ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
We report the synthesis of structurally tunable boron complexes supported by N-heterocyclic imine ligands IPr=N-BR2 (IPr=[(HCNDipp)2 C], Dipp=2,6-iPr2 C6 H3 , 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 H2 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 MeNH2 â BH3 to yield N-methylaminoborane oligomers [MeNH-BH2 ]x .
ABSTRACT
We report the synthesis of an acyclic two-coordinate germylene supported by two bulky and electron donating N-heterocyclic guanidine [IPrâN](-) ligands (IPr = [(HCNDipp)2C:]; Dipp = [2,6-(i)Pr2C6H3]), and its reactivity with molecular hydrogen to form IPrâNH, which presumably proceeds via the unstable intermediate [H2Ge(NâIPr)2]. Our attempts to isolate the corresponding silylene [:Si(NâIPr)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.
ABSTRACT
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.
ABSTRACT
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. CALF-28 was designed based on the known structure of a divalent metal phosphonate that was 2-fold interpenetrated. It has strong sustaining interactions but consequently rapidly precipitates, compromising crystallinity. Using methods to enhance order, and by analogy to the M(II) analogue, insights to the structure are ascertained and corroborated by PXRD and gas sorption analysis. CALF-28 has a surface area >500 m(2)/g and is stable in water.
