Flexible chiral pyrazolate-based metal-organic framework containing saddle-type CuI4(pyrazolate)4 unitsElectronic supplementary information (ESI) available: Ortep-style plot of the asymmetric units; topology analysis; XRPD patterns of lp- and np-CFA-9; and IR spectrum and gas sorption measurements of CFA-9. CCDC 1488850 and 1488851. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ce01594h

The syntheses and crystal structures of [Cu I 2 (phbpz)]·MeOH ( lp-CFA-9 , lp = large-pore) and [Cu I 2 (phbpz)] ( np-CFA-9 , np = narrow-pore; H 2 -phbpz = 3,3′,5,5′-tetraphenyl-1 H ,1′ H -4,4′-bipyrazole) are described. The copper( i )-containing metal-organic framework (termed C&cmb.b.line;oordination F&cmb.b.line;ramework A&cmb.b.line;ugsburg University-9, lp-CFA-9 ) crystallizes in the trigonal crystal system, within the chiral space group P 3 2 21 (no. 154) and with the following unit cell parameters: a =18.2348(6), c = 16.3950(4) Å, and V = 4721.1(2) Å 3 . Lp-CFA-9 features a 3-D microporous framework structure of Cu 4 pz 4 (pz = pyrazolate) SBUs with the D 2d (= 4&cmb.macr;2 m ) symmetry connected by single bonds creating one-dimensional channels expanding in the c -direction of the crystal lattice. The framework flexibility of CFA-9 has been demonstrated by single-crystal and powder X-ray analyses as well as by sorption measurements. CFA-9 exhibits weak binding of carbon monoxide on Cu( i ) centers. The reactivity of CFA-9 towards oxidizing agents, such as H 2 O 2 , t -BuOOH and Br 2 was also investigated. Additionally, CFA-9 shows luminescence upon exposure to UV radiation. CFA-9 , a chiral MOF containing saddle-type Cu I 4 (pyrazolate) 4 units, shows reversible breathing behavior and exhibits binding of CO.