Premium
Proton Conductivities Manipulated by the Counter‐Anions in 2D Co‐Ca Coordination Frameworks
Author(s) -
Bao SongSong,
Wu YuXuan,
Li NanZhu,
Zheng LiMin
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201600203
Subject(s) - coca , chemistry , proton , hydrogen bond , crystallography , molecule , ion , stereochemistry , analytical chemistry (journal) , physics , organic chemistry , psychology , quantum mechanics , psychiatry
Three new layered Co‐Ca phosphonates are reported, namely, [CoCa(notpH 2 )(H 2 O) 2 ]X · n H 2 O (CoCa‐X · n H 2 O; X = Cl – , NO 3 – , PF 6 – ), where notpH 6 is 1,4,7‐triazacyclononane‐1,4,7‐triyltris(methylenephosphonic acid) [C 9 H 18 N 3 (PO 3 H 2 ) 3 ]. The layer topology of these compounds are identical to that of [CoCa(notpH 2 )(H 2 O) 2 ]ClO 4 · n H 2 O (CoCa‐ClO 4 · n H 2 O). The most significant difference lies in the counter‐anions, which not only have different size and shape but also show different capabilities towards hydrogen bonding. Consequently, the number of lattice water molecules and the hydrogen‐bond networks between the layers can be varied depending on the particular counter‐anion. AC impedance measurements reveal that the proton conductivities at 25 °C and 95 % relative humidity (RH) follow the sequence: CoCa‐Cl · n H 2 O > CoCa‐NO 3 · n H 2 O > CoCa‐PF 6 · n H 2 O ≈ CoCa‐ClO 4 · n H 2 O. Compound CoCa‐Cl · n H 2 O shows the highest proton conductivity of 1.40 × 10 –4 S cm –1 at 25 °C and 95 % RH, which is one order of magnitude higher than those of CoCa‐PF 6 · n H 2 O (1.39 × 10 –5 S cm –1 ) and CoCa‐ClO 4 · n H 2 O (1.55 × 10 –5 S cm –1 ).