Organizing Chain and Square-Grid Architectures by Employing Coordination Bonds between Inorganic and Organic Components. New Coordination Polymers Formed from Cd(II), Co(II), and Cu(II) Nitrate Salts and 1,4-Bis(4-pyridyl)butadiyne

Four new coordination polymers containing the long conjugated bidentate ligand 1,4-bis(4-pyridyl)butadiyne (2) and cadmium, cobalt, and copper nitrate hydrates are reported. The
coordination polymers were synthesized using almost identical solution reaction conditions
utilizing the same mixed methanol/methylene chloride solvent system. The first compound
[Cd(1,4-bis(4-pyridyl)butadiyne)(NO3)2(H2O)·CH2Cl2]n (3; monoclinic, C2/c; a = 28.135(3) Å,
b = 8.535(1) Å, c = 17.642(2) Å, β = 91.797(2)°, Z = 8) is obtained by combination of 2 with
Cd(NO3)2·6H2O. The structure includes a rare sinusoidal-type polymer chain architecture,
effected by a combination of hydrogen-bonding interactions and π−π interactions between
adjacent alkyne regions of the ligand. The second species [Co(1,4-bis(4-pyridyl)butadiyne)(NO3)2(H2O)2·2H2O]n (4; orthorhombic, Pccn; a = 22.999(3) Å, b = 23.338(3) Å, c = 7.388(1)
Å, Z = 8) is generated from the reaction of 2 and Co(NO3)2·6H2O and forms a straight-chain
polymeric architecture consisting of double chains that crisscross each other, generating a
new layer architecture. The third species [Cu(1,4-bis(4-pyridyl)butadiyne)2(NO3)2·CH2Cl2]n
(5; orthorhombic, C2221; a = 14.382(1) Å, b = 22.755(2) Å, c = 8.975(1) Å, Z = 4) is prepared
from the reaction of 2 and Cu(NO3)2·3H2O. The structure of 5 exhibits a two-dimensional
interpenetrating square-grid-type architecture from the coordination of four pyridyl rings
at the copper center. The intersection of the grids generates large continuous rhombic
channels that can be occupied by organic molecules. The fourth species [Co(1,4-bis(4-pyridyl)butadiyne)2(NO3)2·CH2Cl2]n (6; orthorhombic, C2221; a = 14.0364(12) Å, b = 23.7595(19) Å,
c = 8.9706(7) Å, Z = 4) is generated from the reaction of 2 and Co(NO3)2·6H2O and is
isostructural with 5.