ChemInform Abstract: Barium Dierbium(III) Tetrasulfide.

Orange needles of BaEr₂S₄ are obtained during an investigation of the Ba/Er/U/S system by solid state reaction of a mixture of ²³⁸U, Er, BaS, and S in the ratio 1:1:3:3 (evacuated C‐coated fused silica tube, 1273 K, 8 d, cooling rate 3 K/h) together with black crystals of Sb₂S₃ and US₂.     

ChemInform Abstract: Tetrayttrium Difluoride Disilicate Orthosilicate,Y4F2[Si2O7][SiO4].

Colorless lath-shaped single crystals of the title compound are obtained from a melt of Y₂O₃, YF₃, and SiO₂ (2:5:3 molar ratio) using CsCl as a flux (evacuated silica tube, 973 K, 9 d, 10 K/h cooling rate).     

ChemInform Abstract: Synthesis and Characterizations of Two Anhydrous Metal Borophosphates: M2IIIBP3O12 (M: Fe,In).

The title compounds are obtained quantitatively by reacting mixtures of M₂O₃ (M: Fe, In), H₃BO₃, and NH₄H₂PO₄ in a molar ratio of 1:1:3 at 1153 K.     

Kristallstruktur des Isothiocyanato‐Komplexes [Ph3PNH2(OEt2)][Sm(NCS)4(DME)2]

Crystal Structure of the Isothiocyanato Complex [Ph₃PNH₂(OEt₂)][Sm(NCS)₄(DME)₂] Colourless single crystals of [Ph₃PNH₂(OEt₂)][Sm(NCS)₄(DME)₂] ( 1 ) have been obtained besides of Ph₃PS from the reaction of the homoleptic phosphorane iminato complex [Sm(NPPh₃)₃]₂ with carbon disulfide in THF solution, followed by recrystallisation from DME/Et₂O. According to the crystal structure analysis 1 consists of [Ph₃PNH₂]⁺ cations with the diethylether molecule forming a N–H…O hydrogen bridge, and anions [Sm(NCS)₄(DME)₂]^–. Sm³⁺ realizes coordination number eight by four nitrogen atoms of the isothiocyanato ions and by four oxygen atoms of the DME chelates. 1 : Space group P 1, Z = 4, lattice dimensions at 193 K: a = 919.0(1), b = 1965.2(2), c = 2401.3(2) pm, α = 96.748(11)°, β = 94.827(10)°, γ = 91.720(11)°, R = 0.029.     

Darstellung und Struktur der Tetrafluoroaurate(III) MI[AuF4] mit MI = Li,Rb

Synthesis and Structure of Tetrafluoroaurates(III) M^I[AuF₄] with M^I = Li, Rb Single crystal investigations on Rb[AuF₄], light yellow, confirm the tetragonal unit cell (K[BrF₄]-type) with a = 618.2(1) and c = 1191(1) pm, Z = 4, space group I 4/mcm-D (No. 140). Li[AuF₄], light yellow too, crystallizes monoclinic with a = 485.32(7), b = 634.29(8), c = 1004.43(13) pm, β = 92.759(12), Z = 4; space group P 2/c-C (No. 13). The structure of Li[AuF₄] is related to the Rb[AuF₄]-type of structure.     

Synthesis,Magnetic Properties,and STM Spectroscopy of Cobalt(II) Cubanes [CoII4(Cl)4(HL)4]

Reaction of cobalt(II) chloride hexahydrate with N‐substituted diethanolamines H₂L^2–4 ( 3 ) in the presence of LiH in anhydrous THF leads under anaerobic conditions to the formation of three isostructural tetranuclear cobalt(II) complexes [Co^II₄(Cl)₄(HL^2–4)₄] ( 4 ) with a [Co₄(μ₃‐O)₄]⁴⁺ cubane core. According to X‐ray structural analyses, the complexes 4 a , c crystallize in the tetragonal space group I4₁/a, whereas for complex 4 b the tetragonal space group P$\bar 4$ was found. In the solid state the orientation of the cubane cores and the formation of a 3D framework were controlled by the ligand substituents of the cobalt(II) cubanes 4 . This also allowed detailed magnetic investigations on single crystals. The analysis of the SQUID magnetic susceptibility data for 4 a gave intramolecular ferromagnetic couplings of the cobalt(II) ions (J₁≈20.4 K, J₂≈7.6 K), resulting in an S=6 ground‐state multiplet. The anisotropy was found to be of the easy‐axis type (D=?1.55 K) with a resulting anisotropy barrier of Δ≈55.8 K. Two‐dimensional electron‐gas (2DEG) Hall magnetization measurements revealed that complex 4 a is a single‐molecule magnet and shows hysteretic magnetization characteristics with typical temperature and sweep‐rate dependencies below a blocking temperature of about 4.4 K. The hysteresis loops collapse at zero field owing to fast quantum tunneling of the magnetization (QTM). The structural and electronic properties of cobalt(II) cubane 4 a , deposited on a highly oriented pyrolytic graphite (HOPG) surface, were investigated by means of STM and current imaging tunneling spectroscopy (CITS) at RT and standard atmospheric pressure. In CITS measurements the rather large contrast found at the expected locations of the metal centers of the molecules indicated the presence of a strongly localized LUMO.     

ChemInform Abstract: YCa3(CrO)3(BO3)4: A Cr3+ Kagome Lattice Compound Showing No Magnetic Order Down to 2 K.

Polycrystalline gaudefroyite‐type YCa₃(CrO)₃(BO₃)₄ with Cr³⁺ ions (3d³, S = 3/2) forming an undistorted Kagome lattice is prepared by reaction of a stoichiometric mixture of Y₂O₃, CaCO₃, Cr₂O₃, H₃BO₃ in a KCl flux (Al₂O₃ crucible, 1000 °C, 1 d) followed by re‐grinding and further annealing (1000 °C, 2 d, 95% yield).     

Neue Phosphor-verbrückte Übergangsmetallcarbonyl-Komplexe Die Kristallstrukturen von [Re2(CO)7(PtBu)3], [Co4(CO)10(PtBu)2], [Ir4(CO)6(PtBu)6] und [Ni4(CO)10(PiPr)6]

New Phosphorus-bridged Transition Metal Carbonyl Complexes. The Crystal Structures of [Re₂(CO)₇(P^tBu)₃], [Co₄(CO)₁₀(P^tBu)₂], [Ir₄(CO)₆(P^tBu)₆], and [Ni₄(CO)₁₀(PⁱPr)₆], (P^tBu)₃ reacts with [Mn₂(CO)₁₀], [Re₂(CO)₁₀], [Co₂(CO)₈] and [Ir₄(CO)₁₂] to form the multinuclear complexes [M₂(CO)₇(P^tBu)₃] (M = Re ( 1 ), Mn ( 5 )), [Co₄(CO)₁₀(P^tBu)₂] ( 2 ) and [Ir₄(CO)₆(P^tBu)₆] ( 3 ). The reaction of (PⁱPr)₃ with [Ni(CO)₄] leads to the tetranuclear cluster [Ni₄(CO)₁₀(PⁱPr)₆] ( 4 ). The complex structures were obtained by X-ray single crystal structure analysis: ( 1 : space group P1 (Nr. 2), Z = 2, a = 917.8(3) pm, b = 926.4(3) pm, c = 1 705.6(7) pm, α = 79.75(3)°, β = 85.21(3)°, γ = 66.33(2)°; 2 : space group C2/c (Nr. 15), Z = 4, a = 1 347.7(6) pm, b = 1 032.0(3) pm, c = 1 935.6(8) pm, β = 105.67(2)°; 3 : space group P1 (Nr. 2), Z = 4, a = 1 096.7(4)pm, b = 1 889.8(10)pm, c = 2 485.1(12) pm, α = 75.79(3)°, β = 84.29(3)°, γ = 74.96(3)°; 4 : space group P2₁/c (Nr. 14), Z = 4, a = 2 002.8(5) pm, b = 1 137.2(8) pm, c = 1 872.5(5) pm, β = 95.52(2)°).     

Zur Kristallchemie der Blei-Lanthanoid-Oxoaluminate. Zur Kenntnis von Pb2HoAl3O8 und Pb2LuAl3O8

Crystal Chemistry of the Lead Lanthanide Oxoaluminates. On Pb₂HoAl₃O₈ and Pb₂LuAl₃O₈ . Single crystals of (I) Pb₂HoAl₃O₈ and (II) Pb₂LuAl₃O₈ were prepared by flux technique and investigated by X-ray methods. It crystallizes with cubic symmetry, space group O–P4₂/n 3 2/m, (I): a = 9.4164(13) Å, (II): a = 9.3486(8) Å, Z = 4. The new structure type shows AlO₄ tetrahedra, LnO₈ hexagonal bipyramids and one sided coordinated Pb²⁺ within heterocubane units. The crystal chemical relationships to other lead oxides containing heterocubane Pb₄O₄ units are discussed.     

Synthesen und Kristallstrukturen von [Pd9As8(PPh3)8] und [Pd9Sb6(PPh3)8]

Syntheses and Crystal Structures of [Pd₉As₈(PPh₂)₈] and [Pd₉Sb₆(PPh₃)₈] [PdCl₂(PPh₃)₂] reacts with As(SiMe₃)₃ to give the new cluster [Pd₉As₈(PPh₃)₈] ( 4 ). 4 has been characterized by X-ray crystal structure analysis. It is a molecule in which four [Pd₂(PPh₃)₂]-units are bridged by As₂-units. A further Pd atom is located in the centre of the cluster. 4 crystallizes in the space group C2/c with four formula units per unit cell. The lattice constants at 200 K are: a = 3 970.6(3), b = 1 648.90(16), c = 3 266.30(20) pm, β = 131,44(4)°. The reaction of [PdCl₂(PPh₃)₂] with Sb(SiMe₃)₃ yields [Pd₉Sb₆(PPh₃)₈] ( 5 ). 5 consists of a body centred cubic Pd₉-cluster. All of the cube faces are capped by μ₄-Sb-ligands. 5 crystallizes in the space group Pn3 with two formula units per unit cell. The lattice constants at 200 K are: a = b = c = 1 995.4(2) pm.     

Ein neues Kupfercobaltboratoxid mit isolierten B2O5-Baugruppen: Cu2Co(B2O5)O

On a New Copper Cobalt Borate Oxide with Isolated B₂O₅ Units: Cu₂Co(B₂O₅)O Single crystals of a new compound with the empirical formula Cu₂CoB₂O₆ were obtained by using a B₂O₃ flux technique. X-ray single crystal technique led to a new structure type. Cu₂CoB₂O₆ crystallizes monoclinic, space group C-P2₁/c (No. 14); a = 3.2250(6); b = 14.847(1); c = 9.1171(6) Å; β = 93.67°; Z = 4. All metal sites are octahedrally coordinated and form a two dimensional framework consisting of edge sharing octahedra ribbons. In addition one observes isolated B₂O₅-units and oxygen which is not coordinated to boron. The far relation to the crystal structure of the mineral Warwickite is illustrated.     

Zur Kristallstruktur von KGaO2 und NaGaO2(II) [1]

The Crystal Structure of KGaO₂ and NaGaO₂(II) By annealing intimate mixtures of K₂O, Na₂O and β-Ga₂O₃ (K : Na : Ga = 2.2 : 1.1 : 1) we obtained single crystals of K₂Na₄[(GaO₃)₂] and KGaO₂ (Ag-cylinder; 600°C, 26 d). Structure refinement for KGaO₂ (four-circle diffractometer data, Mo-Kα , 1 390 or 1 390 I_o(hkl); R = 5.55%, R_w = 3.05%) confirms the space group Pbca; a = 552.1 pm, b = 1 107.5 pm, c = 1 580.7 pm, Z = 16. According to K[GaO_4/2] we have a stuffed cristobalite-related structure. Single crystals of NaGaO₂(II) were grown by annealing intimate mixtures of Na₂O₂ and GaAs (Na₂O₂ : GaAs 4.1 : 1) in Ag-cylinders that were not completely closed (570°C, 6 weeks). Structure refinement for NaGaO₂(II) (four-circle diffractometer data, Mo-Kα , 588 of 616 I_o(hkl); R = 4.54%, R_w = 4.06%) confirms the spacegroup Pna2₁; a = 549.8(1) pm, b = 720.6(1) pm, c = 529.8(1) pm, Z = 4. In NaGaO₂(II) we have a wurtzite-related structure.     

Synthese und Struktur der Phosphor-verbrückten Übergangsmetallkomplexe [Fe2(CO)6(PR)6] (R = tBu,iPr), [Fe2(CO)4(PiPr)6], [Fe2(CO)3Cl2(PtBu)5], [Co4(CO)10(PiPr)3], [Ni5(CO)10(PiPr)6] und [Ir4(C8H12)4Cl2(PPh)4]

Synthesis and Structure of the Phosphorus-bridged Transition Metal Complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu, ⁱPr), [Fe₂(CO)₄(PⁱPr)₆], [Fe₂(CO)₃Cl₂(P^tBu)₅], [Co₄(CO)₁₀(PⁱPr)₃], [Ni₅(CO)₁₀(PⁱPr)₆], and [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] (P^tBu)₃ and (PⁱPr)₃ react with [Fe₂(CO)₉] to form the dinuclear complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu: 1 ; ⁱPr: 2 ). 2 is also formed besides [Fe₂(CO)₄(PⁱPr)₆] ( 3 ) in the reaction of [Fe(CO)₅] with (PⁱPr)₃. When PⁱPr(P^tBu)₂ and PⁱPrCl₂ are allowed to react with [Fe₂(CO)₉] it is possible to isolate [Fe₂(CO)₃Cl₂(P^tBu)₅] ( 4 ). The reactions of (PⁱPr)₃ with [Co₂(CO)₈] and [Ni(CO)₄] lead to the tetra- and pentanuclear clusters [Co₄(CO)₁₀(PⁱPr)₃] ( 5 ), [Ni₄(CO)₁₀(PⁱPr)₆] [2] and [Ni₅(CO)₁₀(PⁱPr)₆] ( 6 ). Finally the reaction of [Ir(C₈H₁₂)Cl]₂ with K₂(PPh)₄ leads to the complex [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] ( 7 ). The structures of 1–7 were obtained by X-ray single crystal structure analysis (1: space group P2₁/c (Nr. 14), Z = 8, a = 1 758.8(16) pm, b = 3 625.6(18) pm, c = 1 202.7(7) pm, β = 90.07(3)°; 2 : space group P1 (Nr. 2), Z = 1, a = 880.0(2) pm, b = 932.3(3) pm, c = 1 073.7(2) pm, α = 79.07(2)°, β = 86.93(2)°, γ = 72.23(2)°; 3 : space group Pbca (Nr. 61), Z = 8, a = 952.6(8) pm, b = 1 787.6(12) pm, c = 3 697.2(30) pm; 4 : space group P2₁/n (Nr. 14), Z = 4, a = 968.0(4) pm, b = 3 362.5(15) pm, c = 1 051.6(3) pm, β = 109.71(2)°; 5 : space group P2₁/n (Nr. 14), Z = 4, a = 1 040.7(5) pm, b = 1 686.0(5) pm, c = 1 567.7(9) pm, β = 93.88(4)°; 6 : space group Pbca (Nr. 61), Z = 8, a = 1 904.1(8) pm, b = 1 959.9(8) pm, c = 2 309.7(9) pm. 7 : space group P1 (Nr. 2), Z = 2, a = 1 374.4(7) pm, b = 1 476.0(8) pm, c = 1 653.2(9) pm, α = 83.87(4)°, β = 88.76(4)°, γ = 88.28(4)°).     

Sulfidchloride (MSCl) der leichten Lanthanide (M = La–Pr)

Sulfide Chlorides (MSCl) of the Light Lanthanides (M = La–Pr) The reactions of the light lanthanides (M = La–Nd) with sulfur and the respective trichlorides (MCl₃) in evacuated silica tubes (850 °C, 7 d) yield single-phase sulfide chlorides of the composition MSCl when appropriate molar ratios (2 : 3 : 1) of the reactants (M : S : MCl₃) are used. A slight excess of trichloride as a flux promotes the formation of lath-shaped transparent single crystals (colorless for M = La and Ce, apple-green for M = Pr) which prove to be water soluble and sensitive to hydrolysis. The crystal structure was determined from X-ray single-crystal data taking LaSCl (orthorhombic, Pbcm (no. 57), a = 680.22(5), b = 705.26(7), c = 4203.7(3) pm, Z = 24, R = 0.069, R_w = 0.043) as an example. According to Guinier powder data CeSCl and quickly quenched samples of PrSCl crystallize isotypically. Thus four crystallographically independent cations (M³⁺) are present, each coordinated by four S^2– but differing in the number of their next Cl^– neighbors. The figures of coordination are completed by four Cl^– about M1 (square antiprism, CN = 8), by only two Cl^– about M2 (trigonal prism, CN = 6), and by three Cl^– each about M3 and M4 (capped trigonal prisms, CN = 7). Six crystallographically different anions, although indistinguishable by X-ray diffraction, exhibit coordination numbers of four (S^2–, 3 ×) and three (Cl^–, 3 ×) with respect to the cations. So PbO-analogous layers of the composition [SM_4/4]⁺ parallel (100) are formed and held together along [100] by alternatingly sheathed Cl^– layers.     

ChemInform Abstract: Three Alkali Metal Lead Orthophosphates - Syntheses,Crystal Structures and Properties of APbPO4(A:K,Rb, Cs).

Single crystals of the title compounds are prepared by solid state reactions of M₂CO₃ (M: K, Rb, Cs), PbO, PbF₂, H₃BO₃, and (NH₄)H₂PO₄ in a molar ratio of 2:5:5:4:3 (Pt crucible, 700 °C, 10 h).     

Azidokomplexe von Vanadium(IV) und Vanadium(V): (Ph4P)2[VOCl2(μ‐N3)]2 und (Ph4P)2[VOCl(μ‐N3)(N3)2]2

Azido Complexes of Vanadium(IV) and Vanadium(V): (Ph₄P)₂[VOCl₂(μ‐N₃)]₂ and (Ph₄P)₂[VOCl(μ‐N₃)(N₃)₂]₂ (Ph₄P)₂[VOCl₂(μ‐N₃)]₂ ( 1 ) was prepared by reaction of (Ph₄P)[VO₂Cl₂] with trimethylsilylazide in the molar ratio 1:2 in dichloromethane solution to give dark green, moisture sensitive, non‐explosive single crystals. The reaction is accompanied by the formation of the dark blue side‐product (Ph₄P)₂[VOCl(μ‐N₃)(N₃)₂]₂ ( 2a ), which can be obtained as the main product by application of a large excess of Me₃SiN₃. Dark blue needles of 2a crystallize spontaneously from the CH₂Cl₂ solution within one hour at 4 °C. After standing at 4 °C under its mother liquid within 24 hours a first‐order phase transition of 2a occurs forming dark blue prismatic single crystals of 2b . According to single crystal X‐ray structure determinations, 2a and 2b crystallize in the same type of space group , however, with different lattice dimensions. The vanadium(IV) complex 1 is characterized by X‐ray structure determination and by vibrational spectroscopy (IR, Raman) as well as by EPR spectroscopy, whereas 2b is characterized by IR spectroscopy. 1 : Space group P2₁/n, Z = 2, a = 1009.5(1), b = 1226.6(2), c = 1943.0(2) pm, β = 98.42(1)°, R₁ = 0.0672. The complex anion forms centrosymmetric units with V₂N₂‐four‐membered rings with a V···V distance of 335.6(1) pm and coordination number five on the vanadium(IV) atoms. 2a : Space group , Z = 1, a = 1089.0(2), b = 1097.1(2), c = 1310.1(2) pm, α = 92.99(1)°, β = 106.12(2)°, γ = 117.05(2)°, V = 1309.8(4) ų, d_calc. = 1.440 g·cm^?3, R₁ = 0.0384. The complex anion forms centrosymmetric units of symmetry C_i with V₂N₂ four‐membered rings and VN bond lengths of 200.4(3) and 234.4(2) pm, respectively. The non‐bonding V···V distance amounts to 356.2(1) pm. 2b : Space group , Z = 1, a = 1037.3(2), b = 1157.6(2), c = 1177.2(2) pm, α = 98.48(2)°, ° = 103.82(2)°, γ = 106.33(2)°, V = 1281.8(4) ų, d_calc. = 1.471 g·cm^?3, R₁ = 0.0724. The structure of the complex anion is similar to the anion of 2a with VN bond lengths of the four‐membered V₂N₂ ring of 203.3(4) and 235.2(4) pm, respectively, and a non‐bonding V···V distance of 357.5(1) pm.     

Ein neues Kupferzinnboratoxid mit isolierten BO3-Baugruppen: Cu5Sn(BO3)2O4

On a New Copper Tin Borate Oxide with Isolated BO₃ Units: Cu₅Sn(BO₃)₂O₄ Single Crystals of the new compound Cu₅Sn(BO₃)₂O₄ were obtained by a B₂O₃ fluxtechnique. They crystallize in a monoclinic distorted variant of a Ludwigite structure with a partly ordered metal distribution. X-ray investigations on single crystals led to the space group C–P2₁/c (No. 14); a = 6.3526(7); b = 9.502(1); c = 12.100(9) Å; β = 93.30(3)°; Z = 4. All metal-sites are distorted octahedraly coordinated by oxygen-ions. The structure contains BO₃-units and oxygen which is not coordinated to boron.     

Structure Cristalline de l'Arseniate Double de Potassium et de Zirconium: KZr2(AsO4)3

Crystal Structure of KZr₂(AsO₄)₃ KZr₂(AsO₄)₃ crystals have been prepared by the flux method. The compound crystallizes in the rhombohedral system with the parameters: a = 9.028(1), c = 24.399(3) Å. The density is d = 3.694 g/cm³ and Z = 6. The space group is R3 c. The structure has been solved by isotypism with that of NaZr₂(PO₄)₃ to R = 0.041, for 353 independent reflections. It consists in 3-dimensional chains of AsO₄ tetrahedra and ZrO₆ octahedra. K⁺ ions are the center of the antiprism with K—O distances equal to 2.813 Å. The Zr–O and As–O distances have the same values of those usually observed (Zr–O = 2,05 Å and As–O = 1.66 Å).     

Structures and Electrical Properties of Some New Organic Conductors Derived from the Donor Molecule TMET (S,S,S,S,-Bis(dimethylethylenedithio) tetrathiafulvalene)

Crystal structures and electrical properties of radical-cation salts of the chiral organic donor TMET (S,S,S,S,-bis-(dimethylethylenedithio)tetrathiafulvalene) are described. Two structural types, 2:1 with octahedral anions Pf, AsF, SbF, I (incommensurate), and 3:2 with tetrahedral anions BF^?₄, CIO^?₄, ReO^?₄ are observed. Resistivity measurements between 2 and 298 K indicate that the 3:2 types are organic metals, while the other compounds are semiconductors. (TMET)₃(CIO₄)₂ is metallic down to about 120 K at ambient pressure and remains metallic down to 2 K at 8 kbar.     

3D Metal–Organic Frameworks Based on Co(II) and Bithiophendicarboxylate: Synthesis,Crystal Structures,Gas Adsorption,and Magnetic Properties

Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc²⁻) [Co₃(btdc)₃(bpy)₂]·4DMF, 1; [Co₃(btdc)₃(pz)(dmf)₂]·4DMF·1.5H₂O, 2; [Co₃(btdc)₃(dmf)₄]∙2DMF∙2H₂O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co₃(RCOO)₆}, connected either by btdc^2– ligands (1, 3) or by both btdc^2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N₂, O₂, CO, CO₂, CH₄ adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m²⋅g⁻¹ and promising gas separation performance with selectivity factors up to 35.7 for CO₂/N₂, 45.4 for CO₂/O₂, 20.8 for CO₂/CO, and 4.8 for CO₂/CH₄. The molar magnetic susceptibilities χ_p(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μ_eff (300 K) ≈ 4.93 μ_B. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2.