NH3 Ligands Research Articles

Tetrel bonds, penta‐ and hexa‐coordinated tin and lead centres

A tetrel bond – an interaction between a Group 14 element acting as Lewis acid centre and an electron‐donating moiety – is analysed for ZF4 (Z = Sn, Pb) complexes with NH3 and HCN species. MP2/aug‐cc‐pVTZ calculations were performed and supported by results of the quantum theory of atoms in molecules. The results of calculations show that the tetrel centre may be considered as a pentavalent one if ZF4 interacts with one NH3 or HCN ligand or even as a hexavalent centre if it interacts with two ligands; thus the hypervalency phenomenon is discussed for the complexes analysed here. The theoretical analysis is supported by a discussion of the crystal structures containing the SnF4 fragment; these structures are characterized by a hexa‐coordinated tin centre.

Synthesis and Characterization of the First Nickel(II)‐Centered Single‐Side Tris‐Functionalized Anderson‐Type Polyoxomolybdate

The Ni‐centered Anderson‐type polyoxomolybdate [Ni(OH)3Mo6O18(OCH2)3CNH3]3– was prepared in a two‐step aqueous reaction by covalent postfunctionalization of [Ni(OH)6Mo6O18]4–, isolated as its sodium Tris–NH3 salt, and characterized by single‐crystal X‐ray diffraction, mass spectrometry, thermogravimetric analysis, and IR spectroscopy. The incorporation of a Tris–NH2 ligand into the framework of a heteropolymolybdate bearing a divalent heteroatom, which resulted in the single‐sided product, was shown for the first time.

Cobalt nanoparticles/nitrogen-doped graphene with high nitrogen doping efficiency as noble metal-free electrocatalysts for oxygen reduction reaction

Nitrogen-doped graphene (N/GR) has been considered as active metal-free electrocatalysts for oxygen reduction reaction (ORR). However, the nitrogen (N) doping efficiency is very low and only few N atoms are doped into the framework of GR. To boost the N doping efficiency, in this work, a confined pyrolysis method with high N doping efficiency is used for the preparation of cobalt nanoparticles/nitrogen-doped GR (Co/N/GR). Under the protection of SiO2, the inorganic ligand NH3 in cobalt amine complex ([Co(NH3)6]3+) is trapped in the confined space and then can be effectively doped into the framework of GR without the introduction of any carbon residues. Meanwhile, due to the redox reaction between the cobalt ions and carbon atoms of GR, Co nanoparticles are supported into the framework of N/GR. Due to prevention of GR layer aggregation with SiO2, the Co/N/GR with high dispersion provides sufficient surface area and maximum opportunity for the exposure of Co nanoparticles and active sites of N dopant. By combination of enhanced N doping efficiency, Co nanoparticles and high dispersion of GR sheets, the Co/N/GR is remarkably active, cheap and selective noble-metal free catalysts for ORR.

Dynamics of NH3 ligands and ClO4− anions in the phase transition in [Cd(NH3)6](ClO4)2 studied by x-ray powder diffraction, neutron scattering methods and infrared spectroscopy

Phase transition, reorientational dynamics of NH3 ligands and ClO4− anions and crystal structure changes were investigated using x-ray powder diffraction (XRPD), neutron powder diffraction (NPD), quasi-elastic neutron scattering (QENS) and Fourier transform infrared spectroscopy (FT-IR). Most measurements were carried out in the temperature range 9–300K. The diffraction techniques revealed that NH3 ligands and ClO4− anions are orientationally disordered at room temperature. During the cooling process, the high temperature cubic phase transforms into a lower symmetry phase (most probably of monoclinic structure). The QENS results confirm that NH3 ligands perform picoseconds reorientational motions both in the high and low temperature phases. This motion is almost unaffected by the observed phase transition (Tc=138.9K on heating) and can be well described assuming the three fold jump model. On the other hand, the band shape analysis performed for the IR band connected with ClO4− internal vibration mode δd(OClO)E at 461cm−1 clearly shows that ClO4− anions reorientate quickly in the high temperature phase, but that motion begins slowing down in the vicinity of the phase transition. Below 150K the exponential reorientation relaxation term vanishes and only the vibrational relaxation term is present; small discontinuity is also visible. Moreover, below the phase transition temperature Tc splitting of the infrared absorption bands connected with some NH3 internal vibrations is observed.

Highly dispersed Pd/AlPO-5 catalyst for catalytic hydrogenation of 2-ethylanthraquinone

Highly dispersed Pd/AlPO-5 catalyst was prepared and tested in the hydrogenation of 2-ethylanthraquinone. Characterization results suggested that the abundant surface P-OH groups of AlPO-5 zeolite substituted NH3 ligands of [Pd(NH3)4]2+ precursor to form [Pd(NH3)3(POH)]2+. After calcination, the latter formed Pd-O-P interfacial linkage between Pd nanoparticles and AlPO-5, benefiting the suppression of Pd sintering. SiO2 and SiO2-AlPO-5 composite were used as supports for comparison. Catalyst supported on SiO2-AlPO-5 composite (25wt% AlPO-5) exhibited improved catalytic activity and stability in consideration of reactant activation as well as the mass transfer of reactant molecules, which is expected to decrease precious metal loading in industrial application.

Theoretical studies on BTA-Metal (M=Ni, Cu) Complexes as High Energy Materials

Metal complexes of Nickel and Copper with the dianion of bidentate chelating agent BTA [N,N-bis(1(2)H-tetrazole-5-yl)-amine] along with NH3 and NH2NO2 ligands were designed. A total of four metal complexes having the compositions such as M(BTA)(NH3)(NH2NO2) and M(BTA)(NH2NO2)2 where M is the metal atom, were formulated and subjected to detailed theoretical study to explore their energetic properties. Density Functional Theory (DFT) was used to predict the optimized geometry of the complexes at TPSS / 6-311G(d,p) level. The heats of formation of the metal complexes were determined using atomization method. Crystal densities of the salts were predicted using the data obtained at B3PW91 /6-31G(d,p) level utilizing the wave function analysis (WFA) program. Results indicate that all the designed compounds possess density in the range of 2.18–2.25 g cm−3. This is the remarkable feature of the title compounds because loading density is one of the desired properties for increasing the detonation performance of energetic materials. The calculated impact sensitivities (h50, cm) show that the three of the designed compounds are comfortably insensitive towards impact (h50,cm ∼42) in comparison to the experimentally determined values for the commercially used powerful explosives such as RDX (24–28 cm) and HMX (26–32 cm). Ni(BTA)(NH2NO2)2, the fourth designed compound has a value almost similar to that of RDX and HMX. The calculated detonation parameters D (detonation velocity) and P (detonation pressure) are predicted to be in the range of 7.7–8.5 km s−1 and 29.5–36.1 GPa, respectively. Results obtained in the present study predict that the designed compounds can be used as high energy density materials (HEDs). Computational studies on Ni and Cu complexes containing BTA and NH2NO2 ligands show that these complexes possess the potential for use as high energy materials. The calculated densities of these metal complexes were estimated to be in the range of 2.18 to 2.25 g cm-3. The calculated detonation parameters put these complexes in the category of HEDMs.

Nanoporous IrO2 catalyst with Ultrahigh Specific Surface Area Synthesized through an Ammoniating Method for Acidic Oxygen Evolution

The development of highly active and stable electrocatalysts for OER is urgent due to the slow kinetics and high overpotential of oxygen evolution reaction (OER) [1]. To date, the most promising catalysts for OER are IrO2 based catalysts with ordered porous structures, where a templating method was generally used to ensure the high utilization of the catalysts. However, the synthesis route for such catalysts is generally of high technique complexation, where the templates need to be effectively removed after synthesis [2,3]. Hence, a simple template-free method that leads to the formation of highly porous IrO2 catalysts with high surface area is highly attractive. Herein, a satisfactory template-free ammoniating method was developed in which NH3 ligand was successfully kept until pyrolysis treatment, thus acting as the pore-forming agent to achieve highly porous IrO2. The specific and electrochemical surface areas of as-prepared IrO2 catalysts increased with the increasing quantity of NH3·H2O additive. Specifically, IrO2 (1:100)-450 °C catalyst synthesized with the highest ratio of NH3 ligand exhibited high specific surface area of 363.3 m2 g-1 as metal oxide. Furthermore, IrO2 (1:100)-450 °C showed remarkable electrocatalytic activity for acidic OER in the whole potential window, which can be ascribed to the high catalysts utilization. As shown in Figure 1, the over-potential for the IrO2 (1:100)-450 °C catalysts to attain current at 10 mA cm-2 was only 282 mV, which was shifted negatively by 31 mV and 46 mV in comparison to the home-made IrO2 (without NH3) and commercial IrO2 (CM) catalysts, respectively. Thus, the NH3 mediating method was found a superior method for increasing catalysts utilization, where the IrO2can be conveniently synthesized in large scale. Figure 1. CV curves (Left, the inset shows the specific surface area) and LSV curves (Right, the inset shows the TEM of IrO2 (1:100)-450°C) of IrO2 (1:100)-450°C, IrO2 (1:10)-450°C, IrO2-450°C, and IrO2(CM) catalysts. Acknowledgments This work is supported by National Basic Research Program of China (973 Program, 2012CB932800), National Natural Science Foundation of China (21433003, 21373199), the Science & Technology Research Programs of Jilin Province (20150101066JC, 20160622037JC).

Octaammine EuII and YbII Azides and Their Thermal Decompositions to the Nitrides

The common preparation for many nitrides is the synthesis from the corresponding metals and nitrogen at quite high temperatures and/or high pressures. Here we present a route to metal nitrides by the use of ammine metal azides under relatively mild conditions. Europium(II) and ytterbium(II) azides are prepared in liquid ammonia at –36 °C in form of their temperature‐sensitive octaammine complexes. These were investigated by single‐crystal X‐ray diffraction at low temperatures, and their structures seem to be the first evidence for the existence of homoleptic ammine EuII and YbII complexes, as well as that the coordination number of these divalent cations can go beyond six with NH3 ligands. In one of the cases presented here the observed coordination polyhedron is better described as a bicapped trigonal prism (C2v), in one case better as square‐antiprismatic (D4d). Warming of these compounds to room temperature leads to the lanthanoid metal azides still containing approximately 1 equiv. of ammonia. The behaviour of these azides towards further heating was investigated: By very careful and slow decomposition, the nitrides of europium(III) and ytterbium(III) are obtained at only 230 °C at ambient pressure. This method may be suitable to obtain other metal nitrides at remarkably low temperatures and pressures.

Multiple Condensation Reactions Involving PtII/PdII−OH2, Pt−NH3, and Cytosine−NH2 Groups: New Twists in Cisplatin−Nucleobase Chemistry

The coordination chemistry of the antitumor agent cisplatin and related complexes with DNA and its constituents, that is, the nucleobases, appears to be dominated by 1:1 and 1:2 adducts of the types cis-[Pta2 (nucleobase)X] and cis-[Pta2 (nucleobase)2 ] (a=NH3 or amine; a2 =diamine or diimine; X=Cl, OH or OH2 ). Here, we have studied the interactions of the putative 1:1 adducts cis-[Pta2 (1-MeC-N3)(OH2 )](2+) (with a=NH3 , a2 =2,2'-bpy (2,2'-bipyridine), 1-MeC=model nucleobase 1-methylcytosine) with additional cis-[Pt(NH3 )2 (OH2 )2 ](2+) or its kinetically superior analogues [Pd(en)(OH2 )2 ](2+) (en=ethylenediamine) and [Pd(2,2'-bpy)(OH2 )2 ](2+) . Depending upon the conditions applied different compounds of different nuclearity are formed. Without exception they represent condensation products of the components, containing μ-1-MeC-H , μ-OH(-) , as well as μ-NH2 (-) bridges. In the presence of Ag(+) ions, the isolated products in several cases display additionally Pt→Ag dative bonds. On the basis of the cytosine-containing structures established by X-ray crystallography, it is proposed that any of the feasible initial 1:1 nucleobase adducts of cisplatin could form dinuclear Pt complexes upon reaction with additional hydrolyzed cisplatin, thereby generating nucleobase adducts other than the presently established ones. Two findings appear to be of particular significance: First, hydrolyzed cisplatin can have a moderately accelerating effect on the formation of a secondary nucleobase product. Second, NH3 ligands of the cisplatin moiety can be converted into bridging amido ligands following condensation with the diaqua species of cisplatin.

Elucidation of Nonadditive Effects in Protein-Ligand Binding Energies: Thrombin as a Case Study.

Accurate predictions of free energies of binding of ligands to proteins are challenging partly because of the nonadditivity of protein-ligand interactions; i.e., the free energy of binding is the sum of numerous enthalpic and entropic contributions that cannot be separated into functional group contributions. In principle, molecular simulations methodologies that compute free energies of binding do capture nonadditivity of protein-ligand interactions, but efficient protocols are necessary to compute well-converged free energies of binding that clearly resolve nonadditive effects. To this end, an efficient GPU-accelerated implementation of alchemical free energy calculations has been developed and applied to two congeneric series of ligands of the enzyme thrombin. The results show that accurate binding affinities are computed across the two congeneric series and positive coupling between nonpolar R(1) substituents and a X = NH3(+) substituent is reproduced, albeit with a weaker trend than experimentally observed. By contrast, a docking methodology completely fails to capture nonadditive effects. Further analysis shows that the nonadditive effects are partly due to variations in the strength of a hydrogen-bond between the X = NH3(+) ligands family and thrombin residue Gly216. However, other partially compensating interactions occur across the entire binding site, and no single interaction dictates the magnitude of the nonadditive effects for all the analyzed protein-ligand complexes.

Phase transition and dynamics of NH3 ligands in [Zn(NH3)4](ReO4)2

One phase transition in [Zn(NH3)4](ReO4)2 at Tc=393.5K (on heating) and 392.0K (on cooling) was found. Thermal stability of this compound was investigated by thermal analysis methods. It decomposes in three main stages. The first two are connected with deamination process, whereas Re2O7 evaporates in the last step. The activation energy for NH3 loss processes was determined from thermogravimetric (TG) measurements. The vibrational and reorientational dynamics of NH3 ligands in the low-temperature phase was probed by various complementary techniques. It was found that at temperatures close to 150K, NH⋯O hydrogen bond is formed. Temperature-dependent band shape analysis of properly chosen infrared (IR) band was performed, whose results showed that activation energy for NH3 reorientational motion (<300K) is rather small and is approximately equal to 2kJmol−1. Neutron and X-ray powder diffraction patterns did not reveal any drastic change in the crystal structure in a wide temperature range.

Aluminum Borohydride Complex with Ethylenediamine: Crystal Structure and Dehydrogenation Mechanism Studies

We report the structure of an aluminum borohydride ethylenediamine complex, Al(EDA)3·3BH4·EDA. This structure was successfully determined using X-ray powder diffraction and was supported by first-principles calculations. The complex can be described as a mononuclear complex exhibiting three-dimensional supramolecular structure, built from units of Al[C2N2H8]3, BH4, and ethylenediamine (EDA) molecules. Examination of the chemical bonding indicates that this arrangement is stabilized via dihydrogen bonding between the NH2 ligand in EDA and the surrounding BH4. The partial ionic bonding between the Al and N atoms in EDA forms a five-member ring (5MR), an Al[NCCN] unit. The calculated H2 removal energies confirm that it is energetically favorable to remove the loosely bonded EDA and H atoms with N–H···H–B dihydrogen bonds upon heating. Our results suggest that the NH2 terminal ligand in the EDA molecule combines with a H atom in the BH4 group to release H2 at elevated temperature, and our results confirm that...

Phase transition, thermal dissociation and dynamics of NH3 ligands in [Cd(NH3)4](ReO4)2

High temperature phase transition in [Cd(NH3)4](ReO4)2 at Tc=368.5K (on heating) was reported for the first time. Thermal stability was investigated by thermal analysis methods. The titled compound decomposes in three main stages. The first two are connected with deamination process whereas in the last step Re2O7 evaporates. The activation energy for NH3 lost processes was estimated from TG measurements. The dynamics of NH3 ligands in the low temperature phase was probed by various complementary techniques. Temperature dependent band shape analysis of properly chosen infrared and Raman scattering vibrational bands was performed. It was found that activation energy for NH3 reorientational motion (below 300K) is rather small and is equal to ca. 4kJmol−1. The quasielastic neutron scattering measurements revealed that NH3 groups perform fast stochastic reorientational motion even in the low temperatures. The neutron and X-ray powder diffraction data do not revealed any drastic changes in the crystal structure in the wide temperature range.

Trigonal-Bipyramidal Coordination in First Ammoniates of ZnF2: ZnF2(NH3)3 and ZnF2(NH3)2.

Single crystals of ZnF2(NH3)3 and ZnF2(NH3)2 were obtained under ammonothermal conditions (250 °C, 196 MPa and 500 °C, 136 MPa). Upon thermal decomposition of both ZnF2(NH3)3 and ZnF2(NH3)2, a microcrystalline powder of ZnF2(NH3) was obtained. ZnF2(NH3)3 and ZnF2(NH3)2 represent probable intermediates in a conceivable ammonothermal synthesis of the semiconductor Zn3N2 and manifest a rare trigonal-bipyramidal coordination of F(-) and NH3 ligands around Zn(2+) according to single-crystal X-ray diffraction. Thermal analysis of all three compounds showed not only ZnF2(NH3) but also ZnF2(NH3)2 to be decomposition intermediates of ZnF2(NH3)3 prior to the formation of ZnF2. All three compounds demonstrate hydrogen bonds, as indicated by the intensities and half-widths of the bands in the vibrational spectra and by short N-H···F distances in the crystal structures of ZnF2(NH3)3 and ZnF2(NH3)2. With ZnF2(NH3)3, ZnF2(NH3)2, and ZnF2(NH3), we present the first ammoniates of ZnF2.

Role of NH3 in the Electron-Induced Reactions of Adsorbed and Solid Cisplatin

The electron-induced decomposition of cisplatin (cis-Pt(NH3)2Cl2) was investigated to reveal if ammine (NH3) ligands have a favorable effect on the purity of deposits produced from metal-containing precursor molecules by focused electron beam induced deposition (FEBID). Scanning electron microscopy showed that cisplatin particles of different sizes react violently during electron irradiation. In particular, faceted particles of a few μm in size started to boil, became spherical and subsequently degraded. Energy-dispersive X-ray spectroscopy gave evidence for the formation of nearly pure platinum and a decrease of the chlorine content. Nitrogen, however, was not detected, pointing to an efficient and rapid removal of NH3. In contrast, PtCl2 particles do not degrade under comparable conditions, demonstrating that the ammine ligand plays an important role in the reduction of cisplatin to pure platinum. The fast release of NH3 ligands under electron exposure was confirmed by high resolution electron energy lo...

Ammonia-modified Co(II) sites in zeolites: spin and electron density redistribution through the Co(II)-NO bond.

Electronic factors essential for the bonding of a non-innocent NO ligand to ammonia-modified Co(2+) sites in cobalt-exchanged zeolites are examined for small cluster models using DFT and advanced correlated wave function calculations. The analysis of charge transfer processes between the NO ligand and the cobalt center involves two protocols: valence-bond expansion of the multiconfiguration CASSCF wave function (in terms of fragment-localized active orbitals) and spin-resolved natural orbitals for chemical valence (SR-NOCV). Applicability of SR-NOCV analysis to transition metal complexes involving non-innocent fragments is critically assessed and the approach based on the CASSCF wave function turns out to be much more robust and systematic for all studied models. It is shown that the character and direction of electron density redistribution through the Co-N-O bond, quantified by relative share of the Co(II)-NO(0), Co(III)-NO(-), and Co(I)-NO(+) resonance structures in the total wave function, fully rationalize the activation of the N-O bond upon NH3 co-ligation (evidenced by calculated and measured red-shift of the NO stretching frequency and commonly ascribed to enhanced backdonation). The huge red-shift of νN-O is attributed to an effective electron transfer between the ammonia-modified Co(ii) centers and the NO antibonding π*-orbitals (related to the increased share of the Co(III)-NO(-) form). Unexpectedly, the effect is stronger for the singlet complex with three NH3 ligands than for that with five NH3 ligands bound to the cobalt center. Our results also indicate that high-efficiency electron transfers between the Co(ii) center and the NO ligand may be enabled for the selected spin state and disabled for the other spin state of the adduct. This illustrates how the cobalt center may serve to fine-tune the electronic communication between the NO ligand and its binding site.

Hydrogen Evolution from Water under Visible-Light Irradiation Using Keggin-Type Platinum(II)-Coordinated Phospho-, Silico-, and Germanotungstates as Co-Catalysts

The tetramethylammonium salts of diplatinum(II) complexes composed of mono-lacunary Keggin-type silico and germanotungstates, [(CH3)4N]4[α-SiW11O39{cis-Pt(NH3)2}2]·13H2O (TMA-Si-Pt) and [(CH3)4N]4[α-GeW11O39{cis-Pt(NH3)2}2]·11H2O (TMA-Ge-Pt), were synthesized and crystallized. Single crystals of a tetramethylammonium salt of Keggin-type diplatinum(II)-coordinated phosphotungstate [(CH3)4N]3[α-PW11O39{cis-Pt(NH3)2}2]×10H2O (TMA-P-Pt) were also obtained. The X-ray structural analyses revealed that the two cis-platinum(II) moieties, [cis-Pt(NH3)2]2+, were each coordinated to two oxygen atoms in a mono-vacant site of [XW11O39](12-n)- (Xn+ = Si4+, Ge4+, P5+). FTIR spectra of TMA-Si-Pt and TMA-Ge-Pt also suggested that the two platinum(II) moieties were coordinated to the vacant site of [SiW11O39]8- and [GeW11O39]8-. The 1H NMR spectra in DMSO-d6 of TMA-Si-Pt and TMA-Ge-Pt showed signals assigned to the two sets of NH3 ligands coordinated to the platinum sites. These three platinum compounds showed hydrogen evolution from aqueous triethanolamine solution under visible light irradiation (λ ≥ 400 nm) in the presence of eosin Y, α-Keggin mono-aluminum-substituted silicotungstate, and titanium dioxide. The catalytic activities were influenced by the central atoms, and TMA-P-Pt showed the highest activities among the three platinum compounds.

Diamondoids in octahedral iron complexes: A DFT study

Several octahedral iron complexes that contain two lateral diamondoid (formerly called nanodiamond) units (joined by terminal COO1− groups) have been proposed. All newly proposed coordination species reach a stable configuration. The nature of the apical substituents (H2O, NH3, CO, CN1−, NO) accounts for the change in properties of the resultant compounds, therefore those compounds containing H2O or NH3 ligands manifest a scheme of chemical properties similar to their analogues as coordination compounds. Furthermore the complexes containing CO or CN1− ligands fulfill the typical description of organometallic species, whereas the complexes with the NO ligand, in their three manifestations, range between both behaviors and are studied as a special case. However, in all cases, the diamondoid ligands work as insulator walls restricting electronic movements to the regions which accommodate the metallic center, the apical ligands and the terminal COO1− groups. The nature of the molecular orbitals scheme shows wide variation that ranges between insulator and conductor behavior.

Cobalt-doped TiO2: a computational analysis of dopant placement and charge transfer direction on thin film anatase

ABSTRACTTitanium dioxide (TiO2) nanocrystals are promising materials for photo-electrochemical water splitting. This study focuses on how surface dopant placement can affect the electronic properties. TiO2 anatase thin films are doped two ways: a cobalt ion replacing a surface titanium ion (surface ingrained) and a cobalt ion chemisorbed to two surface oxygen ions and two NH3 ligands. Specifically, when studying the binding pattern, the cobalt ion dopant changes from an electron acceptor for the surface ingrained model to an electron donor for the chemisorbed model. The optical absorption peaks of the surface ingrained model are attributed to p→d transitions and are much stronger when compared to the d→d transitions for the chemisorbed model. It is the conclusion of this computational study that one can alter the cobalt dopant on the anatase thin film to focus a positive or negative charge at the surface by changing the surface dopant location.

X-ray absorption study of the geometry structure of Co2+/Co3+ in ammonia solution

The investigation of the geometrical structure of transition metal ions in solution is mandatory to determine the role of transition metal ions in many chemical reactions. In this contribution, the local structure of Co2+/Co3+ in ammonia solution was investigated by X-ray absorption spectroscopy (XAS). We found that Co2+ ions are coordinated by six NH3 ligands arranged in a Jahn-Teller (JT) distorted octahedral (DT Oc) geometrical configuration with four long Co-Neq bonds (2.17 Å) and two short Co-Nax bonds (2.03 Å). At variance, Co3+ ions in [Co(NH3)6]3+ or [Co(NH3)5Cl]2+ clusters occur depending on the presence of activated carbons during the oxidation reaction process from Co2+ to Co3+. By means of full multiple-scattering theoretical (MXAN) analysis of the Co K-edge XANES (X-ray absorption near edge structure), we show that [Co(NH3)6]3+ is characterized by a regular octahedral (Re Oc) geometrical structure with a Co–N distance 1.91 Å long while [Co(NH3)5Cl]2+ by a distorted octahedral geometrical structure with four Co-Neq bonds (1.94 Å), a shorter Co-Nax bond (1.91 Å) and a Co–Cl bond (2.12 Å).