A series of new supramolecular structures constructed from triethylenediamine and different polyoxometalates

Three new supramolecular compounds based on triethylenediamine and different polyoxometalates [W^VI₃V^V₃O₁₉H]{[Cu(HDABCO)]₂(H₂O)} (1), [P₂Mo^VI₁₈O₆₂][HDABCO]₂[H₂DABCO]₂·12 H₂O (2) and [Mo^VI_7.5W^VI_0.5O₂₇][Cu(HDABCO)]₂·2 H₃O·2 H₂O (3) (DABCO=triethylenediamine) have been synthesized hydrothermally and characterized by IR, TG, XPS and X-ray diffraction analyses. Crystal structure analyses reveal that compound 1 exhibits a face-centered cubic packing motif, compound 2 displays a supramolecular structure constructed form the “chains” arranged hexagonally, compound 3 contains [Mo_7.5W_0.5O₂₇]_∞ chain decorated by [Cu(HDABCO)]²⁺ cations, which was then packed into a layer structure. These results show that the same organonitrogen combining with the different POMs will yield different supramolecular networks.     

Reactions of Chalcogenide β-Diiminate Nickel Complexes with Samarium Bis(pentamethylcyclopentadienide)

The reactions of [(L^iPrNi)₂(μ-η²:η²-S₄)] (I) and [(L^iPrNi)₂(μ-η²:η²-Se₂)] (II) (L^iPr = CH[C(Me)N(2,6- ⁱ Pr₂C₆H₃)]₂) with decamethylsamarocene [Sm(Cp*)₂(Тhf)₂] (Cp* = η⁵-C₅Me₅) are studied. It is assumed that the reactions afford hetero-d/f-metal complexes. However, these complexes are not observed but the transfer of chalcogens from Ni to Sm and the formation of [(Sm(Cp*)₂(Тhf))₂(μ-S)] (III) and [(Sm(Cp*)₂(Тhf))₂(μ-Se)] (IV) occur. The second reaction products are [(L^iPrNi)₂(μ-η²:η²-S₂)] (V) in the case of sulfur and [(L^iPrNi^I)₂(μ-η⁶:η⁶-C₇H₈)₂] (VI) in the case of selenium. All reaction products have been described previously, but compounds III and V are isolated as new crystalline phase, the structures of which are determined by X-ray diffraction analysis (CIF files CCDC nos. 1559045 (V) and 1559046 (III)).     

Two Ag(I)–Ni(II) Heterobimetallic Coordination Polymers Based on Metalloligand and Bridging Ligands: Syntheses,Structures and Luminescence Properties

Two new one-dimensional heterobimetallic coordination polymers, {[Ni(2-pytpy)₂][Ag₂(SCN)₄]}_n (2-pytpy = 4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine) and {[Ni(2-pytpy)₂][Ag₂(N(CN)₂)₃(NO₃)DMSO]}_n (DMSO = dimethyl sulfoxide), were synthesized from the reaction of metalloligand [Ni(2-pytpy)₂]²⁺ and Ag⁺ with bridging ligands (SCN^? for 1, N(CN) ₂ ^? for 2). 1 and 2 were well characterized by elemental analysis, Fourier-transform infrared spectroscopy, thermal analysis and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that both 1 and 2 possess one-dimensional (1D) chain structures, which are constructed from metalloligands [Ni(2-pytpy)₂]²⁺ and dinuclear silver structural units ([Ag₂(SCN)₄] for 1, [Ag₂(N(CN)₂)₃(NO₃)DMSO] for 2). These 1D chains are further constructed into 3D supramolecular structures through the intermolecular hydrogen bonds. The solid-state luminescence properties of 1 and 2 were also investigated.     

Halogen-Dependent Thermochromic Properties in Three Methyl-Viologen/Haloargentate Charge Transfer (CT) Salts

Three charge transfer (CT) salts, [MV(Ag₂X₄)]_n (MV²⁺ = N,N′-dimethyl-4,4′-bipyridinium, X = Cl (1), Br (2)) and [MV(Ag₂I₄)?H₂O]_n (3) have been synthesized by using MV²⁺ as electron acceptor and different haloargentates as electron donor. Notably, the structural and optical characterization for three hybrids reveal halogen-dependent intermolecular CT band (estimated band gaps 3.0, 2.79, and 2.27 eV respectively) and consequent resulted thermochromic behaviors (inactive for 1 and 2 and active for 3).     

Organic/Bismuth Iodides Hybrids: Structural Perturbation of Substitutes and Their Photocurrent Response Properties

Two new organic/bismuth halides hybrids, (Et₂DABCO)₂(Bi₂I₁₀) (1) and (Pr₂DABCO)₂(Bi₂I₁₀) (2) (Et₂DABCO²⁺ = N, N’-diethyl-1,4-diazabicyclo[2.2.2] octane, Pr₂DABCO²⁺ = N, N’-diproyl-1,4- diazabicyclo[2.2.2] octane) have been synthesized. Both hybrids contain (Bi₂I₁₀)^4? halobismuthate dimers and (Et₂DABCO)²⁺/(Pr₂DABCO)²⁺ cations, and C–H···I hydrogen bonds contribute to the structural extending from 0-d clusters to 2-d layer (for 1) and 3-d network (for 2). Theoretical calculations were conducted to reveal the perturbation effects of 1,4-diazabicyclo[2.2.2] octane substitutes on their structures. Their absorption spectra were investigated, and energy band gaps of 2.10/2.16 eV indicate their narrow-gap semiconductor natures. Their photocurrent response properties were also discussed.     

Mono-, Di- and Tetranuclear Complexes and Clusters With Bromine-Functionalized Bis(diphenylphosphino)amine Ligands

We report the preparation of bromo-aryl functionalized bis(diphenylphosphino)amine ligands of the type Ph₂PNArPPh₂ (1, Ar = p-BrC₆H₄; 2, Ar = p-BrC₆H₄–C₆H₄) and their coordination properties. Mono- and dinuclear complexes were formed with Cu(I), Au(I), Pd(II), Pt(II) and tetranuclear cobalt carbonyl clusters were obtained. The crystal structures of [PdCl₂(1)] (3), [PdCl₂(2)] (4), [(AuCl)(μ-1)] (6), [Co₄(CO)₅(μ-CO)₃(μ-dppa)(μ-1)] (dppa = Ph₂PNHPPh₂) (8) and [Co₄(CO)₅(μ-CO)₃(μ-dppm)(μ-1)] (dppm = Ph₂PCH₂PPh₂) (9) have been determined by X-ray diffraction. Whereas the diphosphine ligands chelate the metal center in 3 and 4, and in the Pt(II) complex 5 which is analogous to 3, ligand 1 acts as a bridge in 6 where the separation between the two Au(I) centers is 3.0402(5) Å. In the tetranuclear clusters 8 and 9, and in the cluster 10 analogous to 9 with 2 as bridging ligand, two orthogonal Co–Co edges are bridged by a diphosphine ligand and each cobalt center is thus coordinated by one P donor. Complex 3 was shown to react with the Pd(0) complex [Pd(dba)₂] (dba = dibenzylideneacetone) to afford a tetranuclear complex resulting from both the insertion of Pd(0) into the ligand C–Br bond and Pd(II)/Pd(0) comproportionation to form a doubly ligand-bridged Pd(I)–Pd(I) core.     

Oxorhenium(V) complexes with bidentate carbohydrazide Schiff bases: synthesis,characterization and DNA interaction studies

The respective coordination reactions of trans-[ReOCl₃(PPh₃)₂] with N-[(4-oxo-4H-chromen-3-yl)methylidene]thiophene-2-carbohydrazide (Hchrtc) and N-[1,3-benzothiazol-2-ylmethylidene]thiophene-2-carbohydrazide (Hbztc) afforded two novel oxorhenium(V) complexes, cis-[ReOCl₂(chrtc)(PPh₃)] (1) and cis-[ReOCl₂(bztc)(PPh₃)] (2). These metal compounds were elucidated spectroscopically and their solid-state structures determined by single-crystal X-ray diffraction. The redox properties of the metal complexes were probed using cyclic and square wave voltammetry. The DNA interaction capabilities of 1 and 2 were gauged via UV/Vis spectroscopy DNA titrations and gel electrophoresis studies. A correlation is identified between the DNA cleavage observations and the redox potentials of the metal complexes.     

Syntheses,characterization, and crystal structures of two dinuclear nickel(II) and copper(II) complexes with Schiff bases

The phenolic azide bridged dinuclear nickel(II) complex, [Ni₂(L¹)₂(N₃)(H₂O)(μ_1,1-N₃)] · EtOH (I), and the thiocyanate bridged dinuclear copper(II) complex, [Cu₂(L²)₂(μ_1,1-NCS)₂] (II), where L¹ and L² are the deprotonated forms of 2-mothoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol and 2,4-dichloro-6-[(2-methylaminoethylimino)methyl]phenol, respectively, were synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 12.172(1), b = 20.953(1), c = 29.779(2) Å, V = 7594.8(9) ų, Z = 8. The crystal of II is monoclinic: space group P2₁/n, a = 8.7615(11), b = 19.672(2), c = 16.568(2) Å, β = 99.449(2)°, V = 2816.9(6) ų, Z = 4. The Ni atoms in I are in octahedral coordinations, and the Cu atoms in II are in square-pyramidal coordinations.     

Ring-opening polymerization of ε-caprolactone catalysed by (pyridyl)benzoazole Zn(II) and Cu(II) complexes

This paper describes the synthesis of (pyridyl)benzoazole Zn(II) and Cu(II) complexes and their applications as catalysts in ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). Reactions of 2-(3-pyridyl)-1H-benzimidazole (L1), 2-(2-pyridyl)-1H-benzothiazole (L2) and 2-(2-pyridyl)-1H-benzimidazole (L3) with Zn(II) and Cu(II) acetates produced the corresponding complexes; [Zn₂(L1)₂(OAc)₄)] (1), [Cu₂(L1)₂(OAc)₄] (2), [Zn(L2)(OAc)₂)] (3), [Zn(L3)(OAc)₂)] (4) and [Cu(L3), (OAc)₂)] (5). Molecular structures of complexes 2 and 5a revealed that while L1 adopts a monodentate binding mode, through the pyridyl nitrogen atom, L3 exhibits a bidentate coordination mode. All the complexes formed active catalysts in the ROP of ε-CL to afford moderate molecular weight polymers. The kinetics of the ROP reactions of ε-CL were pseudo-first-order with respect to monomer and catalysts.     

Synthesis,crystal structures and photoluminescence studies of three mixed ligand silver(I) coordination polymers

Three Ag(I) coordination complexes, namely [Ag₃(2-stp)(2-apy)₂·3H₂O]_n (1), [Ag₃(2-stp)(2-apy)₂]_n (2) and [Ag₃(2-stp)(3-apy)(H₂O)]_n (3) (2-NaH₂stp = 2-sulfoterephthalic acid monosodium salt, 2-apy = 2-aminopyridine and 3-apy = 3-aminopyridine), have been synthesized and structurally characterized. They all show two-dimensional network structures. In complex 1, the Ag₃ units are linked by stp ligands to form a 1D chain. Consequently, the 2-apy ligands link the adjacent 1D chain into 2D polymeric sheets. In 2, Ag1 and Ag2 atoms are bridged by stp ligands to form a 2D infinite sheet. In 3, the stp anion adopts a μ₇-(η¹,η²):(η¹,η¹,η⁰):(η¹,η¹) coordination mode to Ag₃ units to 2D layer sheet and the network is consolidated by 3-apy ligands. The thermogravimetric analyses and photoluminescence of the complexes were also investigated.     

Neutral and cationic (pyrazolylmethyl)pyridine palladium(II) complexes: kinetics and chemoselectivity studies in hydrogenation of alkenes and alkynes

Reactions of (3,5-dimethylpyrazolylmethyl)pyridine (L1) and (3,5-diphenylpyrazolylmethyl)pyridine (L2) with either [PdCl₂(NCMe)₂] or [PdClMe(COD)] afforded the respective neutral palladium complexes, [PdCl₂(L1)] (1), [PdCl₂(L2)] (2) and [PdClMe(L1)] (3). Treatment of complex 1 with equimolar amounts of PPh₃ or PPh₃/NaBAr₄ produced the corresponding cationic complexes [Pd(L1)ClPPh₃]Cl (4) and [Pd(L1)ClPPh₃]BAr₄ (5), respectively. Complexes 1–5 formed active catalysts in hydrogenation of alkenes and alkynes. Isomerization reactions were predominant in the hydrogenation reactions of terminal alkenes, while hydrogenation of alkynes involved a two-step process via alkene intermediates prior to the formation of the respective alkenes. The lack of induction periods in the hydrogenation reactions in addition to pseudo-first-order kinetics with respect to the substrates established the homogeneous nature of the active species.     

Synthesis,crystal structures,and properties of copper(II) dicarboxylate complexes with [bis(2-pyridylcarbonyl)amido]

Four new complexes, [Cu₂(Bpca)₂(L¹)(H₂O)₂] · 3H₂O (I), [Cu₂(Bpca)₂(L²)(H₂O)₂] (II), [Cu₂(Bpca)₂(L³)] · 2H₂O (III), [Cu₂(Bpca)₂(L¹)(H₂O)] · 2H₂O (IV) (Bpca = bis(2-pyridylcarbonyl)amido, H₂L¹ = glutaric acid, H₂L² = adipic acid, H₂L³ = suberic acid, H₂L⁴ = azelaic acid) have been synthesized and characterized by single-crystal X-ray diffraction methods (CIF files CCDC nos. 1432836 (I), 1432835 (II), 817411 (III), and 817412 (IV)), elemental analyses, IR spectra. Structural analyses reveal that compounds I, II, and IV have similar structures [Cu(Bpca)]⁺ units bridged by dicarboxylate forming dinuclear units, whereas the dinuclear of compound III are edge-shared through two carboxylate oxygen atoms of different suberate anions. Hydrogen bonds are response for the supramolecular assembly of compounds I to IV. The temperature-dependent magnetic property of III was also investigated in the temperature range of 2 to 300 K, and the magnetic behaviour suggests weak antiferromagnetic coupling exchange.     

Synthesis,Characterization, Crystal Structures,and Antibacterial Activity of Polynuclear Nickel(II) and Copper(II) Complexes with Similar Tridentate Schiff Bases

An end-on azido-bridged dinuclear nickel(II) complex [Ni₂(L¹)₂(μ_1,1-N₃)₂] · CH₃COOH (I) and an end-on azido-bridged polynuclear copper(II) complex [CuL²(μ_1,1-N₃)] _n , where L¹ is the deprotonated form of 2-[(2-ethylaminoethylimino)methyl]-4-fluorophenol and L2 is the deprotonated form of 2-[(2- dimethylaminoethylimino)methyl]-4-fluorophenol, were prepared and characterized by elemental analysis and FT-IR spectra. Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method (CIF files CCDC nos. 942641 (I) and 942642 (II)). Single crystal X-ray structural studies indicate that the Schiff base ligands coordinate to the metal atoms through phenolate oxygen, imine nitrogen, and amine nitrogen. The Ni atoms in the nickel complex are in octahedral coordination, and the Cu atoms in the copper complex are in square pyramidal coordination. Crystals of the complexes are stabilized by hydrogen bonds. The Schiff bases and the complexes showed potent antibacterial activities.     

Europium and Ytterbium Complexes with the Redox Active Acenaphthene-1,2-Diimine Ligand

The oxidation of [(Dpp-Bian)Eu(Dme)₂] (I) (Dpp-Bian is the 1,2-bis[(2,6-diisopropylphenyl) imino]acenaphthene dianion, Dme = 1,2-dimethoxyethane), prepared in situ, with 0.5 mol equiv. of iodine in Thf gives europium(II) dimer, [(Dpp-Bian)Eu(μ-I)(Thf)₂]₂ (II) (Thf = tetrahydrofuran), with the Dpp-Bian ligand as radical anion. The exchange reaction of II with potassium dithiocarbamate affords europium( II) dimer, [(Dpp-Bian)Eu[SC(S)NMe₂](Thf)]₂ (III), which also contains the Dpp-Bian radical anion. However, the oxidation of the ytterbium complex [(Dpp-Bian)Yb(Dme)₂] (IV) with 0.5 mol equiv. of [Me₂NC(S)S]₂ gives the monomeric product [(Dpp-Bian)Yb[SC(S)NMe₂](Dme)] (V), in which Dpp-Bian is still the dianion and the ytterbium atom is oxidized to the trivalent state. The reaction of II with potassium thiocyanate gives europium(II) isothiocyanate complex with the radical anion diimine ligand [(Dpp-Bian)Eu(NCS)(Dme)₂] (VI). The molecular structures of complexes II, III, V, and VI were determined by X-ray diffraction (CIF files CCDC 1576687–1576690, respectively).     

Supramolecular assembly of three Ag(I) coordination polymers derived from flexible N-containing ligands and polycarboxylates: synthesis,structures, and catalytic properties

Three Ag(I) coordination polymers [Ag(L1)]·(H₃bptc)·H₂O (1), [Ag₂(L2)(oba)]·H₂O (2), and [Ag₂(L2)₂]·(H₂bptc) (3) [L1 = 1,4-bis(3,5-dimethylpyrazole)butane, L2 = 1,4-bis(2-methylbenzimidazole)butane, H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, H₂oba = 4,4′-oxybis(benzoic acid)] constructed from N-containing ligands with different flexibilities and organic carboxylates as co-ligands have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis. All three complexes display 1D chain structures, which are further extended into 2D supramolecular networks via non-classical C–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of the complexes 1–3 have been investigated in detail. Complexes 2 and 3 reveal promising catalytic activities for the degradation of methyl orange in a Fenton-like process.     

Synthesis and structural characterization of iron–sulfur complexes with hydrophilic nitrogen–phosphorus ligands

Reaction of the parent complex (μ-PDT)Fe₂-(CO)₆ (A) (PDT = 1,3-SCH₂CH₂CH₂S^2?) with the bidentate N/P ligand [(Ph₂P)₂N(C₆H₄Cl-p)] in the presence of Me₃NO as decarbonylating agent produced an unexpected iron–sulfur complex [(μ-PDT)Fe₂(CO)₅{PPh₂(NHC₆H₄Cl-1,4)}] (1). Extending this chemistry further, two similar complexes [(μ-PDT)Fe₂(CO)₅{PPh₂(NHC₆H₄NO₂-1,4)}] (2) and [(μ-PDT)Fe₂(CO)₅{PPh₂(NHC₆H₄CO₂Et-1,4)}] (3) could be prepared from the simple substitution reactions of the precursor A with the monodentate N/P ligands Ph₂P(NHC₆H₄NO₂-1,4) and Ph₂P(NHC₆H₄CO₂Et-1,4), respectively. These new complexes, which can be considered as active site models of [FeFe] hydrogenases, have been characterized by elemental analysis, FTIR, and NMR (¹H, ¹³C, ³¹P) spectroscopies, as well as by X-ray crystallography for complex 1.     

The Hybrid Organic–Inorganic Assemblies Based on Monocapped Trivacant Keggin Arsenatomolybdate and Cu<Superscript>I</Superscript>-Organic Units

A new arsenomolybdate compound [Cu(imi)₂]₅Na[(AsO₄)Mo₉O₂₇(AsO₃)]·5H₂O(imi = imidazole) 1, has been prepared by hydrothermal method and structurally characterized by elemental analysis, IR, XRD, TG analysis and single-crystal X-ray diffraction analysis. Compound 1 represents the first example of monocapped trivacant Keggin [As^IIIAs^VMo₉O₃₄]^6? subunit as polydentate ligand bonded to five [Cu(imi)₂] complexes through one covalent bond and four weak Cu···O bonds. The electrochemical behavior of 1-modified carbon paste electrode has been studied in detail. In addition, photoluminescence and photocatalysis properties of 1 have been investigated.     

Synthesis,structure, and catalytic activity of new aluminum and titanium complexes based on aminobisphenolate ligands containing bulky substituents

A reaction of aminobisphenols EtN{CH₂[(4-Alk)(6-But)(2-HO)C₆H₂]}₂, Alk = Me (1); Bu^t (2) containing alkyl substituents in the phenol groups with trimethylaluminum and tetra(tert-butoxy)titanium gave two new aluminum derivatives with the Me–Al bond: EtN{CH₂[(2-Alk)-(4-Bu^t)C₆H₂(2-O–)]}2Al–Me, Alk = Me (3); Bu^t (4), and two new titanium derivatives with the Bu^tO–Ti bond: EtN{CH₂[(2-Alk)(4-Bu^t)C₆H₂(2-O–)]}2Ti(O–Bu^t)₂, Alk = Me (5); But (6). The structures of new compounds were confirmed by NMR spectroscopy and elemental analysis. The structures of complexes 3 and 6 were studied by X-ray crystallography. Complexes 3 and 6 are monomeric in the solid phase: a coordination number of Al atom is 4, that of Ti atom is 5, in addition to the M–O bonds the M←N interactions are also present. Complexes 3–6 were studied as initiators of the ring-opening polymerization of ε-caprolactone. The resulting polymers are characterized by relatively high values of number average molecular weight, with the polydispersity being relatively low.     

Germylenes and stannylenes based on aminobisphenolate ligands: insertion into the C—Br bond

A reaction of previously synthesized germylenes and stannylenes based on aminobisphenols RN{CH₂[(5-R´)(3-But)C₆H₂(2-O—)]}₂M^II, M = Ge, R = CH²(2-Py), R´ = But (1); M = Ge, R = Et, R´ = Me (2); M = Sn, R = CH₂(2-Py), R´ = But (3); M = Sn, R = Et, R´ = Me (4), containing (tetrylenes 1 and 3) or not containing (tetrylenes 2 and 4) a group capable of additional donation, with allyl bromide leads to the products of the insertion of tetrylenes into the C—Br bond: RN{CH₂[(5-R´)(3-Bu^t)C₆H₂(2-O—)]}₂M(Br)All, M = Ge, R = CH₂(2-Py), R´ = But (5); M = Ge, R = Et, R´ = Me (6); M = Sn, R = CH₂(2-Py), R´ = But (7); M = Sn, R = Et, R´ = Me (8). The structures of obtained derivatives were confirmed by NMR spectroscopy and elemental analysis. The structures of compounds 4, 5, and 7 were studied by X-ray crystallography. Stannylene 4 was found to be monomeric in the solid phase: the coordination number of the Sn atom is 3. The insertion products 5 and 7 are characterized by the coordination number 6 for the central atom.     

Importance of halide involving interactions at Hoogsteen sites in supramolecular architectures of some coordination metal complexes of N<Superscript>6</Superscript>-benzyl/furfuryl adenine

Background

Most of the benzyladenine and furfuryladenine derivatives inhibit tumor/cancer cell growth; their toxicity is lesser than the compounds used for the treatment of cancer now-a-days. Many cytokinin derivatives are tested for anticancer activity.

Results

A series of transition metal complexes containing N⁶-benzyl/furfuryl aminopurines of formula [Mn(FAH)₂(H₂O)(Cl₃)]₂.Cl₂(1), [Co(FAH)2(H₂O)(Cl₃)]₂.Cl₂(2), [Co(FAH)₂(Cl₄)]_{2 .}[Co(FAH)₂(H₃O)(Cl₃)].Cl₂(3), [Ni(FAH)₂(H₂O)(Cl₃)]₂.Cl_2. (H2O) (4), [Zn(BAH)Br₃] (5) and [Cd₂(BAH)₂(μ-Br)₄Br₂]_n(6) (where BAH and FAH benzyladeninium and furfuryladeninium cations respectively) have been synthesized and characterized. Crystal structures of (1-4) have similar distorted octahedral coordination geometry, while (5) and (6) have distorted tetrahedral geometry and octahedral geometries respectively. In (1-4) two halide ions and two cytokinin cations (BAH⁺/FAH⁺) are laterally coordinated to the metal ion. A water molecule and a halide ion are axially coordinated. But the coordination sphere of (5) consists of N7 coordinated benzyladeninium ion and three halide ions. The complex (6) is a coordination polymer bridged by bromide anions. A common notable feature in (1-4) is the presence of one or more lattice chloride anions. They help in a chain formation by N-H…Cl halide involving hydrogen bonding interactions in between the Hoogsteen site hydrogen.

Conclusions

The observed crystal structures emphasize the role of the halide ions in developing the supramolecular architectures by halide involving hydrogen bonding interactions. Also most of the reported cobalt cytokinin complexes possess tetrahedral coordination geometry, but some cobalt complexes have distorted octahedral coordination geometry, which are discussed and compared.

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Graphical Abstract Supramolecular architectures of some coordination metal complexes of N6-benzyl/furfuryl adenine.