title: Honeycomb nets with interpenetrating frameworks involving iminodiacetato-copper(II) blocks and bipyridine spacers: syntheses, characterization, and magnetic studies.
abstract: Three coordination polymers of copper(II), viz. ([Cu(ida)(4,4'-bipyH)]ClO(4))( proportional, variant ) (1), ([Cu(2)(ida)(2)(micro-4,4'-bipy)].2H(2)O)( proportional, variant ) (2), and [Cu(2)(ida)(2)(bpa)]( proportional, variant ) (3) have been synthesized by the process of self-assembly using Cu(ida) [ida = iminodiacetate(2-)] as the building block and 4,4'-bipyridyl and 1,2-bis(4-pyridyl)ethane (bpa) as linkers. Crystals of 1 are orthorhombic, of space group Pna2(1), with a = 13.8956(12) A, b = 16.3362(16) A, c = 7.3340(12), and Z = 4. Both compounds 2 and 3 crystallize in monoclinic space group P2(1)/a with a = 10.1887(8) A (9.6779(10) A for 3), b = 8.0008(11) A (9.1718(10) A), c = 11.6684(9) A (12.9144(12) A), beta = 98.307(11) degrees (102.796(18) degrees ), and Z = 2 (2). Compound 1 has a zigzag chain structure with an extensive hydrogen-bonded network while compounds 2 and 3 are honeycomb (6,3) nets with interpenetrating structures. Variable temperature (2-300 K) magnetic study indicates the presence of weak antiferromagnetic interactions (J = 0.82 +/- 0.01 cm(-)(1)) in 1 and ferromagnetic in 2 (J = -0.45 +/- 0.05 cm(-)(1)) and 3 (J = -0.21 +/- 0.02 cm(-)(1)). The extent of planarity of the bridging "Cu-O-C-O-Cu" moiety, acting as the super-exchange pathway between the neighboring copper centers, probably controls the sign of the magnetic exchange coupling in these compounds.
authors.affiliation: Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India.
authors.forename: Suman
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Pabitra Baran
authors.initials: PB
authors.lastname: Chatterjee
authors.forename: Debdas
authors.initials: D
authors.lastname: Mandal
authors.forename: Golam
authors.initials: G
authors.lastname: Mostafa
authors.forename: Andrea
authors.initials: A
authors.lastname: Caneschi
authors.forename: Joris
authors.initials: J
authors.lastname: van Slageren
authors.forename: Timothy J R
authors.initials: TJ
authors.lastname: Weakley
authors.forename: Muktimoy
authors.initials: M
authors.lastname: Chaudhury