Structure and magnetism of Co(II) complexes with bidentate heterocyclic ligand Hsalbim derived from benzimidazole

Two mononuclear Co(II) complexes based upon 2-(1H-benzimidazol-2-yl)phenol, abbreviation Hsalbim ligand, have been prepared and studied. The structure of Hsalbim and [Co(salbim)₂] have been confirmed by X-ray structure analysis. The second cobalt(II) complex matches the formula [Co(salbim)₂]·(Hsalbim)·MeOH assuming a co-crystallization of one neutral ligand. The electronic spectra are consistent with the tetrahedral pattern. Magnetic susceptibility measurements down to T = 2 K along with the magnetization data until B = 7 T show that the Co(II) complexes are high-spin with a considerable zero-field splitting of the ⁴B₁(D_2d) term: D/hc = 67 and 55 cm⁻¹, respectively.     

Co(II), Ni(II) and Zn(II)-orotate complexes with N-methylimidazole: Synthesis, crystal structures and antimicrobial activities

Three Co(II), Ni(II) and Zn(II) complexes of orotate with the N-methylimidazole ligand were synthesized and characterized by means of elemental and thermal analysis, magnetic susceptibilities, IR, UV-Vis spectroscopic and antimicrobial activity studies. The crystal structures of [Co(HOr)(H₂O)₂(Nmeim)₂]₃·H₂O (1), [Ni(HOr)(H₂O)₂(Nmeim)₂] (2) and [Zn(HOr)(H₂O)(Nmeim)₂] (3) were determined by the single crystal X-ray diffraction technique (H₃Or = orotic acid and Nmeim = N-methylimidazole). In complexes 1 and 2, the Co(II) and Ni(II) ions have distorted octahedral geometries with two Nmeim, one orotate and two aqua ligands. Complex 3 has a distorted trigonal bipyramidal geometry with two N-methylimidazole, one orotate and one aqua ligands. In the complexes, the orotate is coordinated to the metal(II) ions through the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group as a bidentate ligand. The complexes form a three-dimensional framework by hydrogen bonding, C-H?π and π?π stacking interactions. The MIC values of the complexes against selected microorganisms were determined to be in range 300-2400 μg/mL.     

Paramagnetic ruthenium(III) complexes bearing O,O chelating ligands: Synthesis, spectra, molecular structure and electron transfer properties

Paramagnetic Ru(III) complexes of the type [RuX₂(EPh₃)₂(L)] (where X = Cl or Br; E = P or As; L = monobasic bidentate benzophenone ligand) have been synthesized from the reaction of ruthenium(III) precursors, viz. [RuX₃(EPh₃)₃] (where X = Cl, E = P; X = Cl or Br, E = As) or [RuBr₃(PPh₃)₂(CH₃OH)] and substituted hydroxy benzophenones in a 1:1 molar ratio in benzene under reflux for 6 h. The hydroxy benzophenone ligands behave as monoanionic bidentate O,O donors and coordinate to ruthenium through the phenolate oxygen and ketonic oxygen atoms, generating a six-membered chelate ring. The compositions of the complexes have been established by analytical and spectral (FT-IR, UV-Vis, EPR) and X-ray crystallography methods. The single crystal structure of the complex [RuCl₂(PPh₃)₂(L₁)] (1) has been determined by X-ray crystallography and indicates the presence of a distorted octahedral geometry in these complexes. The magnetic moment values of the complexes are in the range 1.75-1.89 μ_B, which reveals the presence of one unpaired electron in the metal ion. EPR spectra of liquid samples at liquid nitrogen temperature (LNT) show a rhombic distortion (g_x ≠ g_y ≠ g_z) around the ruthenium ion. The complexes are redox active and display quasi-reversible oxidation and quasi-reversible reduction waves versus Ag/AgCl.     

Comparison of crystal structures and magnetic properties of two Co(II) complexes containing different dicarboxylic acid ligands

Two novel cobalt(II) complexes, [Co(μ-succinato)(H₂O)₂(pyridine)₂]_n1 and {[Co₂(μ-H₂O)(μ-glutarato)₂(pyridine)₂]·pyridine}_n2 have been synthesized by a wet chemistry method. In complex 1, the Co(II) ions are linked through succinate ligands to created one-dimensional polymeric chain along the b-axis. Complex 2 consists of a polymeric chain of dinuclear Co(II) moieties in which two cobalt(II) ions are linked through a bridging water and two bridging carboxylate groups from two glutarate ligands. The glutarate ligands in complex 2 display two coordination modes, interbinuclear bridging and intrabinuclear bridging. All the bond angles of the alkyl chain in complex 2 are between 115.7° and 118.5°, supporting the gauche conformation. Free pyridine molecules were found in the cavities between the chains. Two strong intramolecular hydrogen bonds are observed between the coordinated water and the uncoordinated carboxylate oxygen atom in both complexes. Complex 2 is further stabilized by π–π stacking of pyridine molecules. Complex 1 is a paramagnet (C = 3.50(1) cm³ K mol and θ = −5.0(5) K) and complex 2 exhibits a broad maximum at 4 K due to weak coupling within the dimeric unit.     

Synthesis and characterisation of dinuclear and mononuclear Cobalt (II) benzoate complexes

Aqua-bridged binuclear cobalt (II) benzoate complexes having pyridine as auxiliary ligands are synthesised through solid state reactions and characterised. The binuclear core in these complexes comprise of two bridging benzoates and an aqua bridge. Each of the cobalt (II) centre is further co-ordinated to one benzoate and two pyridine ligands. The aqua-bridged cobalt (II) benzoate complex [Co₂(μ-H₂O)(μ-OBz)₂(OBz)₂(Py)₄] ·  (C₆H₆)(BzOH) (1a) is inclusion compounds with benzoic acid and benzene (where OBz  =  benzoate, py  =  pyridine). Analogous complex [Co₂(μ-H₂O)(μ-OBz)₂(OBz)₂(Py)₄] · 1.5(C₆H₆) without benzoic acid included is also prepared by an alternative method and structurally characterised. Analogous aqua-bridged complex derived from p-chlorobenzoic acid in unsolvated form is characterised. The Co–O–Co separation in these complexes is in the range of 3.55–3.64 Å with angles Co–O–Co varying from 111.8° to 116.4°. While similar reaction in solution leads to the formation of mononuclear complex having composition [Co(OBz)₂(Py)₂(H₂O)]. The unsubstituted benzoate complex 1a can be easily oxidised to form a tetrameric cobalt (III) complex having benzoate and oxo-bridged structure with a Co₄O₄ core.     

pH and molar ratio dependent formation of monomeric,dimeric and tetrameric cobalt malate complexes

The reactions of cobalt(II) chloride with racemic malic acid (H₃mal = C₄H₆O₅) result in the isolation of monomeric, dimeric and tetrameric cobalt malato complexes: (NH₄)₂[Co(R-Hmal)(S-Hmal)] · 2H₂O (1), [Co₂(R-Hmal)(S-Hmal)(H₂O)₄]_n · 2nH₂O (2), K₄[Co₄(OH)₂(R-mal)₂(S-mal)₂(H₂O)₄] · 10H₂O (3) and trans-[Co(R-H₂mal)(S-H₂mal)(H₂O)₂] · 2H₂O (4). The formations of the malato complexes are dependent on the pH value, the molar ratio of the solutions, the reaction temperature and the counterions. In the water-soluble compound 1, the Co^II ion is octahedrally coordinated by two tridentate malates via their α-hydroxy, α-carboxy and β-carboxy groups. The malate ligands in 2 coordinate with the cobalt ion via their α-hydroxy and α-carboxy groups, while the β-carboxy group acts as a bridging ligand for the other two cobalt ions, forming a novel dimeric unit [Co₂(R-Hmal)(S-Hmal)(H₂O)₄], which further connects into a layered structure through links from the oxygen atoms of the β-carboxy groups. Complex 3 is a tetranuclear mixed-valence species. Both of the Co^II ions exist in trans-[Co(R-mal)(S-mal)(H₂O)₂] units, which are linked by a Co^III₂(OH)₂ unit with bridging α-alkoxy and β-carboxy groups. Compound 4 is the main product of reaction between cobalt chloride and excess malate under weakly acidic conditions.     

Hexatungstate subunit as building block in the hydrothermal synthesis of organic-inorganic hybrid materials: synthesis, structure and optical properties of Co2(bpy)6 (W6O19)2 (bpy=4,4′-bipyridine)

A hydrothermal reaction of WO₃, CoCl₂ and 4,4′-bipyridine, yields a novel organic-inorganic hybrid compound, Co₂(bpy)₆(W₆O₁₉)₂, at 170°C. X-ray single crystal structure determination reveals a two-dimensional covalent structure belonging to monoclinic crystal system, space group C2/c, with cell parameters a=19.971(4) Å, b=11.523(2) Å, c=16.138(3) Å, β=96.49(3)°, V=3690.0 Å³ and Z=2. The hexatungstate, [W₆O₁₉]²⁻, acts as a building block in bidentate fashion to bridge the Co(II) centers in the crystal structure. The title compound is found to have an optical energy gap of 2.2 eV from UV-Vis-NIR reflectance spectra.     

Reaction studies on some functionalized alkyl transition metal compounds and the crystal structure of [Cp(CO)3W{(CH2)3NO2}]

The reactions of the halogenoalkyl compounds [Cp(CO)₃W{(CH₂)_nX}] (Cp = η⁵-C₅H₅; n = 3-5; X = Br, I) and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃Br}] with the nucleophiles Z = CN⁻ and gave compounds of the type [Cp(CO)₃W{(CH₂)_nZ}] for the tungsten compounds, whilst cyclic carbene compounds were obtained from the reactions of the molybdenum compound. The reactions of [Cp(CO)₃W{(CH₂)_nBr}] (n = 3, 4) and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃Br}] with gave [Cp(CO)₃W{(CH₂)_nONO₂}] and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃ONO₂}], respectively. The reaction of [Cp(CO)₃W{(CH₂)_nBr}] with AgNO₂ gave [Cp(CO)₃W{(CH₂)_nNO₂}]. In the solid state the complex [Cp(CO)₃W{(CH₂)₃NO₂}] crystallizes in a distorted square pyramidal geometry. In this molecule the nitropropyl chain deviates from the ideal, all-trans geometry as a result of short, non-hydrogen intermolecular N-O?O-N contacts. The reactions of the heterobimetallic compounds [Cp(CO)₃W{(CH₂)₃}ML_y] {ML_y = Mo(CO)₃Cp, Mo(CO)₃Cp^∗ and Mo(CO)₂(PMe₃)Cp; Cp^∗ = η⁵-C₅(CH₃)₅} with PPh₃ and CO were found to be totally metalloselective, with the ligand always attacking the metal site predicted by the reactions of the corresponding monometallic analogues above with nucleophiles. Thus the compounds [Cp(CO)₃W{(CH₂)₃}C(O)ML_z] {ML_z = Mo(CO)₂YCp, Mo(CO)₂YCp^∗ and Mo(CO)Y(PMe₃)Cp; Y = PPh₃ or CO} were obtained. Similarly, the reaction of [Cp(CO)₂Fe{(CH₂)₃}Mo(CO)₂(PMe₃)Cp] with CO gave only [Cp(CO)₂Fe{(CH₂)₃C(O)}Mo(CO)₂(PMe₃)Cp]. Hydrolysis of the bimetallic compound, [Cp(CO)₃W(CH₂)₃C(O)Mo(CO)(PPh₃)(PMe₃)Cp], gave the carboxypropyl compound [Cp(CO)₃W{(CH₂)₃COOH}]. Thermolysis of the compound [Cp(CO)₂Fe(CH₂)₃Mo(CO)₃(PMe₃)Cp] gave cyclopropane and propene, indicating that β-elimination and reductive processes had taken place.     

Synthesis and structures of 3-sila-β-diketiminato complexes of the coinage metals

The dimeric copper(I) 3-sila-β-diketiminate [Cu{(N(R)C(Ar))₂SiR}]₂ · (thf) (1) was obtained from CuI and [Li{(N(R)C(Ar))₂SiR}(thf)₂] (B) in toluene (R = SiMe₃, Ar = C₆H₃Me₂-2,6). When [CuI(PPh₃)₃] was used as a starting material, the LiI-containing compound [Cu{Si(R)(C(Ar)N(R))₂Li(μ-I)}(PPh₃)] (2) was isolated. The reaction of [MI(PPh₃)_n] (M = Ag, n = 3; M = Au, n = 2) with two equivalents of B in toluene gave the isomorphous silver and gold 3-sila-β-diketiminates [M{Si(R)(C(Ar)N(R))₂Li}₂(μ-I)] [M = Ag (3), Au (4)]. Each of 1-4 was characterised by the multinuclear NMR spectroscopy and single-crystal X-ray diffraction crystallography.     

Synthesis,spectroscopy, electrochemistry,and methylation reaction of the dithiolate-based cobalt(II) complex derived from tert-butyl N-(2-mercaptoethyl)carbamate

A dithiolate-containing a carbamate mononuclear cobalt(II) complex namely, [Co(Boc-S)₂] (1), was obtained by the reaction of a methanolic solution of cobalt(II) nitrate hexahydrate with two equimolar amounts of the deprotonated form of tert-butyl N-(2-mercaptoethyl)carbamate (Boc-SH). The cobalt(II) complex (1) was characterized in the solid state and in solution by using FT–IR, Raman, UV–visible, and EI–mass spectroscopies, as well as thermal and X-ray diffraction studies. Spectral data showed that the carbamate (Boc-SH) acts as a mono-anionic bidentate ligand coordinating the cobalt(II) ion through two imine nitrogen and two deprotonated thiolate sulfur donor atoms in a distorted tetrahedral geometry. The thermoanalytical data evidence that the complex is stable up to 165 °C and undergoes complete decomposition, resulting in CoO. TEM imaging of the oxide residue shows its nano size clusters, suggesting that the complex (1) may be used as a precursor for nano-oxides. X-ray powder diffraction patterns evidence an isomorphism among the complex. The redox behavior of the cobalt(II) complex was also investigated by cyclic voltammetry. The reaction of the dithiolate cobalt(II) complex (1) with methyl iodide appears to occur intramolecularly with the cobalt-bound dithiolate, forming the cobalt(II)-bound dithioether complex [Co(Boc–SCH₃)₂]I₂ (2), as a dication complex with a clean second-order reaction of 13.24 × 10⁻² M⁻¹·s⁻¹.     

Synthesis of the first examples of stable heterometallic isopropoxides of an organometallic RSn(IV) moiety

Five-, six-, and seven-coordinate volatile butyltin(IV) heterobimetallic derivatives, respectively of the types, [BuSn{(μ-OPrⁱ)₂Al(OPrⁱ)₂}Cl₂] (1), [BuSn{(μ-OPrⁱ)₂Al(OPrⁱ)₂}₂Cl] (2), and BuSn{(μ-OPrⁱ)₂M(OPrⁱ)_x − 2}₃ (3:M = Al (x = 4); 4:M = Ga (x = 4); 5:M = Nb (x = 6)) have been synthesized by the reactions of BuSnCl₃ with potassium tetraisopropoxoaluminate in 1:1, 1:2, and 1:3 molar ratios. Replacement reactions of chloride in (1) and (2) with appropriate alkoxometallate (tetraisopropoxoaluminate, tetraisopropoxogallate, or hexaisopropoxoniobate) ligands result in the formation of novel BuSn(IV) heterotri- and tetra-metallic derivatives. All of these derivatives have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (IR, ¹H, ²⁷Al, and ¹¹⁹Sn NMR) studies. Based on these studies, plausible structures for the new derivatives involving bidentate ligation of the alkoxometallate ligands have been suggested.     

Incorporation of a tripodal ligand with a (N,O,O)-donor set into a new family of nickel and cobalt spin clusters

The reaction of Ni(OAc)₂, NiX₂ (X = Cl, Br) or CoCl₂ with the proligand 2-amino-2-methyl-1,3-propanediol (ampdH₂) affords a new family of tetranuclear complexes. The syntheses of [Ni₄(OAc)₄(ampdH)₄] (1) and [M₄X₄(ampdH)₄] (M = Ni, X = Cl, 2; M = Ni, X = Br, 3; M = Co, X = Cl, 4) are reported, together with the single crystal X-ray structures of 1, 2 and 4 and the magnetochemical characterization of 1, 3 and 4. Each member of this family of complexes displays a low symmetry structure that incorporates a {M₄O₄} core unit based on a distorted cubane. Magnetic measurements reveal ferromagnetic exchange interactions for 1, 3 and 4. These give rise to S = 4 ground state spins for the tetranuclear Ni complexes and an anisotropic effective S′ = 2 ground state for the Co complex.     

Oxidative addition of (PhSe)2 and (FcSe)2 to zerovalent palladium and platinum trialkylphosphine complexes (Fc = ferrocenyl, [Fe(η-C5H5)(η-C5H4)])

Room temperature reaction of [Pd₂(dba)₃]/PR₃ or [Pt(C₂H₄)(PR₃)₂] (dba = dibenzylideneacetone; R = Et, Bu) with the diselenides (R′Se)₂ (R′ = Ph, Fc) yielded the oxidative addition products trans-[M(SeR′)₂(PR₃)₂] (M = Pd, Pt). These have been characterised by multinuclear NMR and UV-Vis spectroscopy, mass spectrometry, and, in the cases of trans-[Pt(SePh)₂(PR₃)₂] (R = Et, Bu) and trans-[Pt(SeFc)₂(PBu₃)₂], also by X-ray crystallography.     

Synthesis, structure and optical limiting properties of organoruthenium-chalcogenide clusters

Treatment of Ru₃(CO)₁₂ with Ph₃PS affords the compounds [Ru₃(μ₃-S)₂(CO)_9 − n(PPh₃)_n] (n = 1 (1a), 2 (2a)) and [Ru₃(μ₃-S)(μ₃-CO)(CO)₇(PPh₃)₂] (3a) as the major products. Single crystal X-ray diffraction studies of [Ru₃(μ₃-S)₂(CO)₈(PPh₃)] and [Ru₃(μ₃-S)(μ₃-CO)(CO)₇(PPh₃)₂] show these two classes of compounds to contain square pyramidal Ru₃S₂ and trigonal pyramidal Ru₃S metal cores, respectively, with the latter being isostructural to the analogous selenide cluster compound. The clusters [Ru₃(μ₃-E)₂(CO)_9 − n(PPh₃)_n] (E = S, n = 1; E = Se, n = 2) readily undergo ligand displacement reactions with PPh₃ to afford the compounds [Ru₃(μ₃-E)₂(CO)₆(PPh₃)₃] (E = S, 5a; E = Se 5b). The mixed chalcogenide cluster, [Ru₃(μ₃-S)(μ₃-Se)(CO)₇(PPh₃)₂] (6), was prepared from the reaction of [Ru₃(μ₃-S)(μ₃-CO)(CO)₇(PPh₃)₂] and SePPh₃. The optical limiting properties of the complexes 1a,b, 2a,b, 5a,b have been measured by the Z-scan technique employing 40 ns pulses at 523 nm; power limiting was observed for all clusters under our experimental conditions.     

Supramolecular networks through second-sphere coordination based on 1D metal-4,4′-dipyridyldisulfide coordination polymers and hydrogenfumarate or sulfonate anions

Four hydrogen-bonded assemblies of formula [M(dpds)₂(OH₂)₂]A₂·nH₂O (A = anion) are described. These assemblies result from the second-sphere coordination interactions between the 1D coordination polymers [M(dpds)₂(OH₂)₂]²⁺, M = Zn(II) and Cu(II), dpds = 4,4′-dipyridyldisulfide, and the pyridine-3-sulfonate (3pySO₃⁻) or hydrogenfumarate (Hfum⁻) anions. Significantly, supramolecular structural variations are observed depending on the presence of water lattice molecules, which formed discrete aggregates when the Hfum⁻ anion was used. The effects of geometrical variations in the building blocks are also evident on using Jahn-Teller-distorted divalent Cu(II) ions or regular octahedral species based on Zn(II) ions. The second-sphere effects on the stabilization of the compounds are illustrated by TGA experiments.     

Syntheses, structures and magnetic properties of two new one-dimensional cobalt (II) phosphites with organic amines acting as ligands

Two new one-dimensional (1D) inorganic-organic hybrid cobalt (II) phosphites Co(HPO₃) (py) (1) and [Co(OH)(py)₃][Co(py)₂][HPO₂(OH)]₃ (2) have been prepared under solvothermal conditions in the presence of pyridine (py). Compound 1 crystallizes in the monoclinic system, space group p2(1)/c, a=5.3577(7) Å, b=7.7503(10) Å, c=17.816(2) Å, β=94.327(2)°, V=737.67(16) Å³, Z=4. Compound 2 is orthorhombic, Cmcm, a=16.3252(18) Å, b=15.7005(16) Å, c=13.0440(13) Å, β=90.00° V=3343.4(6) Å³ and Z=4. Compound 1 possesses a 1D ladder-like framework constructed from CoO₃N tetrahedral, HPO₃ pseudo-pyramids and pyridine ligands. While compound 2 is an unusual inorganic-organic hybrid 1D chain, which consists of corner-shared six-membered rings made of CoO₃N₃/CoO₄N₂ octahedra and HPO₃ pseudo-pyramids through sharing vertices.     

Preparation and structural characterization of nickel(II), cobalt(II), zinc(II) and tin(IV) complexes of the isatin Schiff bases of S-methyl and S-benzyldithiocarbazates

The molecular structures of the isatin Schiff bases of S-methyldithiocarbazate (Hisasme) and S-benzyldithiocarbazate (Hisasbz) have been determined by X-ray diffraction and their complexes of general formula [ML₂]·n(solvate) [M = Co²⁺, Ni²⁺, Zn²⁺; L = anionic forms of Hisasme or Hisasbz; solvate = DMF, DMSO; n = 1, 2] and [Sn(L)Ph₂Cl]·nMeOH (n = 0, 1) have been synthesized and characterized by a variety of physicochemical techniques and X-ray diffraction. The bis-ligand complexes, [Ni(isasbz)₂]·2DMSO and [Co(isasme)₂]·DMF have a six-coordinate, distorted octahedral geometry with the two uninegatively charged tridentate ONS ligands coordinated to the metal ions meridionally via the amide O-atoms, the azomethine nitrogen atoms and the thiolate sulfur atoms. By contrast, the crystal structure of [Zn(isasbz)₂]·2DMF shows a four-coordinate distorted tetrahedral geometry with the two Schiff bases coordinated as NS bidentate ligands via the azomethine nitrogen atoms and the thiolate sulfur atoms. Steric constraints of the rigid tridentate ligands lead to unusual ‘pseudo-coordination’ of the O-donors which occupy sites close to the metal but too distant to be considered as true coordinate bonds.The crystal structures of the tin(IV) complexes [SnLPh₂Cl]·nMeOH (L = isasme and isasbz; n = 0, 1) also show that the Schiff bases act as monoanionic bidentate NS chelating agents coordinating the tin(IV) ion via the azomethine nitrogen atoms and the thiolate sulfur atoms, the tin atom in each complex is five-coordinate with a highly distorted geometry intermediate of square pyramidal and trigonal bipyramidal. Again Sn?O contacts are weak and do not qualify as coordinate bonds.     

Nickel(II) derivatives of N-benzyliminodiacetate(2−) ligands,with and without imidazole: Synthesis,crystal structure and properties

In an attempt to prepare binary and ternary compounds, we have obtained two molecular complexes [Ni(MEBIDA or MOBIDA)(H₂O)₃]·nH₂O (n = 0 or 1) and two iso-type salts [Ni(Him)₆][Ni(MEBIDA or MOBIDA)₂]·4H₂O [MEBIDA = N-(p-methylbenzyl)iminodiacetate(2−) and MOBIDA = N-(p-methoxybenzyl)iminodiacetate(2−) ligands, Him = imidazole]. Our results are discussed with regard to related copper(II) and nickel(II) compounds. The reasons for which these chelating ligands produce nickel(II) salts instead of ternary compounds remain unclear since other iminodiacetate-like ligands give true ternary Ni(II) compounds with imidazole and other N-heterocyclic ligands.     

Second sphere coordination in fluoroanion binding: Synthesis, spectroscopic and X-ray structural study of [Co(phen)2CO3](Pfbz)·6H2O

To explore the anion receptor potential of [Co(phen)₂(CO)₃]⁺ for the pentafluorobenzoate ion, [Co(phen)₂(CO)₃](Pfbz)·6H₂O (where phen = 1,10-phenanthroline and Pfbz = pentafluorobenzoate) was synthesized by reacting appropriate salts in aqueous medium. A detailed packing analysis has been undertaken to delineate the role of second sphere C-H?F interactions amid other heteroatom interactions. The complex salt has been characterized by elemental analyses, spectroscopic studies (IR, UV/Vis, multinuclear NMR) and solubility product measurement. The complex salt crystallizes in the monoclinic crystal system with space group P2₁/n having the cell dimensions a = 13.377(3) Å, b = 17.204(3) Å, c = 15.408(3) Å, β = 108.11(3)°, V = 3370.1(12) Å³ and Z = 4. Single crystal X-ray structure determination revealed ionic structure consisting of complex cation, [Co(phen)₂(CO)₃]⁺, Pfbz anion and six lattice water molecules. In the crystal lattice, discrete ions [Co(phen)₂CO₃]⁺ are forming rectangular voids in which the Pfbz anions are entrapped. Crystal lattice is stabilized by electrostatic forces of attraction and hydrogen bonding interactions, i.e. O-H?O, C-H?O, and C-H?F, involving second sphere coordination besides π?π interactions.