A series of Cu(II) coordination polymers, [Cu(m 2 -L1) 3 ]PO 3 F (1), [Cu 2 (m 2 -L1) 4 (m 4 -L1)](NO 3 ) 4 $2H 2 O (2), [Cu(m 2 -L1) 2 (m 2 -involving new bifunctional p-phenylene bridged bi(1,2,4-triazole) and mixed 1,2,4-triazole-tetrazolate based ligands (L1¼ 1,4-phenylene-4,4 0 -bi(1,2,4-triazole), HL2¼ 5-(4-[1,2,4]triazol-4-yl-phenyl)-1H-tetrazole) has been prepared under hydrothermal conditions and their structures have been established by means of X-ray diffraction. In crystal structures 1-8, the organic ligands, utilizing two neighboring nitrogen atoms (N1, N2 in triazole (trz) and N2, N3 in tetrazolate), behave either in m 2 or in m 2 + m 4 manner binding the adjacent metal centers or Cu 3 (m 2 -OH) 2 clusters into 1D columns (1, 3, 4), 2D zigzag layers (2) and 3D frameworks (5-8). The mutual coplanarity between uncoordinated trz moiety and p-phenylene spacer as well as its radial disposition around the ''propeller-like'' [Cu 2 (h 2 -trz) 3 ] subunits is a crucial factor, which specifically mediates multiple p-p interactions through intercalation of the neighboring Cu(h 2 -trz) n (n ¼ 2,3) axles, and as a consequence, affording one-dimensional channels with trigonal (1, 2) or rhombic geometry (3, 4). Large rectangular channels have been realized in neutral [Cu(m 4 -L1)(m 2 -SO 4 )] n (7) and cationic [Cu 2 (m 4 -L2) 3 ] n n+ (8) frameworks, in which the remaining void space is filled by water molecules and counter anions (Cl À ).

Nuclear Magnetic Resonance allows the non-invasive detection and quantitation of metabolites to be carried out in cells and tissues. This means that that metabolic changes can be revealed without the need for sample processing and the destruction of the biological matrix. The main limitation to the application of this method to biological studies is its intrinsic low sensitivity. The introduction of hyperpolarization techniques and, in particular, of dissolution-Dynamic Nuclear Polarization (d-DNP) and ParaHydrogen Induced Polarization (PHIP) is a significant breakthrough for the field as the MR signals of molecules and, most importantly, metabolites, can be increased by some orders of magnitude. Hyperpolarized pyruvate is the metabolite that has been most widely used for the investigation of metabolic alterations in cancer and other diseases. Although d-DNP is currently the gold-standard hyperpolarization method, its high costs and intrinsically slow hyperpolarization procedure are a hurdle to the application of this tool. However, PHIP is cost effective and fast and hyperpolarized pyruvate can be obtained using the so-called Side Arm Hydrogenation approach (PHIP-SAH). The potential toxicity of a solution of the hyperpolarized metabolite that is obtained in this way is presented herein. HP pyruvate has then been used for metabolic studies on different prostate cancer cells lines (DU145, PC3, and LnCap). The results obtained using the HP metabolite have been compared with those from conventional biochemical assays.

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An efficient synthesis of vinyl‐[1‐13C]pyruvate has been reported, from which 13C hyperpolarized (HP) ethyl‐[1‐13C]pyruvate has been obtained by means of ParaHydrogen Induced Polarization (PHIP). Due to the intrinsic lability of pyruvate, which leads quickly to degradation of the reaction mixture even under mild reaction conditions, the vinyl‐ester has been synthesized through the intermediacy of a more stable ketal derivative. 13C and 1H hyperpolarizations of ethyl‐[1‐13C]pyruvate, hydrogenated using ParaHydrogen, have been compared to those observed on the more widely used allyl‐derivative. It has been demonstrated that the spin order transfer from ParaHydrogen protons to 13C, is more efficient on the ethyl than on the allyl‐esterdue to the larger J‐couplings involved. The main requirements needed for the biological application of this HP product have been met, i. e. an aqueous solution of the product at high concentration (40 mM) with a good 13C polarization level (4.8 %) has been obtained. The in vitro metabolic transformation of the HP ethyl‐[1‐13C]pyruvate, catalyzed by an esterase, has been observed. This substrate appears to be a good candidate for in vivo metabolic investigations using PHIP hyperpolarized probes.

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