Solvent-free synthesis of three layered manganese sulfate-oxalates with different pore apertures

Three manganese sulfate-oxalates, namely, H₂pip·Mn₂(SO₄)₂(ox)(H₂O)₂·2H₂O (1), H₃ipa⋅Mn₂(SO₄)(ox)_2.5·H₂O (2), and H₃dpta⋅Mn₂(SO₄)₂(ox)_1.5(H₂O)₃ (3), were prepared under solvent-free conditions, where pip = piperazine, ox = oxalate, ipa = 3,3′-iminobis(N,N-dimethylpropylamine), and dpta = dipropylenetriamine. These compounds have different layered structures intercalated with organic cations. Their pore apertures range from small 8-membered ring (8 MR) to large 12 MR and extra-large 20 MR. The temperature dependence of the magnetic susceptibility of these compounds were also investigated.     

Diffraction from phase modulated apertures

We apply the Rayleigh-Sommerfeld diffraction integral to solve the diffracted fields of periodically phase-modulated apertures. We show that the diffraction of small phase modulated apertures (with few refractive index modulation periods) behaves as for phase gratings, but the sharp diffraction peaks may already appear in the Fresnel region behind the aperture. Thus, these components may serve as lensless miniature interconnection gratings in micro-optics.