Porous Coordination Polymers of Transition Metal Sulfides with PtS Topology Built on a Semirigid Tetrahedral Linker

Four novel porous metal sulfide coordination polymers, [M(tpom)Sx(SH)y]·z(H2O) (metal-sulfide frameworks, denoted MSF-n, n = 1, Cd; 2, Mn; 3, Fe; 4, Co; x = 0, y = 2 for 1, 2, and 4 and x = 0.54, y = 1.46 for 3), were solvothermally prepared by using a quadridentate linker, tetrakis(4-pyridyloxymethylene)methane (tpom), in the presence of organic sulfur compound under an acidic conditions. MSF-n (n = 1−4) is isostructural and built upon the tetrahedral tpom linker and square planar MSx(SH)y unit, which form a binodal 4,4-connected porous framework with a 2-fold interpenetrated 4284-pts net. With rectangular pore channels of about 5 × 6 Å2 (interatomic distances between the nearest protruding H atoms across) running along both the crystallographic a and b directions, MSF-n possesses permanent porosity with a BET surface area of 575, 622, 617, and 767 m2/g for MSF-1, -2, -3, and -4, respectively, as estimated from N2 adsorption measurements. MSF-n (n = 1−4) has hydrogen storage capacities of 1.03, 1.37, 1.29, and 1.58 wt % at 77 K and 1 atm, respectively, each corresponding to 2.0 H2 molecules per unit cell. In addition, MSF-n (n = 1−4) can adsorb 24.1, 25.0, 21.6, and 24.1 wt % of carbon dioxide and 6.0, 6.1, 5.6, and 6.4 wt % of methane, respectively, at room temperature and 20 atm.