| Title: | Dimensionality control of vapochromic hydrogen-bonded proton-transfer assemblies composed of a bis(hydrazone)iron(II) complex |
| Author(s): | Chang M; Kobayashi A; Nakajima K; Chang HC; Kato M; |
| Address: | "Department of Chemistry, Faculty of Science, Hokkaido University, North-10 West-8, Kita-ku, Sapporo 060-0810, Japan" |
| ISSN/ISBN: | 1520-510X (Electronic) 0020-1669 (Linking) |
| Abstract: | "We describe the novel synthesis of a bis(hydrazone)iron(II) complex in protonated [Fe(Hpbph)(2)]Cl(2) (1) and deprotonated [Fe(pbph)(2)] (2) forms and several hydrogen-bonded proton-transfer (HBPT) assemblies having different dimensionalities of hydrogen-bonded network structures, [Fe(Hpbph)(2)](CA).2CH(3)OH (3), [Fe(Hpbph)(2)](HCA)(2).2THF (4), and [Fe(Hpbph)(2)](CA)(H(2)CA)(2).2CH(3)CN (5) (Hpbph = 2-(diphenylphosphino)benzaldehyde-2-pyridylhydrazone), consisting of a deprotonated Fe(II)-hydrazone complex (2) as a proton acceptor (A) and chloranilic acid (H(2)CA) as a proton donor (D). The deprotonated complex 2 exhibited two-step reversible protonation reactions to form the double-protonated form 1, and the acid-dissociation constants were determined to be 7.6 and 10.3 in methanol solution. Utilizing this proton-accepting ability of 2, we succeeded in synthesizing HBPT assemblies 3, 4, and 5 from the reactions in CH(3)OH, THF, and CH(3)CN, respectively, with the same D/A ratio of H(2)CA/[Fe(pbph)(2)] = 10:1. These assemblies were found to have one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) hydrogen-bonded networks with D/A ratios of 1:1, 2:1, and 3:1 for 3, 4, and 5, respectively. In 3, a 1-D hydrogen-bonded chain composed of the alternate arrangement of [Fe(Hpbph)(2)](2+) and CA(2-), ...[Fe(Hpbph)(2)](2+)...CA(2-)...(infinity), was surrounded by solvated methanol molecules to form isolated 1-D hydrogen-bonded chains. In the HBPT assembly 4, a 2-D hydrogen-bonded sheet was formed from two types of hydrogen-bonded chains, ...[Fe(Hpbph)(2)](2+)...HCA(-)...HCA(-)...(infinity) and ...HCA(-)...HCA(-)...(infinity), and solvated THF molecules did not form any hydrogen bonds. In 5, two orthogonal hydrogen-bonded chains constructed from the neutral chloranilic acid molecules, ...CA(2-)...2(H(2)CA)...(infinity), were formed in addition to the 1-D hydrogen-bonded chain similar to that in 3, resulting in the formation of a rigid 3-D hydrogen-bonded network structure. By controlling the dimensionality of the hydrogen bond network, we found that the 2-D HBPT assembly 4 is sufficiently flexible to exhibit interesting vapochromic behavior in response to various organic vapors" |
| Keywords: | "Crystallography, X-Ray Ferrous Compounds/*chemical synthesis/chemistry Hydrazones/*chemistry Hydrogen Bonding Models, Molecular Powder Diffraction *Protons Volatilization;" |
| Notes: | "MedlineChang, Mee Kobayashi, Atsushi Nakajima, Kiyohiko Chang, Ho-Chol Kato, Masako eng Research Support, Non-U.S. Gov't 2011/08/02 Inorg Chem. 2011 Sep 5; 50(17):8308-17. doi: 10.1021/ic2008396. Epub 2011 Jul 29" |
