Engaging dual donor sites within an N-heterocyclic olefin phosphine ligand.

By investigating the coordination chemistry of a neutral N-heterocyclic olefin phosphine ligand, a new digold(i) chloride complex was discovered, demonstrating that mixed element (P/C) donor sites can be accessed at the same time. However attempts to extend this strategy for the preparation of heterobimetallic complexes featuring copper(i) and gold(i) centers with this mixed donor ligand were unsuccessful. The related monometallic copper(i) and gold(i) iodide complexes were discovered to be emissive in the solid state.

Structurally versatile phosphine and amine donors constructed from N-heterocyclic olefin units.

A general strategy for the synthesis of hindered N- and P-based donors is presented whereby the strongly electron releasing N-heterocyclic olefin (NHO) unit, IPr[double bond, length as m-dash]CH-, (IPr[double bond, length as m-dash]CH- = [(HCNDipp)2C[double bond, length as m-dash]CH](-); Dipp = 3,6-(i)Pr2C6H2) is linked to terminally bound phosphine and amine donors. Preliminary coordination chemistry is presented involving phosphine (IPr[double bond, length as m-dash]CH)PR2 (R = (i)Pr and Ph) and amine (IPr[double bond, length as m-dash]CH)NMe2 ligands and the Lewis acids BH3 and AuCl. Interestingly, (IPr[double bond, length as m-dash]CH)NMe2 binds AuCl through an exocyclic olefin unit, while the softer phosphorus centers in (IPr[double bond, length as m-dash]CH)PR2 coordinate to yield Au-P linkages; thus the reported NHO-based ligands exhibit tunable binding modes to metals.

Metal-Free Dehydrogenation of Amine-Boranes by Tunable N-Heterocyclic Iminoboranes.

We report the synthesis of structurally tunable boron complexes supported by N-heterocyclic imine ligands IPr=N-BR (IPr=[(HCNDipp) C], Dipp=2,6-iPr C H , R=Cl and/or Ph) that have the ability to abstract dihydrogen from amine-boranes, and instigate their dehydrocoupling. In one instance, mild heating of the hydrogen addition product IPr=NH-B(Ph)HCl releases H to regenerate the starting N-heterocyclic iminoborane; accordingly IPr=N-B(Ph)Cl can be used as a metal-free catalyst to promote the dehydrocoupling of MeNH ⋅BH to yield N-methylaminoborane oligomers [MeNH-BH ] .

Contrasting reactivities of silicon and germanium complexes supported by an N-heterocyclic guanidine ligand.

We report the synthesis of an acyclic two-coordinate germylene supported by two bulky and electron donating N-heterocyclic guanidine [IPr═N](-) ligands (IPr = [(HCNDipp)2C:]; Dipp = [2,6-(i)Pr2C6H3]), and its reactivity with molecular hydrogen to form IPr═NH, which presumably proceeds via the unstable intermediate [H2Ge(N═IPr)2]. Our attempts to isolate the corresponding silylene [:Si(N═IPr)2] led to an unexpected ligand activation/rearrangement process involving N-C(aryl) bond cleavage within the N-heterocyclic guanidine ligand; this transformation was also studied by computational methods.

Accessing zinc monohydride cations through coordinative interactions.

We present isolable examples of formal zinc hydride cations supported by N-heterocyclic carbene (NHC) donors, and investigate the dual electrophilic and nucleophilic (hydridic) character of the encapsulated [ZnH](+) units by computational methods and preliminary hydrosilylation catalysis.

Enhancing order and porosity in a highly robust tin(IV) triphosphonate framework.

Metal organic frameworks (MOFs) are noted for crystallinity, stability, and porosity. For many industrial challenges though, beyond stability to pore activation, porous materials require high thermal and moisture stability. Here, we report a Sn(IV) triphosphonate framework, CALF-28, that is highly robust and porous.