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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. 

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 syntheses of [2-(CH 3 ECH 2 )C 6 H 4 ]PbPh 3− n Cl n , ( n = 0, E = O (4), E = S (5); n = 1, E = O (6), E = S (7); n = 2, E = O (8), are described. NMR and single crystal data illustrate significant Pb⋯E interactions increasing as n progresses from 0 to 2. The Pb⋯E interactions stabilize the Pb–aryl bonding to the extent that the reactions of 4 and 5 with Me 2 SnCl 2 result in interchange of a Ph group and Cl to produce 6 and 7, respectively, together with Me 2 PhSnCl.