Zur Elektronenstruktur hochsymmetrischer Verbindungen der f‐Elemente. 41 Synthese,Kristall‐, Molekül‐ und Elektronenstruktur eines Bis(cyclohexylisonitril)‐Addukts des Grundkörpers Tris(bis(trimethylsilyl)amido)erbium(III) sowie Elektronenstrukturen ausgewählter Monoaddukte

Electronic Structures of Highly Symmetrical Compounds of f Elements. 41 Synthesis, Crystal, Molecular and Electronic Structure of a Bis(cyclohexylisonitrile) Adduct Derived from the Tris(bis(trimethylsilyl)amido)erbium(III) Moiety and Electronic Structures of Selected Mono Adducts The reaction of tris(bis(trimethylsilyl)amido)erbium(III) (Er(btmsa)₃) with two equivalents of cyclohexylisonitrile yields the corresponding bis adduct [Er(btmsa)₃(CNC₆H₁₁)₂] ( 1 ). Complex 1 crystallizes in the monoclinic space group C2/c with a = 2542.9(11) pm, b = 1208.4(4) pm, c = 1783.0(2) pm, β = 122.39(3)°, V = 4.638(5)·10⁹ pm³, Z = 4 and R = 0.0380. The structure of compound 1 features the five coordinate Er³⁺ central ion in a nearly exact trigonal bipyramidal environment, with three btmsa ligands in the equatorial and the two cyclohexylisonitrile molecules in the axial positions. On the basis of the absorption spectra of bis adduct 1 and the mono(tetrahydrofuran) as well as the mono(triphenylphosphine oxide) adducts [Er(btmsa)₃(THF)] ( 2 ) and [Er(btmsa)₃(OPPh₃)] ( 3 ), respectively, the underlying truncated crystal field (CF) splitting patterns of these compounds could be derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian. Reduced r.m.s. deviations of 13.0 cm^?1 (42 assignments), 16.0 cm^?1 (63 assignments) and 17.5 cm^?1 (55 assignments) could be achieved for compounds 1 , 2 and 3 , respectively. Making use of the phenomenological CF parameters of the fits, the experimentally based non‐relativistic molecular orbital schemes of complexes 1 , 2 and 3 were set up, and compared with that of base‐free Er(btmsa)₃.     

Zur Elektronenstruktur hochsymmetrischer Verbindungen der f‐Elemente. 36 [1] Parametrische Analyse der optischen Spektren eines orientierten Tris(hydrotris(1‐pyrazolyl)borato)praseodym(III)‐Einkristalls

Electronic Structures of Highly Symmetrical Compounds of f Elements. 36 [1] Parametric Analysis of the Optical Spectra of an Oriented Tris(hydrotris(1‐pyrazolyl)borato)praseodymium(III) Single Crystal The absorption and luminescence spectra of polycrystalline tris(hydrotris(1‐pyrazolyl)borato)‐praseodymium(III) (PrTp₃) were measured at room temperature as well as at low temperatures. At room temperature the “polarized” luminescence spectra of a small oriented PrTp₃ single crystal could also be recorded. On the basis of these spectroscopic findings the underlying crystal field splitting pattern could be derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian, achieving a reduced r.m.s. deviation of 17.3 cm^—1 for 37 assignments. On the basis of the parameters used, the global ligand field strength experienced by the Pr³⁺ central ion as well as the individual ligand field strength associated with one Tp ligand are determined, nephelauxetic and relativistic nephelauxetic effects are estimated, and the experimentally orientiented nonrelativistic and relativistic molecular orbital schemes in the f range are set up.     

Zur Elektronenstruktur hochsymmetrischer Verbindungen der f‐Elemente. 42 Ableitung und Simulation des Kristallfeld‐Aufspaltungsmusters von Tris(bis(trimethylsilyl)amido)ytterbium(III)

Electronic Structures of Highly Symmetrical Compounds of f Elements. 42 Derivation and Simulation of the Crystal Field Splitting Pattern of Tris(bis(trimethylsilyl)amido)ytterbium(III) Tris(bis(trimethylsilyl)amido)ytterbium(III), (Yb(btmsa)₃ ( 1 )) was grown as a single crystal of the size 6×2×2 mm. The unpolarized absorption and luminescence as well as the σ and π absorption spectra of this crystal were recorded at room and low temperatures. The observed polarization properties as well as identificational calculations allowed the separation of zero‐phonon‐ and phonon‐assisted transitions of comparable intensities. The thus derived crystal field splitting pattern could be simulated by fitting the free parameters of a phenomenological Hamiltonian. In order to assign the coupling vibrations, FIR/MIR‐ and unpolarized Raman spectra of 1 as well as polarized Raman spectra of Y(btmsa)₃ ( 2 ) were recorded and compared with previously assigned ones of MeGa(btmsa)₂ and H(btmsa).     

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 60 [1] Strukturelle,einkristalloptische und magnetooptische Untersuchungen von Trialkylphosphat‐Addukten des Grundkörpers Tris(cyclopentadienyl)lanthanid(III) (Ln = La,Pr) sowie Ergebnisse vergleichender optischer Studien an [Pr(Ind)3(OP(OEt)3)] (Ind = Indenyl)

Electronic Structures of Organometallic Complexes of f Elements. 60 [1] Structural, Single Crystal Optical and Magnetooptical Investigations on Trialkylphosphate Adducts of the Tris(cyclopentadienyl)lanthanide(III) (Ln = La, Pr) Moiety as well as Results of Comparing Optical Studies of [Pr(Ind)₃(OP(OEt)₃)] (Ind = indenyl) [Ln(Cp)₃(OP(OR)₃)] (Cp = η⁵‐cyclopentadienyl; Ln = La, R = Et ( 1 ); Ln = Pr, R = Me ( 2 ); Ln = Pr, R = Et ( 3 )) and [Pr(Ind)₃(OP(OEt)₃)] ( 4 ) have been synthesized and spectroscopically as well as partly structurally (only compounds 1 and 2 ) characterized. On the basis of variable temperature measurements of α absorption spectra of an oriented single crystal, the magnetic circular dichroism spectra of dissolved, and the luminescence spectra of powdered material, a nearly complete crystal field (CF) splitting pattern could be derived for 3 , and simulated by fitting the free parameters of a phenomenological Hamiltonian. The parameters used in the fit allowed the calculation of the global CF strength experienced by the Pr³⁺ central ion, the estimation of the nephelauxetic and relativistic nephelauxetic parameters, as well as the setup of experimentally based non‐relativistic and relativistic molecular orbital schemes in the f range. The optical spectra of compound 4 suggest that two different species exist at low temperatures, thus preventing a successful CF analysis.     

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 64 Äußert sich die zwitterionische Natur des Triphenylphosphanoxid‐Liganden auch in seinen spektrochemischen Eigenschaften?

Electronic Structures of Organometallic Compounds of f Elements. 64 Does the Zwitterionic Nature of the Triphenylphosphine Oxide Ligand Manifest itself in its Spectrochemical Properties? The triphenylphosphine oxide mono adducts of the moiety tris(η⁵‐cyclopentadienyl)lanthanide(III) (Ln(Cp)₃; Ln = Pr ( 1 ), La ( 2 )) were synthesized and structurally characterized. The Ln–O distances of these compounds are noticeably shorter than those of the corresponding THF adducts. A crystal field (CF) analysis of the optical spectra of 1 leads to a low absolute value of the quadratic CF parameter which is comparable with those of [Pr(Cp)₃(L)]^? adducts with anionic bases but not with [Pr(Cp)₃(MeTHF)]. Reasons for the latter finding are presented.     

Spektroskopische und strukturelle Charakterisierung von Tris(2, 6‐di‐t‐butyl‐phenolato)lanthanid(III) (Ln(OAr′)3; Ln = Pr,Nd) sowie parametrische Analyse des Kristallfeld‐Aufspaltungsmusters von Nd(OAr′)3

Electronic Structures of Highly Symmetrical Compounds of f Elements. 37 [1] Spectroscopic and Structural Characterization of Tris(2, 6‐di‐t‐butyl‐phenolato)lanthanide(III) (Ln(OAr′)₃; Ln = Pr, Nd), and Parametric Analysis of the Crystal Field Splitting Pattern of Nd(OAr′)₃ Pr(OAr′)₃ and Nd(OAr′)₃ crystallize (at approximately 150 K and 200 K, respectively) in the monoclinic space group P2₁ with four molecules in the unit cell. If one considers only the directly coordinating oxygen atoms, the effective crystal field is of C_3v symmetry. The signals in the optical spectra of Pr(OAr′)₃ are broad using either solutions or solids, even at ca. 80‐90 K, thus they are not suitable for interpretation purposes. Nd(OAr′)_3, however, exhibits sharp absorption bands at room and low temperatures, which are assigned in analogy to the previously identified absorption transitions of Nd[N(SiMe₃)₂]₃ based on optical polarization measurements. The thus derived crystal field splitting pattern is simulated by fitting the free parameters of a phenomenological Hamiltonian, achieving a reduced r.m.s. deviation of 26.4 cm^—1 for 64 assignments. The parameters used allow the estimation of the ligand field strength associated with the (OAr′)^— ligand, the insertion of this ligand into empirical nephelauxetic and relativistic nephelauxetic series, and the setup of experimentally‐based non‐relativistic and relativistic molecular orbital schemes in the f range.     

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 65 Erstmalige Beobachtung des linearen Dichroismus bei einem homoleptischen metallorganischen π‐Komplex der f‐Elemente: Tris(η5‐tetramethylcyclopenta‐dienyl)neodym(III)

Electronic Structures of Organometallic Complexes of f Elements. 65 First Observation of Linear Dichroism of a Homoleptic Organometallic π Complex of f Elements: Tris(η⁵‐tetramethylcyclopentadienyl)neodymium(III) The absorption spectrum of a powder sample of pseudo (Ψ) trigonal planar Nd(η⁵‐C₅Me₄H)₃ ( 1 ) has been measured at room temperature and ca. 40 K, respectively, and the linear dichroism spectra of σ‐ and π‐type of an oriented single crystal at ambient temperature and 77 K. Neglecting the signals of the C–H combination vibrations and overtones extracted from the absorption spectrum of La(η⁵‐C₅Me₄H)₃ ( 2 ), the observed polarization properties of the remaining f‐f transitions allowed the derivation of a truncated crystal field splitting pattern. The free parameters of a phenomenological Hamiltonian were fitted to this pattern leading to a reduced r.m.s. deviation of 16.1 cm^?1 for 38 assignments. The temperature dependence of the paramagnetic susceptibility of 1 was calculated, making use of the crystal field energies and wavefunctions of the fit. Introducing an orbital reduction factor of 0.98, calculated values of 1 agree well with the experimental ones of Ψ trigonal planar Nd(C₅H₄tBu)₃.     

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 67 Erstmalige parametrische Analyse des Absorptionsspektrums einer Molekülverbindung des CeIIIμ: Tris(η5‐tetramethylcyclopentadienyl)cer

Electronic Structures of Organometallic Complexes of f Elements. 67 First Parametric Analysis of the Absorption Spectrum of a Molecular Compound of Ce^IIIμ: Tris(η⁵‐tetramethylcyclopentadienyl)cerium(III) The absorption spectra (in the IR/NIR/Vis/UV range) of Ce(C₅Me₄H)₃ ( 1 ) and La(C₅Me₄H)₃ ( 2 ) were recorded at room and low temperatures. From the spectra obtained, two alternative closely related crystal field (CF) splitting patterns of 1 could be derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian. The fact that the difference of the experimental energies of the barycenters of CF levels of the multiplets ²F_7/2 and ²F_5/2 is larger than in the gaseous free Ce³⁺ ion (“anti”‐relativistic nephelauxetic effect) could be explained by coupling effects of these multiplets via the CF, resulting in lower spin‐orbit coupling parameters than in the case of the gaseous free Ce³⁺ ion. The experimentally derived CF splitting pattern of 1 is compared with the predictions of previous non‐relativistic SW‐Xα and relativistic DV‐Xα calculations.     

Koordination von Rhodium(III), Iridium(III) und Kupfer(II) mit dem potentiell vierzähnigen Akzeptorliganden Bis(1‐methylimidazol‐2‐yl)glyoxal (big)

Coordination of Rhodium(III), Iridium(III), and Copper(II) with the Potentially Tetradentate Acceptor Ligand Bis(1‐methylimidazol‐2‐yl)glyoxal (big) Bis(1‐methylimidazol‐2‐yl)glyoxal (big) which has hitherto not been used in coordination chemistry crystallizes to form two perpendicular 1‐methylimidazol‐2‐yl‐carbonyl molecular halves. Out of the various possibilities for mono‐ and bis‐chelate coordination the N,N′‐alternative with a seven‐membered chelate ring is realized in [Cp*Cl(big)Rh](PF₆) as evident from crystal structure analysis. The iridium analogue reacts under hydration of big and elimination of HCl to form a complex cation [Cp*(bigOH)Ir]⁺ which dimerizes in the crystal through hydrogen bonding and contains one five‐ and one six‐membered chelate ring involving the alcoholate‐O. Cu(ClO₄)₂ and the ligand big yield a complex ion [Cu(big)₂]²⁺ with an ESR spectrum that suggests the coordination of the central metal by four N atoms in an approximately planar setting.     

Tris[3‐hydroxy‐2(1 H)‐pyridinonato]‐Komplexe von Al3+, Cr3+ und Fe3+ – Kristall‐ und Molekülstrukturen von 3‐Hydroxy‐2(1 H)‐pyridinon und Tris[3‐hydroxy‐2(1 H)‐pyridinonato]chrom(III)

Tris[3‐hydroxy‐2(1 H)‐pyridinonato] Complexes of Al³⁺, Cr³⁺, and Fe³⁺ – Crystal and Molecular Structures of 3‐Hydroxy‐2(1 H)‐pyridinone and Tris[3‐hydroxy‐2(1 H)‐pyridinonato]chromium(III) Tris[3‐hydroxy‐2(1 H)‐pyridinonato] complexes of Al³⁺, Cr³⁺ and Fe³⁺ are obtained by reactions of 3‐hydroxy‐2(1 H)pyridinone with the hydrates of AlCl₃, CrCl₃ or Fe(NO₃) in aqueous alkaline solutions as polycrystalline precipitates. The compounds are isotypic. X‐ray structure determinations were performed on single crystals of the uncoordinated 3‐hydroxy‐2(1 H)‐pyridinone ( 1 ) (orthorhombic, space group P2₁2₁2₁, a = 405.4(1), b = 683.0(1), c = 1770.3(3) pm, Z = 4) and of the chromium compound 3 (rhombohedral with hexagonal setting, space group R3c, a = 978.1(1), c = 2954.0(1) pm, Z = 6).     

CuYS2: Ein ternäres Kupfer(I)‐Yttrium(III)‐Sulfid mit Ketten {[Cu(S1)3/3(S2)1/1]3–} cis‐kantenverknüpfter [CuS4]7–‐Tetraeder

CuYS₂: A Ternary Copper(I) Yttrium(III) Sulfide with Chains {[Cu(S1)_3/3(S2)_1/1]^3–} of cis ‐Edge Connected [CuS₄]^7– Tetrahedra Pale yellow, lath‐shaped single crystals of the ternary copper(I) yttrium(III) sulfide CuYS₂ are obtained by the oxidation of equimolar mixtures of the metals (copper and yttrium) with sulfur in the molar ratio 1 : 1 : 2 within fourteen days at 900 °C in evacuated silica ampoules, while the presence of CsCl as fluxing agent promotes their growth. The crystal structure of CuYS₂ (orthorhombic, Pnma; a = 1345.3(1), b = 398.12(4), c = 629.08(6) pm, Z = 4) exhibits chains of cis‐edge linked [CuS₄]^7– tetrahedra with the composition {[Cu(S1)_3/3(S2)_1/1]^3–} running along [010] which are hexagonally bundled as closest rod packing. Charge equalization and three‐dimensional interconnection of these anionic chains occur via octahedrally coordinated Y³⁺ cations. These are forming together with the S^2– anions a network [Y(S1)_3/3(S2)_3/3]^– of vertex‐ and edge‐shared [YS₆]^9– octahedra with ramsdellite topology. The metall‐sulfur distances of the [CuS₄]^7– tetrahedra (230 (Cu–S2), 232 (Cu–S1), and 253 pm (Cu–S1′, 2 × )) cover a very broad interval, whilst these (Y–S: 267–280 pm) within the [YS₆]^9– octahedra range rather closely together.     

Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 68 Absorptions‐ sowie erstmalige lumineszenz‐ und Raman‐spektroskopische Polarisationsmessungen an einem orientierten metallorganischen Einkristall: Pr(C5Me4H)3

Electronic Structures of Organometallic Complexes of f Elements. 68 Absorption and First Luminescence and Raman Spectroscopic Polarization Measurements of an Oriented Organometallic Single Crystal: Pr(C₅Me₄H)₃ Optical polarization measurements of oriented single crystals of Pr(C₅Me₄H)₃ ( 1 ) were performed at room temperature. In order to separate “cold” and “hot” f‐f‐transitions and νC–H combination vibrations, the absorption spectra of KBr pellets of compound 1 and La(C₅Me₄H)₃ ( 2 ) were additionally recorded at ca. 77 K. To gather additional information about the wavefunctions of the crystal field (CF) states of complex 1 , a magnetic circular dichroism spectrum of 1 was recorded too. From the spectra obtained, a partial CF splitting pattern of 1 was derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian, leading to a reduced r.m.s. deviation of 24.8 cm⁻¹ for 24 assignments. On the basis of these phenomenological CF parameters, the global CF strength experienced by the Pr³⁺ central ion was estimated, and seems to be the largest one ever encountered in Pr^III chemistry. The obtained Slater parameter F² and the spin‐orbit coupling parameter ζ_4f allow the insertion of compound 1 into empirical nephelauxetic and relativistic nephelauxetic series, respectively, of Pr^III compounds. With its low F² value, complex 1 is the most covalent Pr^III compound (considering only f electrons) found to date. The experimentally‐based non‐relativistic molecular orbital scheme (in the f range) of complex 1 was determined and compared with the results of a previous Xα‐SW calculation on the ψ trigonal planar model compound Pr(η⁵‐C₅H₅)₃. In the framework of the search for “polarized” luminescence transitions, polarized Raman spectra of 1 were recorded too, and compared to the corresponding FIR and IR spectra run by means of pellets.     

Nitrides with Inverse K2[NiF4] Structure: (R1–xCa3+xN1–x/3)Bi2 with R = Rare‐Earth Metal

The novel nitrides (R_1–xCa_3+xN_1–x/3)Bi₂ (with R = La, Ce, Pr) crystallize in the K₂[NiF₄] structure type (I4/mmm, No. 139, Z = 2). Samples (La_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.10, 0.05, 0.00, (Ce_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.30, and (PrCa₃N)Bi₂ were obtained as single phase microcrystalline powders according to X‐ray diffraction and the crystal structure details were derived from Rietveld refinements based on X‐ray and neutron diffraction powder patterns. A partial order of R³⁺/Ca²⁺ on two crystallographic sites is governed by different ionic radii and charges. (La_1–xCa_3+xN_1–x/3)Bi₂ and (Ce_1–xCa_3+xN_1–x/3)Bi₂ exhibit small homogeneity ranges and typically a nitrogen deficiency. In contrast, for (PrCa₃N)Bi₂ no indications for a significant homogeneity range or deficiency of nitrogen was observed. (La_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.05 is a diamagnet. X‐ray absorption spectroscopy at the CeL₃‐edge as well as magnetic susceptibility measurements evidence that (Ce_1–xCa_3+xN_1–x/3)Bi₂ with x = 0.30 contains Ce³⁺ in the 4f¹ configuration. According to electrical resistivity data, samples from all three systems are heavily doped semiconductors.     

Electronic Structures of Highly Symmetrical Compounds of f Elements. 34 [1] Synthesis and Spectroscopic Characterization of Biscyclohexylisocyanide Adducts derived from the Tris(bis(trimethylsilyl)amido)lanthanide(III) Moiety as well as Crystal,Molecular, and Electronic Structure of the Corresponding Neodymium Compound

The reaction of tris(bis(trimethylsilyl)amido)lanthanide(III) (Ln(btmsa)₃) with two equiv. of cyclohexylisocyanide gives good yields of complexes of composition Ln(btmsa)₃(CNC₆H₁₁)₂ (Ln = Y( 1 ), La( 2 ), Ce( 3 ), Pr( 4 ), Nd( 5 ), Sm( 6 ), Eu( 7 ), Tb( 8 ), Dy( 9 ), Ho( 10 ), Tm( 11 ) and Yb( 12 )). Complex 5 crystallizes in the monoclinic space group C2/c with a = 25.689(8) Å, b = 12.165(2) Å, c = 17.895(15) Å, β = 122.47 (2)°, V = 4718.07 ų, Z = 4 and R = 0.0342. The structure of compound 5 shows the five‐coordinate Nd³⁺ ion in a nearly exact trigonal bipyramidal environment with two CNC₆H₁₁ molecules in the axial and the three btmsa ligands in the equatorial positions. The linear dichroism spectrum of a single crystal of complex 5 was measured at room temperature, and the absorption spectrum of powdered material at low temperatures. From the spectra obtained a truncated crystal field (CF) splitting pattern is derived, and simulated by fitting the parameters of a phenomenological Hamiltonian. For 80 assignments a reduced r.m.s. deviation of 20.7 cm^—1 is achieved. Making use of the calculated wavefunctions and eigenvalues the experimentally determined temperature dependence of μ²_eff could be reproduced by adopting an orbital reduction factor k = 0.991, and on the basis of the CF parameters used the experimentally oriented non‐relativistic molecular orbital scheme of compound 5 is set up.     

Reactivity of 2,2′‐Bis(2N‐(1,1′,3,3′‐tetramethyl‐guanidino))diphenylene‐amine with CuI and [Cu(MeCN)4][PF6]: Benzimidazole Formation vs. Cu Oxidation

The reaction of 2,2′‐Bis(2N‐(1,1′,3,3′‐tetramethyl‐guanidino))diphenylene‐amine (TMG₂PA) ( 1 ) with CuI in MeCN results in the formation of [Cu^II(TMG₂PA^amid)I] ( 2 ) indicatingthat Cu^I is the target of an oxidative attack of the N‐H proton of the ligand which itself is converted to molecular hydrogen. In contrast, if [Cu(MeCN)₄][PF₆] is used as the Cu^I source, [Cu^I₂(TMGbenz)₂][PF₆]₂ ( 3 ) is obtained instead. The use of the non‐coordinating counterion [PF₆]^– apparently prevents Cu^I from oxidation but induces itself a cyclisation reaction within the ligand which results in the formation of a benzimidazole‐guanidine ligand.     

Activation of Molecular Hydrogen by Bis(η5,η1‐pentafulvene)‐titanium Complexes – Efficient Formation of Titanium(III)hydrides

The synthesis and crystal structures of two dinuclear titanocene hydride complexes are reported. Both complexes, namely bis(η⁵‐(di‐para‐tolylmethyl)cyclopentadienyl)titanium hydride dimer, [(η⁵‐C₂₀H₁₉)₂Ti(μ‐H)]₂ ( 2a ), and bis(η⁵‐2‐adamantylcyclopentadienyl)‐titanium hydride dimer, [(η⁵‐C₁₅H₁₉)₂Ti(μ‐H)]₂ ( 2b ), are formed via activation of molecular hydrogen by the corresponding bis(η⁵,η¹‐pentafulvene)titanium complexes 1a and 1b at ambient temperatures and pressures in high yields. The hydride complexes 2a and 2b exhibit planar [Ti₂H₂] cores and, as a result of the heterolytic cleavage of molecular hydrogen, substituted Cp Ligands were formed during the reaction.     

N‐Methylimidazolkomplexe des Berylliums: [Be(Me‐Im)4]I2 und [Be3(μ‐OH)3(Me‐Im)6]Cl3

Tetra(N‐methylimidazole)‐beryllium‐di‐iodide, [Be(Me‐Im)₄]I₂ ( 1 ), was prepared from beryllium powder and iodine in N‐methylimidazole suspension to give yellow single crystal plates, which were characterized by X‐ray diffraction and IR spectroscopy. Compound 1 crystallizes tetragonally in the space group I 2d with four formula units per unit cell. Lattice dimensions at 100(2) K: a = b = 1784.9(1), c = 696.2(1) pm, R₁ = 0.0238. The structure consists of homoleptic dications [Be(Me‐Im)₄]²⁺ with short Be–N distances of 170.3(3) pm and iodide ions with weak interionic C–H ··· I contacts. Experiments to yield crystalline products from reactions of N‐methylimidazole with BeCl₂ and (Ph₄P)₂[Be₂Cl₆], respectively, in dichloromethane solutions were unsuccessful. However, single crystals of [Be₃(μ‐OH)₃(Me‐Im)₆]Cl₃ ( 2 ) were obtained from these solutions in the presence of moisture air. According to X‐ray diffraction studies, two different crystal individuals ( 2a and 2b ) result, depending on the starting materials BeCl₂ and (Ph₄P)₂[Be₂Cl₆], respectively [ 2a : Space group P2₁/n, Z = 4; 2b : Space group P , Z = 2]. As a side‐product from the reaction of N‐methylimidazole with (Ph₄P)₂[Be₂Cl₆] single crystals of (Ph₄P)Cl·CH₂Cl₂ ( 3 ) were identified crystallographically (P2₁/n, Z = 4) which are isotypical with the corresponding known bromide (Ph₄P)Br·CH₂Cl₂.     

Synthesis,Structures, and Properties of Four Novel Coordination Compounds based on a Flexible Tetrakis(imidazol‐1‐ylmethyl)methane Ligand

Four coordination polymers, namely, [Zn₂(TIYM)(2,6‐PYDC)₂]_n · n(CH₃OH) · 3n(H₂O) ( 1 ), [Cu(TIYM)(2,6‐PYDC)]_n · 3n(H₂O) ( 2 ), [Co(TIYM)(2,6‐PYDC)]_n · n(CH₃OH) · 3n(H₂O) ( 3 ), and [Cd₂(TIYM)(2,6‐PYDC)₂(H₂O)]_n · n(H₂O) ( 4 ) with the flexible N‐containing ligand [tetrakis(imidazol‐1‐ylmethyl)methane (TIYM)] and the N‐containing dicarboxylic acid [2,6‐pyridinedicarboxylic acid (2,6‐PYDC)] were prepared. Compounds 1 – 4 show various structures because of different N–C_center–N angles (θ) of TIYM ligands and changing coordination modes of 2,6‐PYDC. Compounds 1 , 2 , and 3 display a similar 1D ladder‐like chain, whereas 4 gives a 1D quad‐core lifting platform shaped belt. The structural diversities in 1 – 4 suggest that the multiple coordination modes or the different freely twist angles of ligands and the presence of different metal atoms play important roles in the resulting structures of the coordination polymers. Furthermore, the solid‐state luminescence properties of 1 and 4 , and the magnetic properties of 3 were investigated.     

Hypervalent Organoselenium(II) Compounds with Organophosphorus Ligands. Crystal and Molecular Structure of [2‐(iPr2NCH2)C6H4]Se[S2PR′2] (R′ = Ph,OiPr)

Redistribution reactions between diorganodiselenides of type [2‐(R₂NCH₂)C₆H₄]₂Se₂ [R = Et, iPr] and bis(diorganophosphinothioyl disulfanes of type [R′₂P(S)S]₂ (R = Ph, OiPr) resulted in the hypervalent [2‐(R₂NCH₂)C₆H₄]SeSP(S)R′₂ [R = Et, R′ = Ph ( 1 ), OiPr ( 2 ); R = iPr, R′ = Ph ( 3 ), OiPr ( 4 )] species. All new compounds were characterized by solution multinuclear NMR spectroscopy (¹H, ¹³C, ³¹P, ⁷⁷Se) and the solid compounds 1 , 3 , and 4 also by FT‐IR spectroscopy. The crystal and molecular structures of 3 and 4 were determined by single‐crystal X‐ray diffraction. In both compounds the N(1) atom is intramolecularly coordinated to the selenium atom, resulting in T‐shaped coordination arrangements of type (C,N)SeS. The dithio organophosphorus ligands act monodentate in both complexes, which can be described as essentially monomeric species. Weak intermolecular S ··· H contacts could be considered in the crystal of 3 , thus resulting in polymeric zig‐zag chains of R and S isomers, respectively.     

Organometallic Compounds of the Lanthanides. 157 [1] The Molecular Structure of Tris(trimethylsilylmethyl)samarium, ‐erbium, ‐ytterbium,and ‐lutetium

SmCl₃ reacts with Me₃SiCH₂Li in THF yielding Sm(CH₂SiMe₃)₃(THF)₃ ( 1 ). The single crystal X‐ray structural analyses of 1 , Er(CH₂SiMe₃)₃(THF)₂ ( 2 ), Yb(CH₂SiMe₃)₃(THF)₂ ( 3 ), and Lu(CH₂SiMe₃)₃(THF)₂ ( 4 ) show the Sm atom in a fac‐octahedral coordination and the heavier lanthanides Er, Yb, and Lu trigonal bipyramidally coordinated with the three alkyl ligands in equatorial and two THF molecules in axial positions.