Syntheses and structures of dinuclear rhodium(I) complexes and 1-D zigzag-chain rhodium(I) co-ordination polymers bridged by rod-like bidentate nitrogen ligands

Novel dinuclear rhodium(I) complexes, [Rh-2(2-bpbd)(2)(cod)(2)]X-2 (X=BF4 1 a, PF6 1b or ClO4 1c; cod=cycloocta-1,5-diene) and 1-D rhodium(I) co-ordina tion polymers with the linkage of square-planar rhodium(I) centers, {[Rh(4- bpbd)(cod)]X}(n)(X=BF4 2a, PF6 2b or ClO4 2c) and {[Rh(4-bpe)(cod)]X}(n) (X =BF4 3a, PF6 3b or ClO4 3c), were systematically synthesized using 1,4-bis( 2-pyridyl)butadiyne (2-bpbd), 1,4-bis(4-pyridyl)butadiyne (4-bpbd) and tran s-1,2-bis(4-pyridyl)ethylene (4-bpe). The structures of 1a, 2a, 2b and 3a w ere crystallographically characterized. In 1a each Rh atom is bridged by tw o N atoms of 2-bpbd to afford a unique dinuclear structure with an 18-membe red Rh2N4C12 framework. In 2a, 2b and 3a, each Rh atom is bonded to two N a toms of 4-bpbd (2a and 2b) or 4-bpe (3a) and two C=C bonds of cod in a squa re-planar geometry. The square-planar centers are in turn linked by 4-bpbd or 4-bpe ligands to form a 1-D zigzag-chain structure. The zigzag chains ar e located in parallel 9.6, 9.9 and 10.7 Angstrom apart in 2a, 2b and 3a, re spectively, and no effective intermolecular interactions were found.