Synthesis, structure, and magnetic properties of Co{sub 2}{l_brace}[N(CN){sub 2}]{sub 4}bpym{r_brace}{center_dot}H{sub 2}O and M{l_brace}[N(CN){sub 2}]{sub 2}bpym{r_brace}{center_dot}H{sub 2}O (M = Mn, Fe, Co; bpym = 2,2{prime}-bipyrimidine)
Co{sub 2}{l_brace}[N(CN){sub 2}]{sub 4}bpym{r_brace}{center_dot}H{sub 2}O (1) and M{l_brace}[N(CN){sub 2}]{sub 2}bpym{r_brace}{center_dot}H{sub 2}O [M = Mn (2a), Fe (2b), Co (2c); bpym = 2,2{prime}-bipyrimidine] have been synthesized and characterized structurally and magnetically. All of the compounds crystallize in the orthorhombic space group Pnma. The unit cell parameters for 1 are a = 16.1684(5) {angstrom}, b = 12.9860(3) {angstrom}, c = 10.4207(3) {angstrom}, and Z = 4. Compound 1 is a 2-D layered structure with water intercalated between sheets. The sheets are composed of {hor_ellipsis}M-[NCNCN]{sub 2}-M-bpym-M-[NCNCN]{sub 2}-M{hor_ellipsis} chains, which are linked together by dicyanamides. 21--c are isomorphic with the unit cell parameters a = 17.5112(4) {angstrom}, b = 11.9955(4) {angstrom}, c = 7.4684(2) {angstrom} for 2a, a = 17.5814(7) {angstrom}, b = 11.9453(5) {angstrom}, c - 7.3292(3) {angstrom} for 2b, a = 17.8642(2) {angstrom}, b = 11.9216(2) {angstrom}, c = 7.2860(2) {angstrom} for 2c, and Z = 4 for all. They crystallize as chains containing metal centers coordinated to two bridging dicyanamides, one terminal dicyanamide, one terminal chelating bpym, and one water molecule. 2a--c are the first examples of compounds containing terminal and {mu}-bound dicyanamides in the same structure. The broad maximum in the magnetic susceptibility of 1 could not be fit to any known dimer models. However, the high-temperature data were fit to the Curie-Weiss expression with g = 2.86 and {theta} = {minus}42 K. 2a--c could best be modeled as uniform 1-D chains with g = 2.04, {theta} = {minus}0.76, and J/{kappa}{sub B} = {minus}0.15 K for 2a, g = 2.34, {theta} = {minus}7.6, and J/{kappa}{sub B} = {minus}0.42 K for 2b, and g = 2.58, {theta} = {minus}5.4, and J/{kappa}{sub B} = {minus}1.42 K for 2c. Because of small exchange coupling throughout the extended networks, no long-range magnetic ordering was observed.
- Research Organization:
- Univ. of Utah, Salt Lake City, UT (US)
- Sponsoring Organization:
- American Chemical Society; USDOE
- DOE Contract Number:
- FG03-93ER45504
- OSTI ID:
- 20075880
- Journal Information:
- Inorganic Chemistry, Vol. 39, Issue 9; Other Information: PBD: 1 May 2000; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
Similar Records
Racemic-meso interconversion for ansa-scandocene and ansa-yttrocene derivatives. Molecular structures of rac-{l_brace}Me{sub 2}Si[{eta}{sup 5}-C{sub 5}H{sub 2}-2,4-(CHMe{sub 2}){sub 2}]{sub 2}{r_brace}ScCl {center_dot} LiCl(THF){sub 2}, [meso-{l_brace}Me{sub 2}Si[{eta}{sup 5}-C{sub 5}H{sub 2}-2,4-(CHMe{sub 2}){sub 2}]{sub 2}{r_brace} Y({mu}{sub 2}-Cl)]{sub 2}, and meso-{l_brace}Me{sub 2}Si[{eta}{sup 5}-C{sub 5}H{sub 2}-2,4-(CHMe{sub 2}){sub 2}]{sub 2}{r_brace}Zr(NMe{sub 2}){sub 2}
Gibbs energies of formation for hydrocerussite [Pb(OH){sub 2}{center_dot}(PbCo{sub 3}){sub 2}(s)] and hydrozincite {l_brace}[Zn(OH){sub 2}]{sub 3}{center_dot}(ZnCO{sub 3}){sub 2}(s){r_brace} at 298 K and 1 bar from electrochemical cell measurements