Terphenyl Ligand Stabilized Lead(II) Derivatives of Simple Organic Groups:  Characterization of Pb(R)C 6 H 3 -2,6-Trip 2 (R = Me, t-Bu, or Ph; Trip = C 6 H 2 -2,4,6-i-Pr 3 ), {Pb(μ-Br)C 6 H 3 -2,6-Trip 2 } 2 , py·Pb(Br)C 6 H 3 -2,6-Trip 2