Hydrothermal syntheses and structures of a novel zincophosphite, [C6N2H18] · [Zn3(HPO3)4]

A novel three-dimensional organically templated zincophosphite, [C₆N₂H₁₈] · [Zn₃(HPO₃)₄], was synthesized under milder hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, differential thermal-thermogravimetric analysis, powder X-ray diffraction, ³¹P MAS NMR spectrum, and IR spectroscopy. It crystallizes in the monoclinic system, space group C2/c with cell parameters: a = 8.7820(4) Å, b = 14.9417(7) Å, c = 15.4943(5) Å, β = 92.940(2)°, and Z = 4. The structure consists of a network of strictly alternating ZnO₄ tetrahedra and pseudo-pyramid, forming 4-membered ring chains. The structure has a 4.8.16-net and 8- and 16-membered ring channels where completely protonated N,N,N′,N′-tetramethylenediamine cations are encapsulated. The structure is stabilized by template-to-framework hydrogen bonding. In phosphites system, this compound possesses extra-large-pores.     

Synthesis and crystal structure of the low-spin iron(II) complex [Fe(bpz)3](ClO4)2 · H2O (bpz=2,2-bipyrazine)

The crystal structure of the title compound [Fe(bpz)₃](ClO₄)₂ · H₂O (bpz=2,2^′-bipyrazine) has been determined by a single crystal X-ray diffraction study at 293(2) K. The complex is monoclinic, P2₁/c, a=17.263(3), b=9.983(2), c=17.921(4) Å, β=107.94(3)°, V=2938.3(10) ų, Z=4, R=0.073 and R_w=0.118. The structure is made up of tris-chelated [Fe(bpz)₃]²⁺ cations, uncoordinated perchlorate anions and crystallization water molecules. The iron atom exhibits a FeN₆ distorted octahedral geometry with average Fe-N bond length and N-Fe-N bidentate angle of 1.962(5) Å and 81.6(2)°. The value of the Fe-N bond distance and that of the room temperature magnetic moment are in agreement with a singlet ¹A₁ ground state. The structure of 1 is compared to those of other tris-chelated iron(II) complexes with bidentate nitrogen heterocycles.     

A bimetallic oxide hybrid material constructed from a coordination complex polymer and molybdenum oxide subunits, [Ni(3,4′-bipyridine)2MoO4]·3H2O

The hydrothermal reaction of NiCl₂·6H₂O, MoO₃, 3,4′-bipyridine (3,4′-bpy) and H₂O in the mole ratio 1.0:1.0:2.1:1500 yields [Ni(3,4′-bpy)₂MoO₄]·3H₂O (1·3H₂O) in 80% yield. The structure of 1·3H₂O consists of a three-dimensional coordination polymer {Ni(3,4′-bpy)₂}_n²ⁿ⁺ with entrained {MoO₄}²⁻ tetrahedra and with water molecules of crystallization occupying channels within the bimetallic oxide-ligand framework. Crystal data: C₂₀H₁₆N₄O₄NiMo·3H₂O (1·3H₂O), tetragonal P4₁2₁2, a=13.1866(5) Å, c=29.458(2) Å, V=5122.3(4) ų, Z=8, D_calc=1.532 g cm⁻³.     

Hydrothermal synthesis and characterization of a zinc-substituted gallium phosphite, [H3N(CH2)2NH3]1/2 · [GaZn(HPO3)3(H2O)2]

An organically templated zinc-substituted gallium phosphite, [H₃N(CH₂)₂NH₃]_1/2 · [GaZn(HPO₃)₃(H₂O)₂] was synthesized under mild hydrothermal conditions in the presence of ethylenediamine (en) as structure-directing agent and characterized by single-crystal X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pbcn with unit cell parameters: a = 18.6146(10) Å, b = 11.0454(6) Å, c = 10.9074(4) Å, V = 2242.62(19) Å³ and Z = 8. This compound has a three-dimensional framework built up from secondary building units (SBU) of Ga(III) (or Zn(II)) and HPO₃ pseudopyramid by sharing vertices. The structure displays a two-dimensional channel system running along the [0 0 1] and [0 1 0] direction with 5-, 8- and 10-membered rings. The diprotonated ethylenediamine template molecules are located in the channels. In this structure, some of the Ga(III) sites are occupied by Zn(II) atoms. The compound was also characterized by IR spectroscopy, inductively coupled plasma (ICP), X-ray photoelectron spectra (XPS), differential thermal and thermogravimetric analyses.     

A novel unexpected luminescent quarternary coordination polymer {Sm3(C8H4O4)4(C12N2H8)2(NO3)}n with three high asymmetrical central Sm fragments by hydrothermal assembly

A novel chain-like luminescent samarium coordination polymer {Sm₃(C₈H₄O₄)₄(C₁₂N₂H₈)₂(NO₃)}_n (C₈H₄O₄ = phthalate, C₁₂N₂H₈ = 1,10-phenanthroline) has been assembled by hydrothermal process. The title complex crystallizes in the monoclinic system, space group P2(1)/c, with lattice parameters a = 22.56(3) Å, b = 11.155(15) Å, c = 20.32(3) Å, β = 96.70(2)°, V = 5078(12) ų, F(000) = 2964, GOF = 0.857, R₁ = 0.0358, wR₂ = 0.0597, Z = 4. Samarium ions exhibit different coordination modes from each other and lead to the unexpected high asymmetrical structure. To our knowledge, it is the first example of lanthanide coordination polymers comprising the three asymmetrical central Sm³⁺ fragments. The photophysical properties have been studied with excitation and emission spectra.     

A nearly symmetric trinuclear chromium(III) oxo carboxylate assembly: preparation, molecular and crystal structure, and magnetic properties of [Cr3O(O2CPh)6(MeOH)3](NO3) · 2MeOH

Complex [Cr₃O(O₂CPh)₆(MeOH)₃](NO₃) · 2MeOH (1 · 2MeOH) has been synthesized from the one-pot reaction between Cr(NO₃)₃ · 9H₂O and NaO₂CPh in MeOH. The structure of the complex has been solved by single-crystal X-ray crystallography. It crystallizes in the monoclinic space group P2₁/n with a=14.716(6) Å, b=22.569(8) Å, c=15.755(6) Å, β=95.02(1)°, V=5212.5(4) ų and Z=4. Although the cation does not possess any crystallographically imposed symmetry element, its {Cr₃(μ₃-O)} core is nearly symmetric. Each Cr^III…Cr^III vector is further bridged by two η¹:η¹:μ₂ benzoates, with a terminal MeOH molecule completing octahedral coordination at each metal ion. The crystal structure consists of layers that are parallel to (0 1 0) crystallographic plane and are formed through π-π stacking interactions and hydrogen bonds. Variable-temperature magnetic susceptibility and solid-state ¹H NMR studies indicate that the total spin value of the ground state is 1/2. EPR experiments reveal the existence of a distribution of trimers with axial anisotropy in the g tensor.     

[Hg(9-methyl-1-deazapurine)2](NO3)2 · H2O: a complex with a distorted hexagonal bipyramidal metal ion coordination sphere

Reaction of 9-methyl-1-deazapurine (9-MeDP) with Hg(CF₃COO)₂ in the presence of NaNO₃ yields the title compound [Hg(9-MeDP)₂](NO₃)₂ · H₂O with the two 9-MeDP ligands bound to the metal ion via their N7 positions. The X-ray structure is reported: monoclinic, P2₁/c (no. 14), a = 5.4015(11), b = 20.467(4), c = 17.775(4) Å, β = 97.00(3)°, V = 1950.4(7) ų, Z = 4. Hg is eight-coordinate with two trans-oriented Hg-N bonds (2.073(3) and 2.075(3) Å) and three nearly coplanar, bidentate nitrate moieties (Hg-O: 2.716(3)-2.985(4) Å), leading to a distorted hexagonal bipyramidal environment of the metal ion. Within this structure, the nitrate ions form a honeycomb-like chain structure with Hg^II being positioned inside the combs. This work represents the first report of such geometry for a transition metal ion surrounded by symmetrically bidentate nitrate ions. The corresponding nucleoside, 1-deazapurine 2′-deoxyribonucleoside, also forms a stable 2:1 complex with Hg^II, as was shown by ¹H NMR spectroscopy, making it a potential candidate for incorporation into nucleic acids based on metal-mediated base pairs.     

Preparation and structure of [Ru2(O2CMe)4]2[Fe(CN)5NO] and magnetically ordered Hx[Ru2(O2CMe)4]3−x[Cr(CN)5NO] possessing interpenetrating lattices

Reaction of [Ru₂(O₂CMe)₄]Cl with K₃[Cr(CN)₅NO] in water forms H_x[Ru^II/III₂(O₂CMe)₄]_3−x-[Cr(CN)₅NO]·zH₂O (x = 0.2) that magnetically orders at 4.0 K and possesses an interpenetrating body centered cubic [a = 13.2509(2) Å] structure with random locations of the bridging nitrosyl ligands, and x/3 vacant cation sites. Similarly, the aqueous reaction of [Ru₂(O₂CMe)₄]Cl with Na₂[Fe(CN)₅NO] forms paramagnetic [Ru₂(O₂CMe)₄]₂[Fe(CN)₅NO]·H₂O, which has a similar tetragonal interpenetrating structure [a = 13.0186(1) Å, c = 13.0699(2) Å] where the NO ligands are presumably nonbridging and 1/3 of the expected cation sites are unoccupied. The presence of uncoordinated NO sites in addition to missing neighboring [Ru₂(O₂CMe)₄]⁺ units, results in significant vacancies (or holes) in the lattice.     

Salts of cationic platinum dithiolenes with anionic platinum complexes: structural characterization of [Pt(Me2pipdt)2][Pt(SCN)4] (Me2pipdt = N,N-dimethyl-piperazine-2,3-dithione)

[Pt(Me₂pipdt)₂](BF₄)₂ salts [Me₂pipdt = N,N^′-dimethyl-piperazine-2,3-dithione] bearing cationic dithiolene complexes react with (Bu₄N)₂[Pt(X)₄] (X = SCN, CN) to form [Pt(Me₂pipdt)₂][Pt(SCN)₄ ] (1) and [Pt(Me₂pipdt)₂][Pt(CN)₄] (2) salts by metathesis. Black crystals of 1 have been structurally characterized showing that the two metals lie on inversion centers and exhibit a square planar coordination. The Pt-S bond distances in the anion complex (2.324(2) Å) are longer than in the cation complex (2.280(2) Å) whereas the C-S bond distances are shorter in SCN⁻ (average 1.669 Å) than in Me₂pipdt (average 1.694 Å). The chelating Me₂Pipdt ligand is found disordered in the λ/δ conformations with site occupancies of 50/50, respectively. The cation and anion complexes run parallel to a.     

DNA-binding and photocleavage studies of [Ru(phen)2(NMIP)]

A novel ligand 2′-(2″-nitro-3″,4″-methylenedioxyphenyl)imidazo[4′,5′-f][1,10]-phenanthroline (NMIP) and its complex [Ru(phen)₂(NMIP)]²⁺ have been synthesized and characterized by mass spectroscopy, ¹H NMR and cyclic voltammetry. Binding of the complex with calf thymus DNA (CT DNA) has been investigated by spectroscopic methods, viscosity and electrophoresis measurements. The experimental results indicate that [Ru(phen)₂(NMIP)]²⁺ binds to DNA via partial intercalative mode and the individual enantiomers of it bind to DNA in different rates. [Ru(phen)₂(NMIP)]²⁺ has also been found to promote cleavage of plasmid pBR 322 DNA from the supercoiled Form I to the open circular Form II upon irradiation.     

Iron(III) induced 2-phenyl imidazolidine ring hydrolysis of a new binucleating Schiff base ligand: X-ray structure of the mononuclear Fe(NNO)2 end product

The reaction of triethylenetetramine, salicylaldehyde and benzaldehyde in 1:2:1 mole ratio in methanol at room temperature affords a novel μ-bis(tridentate) ligand H₂L′ through the formation of an imidazolidine ring within the parent hexadentate precursor in a two step reaction. The ligand H₂L′ reacts with Fe(ClO₄)₂ · 6H₂O in aqueous methanol in the presence of triethylamine to form the mononuclear [Fe^IIIL](ClO₄) complex, (where L²⁻ is the anion of the parent hexadentate H₂saltrien ligand) after the cleavage of the imidazolidine ring. The mononuclear complex has a structure with an N₄O₂ donor atom set of the hexadentate ligand forming a distorted octahedral coordination geometry around the metal atom as established from a crystal structure determination. The Fe-N(imine) distances are 1.934(10) and 1.948(9) Å, Fe-N(amine) distances are 2.062(8) and 2.076(9) Å and Fe-O(phenol) distances are 1.864(8) and 1.872(7) Å. The terminal oxygen donor atoms occupy cis positions and the remaining four nitrogen atoms (two cis amine and two trans imine) complete the coordination sphere. The mononuclear complex has a magnetic moment 1.89 μ_B corresponding to the low-spin 3d⁵ configuration. The UV-Vis spectrum of the end product, after the imidazolidine ring hydrolysis, is different from the spectrum of the initial reaction mixture containing the μ-bis(tridentate) ligand H₂L′.     

Solid state coordination chemistry: the hydrothermal synthesis and structure of a bimetallic oxide incorporating 2,2′:6′,2″-terpyridine (terpy), [{VO(terpy)}MoO4]

The hydrothermal reaction of MoO₃, Na₃VO₄, 2,2′:6′,2″-terpyridine (terpy) and H₂O in the mole ratio 1.53:1.00:1.30:1460 at pH 3 yields red crystals of [{VO(terpy)}MoO₄] (1) in 55% yield. The structure of 1 is a one-dimensional chain of {VO(terpy)}²⁺ units bridged in the characteristic O,O′-mode by {MoO₄}²⁻ tetrahedra. Crystal data: C₁₅H₁₁N₃O₅MoV, orthorhombic, P2₁2₁2₁, a=26.145(1) Å, b=6.7607(4) Å, c=9.2496(5) Å, V=1634.9(2) ų, Z=2, D_calc=1.869 g cm⁻³; structure solution and refinement converged at R₁=0.0335 and wR₂=0.0735.     

Structural analysis and magnetic properties of the copper(II) dicyanamide complexes [Cu2(dmphen)2(dca)4], [Cu(dmphen)(dca)(NO3)]n and [Cu(4,4-dmbpy)(H2O)(dca)2] (dca=dicyanamide; dmphen=2,9-dimethyl-1,10-phenanthroline; 4,4-dmbpy=4,4-dimethyl-2,2-bipyridine)

The preparation, crystal structures and magnetic properties of three copper(II) compounds of formulae [Cu₂(dmphen)₂(dca)₄] (1), [Cu(dmphen)(dca)(NO₃)]_n (2) and [Cu(4,4^′-dmbpy)(H₂O)(dca)₂] (3) (dmphen=2,9-dimethyl-1,10-phenanthroline, dca=dicyanamide and 4,4^′-dmbpy=4,4^′-dimethyl-2,2^′-bipyridine) are reported. The structure of 1 consists of discrete copper(II) dinuclear units with double end-to-end dca bridges whereas that of 2 is made up of neutral uniform copper(II) chains with a single symmetrical end-to-end dca bridge. Each copper atom in 1 and 2 is in a distorted square pyramidal environment: two (1) or one (2) nitrile-nitrogen atoms from bridging dca groups, one of the nitrogen atoms of the dmphen molecule (1 and 2) and either one nitrile-nitrogen from a terminal dca ligand (1) or a nitrate-oxygen atom (2) build the equatorial plane whereas the second nitrogen atom of the heterocyclic dmphen fills the axial position (1 and 2). The copper-copper separations through double (1) and single (2) end-to-end dca bridges are 7.1337(7) (1) and 7.6617(7) (2). Compound 3 is a mononuclear copper(II) complex whose structure contains two neutral and crystallographically independent [Cu(4,4^′-dmbpy)(H₂O)(dca)₂] molecules which are packed in two different layer arrangements running parallel to the bc-plane and alternating along the a-axis. The copper atoms in both molecules have slightly distorted square pyramidal surroundings with the two nitrogen atoms of the 4,4^′-dmbpy ligand and two dca nitrile-nitrogen atoms in the basal plane and a water oxygen in the apical position. A semi co-ordinated dca nitrile-nitrogen from a neighbour unit [2.952(6) Å for Cu(2)-N] is in trans position to the apical water molecule in one of the two molecules, this feature representing part of the difference in supramolecular connections in the alternating layers referred to above. Magnetic susceptibility measurements for 1-3 in the temperature range 1.9-290 K reveal the occurrence of weak antiferromagnetic interactions through double [J=−3.3 cm⁻¹ (1), ] and single [J=−0.57 cm⁻¹ (2), ] dca bridges and across intermolecular contacts [θ=−0.07 K (3)].     

A new self-assembled inorganic-organic hybrid layered compound containing hexarhenium cluster: [MV][{Mn(CH3OH)2}{Re6Se8(CN)6}]

A new layered compound, [MV][{Mn(CH₃OH)₂}{Re₆Se₈(CN)₆}] (1) consists of a layer alternately knitted by hexarhenium cluster and Mn complex, and MV²⁺ cations (methyl viologen dication = 1,1′-dimethyl-4,4′-bipyridilium dication) reside between the layers. The title compound 1 is the first layered framework containing cyano-hexarhenium clusters with photoactive guest molecules, MV²⁺. The MV²⁺ can be partly exchanged by H₂TMB²⁺ (N,N,N′,N′-tetramethylbenzidine dication) to form a compound [H₂TMB²⁺]_x[MV²⁺]_1−x [{Mn(CH₃OH)₂}{Re₆Se₈(CN)₆}] (2) showing an electronic interaction between the layered framework and [H₂TMB]²⁺ cation.     

Ruthenium(II/III) mediated transformation of 1,2-bis(2′-pyridylmethyleneimino)benzene (L) to 2-(2′-benzimidazolyl)pyridine (L′H) and its in situ formed complexes with Ru(II): X-ray structure of trans-[Ru(PPh3)2(L′H)2](ClO4)2

A series of ruthenium (II) complexes of formulae trans-[Ru(PPh₃)₂(L′H)₂](ClO₄)₂ (1), [Ru(bpy)(L′H)₂](ClO₄)₂ (2), [Ru(bpy)₂(L′H)](ClO₄)₂ (3), cis-[Ru(DMSO)₂(L′H)₂]Cl₂ (4), and [Ru(L′H)₃](PF₆)₂ (5) (where L′H = 2-(2′-benzimidazolyl)pyridine) have been synthesized by reaction of the appropriate ruthenium precursor with 1,2-bis(2′-pyridylmethyleneimino)benzene (L). The complexes were characterized by elemental analyses, spectroscopic and electrochemical data. All the complexes were found to be diamagnetic and hence metal is in +2 oxidation state. The molecular structure of trans-[Ru(PPh₃)₂(L′H)₂](ClO₄)₂ has been determined by the single crystal X-ray diffraction studies. The molecular structure shows that Ru(II) is at the center of inversion of an octahedron with N₄P₂ coordination sphere. The ligand acts as a bidentate N,N′donor. The electronic spectra of the complexes display intense MLCT bands in the visible region.Cyclic voltammetric studies show quasi-reversible oxidative response at 0.99-1.32 V (vs Ag/AgCl reference electrode) due to Ru(III)/Ru(II) couple.     

Electrochemical reduction properties of A-frame compounds and crystal structure of Pd2(dppm)2(Me)2(Br) dimer

Two series of A-frame complexes, [Pd₂(dppm)₂(R)₂(μ-X)]⁺ (R = Me and X = Cl, Br, I, H; R = Mes and X = Br, I), were investigated by cyclic voltammetry (CV). The 2-electron reduction potentials for the first series increase from I (−1.10), Br (−1.17), Cl (−1.25) to H (−1.65 V versus SCE, in CHCl₃), as well as in the second series; Br (−1.35) and I (−1.38 V versus SCE, in THF). The nature of the LUMO where the electron reduction takes place is qualitatively addressed by DFT on the corresponding model complexes [Pd₂(H₂PCH₂PH₂)₂(R)₂(μ-X)]⁺. The LUMO and (LUMO + 1) of the halide derivatives exhibit the presence of Pd d_x²-y² atomic orbitals interacting in an anti-bonding fashion with the n-donor orbitals of X⁻, P, and Me⁻, explaining in part the observed reactivity upon reduction. The X-ray structure of [Pd₂(dppm)₂(Me)₂(μ-Br)]⁺ compound exhibits the typical A-frame structure with a Pd?Pd non-bonding distance of 3.036(1) Å, and long Pd-Br bonds of 2.5623(5) and 2.5793(5) Å.     

Structure and magnetic properties of Ln2[Cu(opba)]3(DMSO)6(H2O) · (H2O) compounds with LnLa-Lu exhibiting ladder-like molecular motifs

The reaction of Ln(III) ions with the precursor [Cu(opba)]²⁻ in DMSO has afforded a series of isostructural compounds of general chemical formula Ln₂[Cu(opba)]₃(DMSO)₆(H₂O) · (H₂O), where Ln(III) stands for a lanthanide ion and opba stands for ortho-phenylenebis(oxamato). The crystal structure has been solved for the Gd(III) containing compound. It crystallizes in the orthorhombic system, space group Pbn2₁ (No. 33) with a = 9.4183(2) Å, b = 21.2326(4) Å, c = 37.9387(8) Å and Z = 4. The structure consists of ladder-like molecular motifs parallel to each other. To the best of our knowledge, this is the first Ln(III)Cu(II) coordination polymer family exhibiting the same crystal structure over the whole lanthanide series. The magnetic properties of the compounds have been investigated and the magnetic behavior of the Gd(III) containing compound was studied in more detail.     

Novel long bipyridine-type linking ligands containing an intervening naphthalene fragment: [Zn(L)(NO3)2], [Zn(L)(NO3)2], and [Cd(L)1.5(NO3)2] (L = (4-py)-CHN-C10H6-NCH-(4-py); L = (3-py)-CHN-C10H6-NCH-(3-py))

Novel bipyridine-type linking ligands L¹ ((4-py)-CHN-C₁₀H₆-NCH-(4-py)) and L² ((3-py)-CHN-C₁₀H₆-NCH-(3-py)), a pair of isomers due to possessing different pairs of terminal pyridyl groups, were prepared by the Schiff-base condensation. In ligand L¹, the N?N separation between the terminal pyridyl groups is 16.0 Å, with their nitrogen donor atoms at the para positions (4,4′). The corresponding N?N separation in ligand L² is 14.2 Å, with the nitrogen donor atoms at the meta positions (3,3′). 1-D zigzag-chain coordination polymers [Zn(L¹)(NO₃)₂] (1) and [Zn(L²)(NO₃)₂] (2) were prepared by reactions of Zn(NO₃)₂ · 6H₂O with ligands L¹ and L², respectively, by solution diffusion. Polymer 3, [Cd(L¹)_1.5(NO₃)₂], prepared from Cd(NO₃)₂ · 4H₂O and L¹, exhibits a 1-D ladder structure, whose repeating ladder unit consists of four Cd metals and four L¹ ligands to create a large 76-membered ring with dimensions of 20.8 × 20.8 Å. All products were structurally characterized by X-ray diffraction.     

Synthesis, crystal structure, magnetic properties and electrochemical behaviour of the mixed valence compound [Cu(CN)3Cu(C3H10N2)2]

The binuclear mixed valence copper(I/II) compound [Cu^I(CN)₃Cu^II(tn)₂] (1) (tn = propane-1,3-diamine) and its acetonitrile adduct [Cu^I(CN)₃Cu^II(tn)₂] · 2MeCN (2) have been synthesized. Complex 1 crystallizes triclinic, space group , a = 8.117(2) Å, b = 8.389(2) Å, c = 11.920(2) Å, α = 108.728(3)°, β = 100.024(3)°, γ = 104.888(4)°, Z = 2, and compound 2 monoclinic, space group P2₁/m, a = 8.752(2) Å, b = 13.243(3) Å, c = 9.549(2) Å, β = 114.678(4)°, Z = 2. In both crystal structures, the binuclear [Cu^I(CN)₃Cu^II(tn)₂] complex with slightly different bonding geometries is formed. One of the three nitrogen atoms of a Cu^I(CN)₃ moiety is coordinated to Cu(II) at the apex of a square-pyramid with two chelating ligands tn on its base. The shortest intramolecular Cu^II?Cu^II distance in 1 is 5.640(7) Å. The EPR behaviour of 1 has been investigated at room temperature and at 77 K. The magnetic properties were measured in the temperature range 1.8-300 K.     

Octahedral cyanohydroxo cluster complex trans-[Re6Se8(CN)4(OH)2]: Synthesis, crystal structure, and properties

A hexarhenium cyanohydroxo anionic cluster complex [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was synthesized for the first time starting from [Re₆Se₈(OH)₆]⁴⁻, which was crystallized as a salt of the composition Cs_2.75K_1.25[Re₆Se₈(CN)₄(OH)₂]·H₂O (1). The reaction of the complex with Cu²⁺ in an aqueous ammonia or methylamine solutions afforded [Cu(NH₃)₅]₂[Re₆Se₈(CN)₄(OH)₂]·8H₂O (2) or [{Cu(CH₃NH₂)₄}₂Re₆Se₈(CN)₄(OH)₂] (3), respectively. All of these three compounds were characterized by a single-crystal X-ray diffraction method. Compound 1 is crystallized in the tetragonal space group I4/m with eight formula units per cell (a = b = 17.4823(14) Å, c = 19.430(2) Å, V = 5938.3(10) Å³); compound 2 is crystallized in the monoclinic space group P2₁/n with two formula units per cell (a = 12.1845(13) Å, b = 8.6554(9) Å, c = 19.2568(19) Å, β = 91.081(2)°, V = 2030.5(4) Å³); compound 3 is crystallized in the orthorhombic space group Cmcm with four formula units per cell (a = 19.816(4) Å, b = 14.611(3) Å, c = 13.751(3) Å, V = 3981.2(13) Å³). The luminescence properties of 1 were studied in both aqueous solution and solid state. In addition, the electronic structure of [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was elucidated by DFT calculations.