Crystal structure and spectral studies of green fluorescent protein (GFP) chromophore analogue ethyl 2-[(4Z)-(6-hydroxy naphthalen-2-yl) methylene)-2-methyl-5-oxo-4,5-di hydro-1H-imidazol-1-yl] acetate

Synthetically modified green fluorescent protein chromophore derivative was prepared, its crystal structure and spectral properties were studied. Crystal data for C19H18N2O4: triclinic, space group P-1 (no. 2), a = 8.2506(17) Å, b = 11.934(2) Å, c = 17.461(4) Å, α = 102.89(3)°,   β = 94.62(3)°, γ = 96.68(3)°, V = 1654.5(6) Å3, Z = 4, T = 173(2) K, μ(MoKα) = 0.096 mm-1, Dcalc = 1.358 g/cm3, 7227 reflections measured (4.722° ≤ 2Θ ≤ 53.996°), 7227 unique (Rint = 0.0453, Rsigma = 0.0662) which were used in all calculations. The final R1 was 0.0561 (I > 2σ(I)) and wR2 was 0.1658 (all data). The single crystal structure showed, the benzylidine moiety adopts Z-conformation in solid state and the molecules were associated by various O−H···O and C−H···O non-covalent interactions. The UV absorption-emission spectral analysis indicated that a significant red shift of emission observed at alkaline pH indicating its utility for live cell imaging applications.

Crystal engineering of homochiral molecular organization of naproxen in cocrystals and their thermal phase transformation studies

Crystal engineering principles were used to produce the homochiral R- and S-chains of naproxen (NPX) by cocrystallization with bipyridine (BPY) and piperazine (PIZ).

Chiral crystals from an achiral molecule: 4,6-di-O-benzyl-1,3-O-benzylidene-2-O-(4-methoxybenzyl)-myo-5-inosose

The title achiral compound, C(35)H(34)O(7), crystallizes in the chiral monoclinic space group P2(1). The molecules are densely packed to form a helical assembly along the crystallographic twofold screw axis via C-H···O and C-H···π interactions. Interestingly, the unit-translated helical chains are loosely connected via a rather uncommon edge-to-edge Ph-H···H-Ph short contact (H···H = 2.33 Å).