Framework engineering by anions and porous functionalities of Cu(II)/4,4′-bpy coordination polymers

A combination of framework-builder (Cu(II) ion and 4,4'-bipyridine (4,4'-bpy) ligand) and framework-regulator (AF(6) type anions; A = Si, Ge, and P) provides a series of novel porous coordination polymers. The highly porous coordination polymers {[Cu(AF(6))(4,4'-bpY)(2)].8H(2)O}(n) (A = Si (1a-8H(2)O), Ge (2a.8H(2)O)) afford robust 3-dimensional (3-D), microporous networks (3-D Regular Grid) by using AF(6)(2)-anions. The channel size of these complexes is ca. 8 x 8 Angstrom(2) along the c-axis and 6 x 2 Angstrom(2) along the a-or b-axes. When compounds 1a.8H(2)O or 2a.8H(2)O were immersed in water, a conversion of 3-D networks (1a.8H(2)O or 2a.8H(2)O) to interpenetrated networks {[Cu(4,4'-bpy)2(H2O)(2)].AF(6)}(n) (A = Si (1b) and Ge (2b)) (2-D Interpenetration) took place. This 2-D interpenetrated network 1b shows unique dynamic anion-exchange properties, which accompany drastic structural conversions. When a PF6- monoanion instead of AF(6)(2-) dianions was used as the framework-regulator with another co-counteranion (coexistent anions), porous coordination polymers with various types of frameworks, {[Cu-2(4,4'-bpy)(5)(H2O)(4)].anions-2H(2)O.4EtOH}(n) (anions= 4PF(6)(-) (3.2H(2)O-4EtOH), 2PF(6) +2ClO(4)(-)(4.2H(2)O-4EtOH))(2-DDouble-Layet),{[CU2-(PF6)(NO3)(4,4'-bPY)(4)].2PF(6).2H(2)O}(n) (5.2PF(6).2H(2)O) (3-D Undulated Grid), {[Cu(PF6)(4,4'-bPY)(2)(MeCN)].PF6.2MeCN}(n) (6.2MeCN) (2-D Grid), and {[Cu(4,4'-bpy)(2)(H2O)(2)].PF6.BF4}(n) (7) (2-D Grid), were obtained, where the three modes of PF6- anions are observed. 5.2PF(6).2H(2)O has rare PF6- bridges. The PF6- and NO3- monoanions alternately link to the Cu(II) centers in the undulated 2-D sheets of [Cu(4,4'-bPY)(2)](n) to form a 3-D porous network. The free PF6- anions are included in the channels. 6.2MeCN affords both free and terminal-bridged PF6- anions. 3.2H(2)O.4EtOH, 4.2H(2)O.4EtOH, and 7 bear free PF6- anions. All of the anions in 3-2H(2)O.4EtOH and 4.2H(2)O.4EtOH are freely located in the channels constructed from a host network. Interestingly, these Cu(II) frameworks are rationally controlled by counteranions and selectively converted to other frameworks.