Synthesis and Study of Electrochemically Grown Salts of Organic II-Donors

Abstract

The effects of purity and crystal perfection on the properties of (TMTSF)₂ClO₄ are examined via SEM's and transition temperatures. Careful electrochemical techniques using gradient sublimed TMTSF starting material and short term oxidation result in high quality crystals. Preliminary work on HMTSF salts of PF ^? ₆ and AsF^? ₆ is also reported.     

Synthesis and Molecular Structure of Sulfur Containing Cobalt Compounds

Abstract  

The reaction of cobalt (II) chloride hexahydrate and N-tert-butyl-2-thioimidazole (tm^t-Bu) yielded products [k²-(tm^t-Bu)₂]CoCl₂ (1) and [(tm^t-Bu)₂Co₂(μ-tm^t-Bu)₂Cl₂]·CH₃CN (2) at different reaction time. The single crystal X-ray diffraction analysis was carried out for 1 and 2 {Bruker Kappa Apex-II CCD diffractometer, MoK_α radiation}. Crystal data for 1: orthorhombic P212121 unit cell a = 8.195(6) ?, b = 13.778(10) ?, c = 17.354(11) ? and V = 1960(2) ?³ whereas the compound 2 crystallizes in monoclinic system P21/c with unit cell a = 10.069(7) ?, b = 11.181(7) ?, c = 18.156 ?, β = 95.322(4)° and V = 2035.4(2) ?³. The complex 1 contains one dimensional chain running along the a-axis and the complex 2 contains one dimensional chain running along the b-axis due to existence of different types of intermolecular interaction. The change in structure of the product is directly related to the reaction time i.e. reaction for lesser time produces mononuclear product and for longer time produces binuclear compound.     

The synthesis and crystal structures of new trinuclear and hexanuclear nickel complexes with metallodithiolate ligands

Two nickel complexes with metallodithiolate ligands, which can be regarded as the active site models of the acetyl coenzyme A synthase, were prepared and structurally characterized by X-ray crystallography. Reactions of Ni(PPh₃)₂Cl₂ with Ni(bme-dach) [bme-dach = N,N'-bis(mercaptoethyl)-1,4-diazacycloheptane] or Ni(bme-dach^*) [bme-dach^* = N,N'-bis(mercaptoethyl)-1,4-diazacyclohexane] in MeCN in the presence of NH₄PF₆ resulted in the formation of a trinuclear nickel complex {Ni[Ni(bme-dach)]₂}[PF_6-]₂ (1) and a hexanuclear nickel complex {Ni₂[Ni(bme-dach^*)]₄}[PF₆^?]₄ (2). The crystal structure of 1·2MeCN shows a square planar geometry of nickel atom that is coordinated by four sulfur atoms of the metallodithiolate ligands Ni(bme-dach). The crystal structure of 2·4MeCN reveals that each of the two nickel atoms is ligated by four sulfur atoms of the metallodithiolate ligands Ni(bme-dach^*) to form a square planar coordination sphere.     

Study of optical and transport properties of K2CuCl4 · 2H2O single crystal

Optical absorption, transport properties and EPR of K₂CuCl₄ · 2H₂O single crystals have been studied. The optical absorption in UV, and visible region are characterized by a charge transfer band, and in the near infrared region at 3998, 4336, and 4480 cm⁻¹ are attributed to transitions between the stark levels of copper(II) ion in an extended octahedral crystal field. An anisotrophic ‘g’ value was observed with g_∥ = 2.12 and g_∥ = 2.24 by EPR method. The spin orbit coupling constant is found to be 500 cm₋₁. D.C. electrical conductivity measurements with temperature reveal an anisotropy characteristic of a two-dimensional layered structure and exhibit a first order irreversible structural phase-transition at 377 K, i.e. from tetragonal to monoclinic crystal system. X-ray diffraction studies and density calculations from the crystal structure data in both the phases suggest that the first order irreversible transition occurs following the loss of the two water molecules of hydration.     

Crystal structures of four inclusion compounds of 2,2′-dithiosalicylic acid and tetraalkylammonium

Herein four inclusion compounds of 2,2′-dithiosalicylic acid and tetraalkylammonium, 2(CH₃)₄N⁺·C₁₄H₈O₄S₂^2?·H₂O (1), (C₂H₅)₄N⁺·C₁₄H₉O₄S₂^?·0.25H₂O(2), (n-C₃H₇)₄N⁺·C₁₄H₉O₄S₂^? (3) and (n-C₄H₉)₄N⁺·C₁₄H₉O₄S₂^?(4) are prepared and characterized by X-ray single crystal diffraction. As shown in the results, compounds 1 and 3 belong to orthorhombic crystal system with different space groups of P2₁2₁2₁ and Pca2₁, and 2 and 4 are monoclinic system with similar groups of P2₁/n and P2₁/c. The crystallography data are displayed below: 1: a = 10.5903(7) Å, b = 10.6651(7) Å, c = 21.9476(13) Å, V = 2478.9(3) ų, Z = 4, R₁ = 0.0359; 2: a = 8.13340(1) Å, b = 22.0741(3)Å, c = 13.2143(2)Å, β = 101.6360(1) °, V = 2323.70(6) ų, Z = 1, R₁ = 0.0385; 3: a = 15.7857(2) Å, b = 8.24830(1) Å, c = 20.2599(2) Å, V = 2637.94(5) ų, Z = 4, R₁ = 0.0308_degree4: a = 11.7476(2) Å, b = 17.1346(1) Å, c = 16.3583(3)Å, β = 109.4560(1) °, V = 3104.74(9)ų, Z = 4, R₁ = 0.0562. Interestingly, although the carbon chains of the guest templates vary from methyl group to butyl group, the host molecules of 2,2′-dithiosalicylic acid all construct the similar 2D hydrogen-bonded host layers with or without the existence of water molecules to contain the guest templates to yield analogous sandwich-like inclusion compounds. Obviously, although the guest templates will have certain effects on the ultimate formation of these crystal structures, the host molecule of 2,2′-dithiosalicylic acid is a controlling factor to form these four inclusion compounds.     

Problems in crystal chemistry of ferroelectric and antiferroelectric perovskites PbB

The most interesting problems in the crystal chemistry of ferroelectric and antiferroelectric perovskites PbB _0.5 ^′ B _0.5 ^″ O₃ are considered. The properties and specific features of perovskites (such as the smearing of ferroelectric phase transitions, relaxor state, ferroelectric-antiferroelectric transformations, and spontaneous phase transitions to a macrodomain state) depend on the distribution of B′ and B″ ions over octahedral positions of the crystal lattice, i.e., on the order and disorder of these ions. __________ Translated from Kristallografiya, Vol. 49, No. 5, 2004, pp. 806–810. Original Russian Text Copyright ? 2004 by Isupov.     

Two-Dimensional Layers Using Different Combinations of Hydrogen Bonded Rings in Three Ammonium Carboxylate Salts

Abstract  

The crystal structure of the ammonium carboxylate salts (cyclohexylammonium)₂·(terephthalate) (1), (cyclohexylammonium)₂·(trans-1,4-cyclohexanedicarboxylate) (2) and (cyclododecylammonium)₂·(trans-1,4-cyclohexanedicarboxylate) (3) were determined by low temperature single crystal X-ray diffraction. The molecular salts were prepared by solution crystallization of the carboxylic acids with the respective amines in a 1:2 stoichiometric ratio. The crystal structure of 1 belongs to the monoclinic space group Cc with a = 11.5643(7) ?, b = 22.8180(13) ?, c = 8.4163(5) ? and β = 117.020(2)°. The crystal structure of 2 belongs to the monoclinic space group P2₁/n with a = 16.9546(10) ?, b = 6.4352(4) ?, c = 19.3948(12) ? and β = 94.677(4)°. The crystal structure of 3 belongs to the monoclinic space group P2₁/c with a = 8.1714(5) ?, b = 34.3887(17) ?, c = 11.0230(6) ? and β = 95.790(4)°. The changes in cation and anion species produces three distinct types of layers, with corresponding changes in the hydrogen bonded ring patterns linking the ionic species together using charge-assisted N⁺–H···O⁻ hydrogen bonds.     

An Iodoargentate Hybrid Coordination Polymer Constructed by Methyl Viologen: Structure,Properties and Theoretical Study

Abstract  

An iodoargentate hybrid coordination polymer induced by MV²⁺, [MV(Ag₂I₄)] _n (1) (MV = methyl viologen, i.e., 1,1-dimethyl-4,4-bipyridinium), has been obtained and structurally determined. In 1, (Ag₂I₄) _n ²⁻ chain exhibits a new type of zigzag-like configuration constructed from edge-sharing of normal and distorted AgI₄ tetrahedra, hydrogen bonds between MV²⁺ cations and (Ag₂I₄) _n ²⁻ chains contributed to the formation of quasi-two-dimensional structure. The band gap of 2.12 eV based on optical absorption spectrum indicated its semiconductor nature. Quantum chemistry calculation with DFT method was carried out to reveal its electronic structure.     

Magnetic Resonance on (QP)4(SbF6)3, a Radical Cation Salt of P-Quaterphenylene

Abstract

The unit cell of (QP)₄(SbF₆)₃ shows triads of QP in an arene stack and one QP in the anion sheet. The sum formula is therefore (QP)₃QP(SbF₆)₃. Electron-electron repulsion force le^?/site resulting in a semi-conducting state. This is in agreement with an activated conductivity of max 10^?1 Scm^?1 at 300 K.

Magnitude and activation energy of the paramagnetic susceptibility do not coincide with those of the conductivity; spins and charges are localized and decoupled due to the strong alternation of distances within the cation stack. Spin diffusion along the stacks governs, at least above 180 K, the magnetic properties: narrow ESR-lines and proton spin relaxation via hyperfine interaction with the relaxation dispersion T ^?1 _1H α ω^?1/2 above 200 K.

A lower value for the intrachain exchange rate τ₁ ^?1> 8.10¹¹ sec^?1 and a lower limit of 10³ for the anisotropy can be evaluated.

Keywords: quaterphenylene, molecular crystal, radical cation salt, low dimensionality, magnetic resonance     

Optical Properties,Conductivity and Structure of the DTT-TCNQ CT Complex

Abstract

The crystal structure, the optical spectra and electrical conductivity of dithieno(3,2-b; 2′,3′-d)thiophene-tetracyanoquinodimethane (DTT-TCNQ) charge-transfer complex have been measured. DTT-TCNQ crystallizes in the monoclinic space group P2₁/c with a = 7.206(2), b = 7.574(2), c = 32.324(9), β - 92.18(4)°, Z - 4, and the donor and acceptor molecules are arranged in alternated stacks.

The low conductivity (a = 10^?2 S cm^?1 for the single crystal, along the stacking axis a) is characteristic of a semiconductor with activation energy of .61-.76 eV, and is related to the alternate stack structure.

Despite the poor condctivity of the DTT-TCNQ CT complex we estimated, from structure and IR data, a low degree of ionicity (p = .2–.3) which characterizes the DTT molecule as an interestign donor.

The polarized IR spectra shows the effect of vibronic activation of some of the a_g modes of TCNQ.     

Heat Capacity and Thermodynamic Properties of p'-Substituted p-n-Hexyloxybenzylideneaniline. I. p-n-Hexyloxybenzylideneamno-p'-Benzonitrile (HBAB)

Abstract

The heat capacity of the nematogenic liquid crystal, HBAB, has been measured between 15 K and 385 K by using an adiabatic calorimeter. The crystal-crystal phase transition has been discovered at 27 K below the crystal-nematic phase transition temperature. The transition temperatures, the enthalpies and the entropies of the three phase transitions have been determined: T ₁ = 306.98 K, ΔH _t = 5.11 kJ mol^?1, ΔS _t = 16.7 JK^?l; T _m = 334.05 K, ΔH _m = 23.77 kJ mol^?1, ΔS_m = 71.2 J K^?l mol^?1; and T _c = 375.10 K, ΔH _c = 1.75 kJ mol^?1, ΔS _c = 3.2 J K^?1 mol^?1, respectively. The thermodynamic functions of HBAB from 0 K to 385 K have been determined from the heat capacity data and the enthalpies of the transitions. Two crystal modifications, one yellow and granular form and the other white and needle-like form, have been obtained during the course of the preparation of the sample. It turned out that the yellow form was the stable crystal and the white the metastable modification. The crystal-crystal phase transition has been discussed as an onset of partial melting from the entropy consideration. In this connection the total entropies of the transitions, 91.1 J K^?1 mol^?1 has been proposed to be an important measure of melting.     

Crystal Structures of a Series of Bis{(2-Aminobenzoyl-)amino}alkanes

Abstract  The crystal structures of 1,2-bis-{(2-aminobenzoyl-)amino}ethane(1), 1,4-bis-{(2-aminobenzoyl-)amino}butane(2) and 2,2-dimethyl-1,3-bis-{(2-aminobenzoyl-)amino}-propane(3) have been determined by single crystal X-ray diffraction analysis. 1 and 2 are centrosymmetric molecules which lie on crystallographic centers of symmetry and adopt extended conformations. On the other hand, owing to the odd number of carbon atoms in the spacer unit, 3 does not show centrosymmetry, but crystallizes in a non-centrosymmetric space group and assumes a folded conformation. The crystal structures of 1, 2 and 3 are compared with the known structures of anthranilamide (7) and the N-alkyl anthranilamide derivative 8. Crystal data: 1 C₁₆H₁₈N₄O₂, monoclinic, space group P2₁/a, a = 9.5262(8) ?, b = 5.4200(5) ?, c = 15.3821(14) ?, β = 105.980(5)° and V = 763.52(12) ?³, for Z = 2. 2 C₁₈H₂₂N₄O₂, monoclinic, space group C2/c, a = 32.0710(17) ?, b = 5.4732(4) ?, c = 9.7326(5) ?, β = 102.570(4)° and V = 1667.42(17) ?³, for Z = 4. 3 C₁₉H₂₄N₄O₂, orthorhombic, space group Pca2₁, a = 16.7676(4) ?, b = 10.1847(2) ?, c = 10.5338(5) ?, and V = 1798.89(7) ?³, for Z = 4. Index Abstract  The crystal structures of 1,2-bis-{(2-aminobenzoyl-)amino}ethane(1), 1,4-bis-{(2-aminobenzoyl-)amino}butane(2) and 2,2-dimethyl-1,3-bis-{(2-aminobenzoyl-)amino}-propane(3) have been determined by single crystal X-ray diffraction analysis. 1 and 2 are centrosymmetric molecules which lie on crystallographic centers of symmetry and adopt extended conformations, whereas 3 does not show centrosymmetry, but crystallizes in a non-centrosymmetric space group and assumes a folded conformation.      

Synthesis and Structure of (TMEDA)Cr(I)<Subscript>2</Subscript>(THF) and [(<Emphasis Type="Italic">N,N</Emphasis>-DMEDA)<Subscript>2</Subscript>CrI] I

Abstract  

The complexes (TMEDA)Cr(I)₂(THF) (1) and [(N,N-DMEDA)₂CrI] I (2) were synthesized and spectroscopically characterized (TMEDA = tetramethylethylenediamine, N,N-DMEDA = N,N dimethylethylenediamine). Complex 1 possesses square pyramidal geometry and crystallizes in spacegroup Pbca with crystal cell parameters a = 11.206(2) ?, b = 12.698(3) ?, c = 23.434(5) ?, V = 3,334.6(12) ?³ and Z = 4. Complex 2 also possesses square pyramidal geometry with a non-coordinated iodide counter anion and crystallizes in spacegroup P2₁/n with crystal cell parameters a = 9.4071(13) ?, b = 14.628(2) ?, c = 11.7516(16) ?, β = 98.904(2) ?°, V = 1,597.6(4) ?³ and Z = 4. Complex 2 has previously been incorrectly assigned as an octahedral complex based on spectroscopy.     

Unusual Glassy Smectic-G Liquid Crystal: Heat Capacity of N-p-n-Pentyloxybenzylidene-p'-n-butylaniline between 11 and 393 K

Abstract

The heat capacities of the title compound (C₃H₁₁,O—C₆H₄,- CH=N—C₆H₄,—C₄H₉, abbreviation 5O ? 4) with a purity of 99.92 mole percent have been measured with an adiabatic-type calorimeter between 11 and 393 K. The transition temperature and the enthalpy and entropy of phase transition for stable crystal → S_G, S_G → N and N → isotropic liquid were T _c = 299.69 K/ΔH = 22.68 kJ mol^?1/ΔS = 75.70 JK^?1 mol^?1, 325.72/7.11/21.79 and 342.48/1.78/5.22, respectively. The crystal which melts at 285.5 K is a metastable modification. The S_A phase hitherto reported in between S_G and N does not exist. The glassy So state was realized by rapid cooling of the specimen from the So phase. The molar enthalpy of the glassy S_G state at 0 K was by (10.1±0.1) kJ mol^?1 higher than that of the stable crystalline state and the residual entropy of the glassy state was (9.40±0.83) JK^?1 mol^?1. The relaxational heat-capacity anomaly was observed from as low as 100 K and double glass transition phenomenon occurred around 200 K; a quite unusual phenomenon which has never been observed for the glassy states of nematic and cholesteric liquid crystals. The present results give a fair evidence that the unusual glass transition phenomenon previously found for the S_G state of 6O?4 (a homologous compound) is not exceptional at all but common to the smectic glasses; at least common to the glassy S_G states. Two possible origins responsible for the double glass transitions have been discussed.     

The Zolmitriptan-Pyridine (1:1) and Zolmitriptan-Propiophenone (3:2) Inclusion Complex

Abstract  

The crystal structures of zolmitriptan with pyridine (I) and propiophenone (II) solvates have been determined by single crystal X-ray diffraction studies. Compound (I) crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 8.5610(5) ?, b = 12.2709(7) ?, c = 19.6201(12) ?, V = 2061.1(2) ?³, and Z = 4, while compound (II) crystallizes in the monoclinic space group P2₁ with a = 15.085(1) ?, b = 19.656(12) ?, c = 21.0860(13) ?, β = 92.068(1)°, V = 6248(4) ?³ and Z = 4. The asymmetric unit of (I), C₁₆H₂₁N₃O₂·C₅H₅N, contains one zolmitriptan molecule and one pyridine solvate, while the asymmetric unit of (II), 3(C₁₆H₂₁N₃O₂)·2(C₉H₁₀O) comprises six zolmitriptan molecules and four propiophenone solvates. In both structures, the N–H···N hydrogen bonds, form an infinite helical chain and generate a C(11)-type motif in (I) and a D₂²(13)-type motif in (II). Both the complexes have layer structures, the layers being constructed from rings (cavity) of four zolmitriptan molecules, hydrogen bonded through N–H···N and N–H···O bonds, where the pyridine (I) and propiophenone (II) solvates are included in an R₄⁴(33) ring.     

Two-Dimensional Hydrogen-Bonded Polymer from Nickel(II) Tetraaza Macrocyclic Complex and Succinate Ligand

Abstract  

The reaction of [Ni(L)]Cl₂·2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12] docosane) with succinic acid (C₄H₆O₄) yields a 2D hydrogen-bonded polymer with formula [Ni(L)(C₄H₅O₄)₂] (1). This polymer complex has been characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The complex has a center of symmetry. The crystal structure of 1 exhibits a distorted octahedral geometry about Ni atom with four nitrogen atoms of the macrocycle and two oxygen atoms of the succinate ligand at the trans position. Compound 1 crystallizes in the monoclinic system C2/c with a = 14.8203(11), b = 12.3070(8), c = 17.4164(12) ?, β = 107.356(6)°, V = 3032.1(4) ?³, Z = 4. Electronic spectrum of 1 reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes two waves of a one-electron transfer corresponding to Ni^II/Ni^III and Ni^II/Ni^I processes.     

Octahedral Copper(II) Carboxylates with 1,10-Phenanthroline: Synthesis,Structural Characterization,DNA-Binding and Anti-Fungal Properties

Two mono-nuclear axially distorted octahedral copper(II) complexes have been prepared and characterized via FT-IR, UV–Visible, elctrochemical, electron spin resonance and powder and single crystal XRD techniques. The complexes consist of a phenanthroline and two carboxylate ligands each bonded in bidentate fashion. Carboxylates are ortho-nitro-2-phenyl acetate (L1) and para-chloro-2-phenyl acetate (L2). Structural study showed that both complexes possess Jahn–Teller distorted octahedral geometry. The bulk purity was assessed from the matching experimental and simulated powder XRD spectra. The results of spectroscopic techniques are consistent with each other. ESR data revealed single electron occupancy of d_x² ? _y² orbital with ²B_1g as ground state typical of tetragonally distorted octahedral geometry. Electrochemical solution study showed diffusion controlled electron transfer processes with diffusion co-efficient values of 10.323?×?10^–8 cm²s^–1 and 0.972?×?10^–8 cm²s^–1 for 1 and 2. Complexes exhibited excellent DNA-binding activity studied via UV–Visible spectroscopy, cyclic voltammetry, florescence spectroscopy and viscometry yielding K_b values of 1.871?×?10⁴ M^–1 (1) and 1.577?×?10⁴ M^–1 (2), 0.38?×?10⁴ M^–1 (1) and 6.39?×?10⁴ M^–1 (2) and 2.1?×?10⁶ M^–1 (1) and 2.0?×?0⁶ M^–1 (2), respectively, for the first three techniques. Complexes possess good antifungal activity against three fungal strains.

Graphic Abstract

     

An X-Ray Crystallographic Study of the Novel Aminal bis-(<Emphasis Type="Italic">p</Emphasis>-Ethoxycarbonylphenylamino-)methane

Abstract  The crystal structure of bis-(p-Ethoxycarbonylphenylamino-)methane (1) has been determined by single crystal X-ray diffraction analysis. The bis-aminal (1) molecule is V-shaped and situated on a twofold axis passing through C1 with the phenyl rings forming a dihedral angle of 70.2(1)°. The carboxylate and phenyl groups are coplanar. The crystal structure of 1 is compared with the structure of the closely related aminals, 2–5. Crystal data: 1 C₁₉H₂₂N₂O₄, tetragonal, space group I4 ₁ cd (N.110), a = 20.4760(7) Ǻ, b = 20.4760(7) Ǻ, c = 8.2984(3) ?, and V = 3477.7(2) ?³, for Ζ = 8. Index Abstract  The crystal structure of bis-(p-ethoxycarbonylphenylamino-)methane (1) has been determined by single crystal X-ray diffraction analysis.      

Generation and intermolecular trapping of a cage-annulated cycloalkylidenecarbene

Base-promoted reaction of 11-methylenepentacyclo[5.4.0.0^2,6.0^3,10.0^{5, 9}]undecan-8-one (5) with diethyl diazomethylphosphonate when performed in the presence of excess cyclohexene, resulted in the formation of the corresponding cycloalkylidenecarbene, 6, which subsequently was trapped in situ to afford 8-methylene-11-(7-bicyclo[4.1.0]heptylidene)pentacyclo-[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane (7, obtained in 44% yield as a mixture of exo, endo isomers). Subsequent reaction of 7 with dichlorocarbene (generated under phase transfer catalytic conditions) produced the corresponding mono- and di-:CCl₂ adducts [i.e., 8 (64% yield) and 9 (5% yield), respectively]. The structure of 9 was established unequivocally via application of single crystal X-ray analysis: Triclinic, P1¯, a = 6.276(2), b = 8.700(2), c = 18.550(3) Å, = 76.52(3), = 87.59(3), = 70.88(4)° Z = 2; D _calc 1.486 g cm^–3.     

Synthesis and Structure of bis(β-Diketiminate) Chromium(II) Complexes

Abstract  

The new ligand 2,4-N,N′-bis(napthylamino)-pent-2-ene (L^napth) (1) has been synthesized and crystallizes in space group P2₁2₁2₁ with crystal cell parameters a = 8.196(3) ?, b = 9.119(3) ?, c = 25.746(10) ?, V = 1924.3(12) ?³ and Z = 4. The complexes bis[2,4-pentane-N,N′-bis(napthyl)ketiminato] chromium(II) (2), bis[2,4-pentane-N,N′-bis(isopropylphenyl)ketiminato] chromium(II) (3), and bis[2,4-pentane-N,N′-bis(tertbutylphenyl)ketiminato] chromium(II) (4) were synthesized and structurally characterized. Complex 2, the first complex reported with a bis(napthyl) β-diketiminate ligand, crystallizes in space group P − 1 with crystal cell parameters a = 12.0824(15) ?, b = 12.2462(16) ?, c = 14.8975(19) ?, α = 87.035(2)°, β = 80.615(2)°, γ = 62.756(2)°, V = 1932.9(4) ?³ and Z = 2. Complex 3 crystallizes in space group P2₁/n with crystal cell parameters a = 13.088(3) ?, b = 22.222(5) ?, c = 14.206(3) ?, β = 102.310(4)°, V = 4036.6(17) ?³ and Z = 4. Complex 4 crystallizes in space group P2₁/n with crystal cell parameters a = 20.831(6) ?, b = 11.575(4) ?, c = 21.373(7) ?, β = 107.241(5)°, V = 4922(3) ?³ and Z = 4. The degree of twist between the ligand planes is dependent on the steric bulk of the ligand.