¹H-NMR spectra were recorded on a JEOL JNM-GSX 400 spectrometer with tetramethylsilane (TMS) as the internal standard. IR spectra were recorded with a JASCO FT-IR 4100 spectrometer. Thermogravimetric (TG) analyses were performed on a Rigaku TG8120 instrument. Solid-state circular dichroism (CD) spectra were recorded as KBr pellets on a JASCO J-820 CD system.

(R)- and (S)-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxylic acid (2) were synthesized according to the procedure previously reported by D. J. Cram et al. [49].

A mixture of (R)-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxylic acid (2) (78 mg, 0.2 mmol) and MnCl₂·4H₂O (40 mg, 0.2 mmol) was dissolved in DMF (1 mL) and H₂O (2 mL), and then pyridine (1 mL) was added to the solution. The solution was stirred for 30 min at room temperature and then left for 3 days. Pale yellow prisms were obtained, filtered, and dried at room temperature to give (R)-MOF-2 (132 mg). IR (KBr pellet, cm⁻¹): 3,402, 2,931, 1,655, 1,559, 1,505, 1,457, 1,392, 1,336, 1,309, 1,242, 1,101, 932, 874, 810, 755, 702.

X-ray single-crystal diffraction data for (R)-MOF-2 were collected on a Rigaku RAXIS RAPID imaging plate diffractometer using Cu Kα radiation. Crystal data: Formula C₆₂H₇₄Mn₂N₆O₂₂, Formula weight 1365.17, Space group P2₁(# = 10.9585(3), b = 25.2165(8), c = 11.8505(9) Å, β = 96.629(7)°, V = 3252.8(3) ų, Z = 2, ρ = 1.394 g/cm³, 2θ_max = 136.4°, R1 = 0.0514 (for 8372 reflections with I > 2σ(I)), wR2 = 0.1315 (for 11,652 reflections), GOF = 0.985, Flack parameter = 0.009(4) (calculated using 5,571 Friedel pairs). The structure was solved by SHELXS97 and refined by SHELXL97. The absolute structure was deduced from the Flack parameter.

838075. See http://www.rsc.org/suppdata/cc/….….…./ for crystallographic data in cif or other electric formats.

Chiral ligand (R)-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxylic acid (2) was prepared in good yield by the diastereomeric complexation of rac-2 with L-(+)-leucine methyl ester (Scheme 3). The CD spectra of (R)-(+)- and (S)-(−)-2 in CHCl₃ are shown in Figure 1.

New homochiral (R)-MOF-2 [Mn₂((R)-1)₂(DMF)₄(H₂O)₄]·2DMF was synthesized by the reaction of (R)-(+)-2 and MnCl₂·4H₂O in the presence of pyridine in DMF at room temperature. The product was characterized by IR spectroscopy, CD spectroscopy, thermogravimetric analysis (TGA), and X-ray analysis. The IR spectra of (R)-MOF-2 exhibited peaks of νOH and νCO₂⁻ at 3,401 and 1,559 cm⁻¹, respectively. TGA showed that (R)-MOF-2 loses 34.3% of its total weight in the range of 26–300 °C, which is ascribed to the loss of six DMF and four water molecules per formula unit (calculated at 37.4% of the total weight) (Figure 2).

X-ray diffraction measurement revealed that (R)-MOF-2 crystallizes in a chiral space group of P2₁. An asymmetric unit of (R)-MOF-2 contains two Mn²⁺ ions, two (R)-2²⁻groups, four DMF molecules, four water molecules, and two DMF guest molecules, as shown in Figure 3. The Mn²⁺ ion is coordinated by two (R)-2^2-groups, two DMF molecules, and two water molecules. The sixth coordination site of Mn1, although vacant in Figure 3, is occupied by O11 of the (R)-2 group lying in the next unit cell in the direction of a-axis. A helical chain composed of –Mn–(R)-2–Mn–(R)-2– is thus formed in the right-handed form and extends along the a-axis as shown in Figure 4. The guest molecules are bound to the water molecules by the hydrogen bonds of O21–H…O18 and O22–H…O19.

We also prepared (S)-MOF-2 using (S)-2 as the chiral ligand. As shown in Figure 5, the solid-state CD spectra of (R)- and (S)-MOF-2 synthesized from (R)- and (S)-2, respectively, are mirror images of each other, thus indicating that the helices built from (R)- and (S)-2 are enantiomeric.