| Abstract |
We report design and structural characterization of six new coordination polymers fabricated from PbCl2 and a series of closely related bis-pyridyl ligands L-I and HLII-HLVI, namely, [Pb-2(L-I)Cl-4], [Pb(HLII)-Cl-2](n)center dot nMeOH, [Pb(HLIII)Cl-2](n)center dot 0.5 nMeOH, [Pb-2(L-IV)Cl-3](n), [Pb(HLV)Cl-2](n), and [Pb-3(L-VI)(2)Cl-4](n)center dot nMeOH. The topology of the obtained networks is dictated by the geometry of the organic ligand. The structure of [Pb-2(L-I)Cl-4](n) is constructed from the [PbCl2](n) two-dimensional (2D) sheets, linked through organic linkers into a three-dimensional framework, which exhibits a unique binodal 4,7-connected three-periodic topology named by us as sdal. Topological analysis of the 2D metal-organic sheet in [Pb(HLII)Cl-2](n)center dot nMeOH discloses a binodal 3,4-connected layer topology, regardless of the presence of tetrel bonds. A one-dimensional (1D) coordination polymer [Pb(HLIII)Cl-2](n)center dot 0.5 nMeOH is considered as a uninodal 2-connected chain. The overall structure of [Pb-2(L-IV)Cl-3](n) is constructed from dimeric tetranuclear [Pb-4(mu(3)-L-IV-kappa N-6:N :N :mu(3)-O)(2)(mu(4)-Cl)(mu(2)-Cl)(2)](3+) cationic blocks linked in a zigzag manner through bridging mu(2)-Cl- ligands, yielding a 1D polymeric chain. Topological analysis of this chain reveals a unique pentanodal 3,4,4,5,6-connected chain topology named by us as sda2. The structure of [Pb(HLV)Cl-2](n) exhibits a ID zigzaglike polymeric chain. Two chains are further linked into a 1D gridlike ribbon through the dimeric [Pb-2(mu(2)-Cl)(2)Cl-2] blocks as bridging nodes. With the bulkiest ligand HLVI, a 2D layered coordination polymer [Pb-3(L-VI)(2)Cl-4](n)center dot nMeOH is formed, which network, considering all tetrel bonds, reveals a unique heptanodal 3,3,3,3,4,5,5-connected layer topology named by us as sda3. Compounds [Pb-2(L-I)Cl-4](n), [Pb-2(L-IV)Cl-3](n), and [Pb(HLV)Cl-2] were found to be emissive in the solid state at ambient temperature. While blue emission of [Pb-2(L-I)Cl-4] is due to the ligand-centered transitions, bluish-green and white luminescence of [Pb-2(L-IV)Cl-3] and [Pb(HLV)Cl-2], respectively, was assigned to ligand-to-metal charge transfer mixed with metal-centered excited states. Molecular as well as periodic calculations were additionally applied to characterize the obtained polymers. |
