Cobalt(II) complexes with the non-steroidal anti-inflammatory drug diclofenac and nitrogen-donor ligands

Synthesis, structural determination, in vitro and in silico biological evaluation of divalent or trivalent cobalt complexes with indomethacin

“…IR spectroscopy data reveal that indomethacin ligands are coordinated asymmetrically (Δv(CO 2 ) = 206 cm −1 for 4 and 244 cm −1 for 5 ) as well as the existence of the nitrogen-donor ligands ( ρ (C—H) phen = 728(m) cm −1 for 4 and ρ (C—H) Himi = 757(m) cm −1 for 5 ). In conclusion, the suggested structure of [Co(indo-O,O′) 2 (phen)] 4 is expected to be similar with that of complex 3 as well as with a series of Co(II)-NSAIDs complexes previously reported by our lab, such as [Co(diclofenac-O,O′) 2 (bipy)], [Co(diclofenac-O,O′) 2 (bipyam)] and [Co(diclofenac-O,O′) 2 (phen)] [ 15 ], [Co(tolfenamato-O,O′) 2 (bipyam)] [ 25 ], [Co(flufenamato-O,O′) 2 (bipyam)] and [Co(mefenamato-O,O′) 2 (bipyam)] [ 26 ], bearing an asymmetric bidentate chelating binding mode of the carboxylato group of the corresponding NSAID. In the case of complex [Co(indo-O) 2 (Himi) 2 ] 5 , its structure is expected to resemble the reported structure of complex [Co(diclofenac-O) 2 (Himi) 2 ] [ 15 ] having monodentate NSAID ligands bound to a tetra-coordinate Co(II) ion.…”

“…Furthermore, the presence of the nitrogen-donor ligands was proved via the characteristic bands assigned to the corresponding out-of-plane ρ(C—H) vibrations; these were found at 765(m) cm −1 for ρ (C—H) bipy in 2 , 770(m) cm −1 for ρ (C—H) bipyam in 3 , 728(m) cm −1 for ρ (C—H) phen in 4 , and 757(m) cm −1 for ρ (C—H) Himi in 5 [ 15 , 48 ].…”

“…In 1952, the first reported studies regarding the biological activity of cobalt complexes examined the toxicity of the optical isomers of [Co(en) 3 ](NO 3 ) 3 (en = ethylenediamine) [ 3 ]. Since then, many cobalt complexes of biological interest have been reported with the majority of them showing antiproliferative [ [4] , [5] , [6] , [7] ], antimicrobial [ [8] , [9] , [10] ], antifungal [ 11 , 12 ], antiviral [ 13 , 14 ], and antioxidant [ [15] , [16] , [17] ] activity.…”

“…One of the goals in this area is to synthesize novel compounds with enhanced or different pharmacological profile than that of the free ligand [ 20 , 21 ]. In the literature, there is a plethora of cobalt-NSAID complexes, such as those with tolfenamic acid [ 23 ], diflunisal, niflumic acid, flufenamic acid, mefenamic acid [ [26] , [27] , [28] ], diclofenac [ 15 , 16 , 29 ] and naproxen [ 30 ]. There is also a great number of transition metal complexes with indomethacin ligands [ 21 ], including manganese(II) [ 31 ], nickel(II) [ 32 , 33 ], copper(II) [ 34 , 35 ], tin(IV) [ 36 ] and zinc(II) complexes [ 37 ].…”

Crystal structure of bis(2-(2-((2,6-dichlorophenyl)amino)phenyl)acetato-κ2 O,O′)-(1,10-phenanthroline-κ2 N,N′)zinc(II), C40H28Cl4N4O4Zn

“…The bond angles of O-Zn-O are in the range of 59.36(12)°to 144.6(2)°. All geometric parameters are comparable to related ones [12,13]. There is a hydrogen bond between each O2 oxygen atom and the NH group of the organic ligands…”