Diamine incorporated compounds derived from polymeric nickel(II) fumarates and oxalates

TY - JOUR

T1 - Diamine incorporated compounds derived from polymeric nickel(II) fumarates and oxalates

T2 - Crystal structure, spectral and thermal properties of [Ni(en)3](O2C{single bond}CH{double bond, long}CH{single bond}CO2)·3H2O and [Ni(en)3](O2C{single bond}CO2)

AU - Padmanabhan, M.

AU - Joseph, James C.

AU - Huang, Xiaoying

AU - Li, Jing

PY - 2008/8/14

Y1 - 2008/8/14

N2 - Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)3](fum)·3H2O (1), [Ni(en)3](ox) (2), [Ni(dap)2(fum)] (3) and [Ni(dap)(ox)]·2H2O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)3]2+ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)3]2+ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) Å, b = 11.747(2) Å, c = 10.748(2) Å, β = 125.59(3)°, V = 1837.7(6) Å3, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P-31c with a = 8.8770(13) Å, b = 8.8770(13) Å, c = 10.482(2) Å, γ = 120°, V = 715.3(2) Å3, Z = 2. The octahedral [Ni(en)3] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)3]2+ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV-Visible) and magnetic measurements were carried out and some of the ligand-field parameters like Dq, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η1 form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η4-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)3]2+ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like Ea and ΔS also could be evaluated for various thermal steps for the compounds 1-4 using Coats-Redfern equation.

AB - Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)3](fum)·3H2O (1), [Ni(en)3](ox) (2), [Ni(dap)2(fum)] (3) and [Ni(dap)(ox)]·2H2O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)3]2+ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)3]2+ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) Å, b = 11.747(2) Å, c = 10.748(2) Å, β = 125.59(3)°, V = 1837.7(6) Å3, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P-31c with a = 8.8770(13) Å, b = 8.8770(13) Å, c = 10.482(2) Å, γ = 120°, V = 715.3(2) Å3, Z = 2. The octahedral [Ni(en)3] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)3]2+ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV-Visible) and magnetic measurements were carried out and some of the ligand-field parameters like Dq, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η1 form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η4-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)3]2+ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like Ea and ΔS also could be evaluated for various thermal steps for the compounds 1-4 using Coats-Redfern equation.

KW - 1,2-Diaminoethane

KW - 1,3-Diaminopropane

KW - Fumarate

KW - Nickel(II)

KW - Oxalate

KW - Spectral properties

KW - Thermal properties

KW - X-ray studies

UR - http://www.scopus.com/inward/record.url?scp=46949101639&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=46949101639&partnerID=8YFLogxK

U2 - 10.1016/j.molstruc.2007.10.012

DO - 10.1016/j.molstruc.2007.10.012

M3 - Article

VL - 885

SP - 36

EP - 44

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

SN - 0022-2860

IS - 1-3

ER -