TY - JOUR
T1 - Towards polymorphism control in coordination networks and metallo-organic salts
AU - Adams, Christopher J.
AU - Gillon, Amy L.
AU - Lusi, Matteo
AU - Orpen, A. Guy
PY - 2010/12
Y1 - 2010/12
N2 - [{(4,4′-bipy)ZnCl2}n] (4) is known in three different polymorphs, in the space groups C2/c (4a), Pnma (4b) and Pban (4c). Solution synthesis produces a mixture of 4a and 4b, but solid-state synthesis, either by grinding together 4,4′-bipy and ZnCl2 or by heating [4,4′-H2bipy][ZnCl4] 3 to thermally eliminate HCl, generates only the 4b form, demonstrating that solid-state synthesis can exert control over polymorph formation; other solid-state preparations of 4 such as reaction of basic zinc carbonate with [4,4′-H2bipy]Cl 2 or reaction of [4,4′-H2bipy][ZnCl4] 3 with KOH also increase the amount of 4b generated relative to the solution synthesis. It is also possible to form the mixed-metal phases [{(4,4′-bipy)Co1-xZnxCl2}n] 4x as effectively homogeneous solid-solutions by the same techniques, and when x < 0.5 (i.e. there is more cobalt present than zinc) then only the Pban polymorph of the solid-solution is observed. When x > 0.5, the amount of this polymorph is still greater than would be expected for a predominantly zinc-containing phase.
AB - [{(4,4′-bipy)ZnCl2}n] (4) is known in three different polymorphs, in the space groups C2/c (4a), Pnma (4b) and Pban (4c). Solution synthesis produces a mixture of 4a and 4b, but solid-state synthesis, either by grinding together 4,4′-bipy and ZnCl2 or by heating [4,4′-H2bipy][ZnCl4] 3 to thermally eliminate HCl, generates only the 4b form, demonstrating that solid-state synthesis can exert control over polymorph formation; other solid-state preparations of 4 such as reaction of basic zinc carbonate with [4,4′-H2bipy]Cl 2 or reaction of [4,4′-H2bipy][ZnCl4] 3 with KOH also increase the amount of 4b generated relative to the solution synthesis. It is also possible to form the mixed-metal phases [{(4,4′-bipy)Co1-xZnxCl2}n] 4x as effectively homogeneous solid-solutions by the same techniques, and when x < 0.5 (i.e. there is more cobalt present than zinc) then only the Pban polymorph of the solid-solution is observed. When x > 0.5, the amount of this polymorph is still greater than would be expected for a predominantly zinc-containing phase.
UR - http://www.scopus.com/inward/record.url?scp=78349274574&partnerID=8YFLogxK
U2 - 10.1039/c0ce00230e
DO - 10.1039/c0ce00230e
M3 - Article
AN - SCOPUS:78349274574
SN - 1466-8033
VL - 12
SP - 4403
EP - 4409
JO - CrystEngComm
JF - CrystEngComm
IS - 12
ER -