Polyfluorinated, electron-withdrawing, and sterically demanding supporting ligands are of significant value in chemistry. Here we report the assembly and use of a bis(pyrazolyl)borate, [Ph2B(3-(SF5)Pz)2]- that combines all such features, and involves...

A variety of isolable, 2 : 1 and 1 : 1 copper(i)–alkyne complexes of containing pyrazolate ligand supports are presented as well as the copper pyrazolate mediated acetylenic C–H and alkyne CC bond functionalizations.

The copper(I), silver(I), and gold(I) metals bind π‐ligands by σ‐bonding and π‐back bonding interactions. These interactions were investigated using bidentate ancillary ligands with electron donating and withdrawing substituents. The π‐ligands span from ethylene to larger terminal and internal alkenes and alkynes. Results of X‐ray crystallography, NMR, and IR spectroscopy and gas phase experiments show that the binding energies increase in the order Ag

Purification of C2H4 from an C2H4 /C2H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3)2Bp]Cu}3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3)2Bp]Cu(C2H4). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2H4 /C2H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a “live” picture of the reversible conversion between [(CF3)2Bp]Cu(C2H4) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C2H4. Molecular structures of trinuclear {[(CF3)2Bp]Cu}3 and mononuclear [(CF3)2Bp]Cu(C2H4) are also presented.

The pyridine-based poly(pyridyl)borates are a recent addition to the scorpionate family. Furthermore, pyridyl ring substituted analogues are also rare. The synthesis of a bis(pyridyl)borate featuring trifluoromethyl substituted pyridyl donor arms and its utility in isocyanide and carbonyl chemistry of copper(I) and silver(I) have been described together with related molecules supported by a fluorinated tris(pyridyl)borate, and a comparison to the better-known poly(pyrazolyl)borate relatives. X-ray crystal structures of copper and silver complexes show that the B-arylated, bis-and tris(pyridyl)borate ligands use only two pyridyl moieties for metal ion coordination. Flanking B-aryl groups close to metal sites are also a common feature in copper and silver complexes supported by [Ph 2 B(6-(CF 3 )Py) 2 ] − and [t-BuC 6 H 4 B(6-(CF 3 )Py) 3 ] − . The CN stretching frequencies of the t-BuNC complexes of Cu(I) and Ag(I) are notably higher than that of the free t-BuNC. The CO stretch of the analogous fluorinated poly(pyridyl)borate ligand supported metal carbonyls lies closer to that of the free CO, indicating the presence of fairly Lewis acidic metal sites. Metal bound carbonyl stretching frequencies of comparable poly(pyridyl)borate and poly(pyrazolyl)borate have been utilized to gauge the relative donor properties of the two ligand families.

“Bottle-able” molecules with gold–ethylene bonds have been obtained using electron-rich scorpionates. Resulting molecules display enhanced gold → ethylene backbonding, and properties different from those involving electron-poor scorpionates.

Bis- and tris-pyridyl borate ligands containing pyridyl donor arms, a methylated boron cap, and a fluorine-lined coordination pocket have been prepared and utilized in coinage metal chemistry. The tris­(pyridyl)­borate ligand has been synthesized using a convenient boron source, [NBu4]­[MeBF3]. These N-based ligands permitted the isolation of group 11 metal–ethylene complexes [MeB­(6-(CF3)­Py)3]­M­(C2H4) and [Me2B­(6-(CF3)­Py)2]­M­(C2H4) (M = Cu, Ag, Au). The gold complexes display the largest coordination-induced upfield shifts of the ethylene 13C resonance relative to that of the free ethylene in their NMR spectra, while the silver complexes show the smallest shift. Solid-state structures of five of these metal–ethylene complexes as well as the related free ligands were established by X-ray crystallography. Surprisingly, all three [MeB­(6-(CF3)­Py)3]­M­(C2H4) adopt the rare κ2 coordination mode rather than the typical κ3 coordination mode of facial capping tridentate ligands. Computational analyses indicate that κ2 coordination mode is favored over the κ3-mode in these coinage metal–ethylene complexes and point to the effects CF3-substituents have on κ2/κ3-energy difference. The M–C and M–N bond distances of [MeB­(6-(CF3)­Py)3]­M­(C2H4) follow the trend expected based on covalent radii of M­(I) ions. The calculated ethylene–M interaction energy of κ2-[MeB­(6-(CF3)­Py)3]­M­(C2H4) indicated that the gold­(I) forms the strongest interaction with ethylene. A comparison to the related poly­(pyrazolyl)­borates is also presented.

A metal-free synthesis of biaryl compounds was achieved under photo-irradiation, which represents a milder alternative for cross-coupling reactions.