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Abstract The tetrahedral geometry of organolead(IV) compounds can be readily transformed by using an organic ligand containing a dangling-arm oxygen functionality. The acidity of the Pb center results in so-called secondary bonding between O and Pb thereby pushing the geometry at Pb toward a trigonal bipyramidal (tbp) structure. Replacing a phenyl group by a chlorine atom dramatically enhances this phenomenon. Thus for (o-methoxybenzyl) triphenyllead (4), and (o-methoxybenzyl)diphenyllead chloride (5), the Pb–O internuclear distances are 3.362(4) and 2.845(3) Å, respectively; 83% (4) and 70% (5) of the sum of the van der Waals Pb and O radii. Within the group 14 element congeners the structural analysis of the (o-methoxybenzyl)triphenylE compounds, E = Si, Ge, Sn, and now Pb, demonstrates the relative acidities of E are Si < Ge < Sn < Pb. 

The photochemically generated synthesis of a terminal uranium nitride species is here reported and an examination of its intra- and intermolecular chemistry is presented. Treatment of the U( iii ) complex L Ar UI(DME) ((L Ar ) 2− = 2,2′′-bis(Dippanilide)- p -terphenyl; Dipp = 2,6-diisopropylphenyl) with LiNIm Dipp ((NIm Dipp ) − = 1,3-bis(Dipp)-imidazolin-2-iminato) generates the sterically congested 3N-coordinate compound L Ar U(NIm Dipp ) ( 1 ). Complex 1 reacts with 1 equiv. of Ph 3 CN 3 to give the U( iv ) azide L Ar U(N 3 )(NIm Dipp ) ( 2 ). Structural analysis of 2 reveals inequivalent N α –N β > N β –N γ distances indicative of an activated azide moiety predisposed to N 2 loss. Room-temperature photolysis of benzene solutions of 2 affords the U( iv ) amide ( N -L Ar )U(NIm Dipp ) ( 3 ) via intramolecular N-atom insertion into the benzylic C–H bond of a pendant isopropyl group of the (L Ar ) 2− ligand. The formation of 3 occurs as a result of the intramolecular interception of the intermediately generated, terminal uranium nitride (L Ar )U(N)(NIm Dipp ) ( 3′ ). Evidence for the formation of 3′ is further bolstered by its intermolecular capture, accomplished by photolyzing solutions of 2 in the presence of an isocyanide or PMe 3 to give (L Ar )U[NCN(C 6 H 3 Me 2 )](NIm Dipp ) ( 5 ) and ( N , C -L Ar *)U(NPMe 3 )(NIm Dipp ) ( 6 ), respectively. These results expand upon the limited reactivity studies of terminal uranium–nitride moieties and provide new insights into their chemical properties. 

Dy-based single-molecule magnets (SMMs) are of great interest due to their ability to exhibit very large thermal barriers to relaxation and therefore high blocking temperatures. One interesting line of investigation is Dy-encapsulating endohedral clusterfullerenes, in which a carbon cage protects magnetic Dy 3+ ions against decoherence by environmental noise and allows for the stabilization of bonding and magnetic interactions that would be difficult to achieve in other molecular architectures. Recent studies of such materials have focused on clusters with two Dy atoms, since ferromagnetic exchange between Dy atoms is known to reduce the rate of magnetic relaxation via quantum tunneling. Here, two new dysprosium-containing mixed-metallic sulfide clusterfullerenes, DyScS@ C s (6)–C 82 and DyScS@ C 3v (8)–C 82 , have been successfully synthesized, isolated and characterized by mass spectrometry, Vis-NIR, cyclic voltammetry, single crystal X-ray diffractometry, and magnetic measurements. Crystallographic analyses show that the conformation of the encapsulated cluster inside the fullerene cages is notably different than in the Dy 2 X@ C s (6)–C 82 and Dy 2 X@ C 3v (8)–C 82 (X = S, O) analogues. Remarkably, both isomers of DyScS@C 82 show open magnetic hysteresis and slow magnetic relaxation, even at zero field. Their magnetic blocking temperatures are around 7.3 K, which are among the highest values reported for clusterfullerene SMMs. The SMM properties of DyScS@C 82 far outperform those of the dilanthanide analogues Dy 2 S@C 82 , in contrast to the trend observed for carbide and nitride Dy clusterfullerenes. 

Here, we report the synthesis and characterization of crystalline C 60 nanomaterials and their applications as bifunctional water splitting catalysts. The shapes of the resulting materials were tuned via a solvent engineering approach to form rhombic-shaped nanosheets and nanotubes with hexagonal close packed-crystal structures. The as-synthesized materials exhibited suitable properties as bifunctional catalysts for HER and ORR reactions surpassing by far the electrocatalytic activity of commercially available amorphous C 60 . The C 60 nanotubes displayed the most efficient catalytic performance with a small onset potential of −0.13 V vs. RHE and ultrahigh electrochemical stability properties towards the generation of molecular hydrogen. Additionally, the rotating-disk electrode measurements revealed that the oxygen reduction mechanism at the nanotube electrochemical surfaces followed an effective four-electron pathway. The improved catalytic activity was attributed to the enhanced local electric fields at the high curvature surfaces. 

The masked Ti( ii ) synthon ( Ket guan)(η 6 -Im Dipp N)Ti ( 1 ) oxidatively adds across thiophene to give ring-opened ( Ket guan)(Im Dipp N)Ti[κ 2 - S (CH) 3 C H] ( 2 ). Complex 2 is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate 1 – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from 2 . Finally, pressurizing solutions of 2 with H 2 (150 psi) at 80 °C leads to the hydrodesulphurization of thiophene to give the Ti( iv ) sulphide ( Ket guan)(Im Dipp N)Ti(S) ( 3 ) and butane.