A metal organic framework [Ni1.5(4,40-bipy)1.5(H3L)(H2O)3]$[H2O]7 where H6L ? 2,4,6-trimethylbenzene-

1,3,5-triyl tris(methylene)triphosphonic acid and 4,40-bipy ? 4,40-bipyridine has been prepared. The

structures of [Ni1.5(4,40-bipy)1.5(H3L)(H2O)3]$[H2O]7 and the desolvated form [Ni1.5(4,40-bipy)1.5(H3L)(H2O)3]

have been determined by single crystal X-ray diffraction and the framework structures are virtually

identical with the former having disordered water molecules in the pores. The framework structure

comprises of two-dimensional Ni1.5(H3L) layers and 4,40-bipy linkers acting as pillars with an unusual

framework topology of a (3, 3, 6) net that can be denoted as: {4$62}2{63}2{68$85$102}. The framework has

one-dimensional channels decorated with acidic O–H groups with irregular shape varying from narrow

windows (cross section: 4.2  4.2 °A) to pore cavities (diameter: 12 °A). Thermogravimetric studies

showed that both coordinated and lattice water molecules adsorbed in pores were removed in ultrahigh

vacuum to give [Ni1.5(4,40-bipy)1.5(H3L)]. The water vapor adsorption isotherm for [Ni1.5(4,40-

bipy)1.5(H3L)] showed that 3 coordinated and 7 pore lattice water molecules were adsorbed and the

framework structure was reformed. The desorption isotherm showed that the lattice water was easily

desorbed in vacuum at 20 C to form [Ni1.5(4,40-bipy)1.5(H3L)(H2O)3]. The ethanol adsorption isotherms

for [Ni1.5(4,40-bipy)1.5(H3L)] for temperature range 20–50 C were markedly hysteretic. The stoichiometry

was [Ni1.5(4,40-bipy)1.5(H3L)]$[1.11C2H5OH] at p/p0 ? 0.97 and 20 C gave a total pore volume

approximately half that of [Ni1.5(4,40-bipy)1.5(H3L)(H2O)3]. The desorption isotherms show that ethanol is

strongly retained with decreasing pressure indicating a stable framework structure. The kinetic profiles

for oxygen, nitrogen, carbon dioxide, and water and ethanol vapors, can be described by Fickian,

combined barrier resistance/diffusion (CBRD), and stretched exponential models for both adsorption and

desorption. Gas adsorption studies for [Ni1.5(4,40-bipy)1.5(H3L)] reveal kinetic molecular sieving occurs

with very high kinetic selectivity for O2/N2 at 0 C. Carbon dioxide adsorption has intermediate rates of

adsorption between oxygen and nitrogen. The isosteric enthalpy for CO2 adsorption at zero surface

coverage was 30.7  2.4 kJ mol1. The corresponding activation energy for diffusion of CO2 into the

framework was 48 kJ mol1. Narrow constrictions in the porous structure of [Ni1.5(4,40-bipy)1.5(H3L)]

give rise to kinetic molecular sieving effects and do not allow adsorption of molecules such as methane,

which has a larger cross-section. The selectivity for CO2/CH4 was very high (x1000) at 30 C. The

adsorption results are discussed in terms of diffusion, thermodynamics and surface interactions in pores.