Carving Out Pores in Redox‐Active One‐Dimensional Coordination Polymers

Abstract

Reduction of the insulating one-dimensional coordination polymer [Cu(abpy)PF 6 ] n , 1a(PF 6 ), (abpy = 2,2'-azobispyridine) yields the conductive,p orous polymer [Cu-(abpy)] n , 2a. Pressed pellets of neutral 2a exhibit aconductivity of 0.093 Scm À1 at room temperature and aB runauer-Emmett-Teller (BET) surface area of 56 m 2 g À1 .Fine powders of 2a have aB ET surface area of 90 m 2 g À1 .C yclic voltammetry shows that the reduction of 1a(PF 6 )t o2a is quasireversible,indicative of facile charge transfer through the bulk material. The BET surface area of the reduced polymer 2 can be controlled by changing the size of the counteranion Xinthe cationic [Cu(abpy)X] n .R eduction of [Cu(abpy)X] n with X = Br (2b)orB Ar F (2c;B Ar F = tetrakis(3,5-bis(trifluoromethyl)phenyl)), affords [Cu(abpy)] n polymers with surface areas of 60 and 200 m 2 g À1 ,respectively.

Synthesis and crystal structures of zinc(II) coordination polymers of trimethylenedipyridine (tmdp), 4-nitrobenzoic (Hnba) and 4-biphenylcarboxylic acid (Hbiphen) for adsorptive removal of methyl orange from aqueous solution

“…While porosity in higher dimensional CPs is as a result of the channels in their framework, porosity in 1D CPs depends on their packing [52,53]. For example, a 1D CP that is packed in a manner in which two adjacent linear chains hug each other led to a double stranded structure with less porosity compared to one with its adjacent chains parallel to each other [54].…”

Reactivity of NO2 with Porous and Conductive Copper Azobispyridine Metallopolymers

“…Metallopolymer [Cu(abpy)] n , generated from the chemical reduction of [Cu(abpy)PF 6 ] n with Cp 2 Co, 6 was used for all NO 2 reactivity studies. Black powders of [Cu(abpy)] n were dosed with either a mixture of NO 2 (1%) in dry air (99%) or a mixture of NO 2 (2%) in dry N 2 (98%) at room temperature for variable amounts of time.…”

“…To better understand the metallopolymer's reactivity with NO 2 , we carried out similar studies with (Cu(azpy) 2 ) 6 (1) (azpy = phenylazo-2-pyridine), a molecular analogue of [Cu(abpy)] n where one pyridyl ring per Cu center is replaced by a phenyl ring to prevent bridging to another Cu center. Here, the ligand-based mixed valence is formally designated as Cu + (azpy 0.5− ) 2 .…”

“…We previously described 6 the electrically conductive and porous copper azobispyridine (abpy) metallopolymers [Cu-(abpy)] n . These metallopolymers exhibit an unusual combination of substantial conductivity (0.18 S•cm −1 at room temperature) and porosity (90 m 2 •g −1 ).…”

“…The conductivity of the neutral polymer, with oxidation states formally assigned as [Cu + (abpy −• )] n , was attributed to its mixed-valence character. 6 The [Cu(abpy)] n metallopolymer can be reversibly oxidized at −0.8 V vs Ag/AgNO 3 to the insulating (<10 −10 S•cm −1 ) and nonporous cationic metallopolymer, formally assigned as [Cu + (abpy 0 )X] n (X = monoanion). As a reducing, porous material, we anticipated that the neutral metallopolymer might react with oxidizing gases such as NO 2 .…”