH2R (R = Ph, Cy) affords the secondary phosphinocarbyne complexes [W(≡CPHR)(CO)2(Tp*)], deprotonation of which provides the anionic phosphaisonitrile complexes [W(CPR)(CO)2(Tp*)](-), including the structurally characterized salt [W(CPPh)(CO)2(Tp*)][K(kryptofix)].

Easy access to nucleophilic boron through diborane to magnesium boryl metathesis

Organoboranes are some of the most synthetically valuable and widely used intermediates in organic and pharmaceutical chemistry. Their synthesis, however, is limited by the behaviour of common boron starting materials as archetypal Lewis acids such that common routes to organoboranes rely on the reactivity of boron as an electrophile. While the realization of convenient sources of nucleophilic boryl anions would open up a wealth of opportunity for the development of new routes to organoboranes, the synthesis of current candidates is generally limited by a need for highly reducing reaction conditions. Here, we report a simple synthesis of a magnesium boryl through the heterolytic activation of the B–B bond of bis(pinacolato)diboron, which is achieved by treatment of an easily generated magnesium diboranate complex with 4-dimethylaminopyridine. The magnesium boryl is shown to act as an unambiguous nucleophile through its reactions with iodomethane, benzophenone and N,N′-di-isopropyl carbodiimide and by density functional theory.

The odd bit of carbon

Anthony Hill joined Gordon Stones research group as a post-doctoral research assistant from 1986-8 in the halcyon days of the “E317” lab at the University of Bristol. The supportive environment of creative and imaginative synthetic design that Gordon fostered in Bristol was unparalleled, quite without apology for the pursuit of curiosity-driven science that bordered on molecular fine arts. In 1996 Gordon handed over the reins of Advances in Organometallic Chemistry, the journal series, now running to some 60 volumes, which Gordon inaugurated in 1964 with Bob West. During Gordons mid-career phase, when he had a mere 400 publications to his name, carbyne chemistry held special interest for him. The work to follow reflects the enthusiasm those times engendered in this intriguing class of compounds.

A General, Rhodium-Catalyzed, Synthesis of Deuterated Boranes and N-Methyl Polyaminoboranes

The rhodium complex [Rh(Ph2 PCH2 CH2 CH2 PPh2 )(η6 -FC6 H5 )][BArF4 ], 2, catalyzes BH/BD exchange between D2 and the boranes H3 B⋅NMe3 , H3 B⋅SMe2 and HBpin, facilitating the expedient isolation of a variety of deuterated analogues in high isotopic purities, and in particular the isotopologues of N-methylamine-borane: R3 B⋅NMeR2 1-dx (R=H, D; x=0, 2, 3 or 5). It also acts to catalyze the dehydropolymerization of 1-dx to give deuterated polyaminoboranes. Mechanistic studies suggest a metal-based polymerization involving an unusual hybrid coordination insertion chain-growth/step-growth mechanism.

How Changing the Bridgehead Can Affect the Properties of Tripodal Ligands.

Although a multitude of studies have explored the coordination chemistry of classical tripodal ligands containing a range of main-group bridgehead atoms or groups, it is not clear how periodic trends affect ligand character and reactivity within a single ligand family. A case in point is the extensive family of neutral tris-2-pyridyl ligands E(2-py)3 (E=C-R, N, P), which are closely related to archetypal tris-pyrazolyl borates. With the 6-methyl substituted ligands E(6-Me-2-py)3 (E=As, Sb, Bi) in hand, the effects of bridgehead modification alone on descending a single group in the periodic table were assessed. The primary influence on coordination behaviour is the increasing Lewis acidity (electropositivity) of the bridgehead atom as Group 15 is descended, which not only modulates the electron density on the pyridyl donor groups but also introduces the potential for anion selective coordination behaviour.

Amine-borane Dehydropolymerization: Challenges and Opportunities

Abstract The dehydropolymerization of amine–boranes, exemplified as H2RB⋅NR′H2, to produce polyaminoboranes (HRBNR′H)n that are inorganic analogues of polyolefins with alternating main‐chain B−N units, is an area with significant potential, stemming from both fundamental (mechanism, catalyst development, main‐group hetero‐cross‐coupling) and technological (new polymeric materials) opportunities. This Concept article outlines recent advances in the field, covering catalyst development and performance, current mechanistic models, and alternative non‐catalytic routes for polymer production. The substrate scope, polymer properties and applications of these exciting materials are also outlined. Challenges and opportunities in the field are suggested, as a way of providing focus for future investigations.