Crystal Structure,Magnetic Properties,and Electronic Structure of Ni(NCNH2)4Cl2 and Co(NCNH2)4Cl2

The crystal structures of Ni(NCNH₂)₄Cl₂ and Co(NCNH₂)₄Cl₂, the first complexes with cyanamide as a neutral ligand, have been determined from single crystal data (Im3m, Z = 6, a = 1259.3(2) pm, R₁ = 0.0245 for Ni(NCNH₂)₄Cl₂ and a = 1266.3(2) pm, R₁ = 0.0241 for Co(NCNH₂)₄Cl₂; both 329 intensities and 23 parameters). Ni²⁺ and Co²⁺ are octahedrally coordinated by four equatorial H₂NCN molecules and two axial chloride ions, and the 20 and 19 electron octahedral complexes are connected by a network of hydrogen bonds. The cyanamide ligands are slightly bent (166°), and the two N–C distances are 112 and 133 pm. Ni(NCNH₂)₄Cl₂/Co(NCNH₂)₄Cl₂ are Curie paramagnets with two/three unpaired electrons.     

Darstellung von Organylquecksilber(II)‐di(methansulfonyl)amiden und Kristallstruktur von Ph–Hg–N(SO2Me)2

Polysulfonylamines. CXXIV. Preparation of Organylmercury(II) Di(methanesulfonyl)amides and Crystal Structure of Ph–Hg–N(SO₂Me)₂ Four N,N‐disulfonylated organylmercury(II) amides R–Hg–N(SO₂Me)₂, where R is Me, ⁱPr, Me₃SiCH₂ or Ph, were obtained on treating the appropriate chlorides RHgCl with AgN(SO₂Me)₂, and characterized by ¹H and ¹³C NMR spectra. In the crystal structure of the phenyl compound (orthorhombic, space group Pbca, Z = 8, X‐ray diffraction at –95 °C), the molecule exhibits a covalent and significantly bent C–Hg–N grouping [bond angle 172.7(3)°; Hg–C 204.0(8), Hg–N 209.1(7) pm]. One sulfonyl oxygen atom forms a short intramolecular Hg…O contact [296.1(5) pm] and simultaneously catenates glide‐plane related molecules via a second Hg…O interaction 297.6(5) pm], thus conferring upon Hg^II the effective coordination number 4 and a geometrically irregular coordination polyhedron (bond angles from 173 to 54°).     

LiSr2[ReN4] und LiBa2[ReN4] – isotype Nitridorhenate(VII)

LiSr₂[ReN₄] and LiBa₂[ReN₄] – isotypic Nitridorhenates(VII) The quaternary nitridorhenates(VII) LiAE₂[ReN₄] (AE = Sr, Ba) were synthesized by reaction of the metals with molecular nitrogen at 850–900 °C. The plate‐like, nearly colourless crystals were investigated by X‐ray single crystal methods and were identified as isotypic phases: LiSr₂[ReN₄] (LiBa₂[ReN₄]); monoclinic, P2₁/m; a = 614.64(8) pm (651.04(12) pm), b = 585.97(6) pm (b = 598.86(9) pm), c = 689.70(17) pm (737.43(5) pm), β = 106.375(4)° (108.535(2)°); Z = 2. Crystals of the strontium compound were systematically twinned along [001]. In the crystal structures of the quaternary compounds the alkaline earth‐ and nitride‐ ions are arranged in the motif of the InNi₂‐type structure. Strontium and barium are in a trigonal prismatic coordination by nitrogen (Sr–N: 261.0(7)–284.3(4) pm; Ba–N: 278.0(7)–303.0(6) pm). One half of the tetrahedral voids within the partial structure formed by stacking of trigonal prismatic rod layers is occupied by rhenium (formation of [Re^VIIN₄]^5–‐tetrahedra; Re–N: 181.0(6)–184.5(8) pm), lithium takes the positions of the remaining tetrahedral sites (Li–N: 2 × 198(1) pm, 224(2) pm and 228(2) pm for the strontium phase). In the barium compound the lithium positions show a larger shift from the tetrahedral centres towards a tetrahedral plane (Li–N: 2 × 195(1) pm, 213(2) pm and 304(2) pm).     

Sr2(OLi2Sr4)[CrN4]2, ein Nitridochromat(VI)‐Oxid mit Sauerstoff in tetragonal‐bipyramidaler Koordination durch Lithium und Strontium

Sr₂(OLi₂Sr₄)[CrN₄]₂, a Nitridochromate(VI)‐Oxide with Oxygen in Tetragonal‐Bipyramidal Coordination by Lithium and Strontium Green gleaming crystals of Sr₂(OLi₂Sr₄)[CrN₄]₂ were prepared by reaction of Li, Sr and CrN/Cr₂N (approximate 1 : 1 mixture) with flowing nitrogen at 900 °C (molar overall composition Li : Sr : Cr = 6 : 1 : ∼3). The oxygen content results from a leak in the gas supply. The crystal structure was determined by single crystal methods (triclinic; P1; a = 615.87(9) pm, b = 682.50(10) pm, c = 754.30(8) pm, α = 82.302(14)°, β = 75.197(10)°, γ = 70.133(13)°; Z = 1) and contains distorted tetragonal bipyramids (OLi₂Sr₄)⁸⁺ and [Cr^VIN₄]^6–‐tetrahedra besides Sr²⁺.     

Untersuchungen am Chlordiphenyl‐ und Tribenzylstiban sowie am Tribenzyldibromstiboran – Molekülstrukturen und Isotypie

Element–Element Bonds. X. Studies of Chloro(diphenyl)stibane, Tribenzylstibane and Tribenzyldibromostiborane – Molecular Structures and Isotypism Chlorodiphenylstibane ( 1 d ) {P2₁/c; Z = 4; a = 1191.8(1); b = 853.4(1); c = 1112.0(1) pm; β = 93.60(1)°; –100 ± 2 °C} crystallizes isotypically with a series of homologous (H₅C₆)₂E–X compounds (E = As, X = Cl, Br, I; E = Sb, X = Br, I); the structure type of tribenzylstibane ( 5 d ) {Pbca; Z = 8; a = 832.1(2); b = 2681.3(5) pm; c = 1600.9(3); –100 ± 3 °C} is already known from tribenzylmethanol, ‐silanol and ‐silane. Tribenzyldibromostiborane ( 6 ) {P2₁/n; Z = 4; a = 938.4(2); b = 2292.4(5); c = 1019.7(2) pm; β = 112.71(1)°; –100 ± 3 °C} does not show an analogous relationship to known structure types. Characteristic mean bond lengths and angles are { 1 d , Sb–Cl 240.9(1), Sb–C 214.0 pm, Cl–Sb–C 93.8°, C–Sb–C 98.6(1)°; 5 d , Sb–C 217.5(3) pm, C–Sb–C 94.9(6)°; 6 , Sb–Br 264.6; Sb–C 217.0(8) pm, Br–Sb–Br 179.4(1)°; C–Sb–C 120°; Br–Sb–C 84.8(2)° to 94.7(2)°}. Stiborane 6 exhibits very weak intermolecular Sb‥Br interactions of 417 pm which, however, affect the molecular conformation in a striking way.     

Single Crystals of the Dodecaiodo‐closo‐dodecaborate Cs2[B12I12] · 2 CH3CN (≡ {Cs(NCCH3)}2[B12I12]) from Acetonitrile

Colourless, lath‐shaped single crystals of Cs₂[B₁₂I₁₂] · 2 CH₃CN (monoclinic, C2/m; a = 1550.3(2), b = 1273.2(1), c = 1051.5(1) pm, β = 120.97(1)°; Z = 2) are obtained by the reaction of Cs₂[B₁₂H₁₂] with an excess of I₂ and ICl (molar ratio: 1 : 2) in methylene iodide (CH₂I₂) at 180 °C (8 h) and recrystallization of the crude product from acetonitrile (CH₃CN). The crystal structure contains quasi‐icosahedral [B₁₂I₁₂]^2– anions (d(B–B) = 176–182 pm, d(B–I) = 211–218 pm) which arrange in a cubic closest‐packed fashion. All octahedral interstices are filled with centrosymmetric dimer‐cations {[Cs(N≡C–CH₃)]₂}²⁺ containing a diamond‐shaped four‐membered (Cs–N–Cs–N) ring of Cs⁺ cations and nitrogen atoms of the solvating acetonitrile molecules (d(Cs–N) = 321 pm, 2 ×). The cesium cations themselves actually reside in the distorted tetrahedral voids of the cubic [B₁₂I₁₂]^2– packing (d(Cs–I) = 402–461 pm, 10 ×) if one ignores the solvent particles.     

Synthese und Charakterisierung von Natriumcyanamid

Synthesis and Characterization of Sodium Cyanamide The synthesis of Na₂CN₂ was carried out by reaction of sodium amide with sodium hydrogen cyanamide at 200 °C, in vacuum. Single crystals were obtained while heating the product (500 °C, 8 days) in silver crucibles. The title compound was characterised by single crystal X‐ray diffraction and IR‐spectroscopy (C2/m; Z = 2, a = 5.0456(3), b = 5.0010(3), c = 5.5359(3) Å; β = 110.078(5)°; R1 = 3.18%, wR2 = 6.35%, GOF = 1.078). The CN₂^2– units are linear exhibiting a C–N bond length of 1.236(1) Å, while sodium is coordinated by five nitrogen atoms forming a square pyramid. The structural relationships to aristotypic Na₂HgO₂ are pointed out.     

Electronic Conditions of Diatomic (BN) Anions in the Structure of CaNiBN

CaNiBN was synthesized from Ca, Ni and BN in sealed tantalum containers at 1000 °C. The structure was determined by single‐crystal X‐ray diffraction (P4/nmm, Z = 2, a = 353.24(3) pm, c = 763.59(9) pm, R₁ = 0.019, wR₂ = 0.045 for all collected independent reflections). CaPdBN was synthesized after the same method, and a powder pattern was indexed isotypically (P4/nmm, a = 377.38(1) pm, c = 760.95(4) pm). The CaNiBN structure contains (BN) units with B—N bond lengths of 138.1(4) pm. If the (BN) unit in CaMBN (M = Ni, Pd) is replaced by (C₂), the structure can be considered as being isotypic with the structure of UCoC₂. Crystals of CaNiBN exhibit metallic lustre. According to the calculated band structure an extremely narrow band gap is present. The covalency between Ni and BN is marked by two important σ type interactions. A third type of interaction between (BN) π* and Ni orbitals represents the slightly occupied conduction bands. CaNiBN exhibits temperature independent paramagnetism and no superconducting transition down to 4 K.     

Die Kristallstruktur von Ph3PNBr · Br2

Crystal Structure of Ph₃PNBr · Br₂ Ph₃PNBr · Br₂ ( 1 ) has been prepared besides of other products from the reaction of Ph₃PNH with bromine, forming orange‐yellow single crystals which are characterized by IR‐spectroscopy and by a crystal structure determination. Space group P2₁/n, Z = 4, lattice dimensions at 20 °C: a = 916.76(10), b = 1351.42(8), c = 1494.9(2) pm, β = 96.191(5)°, R₁ = 0.0538. 1 has a molecular structure in which the Br₂ molecule is coordinated at the nitrogen atom of the N‐bromine‐phosphoraneimine Ph₃PNBr in a linear arrangement N–Br–Br with bond lengths N–Br of 224.5(6) pm and Br–Br of 248.4(1) pm. The nitrogen atom of 1 is ψ‐tetrahedrally coordinated in addition by the phosphorus atom with a P–N distance of 165.3(6) pm and by the covalently bonded bromine atom with a bond length of 188.9(6) pm.     

EuCN2 — The First,but Not Quite Unexpected Ternary Rare Earth Metal Cyanamide

Red‐orange, transparent single crystals of EuCN₂ (Pnma (62), a = 1232.41(9), b = 395.26(3) and c = 539.43(4) pm, Z = 4) are obtained by the reaction of EuN, C and NaN₃ in arc‐welded Ta ampoules at 1300 K. The first ternary rare earth metal cyanamide is isotypic to α‐SrCN₂ and shows the characteristic frequencies for the CN₂^2— unit in the optical spectra (ν_s = 1244; ν_as = 1969 and 2087; δ = 655 / 666 cm^—1).     

Synthesis,Crystal Structure,and Spectral Properties of a Cobalt(II) Complex with N‐Salicylidene‐p‐Toluidine

The complex Co(C₁₄H₁₃NO)₂Cl₂ with the protonated N‐salicylidene‐p‐toluidine ligand was synthesized from an ethanolic solution of CoCl₂·6H₂O and N‐salicylidene‐p‐toluidine. The crystal structure was determined from X‐ray single crystal data (monoclinic, space group Cc, a = 1496.2(3) pm, b = 1257.4(4) pm, c = 1544.6(3) pm, β = 115.01(1)°, Z = 4). Co²⁺ adopts a distorted tetrahedral geometry. The UV‐Vis and IR spectra of the complex are discussed.     

Common Features in the Crystal Structures of the Compounds Bis(dimethylstibanyl)oxane and ‐sulfane,and the Minerals Valentinite and Stibnite (Grauspießglanz)

Bis(dimethylstibanyl)oxane ( 1 ) and ‐sulfane ( 2 ), the two simplest organoelement species with an Sb–E–Sb fragment (E = O, S), were prepared by alkaline hydrolysis of bromodimethylstibane and by oxidation of tetramethyldistibane with sulfur [18], respectively. As shown by an x‐ray structure analysis of compound 1 (m. p. < –20 °C; P2₁2₁2₁, a = 675.9(2), b = 803.1(2), c = 1666.8(4) pm at –70 ± 2 °C; Z = 4; R1 = 0.042), the molecules (O–Sb 198.8 and 209.9 pm, Sb–O–Sb 123.0°) adopt a syn‐anti conformation in the solid state and are arranged in zigzag chains along [010] via weak intermolecular O‥Sb interactions (258.5 pm, Sb–O‥Sb 117.8°, O‥Sb–O 173.5°) making use, however, of only one Me₂Sb moiety. Primary and secondary bond lengths and angles agree very well with corresponding values published for valentinite, the orthorhombic modification of antimony(III) oxide [3]. Bis(dimethylstibanyl)sulfane ( 2 ) (m. p. 29 to 31 °C) crystallizes in the uncommon space group P6₅22 (a = 927.8(3), c = 1940.9(7) pm at –100 ± 2 °C; Z = 6; R1 = 0.021). Owing to coordination numbers of (1 + 1) and (2 + 2) for both Me₂Sb groups and the sulfur atom, respectively, molecules with an approximate syn‐syn conformation (S–Sb 249.8 pm, Sb–S–Sb 92.35°) build up a three‐dimensional net of double helices which are linked together by Sb‥S contacts (316.4 pm). These parameters shed more light onto the rather complicated structure and bonding situation in stibnite (antimony(III) sulfide [4]). The molecular packing of compound 2 is compared with the structures of relevant inorganic solids, especially with that of β‐quartz [37].     

Synthese und Kristallstrukturen von (3‐Methylpyridinium)3[DyCl6] und (3‐Methylpyridinium)2[DyCl5(Ethanol)]

Preparation and Structure of (3‐Methylpyridinium)₃[DyCl₆] and (3‐Methylpyridinium)₂[DyCl₅(Ethanol)] The complex chlorides (3‐Methylpyridinium)₃[DyCl₆] ( 1 ) and (3‐Methylpyridinium)₂[DyCl₅(Ethanol)] ( 2 ) have been prepared for the first time. The crystal structures have been determined from single crystal X‐ray diffraction data. 1 crystallizes in the trigonal space group R3c (Z = 36) with a = 2953.3(3) pm, b = 2953.3(3) pm and c = 3252.5(4) pm, compound 2 crystallizes in the triclinic space group P1 (Z = 2) with a = 704.03(8) pm, b = 808.10(8) pm, c = 1937.0(2) pm, α = 77.94(1)°, β = 87.54(1)° and γ = 83.26(1)°. The structures contain isolated octahedral building units [DyCl₆]^3– and [DyCl₅(Ethanol)]^2–, respectively.     

(NH4)3[M2NCl10] (M = Nb,Ta): Synthese,Kristallstruktur und Phasenumwandlung

(NH₄)₃[M₂NCl₁₀] (M = Nb, Ta): Synthesis, Crystal Structure, and Phase Transition The nitrido complexes (NH₄)₃[Nb₂NCl₁₀], and (NH₄)₃[Ta₂NCl₁₀] are obtained in form of moisture-sensitive, tetragonal crystals by the reaction of the corresponding pentachlorides with NH₄Cl at 400 °C in sealed glass ampoules. Both compounds crystallize isotypically in two modifications, a low temperature form with the space group P4/mnc and a high temperature form with space group I4/mmm. In case of (NH₄)₃[Ta₂NCl₁₀] a continuous phase transition occurs between –70 °C and +60 °C. For the niobium compound this phase transition is not yet fully completed at 90 °C. The structure of (NH₄)₃[Nb₂NCl₁₀] was determined at several temperatures between –65 °C und +90 °C to carefully follow the continuous phase transition. For (NH₄)₃[Ta₂NCl₁₀] the structure of the low temperature form was determined at –70 °C, and of the high temperature form at +60 °C. The closely related crystal structures of the two modifications contain NH₄⁺ cations and [M₂NCl₁₀]^3– anions. The anions with the symmetry D_4h are characterized by a symmetrical nitrido bridge M=N=M with distances Nb–N = 184.5(1) pm at –65 °C or 183.8(2) pm at 90 °C, and Ta–N = 184.86(5) pm at –70 °C or 184.57(5) pm at 60 °C.     

Synthesis and Crystal Structure of AgCuVO4

Dark red single crystals of AgCuVO₄ were obtained from hydroxide fluxes in Ag‐containers at 430 °C. According to X‐ray diffraction data AgCuVO₄ crystallizes in the orthorhombic space group Pnma (Z = 4, a = 925.5(1) pm, b = 677.8(1) pm, c = 540.1(1) pm, wR2 = 0.0753). The Pearson code (oP28) and Wyckoff sequence (dc⁴a) indicate that AgCuVO₄ is related to the olivine‐type of structure, but the first coordination sphere of Ag^I and Cu^II differ significantly from the C.N. 6 with irregular square‐pyramidal [AgO₅] polyhedra and distorted square‐planar [CuO₄] units. These differences in crystal chemistry are discussed and MAPLE as well as ECoN values are given.     

Mono‐ and Dimethyl‐1,2,4‐Triazolate as Ligands for the Mercuric Ion in the Cationic Three‐dimensional Coordination Polymer of [Hg2(Mmt)(Dmt)2](NO3)(H2O)

Colourless crystals of [Hg₂(Mmt)(Dmt)₂](NO₃)(H₂O) were obtained from a reaction of mercuric nitrate with monomethyl‐ and dimethyl‐1,2,4‐triazolate (Mmt^? and Dmt^?, respectively). In the crystal structure (monoclinic, C2/c (no. 15), a = 2579.4(4), b = 1231.1(2), c = 1634.8(2) pm, β = 128.32(1)°, V = 4073.3(11)·10⁶·pm³, Z = 8, R₁ [I₀ > 2σ(I₀)]: 0.0355), half of the mercuric ions are essentially two‐coordinate (Hg–N: 210‐215 pm), the other half are tetrahedrally surrounded by N‐donor atoms (Hg–N: 221, 225 pm) of the Mmt^? and Dmt^? anions. These three‐N ligands construct a three‐dimensional framework.     

Darstellung,Kristallstruktur und IR-spektroskopische Untersuchung von Phosphor(V)-nitrid-imid,HPN2

Preparation, Crystal Structure, and IR-spectroscopic Investigation of Phosphorus Nitride Imide, HPN₂ Pure and fine crystalline phosphorus nitride imide (HPN₂) is obtained by heterogeneous ammonolysis of P₃N₅ with gaseous NH₃ (T = 580°C, p = 30 bar, 6 d). X-ray powder diffraction data has been used to refine the crystal structure of HPN₂ by the Rietveld full-profile technique (I4 2d; a = 461.82(2) pm, c = 702.04(3) pm; Z = 4; 41 reflections observed, 17° < 2Θ < 125°, CuKα₁, germanium monochromator; R(wp) = 0.072, R(I,hkl) = 0.048). In the solid HPN₂ contains a three-dimensional framework of corner-sharing PN₄-tetrahedra (P N: 159.9(4) pm; P N P: 130.1(4)°. The hydrogen atoms are covalently bonded to half of the nitrogen atoms. The IR spectrum exhibits six vibrational modes v(N H): 3224; v_as(PNP): 1330, 1223; v_as(PNHP): 971, 901: δ(PNP): 531 cm⁻¹).     

Kristallstrukturen des freien protonierten Liganden HN(SO2)2C6H4 (= HZ) und des lamellaren Caesiumsalzes CsZ

Metal Salts of Benzene‐1,2‐di(sulfonyl)amine. 3. Crystal Structures of the Free Protonated Ligand HN(SO₂)₂C₆H₄ (= HZ) and the Lamellar Cesium Salt CsZ Benzene‐1,2‐di(sulfonyl)amine ( 1 ; HZ), known since 1921, is a very strong NH acid and readily reacts with aqueous CsCl to form crystalline CsZ ( 3 ). For both compounds, crystal structures were determined by X‐ray diffraction at –100 °C ( 1 : monoclinic, space group P2₁/n, Z = 4; 3 : orthorhombic, Cmcm, Z = 4). In 1 , the five‐membered 1,3,2‐dithiazole heterocycle possesses an envelope conformation, the N atom lying 29.4(2) pm outside the mean plane of the S–C–C–S moiety [S–N 167.06(15) and 167.53(15) pm, S–N–S 114.57(8)°]. In the crystal, HZ molecules are linked into chains by a conventional N–H…O hydrogen bond and further associated via four weak C–H…O bonds to form a three‐dimensional network. The conjugate Z^⊖ ion in the layered structure of the salt 3 displays crystallographic C_2v symmetry, leading to an ideally planar bicyclic framework [S–N 158.29(15) pm, S–N–S 116.53(17)°]. Each of the five electronegative atoms bridges two cations, Cs^⊕ attaining a tenfold coordination by forming bonds to two (O,N,O)‐chelating and four κ¹O‐monodentate ligands. The Cs–O/N interactions create a polar [CsN(SO₂)₂]_∞ lamella, which is lipophilically wrapped by parallel benzo rings protruding perpendicularly from its surfaces. In contrast to the previously reported lamellar metal di(arenesulfonyl)amides, the aromatic groups pertaining to adjacent layers of 3 are seen to be markedly interlocked.     

Bifunktionalisierte 1 H‐Phosphiren‐ und g1‐1‐Phosphaallen‐Wolframkomplexe

Bifunctionalized 1 H‐Phosphirene and g¹‐1‐Phosphaallene Tungsten Complexes The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] 1 reacts upon heating with acetylene derivatives 2 a–d in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R)=COEt} · W(CO)₅] 5 a–d ( 5 a : R = SiMe₃; 5 b : R = SiPh₃; 5 c : R = SnMe₃; 5 d : R = SnPh₃) and [{(Me₃Si)₂HCP=C=C(OEt)R} · W(CO)₅] 6 a, b ( 6 a : R = SnMe₃; 6 b : R = SnPh₃), which have been isolated by chromatography; complexes 5 c and 6 a have been characterized as mixtures. Spectroscopic and mass spectrometric data are discussed. The crystal structure of the compound 5 a was determined by X‐ray single crystal structure analysis ( 5 a : space group P2₁/n, Z = 4, a = 977.6(2) pm, b = 1814.6(4) pm, c = 1628.0(4) pm, β = 93.95(2)°).     

Synthesis of the New Silanediyldiphosphinite tBu2Si(OPPh2)2 and its Reactions with the Norbornadiene Complexes C7H8M(CO)4 (M = Cr,Mo, W). Crystal Structures of cis-M(CO)4[tBu2Si(OPPh2)2] (M = Cr,Mo)

Silanediyldiphosphinite tBu₂Si(OPPh₂)₂ 1 has been synthesised. 1 reacts with the norbornadiene complexes C₇H₈M(CO)₄ (M = Cr, Mo, W) to give six-membered chelate rings of the type cis-M(CO)₄[tBu₂Si(OPPh₂)₂] 2–4 . The crystal structures of the chromium and molybdenum complexes cis-Cr(CO)₄[tBu₂Si(OPPh₂)₂] 2 and cis-Mo(CO)₄[tBu₂Si(OPPh₂)₂] 3 have been determined. Both complexes crystallise in the triclinic system (space group P1 ) with unit cell parameters: ( 2 ) a = 1 093(3) pm, b = 1 477(5) pm and c = 1 542(5) pm; α = 108.4(2)°, b? = 103.87(11)° and b? = 104.57(10)°; U = 2.143(12) nm³; Z = 2; ( 3 ) a = 1 097.8(2) pm, b = 1 483.7(2) pm and c = 1 554.3(2) pm; α = 108.10(1)°, b? = 103.956(6)° and γ = 104.213(7)°; U = 2.1899(6) nm³; Z = 2. Both 2 and 3 consist of discrete, slightly distorted, octahedral monomers in which the six-membered chelate rings are essentially planar. In contrast, the conformations of the chelate rings found in crystal structures of analogous complexes vary from twist-boat to “chaise longue”.