Bridging Azido Ligands Research Articles

A Nanosized {NiII 18} Cluster with a 'Flying Saucer' Topology Exhibiting Slow Relaxation of Magnetisation Phenomena at Both 15 K and 1.3 K.

A high-nuclearity {Ni18} complex (1) with a unique 'flying saucer' motif has been prepared from the organic chelate, α-methyl-2-pyridine-methanol (mpmH), in conjunction with bridging azido (N3 -) and peroxido (O2 2-) ligands. Magnetic susceptibility measurements revealed the presence of both ferro- and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end-on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6-bridging peroxides most likely promote the antiparallel alignment of the metals' spin vectors, yielding an overall non-zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single-molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d-metal clusters.

Jellyfish-type Dinuclear Hafnium Azido Complexes: Synthesis and Reactivity.

Di- and multinuclear hafnium complexes bridged by ligands have been rarely reported. In this article, a novel 3,5-disubstituted pyrazolate-bridged ligand LH5 with two [N2 N]2- -type chelating side arms was designed and synthesized, which supported a series of dinuclear hafnium complexes. Dinuclear hafnium azides [LHf2 (μ-1,1-N3 )2 (N3 )2 ][Na(THF)4 ] 3 and [LHf2 (μ-1,1-N3 )2 (N3 )2 ][Na(2,2,2-Kryptofix)] 4 were further synthesized and structurally characterized, featuring two sets of terminal and bridging azido ligands like jellyfishes. The reactivity of 3 under reduction conditions was conducted, leading to a formation of a tetranuclear hafnium imido complex [L1 Hf2 (μ1 -NH)(N3 ){μ2 -K}]2 5. DFT calculations revealed that the mixed imido azide 5 was generated via an intramolecular C-H insertion from a putative dinuclear HfIV -nitridyl intermediate.

An Azido-Bridged Dysprosium Chain Complex Showing Zero-field Slow Magnetic Relaxation.

A one-dimensional (1D) azido-bridged dysprosium coordination polymer featuring a zig-zag chain structure constructed from a halogen-functionalized quinoline derivative and N3 - ligands was structurally and magnetically characterized. Magnetic studies revealed that the chain complex exhibits zero-field slow magnetic relaxation and a significant butterfly-like hysteresis loop, originating from highly magnetic anisotropy of the Dy3+ ions in a D4d symmetry. This compound represents the first azido-bridged lanthanide chain showing zero-field slow magnetic relaxation behavior. These results highlight that the combination of high symmetric Ln3+ ions with the versatile azido bridging ligand provides an effective approach for the design and construction of advanced lanthanides molecular magnets.

Magnetic Properties of End-to-End Azide-Bridged Tetranuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complexes with Reduced Schiff Base Blocking Ligands and DFT Study.

Two tetranuclear mixed-valence cobalt(III/II) complexes having the general formula [(μ1,3-N3){CoII(Ln)(μ-O2CC6H4NO2)CoIII(N3)}2]PF6 (where H2L1 and H2L2 are two reduced Schiff base ligands) have been synthesized and characterized. The structures of both complexes show cobalt(II) and cobalt(III) centers with a distorted octahedral geometry with cobalt(III) and cobalt(II) centers located at the inner N2O2 and outer O4 cavities of the reduced Schiff base ligands, respectively. The oxidation states of both cobalt centers have been confirmed by bond valence sum (BVS) calculations. The magnetic properties show that both compounds behave as cobalt(II) dimers connected through an end-to-end azido bridging ligand and show moderate antiferromagnetic Co(II)–Co(II) couplings of −11.0 and −14.4 cm–1 for 1 and 2, respectively, as also corroborated by DFT calculations, Jtheo = −13.07 cm–1 for 1 and −12.49 cm–1 for 2. The calculated spin densities of both complexes at the cobalt(II) centers are −2.75 and +2.75, respectively, clearly supporting that they are the magnetic centers.

Single-Chain Magnet Based on 1D Polymeric Azido-Bridged Seven-Coordinate Fe(II) Complex with a Pyridine-Based Macrocyclic Ligand

Peculiar magnetic behavior was found for 1D-polymeric seven-coordinate pentagonal bipyramidal Fe(II) complex {[Fe(L)(μ1,3-N3)](ClO4)} n (1) with a pentadentate macrocyclic ligand L (3,12,18-triaza-6,9-dioxabicyclo[12.3.1]octadeca-1(18),14,16-triene) coordinated in the pentagonal equatorial plane and with end-to-end bridging azido ligands in axial positions. The static and dynamic magnetic data revealed that spin-canting in the 1D-chain of 1 results in the single-chain magnet (SCM) behavior with high spin-reversal energy barrier Ueff (Δτ) = 87.5 K, exhibiting magnetic hysteresis below 4 K and coexistence with the metamagnetism altogether resulting in weak 3D-ferromagnetic behavior. This is the first reported example of the exclusively azido-bridged homospin Fe(II)-based SCM.

Increasing the nuclearity and spin ground state in a new family of ferromagnetically-coupled {Ni10} disk-like complexes bearing exclusively end-on bridging azido ligands.

The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2- ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral.

ChemInform Abstract: The Bridging Azido Ligand as a Central “Player” in High‐Nuclearity 3d‐Metal Cluster Chemistry

AbstractReview: 261 refs.

New azido-substituted tantalum compounds: syntheses and DFT examination of nitrogen-rich mono-, di-, and trinuclear tantalum(v) compounds

The syntheses of new tantalum compounds containing an ancillary azido ligand(s) are described. The tantalum compound with the composition Ta(NMe2)4(N3) has been synthesized in high yield from the reaction of TaCl(NMe2)4 with NaN3 in THF. The solid-state structure reveals a dimeric architecture based on Ta2(NMe2)8(μ-N3)2 (), where the eight-membered dimetallocyclic ring possesses a chair-like conformation with bridging azido ligands binding the two Ta(NMe2)4 moieties. Solution molecular weight measurements and electronic structure calculations predict to exist as a monomer at room temperature. reacts with the formamidine (i)PrNC(H)NH(i)Pr to furnish fac-Ta(NMe2)3(η(1)-N3)[(i)PrNC(H)N(i)Pr] () and Me2NH; compound has been characterized by IR and (1)H NMR spectroscopy and X-ray diffraction analysis. Treatment of with p-toluidine affords the trinuclear compound Ta3(NMe2)5(μ-NMe2)(μ-NC6H4Me-4)2(NC6H4Me-4)(μ-N3)2(η(1)-N3) (). Compound contains three non-bonded tantalum atoms that are ligated by edge-bridging imido, amido, and azido ligands. The molecular structure of has been determined by X-ray crystallography, and the unprecedented presence of terminal and bridging imido, amido, and azido ligands in a single tantalum compound confirmed. The bonding in has been examined by DFT, and these data are discussed relative to the crystallographic structure. Compounds represent the first structurally characterized examples of heteroleptic tantalum compounds that possess an all-nitrogen coordination sphere with at least one azido ligand.

Versatility of Azide in Serendipitous Assembly of Copper(II) Magnetic Polyclusters

Engineering at the molecular level is one of the most exciting new developments for the generation of functional materials. However, the concept of designing polynuclear extended structures from bottom up is still not mature. Although progress has been made with secondary building units (SBUs) in metal organic frameworks (MOFs), the control seems to be just an illusion when it comes to bridging ligands such as the azide ion. When we say that the azido ligand is versatile in its bridging capabilities, what we mean is that it would be difficult to predict or control its bridging properties. However, this kind of serendipity is not always bad news. For example, scientists have shown that the azido ligand can mediate magnetic exchanges between paramagnetic metals in a predictable fashion (usually depending upon the bonding geometries). Therefore, it is a well-respected ligand in polynuclear assemblies. Serendipitous assemblies offer new magnetic structures that we may not otherwise even think about synthesizing. The azido ligand forms a variety of complexes with copper(II) using different blocking amines or pyridine based ligands. Its structural nature changes upon changing the substitution on amine, as well as the amount of blocking ligand. In principle, if we take any of these complexes and provide more coordination sites to the bridging azido ligands by removing a fraction of the blocking ligands, we can get new complexes with intricate structural networks and therefore different magnetic properties with the same components as used for the parent complex. In this Account, we mainly discuss the development of a number of new topological and magnetic exchange systems synthesized using this concept. Not all of these new complexes can be grouped according to their basic building structures or even by the ratio of the metal to blocking ligand. Therefore, we divided the discussion by the nuclearity of the basic building structures. Some of the complexes with the same nuclearities have very similar or even almost identical basic structures. However, the way these building units are joined together (by the azido bridges) to form the overall extended structures differ almost in every case. The complexes having the Cu6 core are particularly interesting from a structural point of view. Although they have almost identical basic structures, some of them are extended in three dimensions, but two of them are extended in two dimensions by two different bridging networks. In the complexes having linear Cu4 basic units, we find that using similar ligands does not always give the same bridging networks even within the basic building structures. These complexes have also enriched the field of molecular magnetism. One of the complexes with a Cu3 building unit has provided us with the opportunity to study the competing behavior of two different kinds of magnetic exchange mechanism (ferromagnetic and antiferromagnetic) acting simultaneously between two metal ions. Through density functional theory calculations, we showed how they work independently and their additive nature to produce the overall effect. The exciting methodology for the generation of copper(II) polyclusters presented in this Account will provide the opportunity to explore analogous serendipitous assembly of diverse structures with interesting magnetic behavior using other transition metal ions having more than one unpaired electrons.

Synthesis, X-ray crystal structure, and electrochemistry of polynuclear azido-bridged manganese(III) and copper(II) Schiff base complexes

Abstract New azido-bridged [MnIII(salabza)(μ-1,3-N3)]n (1), and [CuII4(salabza)2(μ-1,1-N3)2(N3)2(HOCH3)2],(2) complexes with an unsymmetrical Schiff base ligand, {H2salabza = N,N’-bis(salicylidene)-2-aminobenzylamine}, have been synthesized, characterized by spectroscopic and electrochemical methods, and their crystal structures have been determined by X-ray diffraction. In complex 1, each manganese(III) atom is coordinated with N2O2 donor atoms from salabza and two adjacent Mn(III) centers are linked by an end-to-end (EE) azide bridge to form a helical polymeric chain with octahedral geometry around the Mn(III) centers. Complex 2 is a centrosymmetric tetranuclear compound containing two types of Cu(II) centers with square pyramidal geometry. Each terminal copper atom is surrounded by N2O2 atoms of a salabza ligand, and the oxygen atom of the methanol molecule. Each central copper(II) ion is coordinated with two phenoxo oxygen atoms from one salabza, one terminal azido, and two end-on (EO) bridging azido ligands. The central copper(II) ions are linked to each other by the two end-on (EO) azido groups.

A new tetranuclear defective dicubane azide-bridged cobalt(II) complex

The new tetranuclear cobalt(II) complex with formula [Co4(N3)8(4,5-diazafluoren-9-one)4] (1) is reported. Complex 1 is a cobalt(II) defective dicubane azide-bridged compound showing only azido bridging ligands in the μ1,1– and μ1,1,1– coordination modes. The magnetic properties of 1 are reported. Magnetic susceptibility measurements indicate ferromagnetic coupling. The magnetic data have been fitted to 2K by considering two different superexchange coupling constants. The out-of-phase signal χM″ displays frequency-dependence below approximately 9K.

Bis(μ-azido-κ2N1:N1)bis{(acetato-κ2O,O′)[2,4,6-tris(2-pyridyl)-1,3,5-triazine-κ3N2,N1,N6]lead(II)}

The complete dinuclear title complex, [Pb2(C2H3O2)2(N3)2(C18H12N6)2], is generated by the application of a crystallographic centre of inversion. The PbII atom is coordinated by three N atoms of the tridentate ligand, two O atoms derived from an asymmetrically coordinating acetate ligand, and two azido-N atoms derived from two asymmetrically bridging azido ligands. The metal coordination geometry can be described as a square anti-prism with one position occupied by an unseen lone pair of electrons. In the ligand, the two coordinating pyridine rings are almost co-planar with the central pyrazine ring [dihedral angles = 0.47 (17) and 0.83 (18)°], but the terminal ring is twisted [dihedral angle = 19.76 (18)°]. In the crystal, the presence of π–π inter­actions [ring centroid distance between pyridyl rings = 3.581 (2) Å] leads to supra­molecular chains along the a-axis direction.

A new dodecanuclear manganese single-molecule magnet from the arrangement of manganese triangles

Bridging-azido ligands are used to create a new dodecanuclear manganese cluster [Mn12O4(salox)12(N3)4(MeOH)6(H2O)2]·5MeOH·2H2O (1·5MeOH·2H2O) from the arrangement of manganese triangles, [Mn3O]. Single-crystal x-ray analysis shows that 1·5MeOH·2H2O contains a [MnIII12(μ3-O)4(μ2-N3)4]24+ core, constructed from four [MnIII3O]7+ building units, which is a new structural type in the family of Mn12 complexes. Variable temperature magnetic susceptibility and magnetization measurements of the complex 1·5MeOH·2H2O were carried out. The magnetic data indicate that complex 1·5MeOH·2H2O exhibits antiferromagnetic with a non-zero ground state spin value of S = 4. The frequency dependence of out-of-phase component in alternating current magnetic susceptibility and magnetic hysteresis loop measurements indicate that complex 1·5MeOH·2H2O is a new single-molecule magnet with a significant magnetoanisotropy of Ueff = 70 K.

Magneto-Structural Correlation Studies and Theoretical Calculations of a Unique Family of Single End-to-End Azide-Bridged NiII4 Cyclic Clusters

The work in this paper aims to portray a complete structural, magnetic, and theoretical description of two original end-to-end (EE) μ(1,3)-azide-bridged, cyclic tetranuclear Ni(II) clusters, [{Ni(II)(L(1))(μ(1,3)-N(3))(H(2)O)}(4)] (1) and [{Ni(II)(L(2))(μ(1,3)-N(3))(H(2)O)}(4)] (2), where the ligands used to achieve these species, HL(1) and HL(2), are the tridentate Schiff base ligands obtained from [1 + 1] condensations of salicylaldehyde with 1-(2-aminoethyl)-piperidine and 4-(2-aminoethyl)-morpholine, respectively. The title compounds, 1 and 2, crystallize in a monoclinic P2(1) space group. Overall, both species can be described in a similar way; where all Ni(II) centers within each molecule are hexacoordinated and bound to [L(1)](-) or [L(2)](-) through the phenoxo oxygen, imine nitrogen, and piperidine/morpholine nitrogen atoms of the corresponding ligand. The remaining coordination sites are satisfied by one molecule of H(2)O and two nitrogen atoms from N(3)(-) anions. The latest act as bridges between Ni(II) ions, and eventually, only four azido groups are linked to the same number of Ni(II) centers resulting in the formation of cyclic Ni(II)(4) systems. Interestingly, compounds 1 and 2 are the two sole examples of tetranuclear clusters generated exclusively by EE azide-bridging ligands to date. All the N(azide)-Ni-N(azide) moieties are almost linear in 1 and 2 indicating trans arrangement of the azido ligand. Variable-temperature (2-300 K) magnetic susceptibilities of 1 and 2 have been measured under magnetic fields of 0.04 T (from 2 to 30 K) and 0.7 T (from 30 to 300 K), and magneto-structural correlations have been performed. Despite the presence of both ferromagnetic and antiferromagnetic interactions in both compounds, significant differences have been observed in their magnetic behaviors directly related to the arrangement of the bridging azido ligands. Hence, compound 1 has an overall moderate antiferromagnetic behavior due to the presence of an exchange pathway with an unprecedented Ni-N···N-Ni torsion angle close to 0°, meanwhile complex 2 exhibits a predominant ferromagnetic behavior, with torsion angles between 50 and 90°. Density functional theory calculations have been performed to provide more insight into the magnetic nature of this new family of Ni(II)-azido complexes and also to corroborate the fitting of the data.

Synthesis, crystal structure and magnetic properties of three unprecedented tri-nuclear and one very rare tetra-nuclear copper(ii) Schiff-base complexes supported by mixed azido/phenoxo/nitrato or acetato bridges

Three novel mixed bridged trinuclear and one tetranuclear copper(II) complexes of tridentate NNO donor Schiff base ligands [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(CH(3)OH)(2)(BF(4))(2)] (1), [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (2), [Cu(3)(L(2))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (3) and [Cu(4)(L(3))(2)(mu(1,1)-N(3))(4)(mu-CH(3)COO-1kappaO:2kappaO')(2)] (4) have been synthesized by reaction of the respective tridentate ligands (L(1) = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, L(2) = 2-[1-(2-diethylamino-ethylimino)-ethyl]-phenol, L(3) = 2-[1-(2-dimethylamino-ethylimino)-methyl]-phenol) with the corresponding copper(ii) salts in the presence of NaN(3). The complexes are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. Complex 1 is composed of two terminal [Cu(L(1))(mu(1,1)-N(3))] units connected by a central [Cu(BF(4))(2)] unit through nitrogen atoms of end-on azido ligands and a phenoxo oxygen atom of the tridentate ligand. The structures of 2 and 3 are very similar; the only difference is that the central unit is [Cu(NO(3))(2)] and the nitrate group forms an additional mu-NO(3)-1kappaO:2kappaO' bridge between the terminal and central copper atoms. In complex 4, the central unit is a di-mu(1,1)-N(3) bridged dicopper entity, [Cu(2)(mu(1,1)-N(3))(2)(CH(3)COO)(2)] that connects two terminal [Cu(L(3))(mu(1,1)-N(3))] units through end-on azido, phenoxo oxygen and mu-CH(3)COO-1kappaO:2kappaO' triple bridges to result in a tetranuclear unit. Analyses of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the copper(II) ions in complexes 1-3, with the exchange parameter J of -9.86, -11.6 and -19.98 cm(-1) for 1-3, respectively. In complex 4 theoretical calculations show the presence of an antiferromagnetic coupling in the triple bridging ligands (acetato, phenoxo and azido) while the interaction through the double end-on azido bridging ligand is strongly ferromagnetic.

Four novel Co(II) and Mn(II) coordination polymers with triazolyl derivate: Syntheses, crystal structures and magnetic properties

Four novel coordination polymers, one-dimensional chains [M(PTE) 2(N 3) 2] n (M = Mn for 1 and Co for 2), and two-dimensional layers [M(PTE) 2(dca) 2] n (M = Mn for 3 and Co for 4) (PTE = 1-(2,4-difluorophenyl-2-(1H-1,2,4-triazol-1-yl)ethanone, dca = dicyanamide anion, N(CN) 2 −), have been synthesized under mild ambient conditions and structurally characterized by single crystal X-ray diffraction. In all four crystal structures, the metal atoms adopt octahedral coordination geometry with six nitrogen atoms from two monodentate PTE ligands and four azido (or dca) bridging ligands. The crystal structures of 1 and 2 are isostructural 1-D polymeric chains, alternatively linked by double end-on and double end-to-end azido bridges. However, the bent dca ligands as bidentate μ 2-1,5 bridging ligands interlink the octahedral metal units to lead to 2-D (4,4) grid networks in 3 and 4. Temperature-dependent magnetic measurements in 2–300 K have been performed for these four polymers, and suggest alternative ferro- and antiferromagnetic couplings for end-on and end-to-end azido bridges in 1, and the dominant ferromagnetic coupling in 2, respectively. Both polymers 3 and 4 show weak antiferromagnetic exchanges through the μ 2-1,5-dca bridges. The effects of auxiliary coligands on the structure and the nature of these magnetic exchanges are discussed in the light of the crystal structures in detail.

New Topology in Azide-Bridged Cobalt(II) Complexes: the Weak Ferromagnet [Co2(N3)4(Hexamethylenetetramine)(H2O)]n

A new polynuclear azido-bridged Co(II) compound with formula [Co(2)(N(3))(4)(HMTA)(H(2)O)](n) (1) (HMTA = hexamethylenetetramine) has been structurally and magnetically characterized. The compound 1 crystallizes in the monoclinic system C2/m space group, and consist of a complex three-dimensional system in which end-to-end and end-on azido bridging ligands between the Co(II) atoms coexist. The HMTA ligand is also linking three different Co(II) atoms. The network analysis shows for 1 a three- and six-connected network topology not previously reported. The magnetic properties of 1 are also reported, and it was found that the magnetic interactions define another new three- and four-connected net assigned as a (6.8(2))(6(4).10(2))-tfo net. In the high temperature region the chi(M) versus T plot can be fitted by using the Curie-Weiss law, and the best fit theta value is -26.6 K. For 1 magnetic ordering and spontaneous magnetization is achieved below T(c) = 15.6 K.

Synthesis, crystal structures, and urease inhibitory activities of two azido-bridged polynuclear copper(II) complexes with Schiff bases

Two azido-bridged polynuclear Cu(II) complexes with the formulae [Cu(L1)(μ1,3-N3)]n and [Cu(L2)(μ1,3-N3)]n (HL1 = 2-[(2-morpholin-4-ylethylimino)methyl]phenol, HL2 = 2-methoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol), have been synthesized and characterized by physico-chemical and spectroscopic methods. The Cu atom in each of the complexes is five-coordinate in a square pyramidal geometry, with one O and two N atoms of a Schiff base ligand and one terminal N atom of a bridging azido ligand defining the base-plane, and with another terminal N atom of a symmetry-related azido ligand occupying the apical position. The molecules are linked through end-to-end azido bridges, forming one-dimensional polymeric chains. Both of the complexes show moderate inhibitory activities against jack bean urease.

Magnetic Structure of the Large-Spin Mn10 and Mn19 Complexes: A Theoretical Complement to an Experimental Milestone

High-spin molecules have been proposed as candidates for the storage of information at the molecular level. The electronic structure of two complex magnetic molecular systems, Mn 10 and Mn 19, is characterized by means of a computational study based on density functional theory. All the exchange interactions in the recently reported Mn 19 complex with the highest known spin value of 83/2, and in its highly symmetric Mn 10 parent compound, are ferromagnetic. In these complexes, there are two kinds of ferromagnetic coupling: the first one corresponds to Mn (II)-Mn (III) interactions through a double mu 2-alkoxo-mu 4-oxo bridge where the high coordination number of the Mn (II) cations results in long Mn (II)-O bond distances, while the second one involves Mn (III)-Mn (III) interactions through mu 2-alkoxo-mu 3-eta (1):eta (1):eta (1) azido bridging ligands with long Mn (III)-N distances due to a Jahn-Teller effect.

Synthesis and structural characterization of three new 1D and 2D zinc(II) azide polymers with some pyridine and pyrazine derivative ligands

Three new polymeric zinc(II) azido complexes, namely [Zn(N 3) 2(3-Brpy)] n ( 1), [Zn(N 3) 2(4-Etpy)] n ( 2) and [Zn 2(N 3) 4(2,5-dmpyz)] n ( 3), where Brpy = bromopyridine, Etpy = ethylpyridine and dmpyz = dimethylpyrazine have been prepared and structurally characterized. The IR spectra of these complexes are measured and discussed. The structures of 1 and 2 are similar and feature one-dimensional zigzag chain of [Zn(N 3) 2] n in which each zinc atom is surrounded by double di-end on (EO) bridging azido ligands forming cyclic Zn 2N 2 units. Furthermore, each zinc atom links a N hetero atom of the pyridine moiety leading to ZnN 5 chromophore. The geometry around the zinc center is best described as distorted trigonal bipyramid. Although complex 3 consists of the 1D chain of [Zn(N 3) 2] n with double di-EO azido bridges around each zinc center with almost planar Zn 2N 2 cyclic units, the pyrazinic moiety behaves as a bidentate bridging N, N′-ligand that binds the zinc centers across the [Zn 2(N 3) 2] n chains extending the structure to be two-dimensional sheets. The Zn … Zn distances within the Zn 2N 2 units are similar, fall within the range of 3.20–3.26 Å, and the azido ligands are asymmetric and linear within experimental error in all of these three complexes.