Generalized 1/Z expansion for heteronuclear molecules

We have first studied empirical regularities in various series of heteronuclear diatomic molecules between the energy E, the total number of electrons N, the equilibrium distance R_e and Z? = (Z₁Z₂)^1/2 where Z₁e and Z₂e are the nuclear charges in the diatom. In particular, for various alkali halide series, R_e²|E|/N^5/3 is shown to correlate rather simply with Z?R_e³. Some theoretical basis is afforded by generalizing the 1/Z expansion used early by the writers in work on homonuclear diatomics. Finally, when Z₂/Z₁ → ∞, a model is presented which predicts a finite asymptotic bond length and this prediction is confronted with available experimental data for both heteronuclear diatoms and for the polyatomic series CH₄ to SnH₄.     

Critical point,singularities and extrapolations in the helium iso-electronic sequence

The Z-expansion of two-electron systems is analyzed with the Padé technique with emphasis on establishing analytical properties of the function E(Z) formally associated with the power series expansion. The concept of critical point in this connection is stressed. For this sequence it occurs at Z_c = 0.911246 with E(Z_c) = ?0.415184. The structure of E(Z) for Z < Z_c is investigated. The use of Padé approximants to extrapolate values of electron affinities is emphasized.     

Oligonucleotide Analogues with Integrated Bases and Backbone. Part 15

The self‐complementary (Z)‐configured U*[c_e]A⁽*⁾ dinucleotide analogues 6, 8, 10, 12, 14 , and 16 , and the A*[c_e]U⁽*⁾ dimers 19, 21, 23, 25, 27 , and 29 were prepared by partial hydrogenation of the corresponding ethynylene linked dimers. Photolysis of 14 led to the (E)‐alkene 17 . These dinucleotide analogues associate in CDCl₃ solution, as evidenced by NMR and CD spectroscopy. The thermodynamic parameters of the duplexation were determined by van't Hoff analysis. The (Z)‐configured U*[c_e]A⁽*⁾ dimers 14 and 16 form cyclic duplexes connected by Watson–Crick H‐bonds, the (E)‐configured U*[c_e]A dimer 17 forms linear duplexes, and the U*[c_e]A⁽*⁾ allyl alcohols 6, 8, 10 , and 12 form mixtures of linear and cyclic duplexes. The C(6/I)‐unsubstituted A*[c_e]U allyl alcohols 19 and 23 form linear duplexes, whereas the C(6/I)‐substituted A*[c_e]U* allyl alcohols 21 and 25 , and the C(5′/I)‐deoxy A*[c_e]U⁽*⁾ dimers 27 and 29 also form minor amounts of cyclic duplexes. The influence of intra‐ and intermolecular H‐bonding of the allyl alcohols and the influence of the base sequence upon the formation of cyclic duplexes are discussed.     

Kinetic Parameters of Alkyl,Alkoxy, and Peroxy Radical Isomerization

The parabolic model of radical abstraction reactions is used to analyze experimental data on monomolecular hydrogen-atom transfer in the reactionsRC^.H(CH₂) _n CH₂R¹ RCH₂(CH₂) _n C^.HR¹(n= 2, 3, 4)RCH(O^.)(CH₂)₂CH₂R¹ RCH(OH)(CH₂)₂C^.HR¹ RCH(OO^.)(CH₂) _n CH₂R¹ RCH(OOH)(CH₂) _n C^.HR¹(n= 1, 2).The activation energies and rate constants that specify each class of these reactions are calculated. Alkyl radical isomerization is characterized by the following activation energies of a thermally neutral reaction depending on the cycle size in the transition state (nis the number of atoms in a cycle): E _{e , 0}(kJ/mol) = 46.6 (n= 6), 59.4 (n= 5), and 57.1 (n= 7). Alkoxy radicals isomerize with E _{e , 0}(kJ/mol) = 53.4 (n= 6), whereas peroxy radicals isomerize with E _{e , 0}(kJ/mol) = 53.2 (n= 6) and E _{e , 0}(kJ/mol) = 54.8 (n= 7). The E _{e , 0}value varies with changes in the cycle size and the strain energy in cycloparaffin C _n H_2n in the same manner. The activation energies E _{e , 0}for the intra- and intermolecular H-atom abstractions are compared. It is found that E _{e , 0}(isomerization) < E _{e , 0}(R^.+ R¹H) for alkyl radicals and that E _{e , 0}(isomerization) E _{e , 0}(RO^.(RO^.) + R¹H) for alkoxy and peroxy radicals.     

Synthesis,spectroscopic characterization and DFT study of dinuclear ruthenium sawhorse-type complexes derived from the reaction of trinuclear aggregates and (Z)-5-arylidenerhodanines

The synthesis of dinuclear ruthenium sawhorse-type complexes [Ru₂(μ-ArCH:Rhod)₂(CO)₄]_n 12a–e and [Ru₂(ArCH:Rhod)₂(μ-ArCH:Rhod)₂(CO)₄] 13a–e through reaction of [Ru₃(CO)₁₀(NCMe)₂] and [Ru₃(CO)₁₂] and the corresponding (Z)-5-arylidenerhodanines (ArCH:Rhod) 10a–e, respectively, are reported. These complexes are arranged in a sawhorse structure in which two bridged (Z)-5-arylidenerhodanines coordinate to the metals using sulfur and nitrogen of the rhodanine ring. A Density Functional Theory method was used to gain insight into the polymerization process by calculating dimerization Gibbs energies (ΔG_dim). Values between ?10.7 and ?5.3 kcal mol^?1 indicate that dimerization is a spontaneous process. A reaction pathway for formation of the sawhorse compounds [Ru₂(μ-ArCH:Rhod)₂(CO)₄] was calculated and the rate-determining step for the mechanism is coordination of a second (Z)-5-arylidenerhodanine ligand with activation energies between 41.1 and 47.8 kcal mol^?1. In order to understand the apparent thermodynamic favorability of the fragmentation step, we calculated the fragmentation energy (ΔE_Frag) for the key intermediate and its energetic contributors, the interaction energy, ΔE_int and the reorganization energy, ΔE_reorg. Low values of ΔE_Frag imply that the fragmentation is thermodynamically facile. Large values of ΔE_int are countered by opposite and large values of ΔE_reorg which indicate that the cleavage of the trimetallic intermediate aggregate is determined by the nature of the ligand and the balance between its interaction with the metal and the extent of structural reorganization.     

Chemical bond breaking/forming as a Franck–Condon electronic process

We describe chemical bond changes as Franck–Condon electronic processes within a new theoretical ansatz that we call ‘rigged’ Born–Oppenheimer (R-BO) approach. The notion of the separability of nuclear and electron states implied in the standard Born–Oppenheimer (BO) scheme is retained. However, in the present scheme the electronic wave functions do not depend upon the nuclear coordinate (R-space). The new functions are obtained from an auxiliary Hamiltonian corresponding to the electronic system (r-coordinates) submitted to a Coulomb potential generated by external sources of charges in real space (α-coordinates) instead of massive nuclear objects. A stationary arrangement characterized by the coordinates α_0A, is determined by a particular electronic wave function, ψ(r;α_0A); it is only at this stationary point, where an electronic Schrödinger equation: H_e(r,α_0A)|Ψ(r;α_0A)=E(α_0A)|Ψ(r;α_0A) must hold. This equation permits us to use modern electronic methods based upon analytic first and second derivatives to construct model electronic wave functions and stationary geometry for external sources. If the set of wave functions {Ψ(r;α_0A)} is made orthogonal, the energy functional in α-space, E(α;α_0A)=Ψ(r;α_0A)|H_e(r,α_0A)|Ψ(r;α_0A) is isomorphic to a potential energy function in R-space: E(R;α_0A)=Ψ(r;α_0A)|H_e(r,R)|Ψ(r;α_0A). This functional defines, by hypothesis, a trapping convex potential in R-space and the nuclear quantum states are determined by a particular Schrödinger equation. The total wave function for the chemical species A reads as a product of our electronic wave function with the nuclear wave function (Ξ_ik(R;α_0A)): Φ_ik(r,R)=Ψ_i(r,α_0A)Ξ_ik(R;α_0A). This approach facilitates the introduction of molecular frame without restrictions in the R-space. Two molecules (characterized with different electronic spectra) that are decomposable into the same number of particles (isomers) have the same Coulomb Hamiltonian and they are then characterized by different electronic wave functions for which no R-coordinate ‘deformation’ can possibly change its electronic structure. A bond breaking/forming process must be formally described as a spectroscopic-like electronic process. The theory provides an alternative to the adiabatic as well as the diabatic scheme for understanding molecular processes. As an illustration of the present ideas, the reaction of H₂+CO leading to formaldehyde is examined in some detail.     

Sarcodictyin A and Sarcodictyin B,Novel Diterpenoidic Alcohols Esterified by (E)-N(1)-Methylurocanic Acid. Isolation from the Mediterranean Stolonifer Sarcodictyon roseum

The Mediterranean stolonifer Sarcodictyon roseum (= Rolandia rosea) (Cnidaria, Anthozoa, Alcyonaria, Stolonifera, Clavulariidae) is shown to contain two novel diterpenoidic alcohols esterified by (E)-N(1)-methyl-urocanic acid (= E)-3-(l-methyl-lH-imidazol-4-yl)acrylic acid). They are sarcodictyin A ( = (?)-(4R,4a,R, 7R,10S,11S,12aR,lZ,5E,8Z)-7,10-epoxy-3,4,4a,7,10,11,12,12a-octahydro-7-hydroxy-6-(methoxycarbonyl)-1,10-dimethyl-4-(1-methylethyl)benzocyclodecen-11-yl (E)-3-(1-methyl-lH-imidazol-4-yl)acrylate; (?)- 1 ) and sarco-dictyin B (the 6-(ethoxycarbonyl analogue; (?)- 2 ). The assignment of the structures is mainly based on 1D- and 2D-NMR data, as well as on chemical transformations of (?)- 1 , such as transesterification with MeONa/MeOH giving methyl (E)-N(1)-methylurocanate ( 3 ) and the free alcohol (+)- 4 and reduction with LiAlH₄ followed by benzoylation giving dibenzoate 7. Absolute configurations are based on Horeau's method of esterification of (+)- 4 .     

An accurate analytical representation for the electron screening function

The screening function Φ [ = V_ee(R) - V_ee(∞)], a key quantity in the theory of isoelectronic molecules, has been given an accurate analytical representation for a large number of states of the species Na₂, Na₂⁺ Li₂ and Li₂⁺. The election-electron repulsion V_ee at various internuclear distances has been obtained from high-quality MC SCF/SCF wavefunctions.     

Critical charges of simple coulomb molecular systems: One‐two electron case

We consider some Coulomb systems with several infinitely massive centers of charge Z and one or two electrons: (Z,e), (2Z,e), (3Z,e), (4Z,e), (2Z,e,e), and (3Z,e,e). It is shown that the physical, integer charges Z = 1,2,… do not play a distinguished role for the total energy and for the equilibrium configuration of a system, giving no indication of a charge quantization. By definition, a critical charge Z_cr for a given Coulomb system (nZ,e) or (nZ,e,e) is a charge which separates the domain of the existence of bound states from the domain of unbound states (the domain of stability), the continuum (the domain of instability). For all the above‐mentioned systems critical charges Z_cr as well as equilibrium geometrical configurations are found. Furthermore, an indication to a branch point singularity at Z = Z_cr with exponent 3/2 was obtained. It is demonstrated that in the domain of the existence the optimal geometrical configuration for both (nZ,e) at n = 2,3,4 and (nZ,e,e) at n = 2,3 corresponds to the Platonic body. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Hartree-Fock-Slater Wave Functions and Magnetic Properties of Atoms and Ions

The nuclear magnetic shielding constants (σ) and diamagnetic susceptibilities (χ) of some atoms and ions have been calculated using Hartree-Fock-Slater (hfs ) wave functions. With the shielding data for rare gas atoms a fourth-order polynomial has been fitted for σ_hfs (Z) of neutral atoms. The calculated shielding values for the six sets of isoelectronic closed-shell atoms and ions revealed that in a given isoelectronic series the shielding values vary linearly with respect to Z. It has been found possible to express the nuclear magnetic shielding values of all atoms and ions by the general formula (Z ± n) = σ_hfs (Z) ± n δ_± (Z), where n is the magnitude of the charge on the atom or ion and δ_±(Z) are the polynomials giving the variation of shielding with respect to n at a given Z value for the positive and negative ions, respectively. Using this relation the nuclear magnetic shielding for neutral atoms and singly-, doubly- and triply-charged ions with Z = 2 to 100 have been obtained. Our results on σ_hfs and χ_hfs compare favourably with other available calculations. On a calculé les constantes d'écran magnétique nucléaire (σ) et les susceptibilités diamagnétiques (χ) de quelques atomes et ions à partir des fonctions d'onde de Hartree-Fock-Slater (hfs ). Un polynôme de degré quatré a été adapté aux σ_hfs (Z) d'atomes neùtres avec des données d'écran pour des atomes de gaz nobles. Dans une série isoélectronique donnée les valeurs d'écran calculées varient d'une façn linéaire par rapport à Z. Il est possible d'exprimer les valeurs d'écran magnétique nucléaire de tous les atomes et les ions par la formule générale (Z ± n) = σ_hfs (Z) ± nσ_± (Z), où n est la grandeur de la charge de l'atome ou l'ion et δ_± (Z) sont des polynômes, qui décrivent la variation de l'effet d'écran par rapport à n à une valeur Z donnée, pour les ions positifs et négatifs, respectivement. Avec tette relation-ci on a calculé les constantes d'écran magnétique nucléalre pour les atomes neutres et les ions à charges différentes avec Z = 2 et Z = 100. Nos résultats pour σ_hfs et χ_hfs sont d'accord avec d'autres calculs. Die kernmagnetische Abschirmungskonstanten (σ), und die diamagnetische Susceptibilitäten (χ) einiger Atomen und Ionen sind mit Hartree-Fock-Slater (hfs )-Wellen-funktionen berechnet worden. Ein Polynom vierten Grades wurde für σ_hfs (Z) neutraler Atomen mit experimentellen Abschirmungswerten von Edelgasatomen angepasst. In einer gegebenen isoelektronischen Reihe variieren die Abschirmungskonstanten in linearer Weise mit Rücksicht auf Z. Es ist möglich die kernmagnetische Abschirmungswerte aller Atomen und Ionen mit der allgemeinen Formel (Z ± n) = σ_hfs (Z) ± n δ_±(Z) auszudrücken, wo n die Grösse der Ladung des Atoms oder Ions ist und δ_± (Z) die Polynome sind, die die Variation mit n der Abschirmungskonstante für ein gegebenes Z-Wert der positiven und negativen Ionen beziehungsweise, beschreiben. Mit diesem Ausdruck wurden die kernmagnetische Abschirmungskonstanten neutraler Atome samt einfach, zweifach und dreifach geladener Ionen mit Z = 2 und Z = 100 berechnet. Unsere Resultate für σ_hfs und χ_hfs stimmen mit anderen Berechnungen überein.     

Light-Controlled Destruction and Assembly: Switching between Two Differently Composed Cage-Type Complexes

We report on two regioisomeric, diazocine ligands 1 and 2 that can both be photoswitched between the E- and Z-configurations with violet and green light. The self-assembly of the four species ( 1 -Z, 1 -E, 2 -Z, 2 -E) with Co^II ions was investigated upon changing the coordination vectors as a function of the ligand configuration (E vs Z) and regioisomer ( 1 vs 2 ). With 1 -Z, Co₂( 1 -Z)₃ was self-assembled, while a mixture of ill-defined species (oligomers) was observed with 2 -Z. Upon photoswitching with 385 nm to the E configurations, the opposite was observed with 1 -E forming oligomers and 2 -E forming Co₂( 2 -E)₃. Light-controlled dis/assembly was demonstrated in a ligand competition experiment with sub-stoichiometric amounts of Co^II ions; alternating irradiation with violet and green light resulted in the reversible transformation between Co₂( 1 -Z)₃ and Co₂( 2 -E)₃ over multiple cycles without significant fatigue by photoswitching.     

The effect of cation size on ion pairing of methyl orange dye with tetraalkylammonium and benzyltrialkylammonium ions in aqueous solution

Formation constants have been measured by a solvent distribution method for the ion pairing of an arene sulfonate, methyl orange dye, with two series of quaternary ammonium ions: R₄N⁺(R=Et,n-Pr,n-Bu, andn-Pent) and C₆H₅CH₂R₃N⁺ (R=Me, Et,n-Pr,n-Bu,n-Pent, andn-Hex). Ion pairing increases dramatically as the length of the R group increases beyond butyl. Using a hard-sphere model for contact ion pairs, it is estimated that coulombic attraction contributes about –kT to the binding free energy and decreases slightly with increasing size of R₄N⁺. Other factors related to solvation effects, of which cosphere overlap predominates, contribute from –2kT to –7kT of binding energy. Plots of logK for association as a function of cation size show an inflection with decreasing slope between R=propyl and R=butyl. Possible causes for the inflection are considered.     

Relation between total energy,electronic potential at the nucleus,and chemical potential of positive ions

Simple density functional theory gives the following relation between the energy E_{Z, N} of an ion of nuclear charge Z and N electrons, the potential V(0) created at the nucleus by the electronic cloud, and the chemical potential μ Using Hartree—Fock values for V(0) and μ, this equation has been tested in several isoelectronic series with 3 ≤ N ≤ 28. The importance of the term 3Nμ/7 increases as the degree of ionization increases.     

Optical spectroscopy of (C2H5NH3)2CdCl4:Cu2+ under pressure: Study of Cu2+ local structure from theoretical calculations

The variations experienced by the energy E_u(π) of the e_u(π)→b_1g (～x²–y²) charge‐transfer transition of (C₂H₅NH₃)₂CdCl₄:Cu²⁺ upon pressure in the 0‐ to 40‐kbar range have been measured at room temperature by means of a sapphire anvil cell. These data reveal that E_u(π) undergoes a red shift of 1400 cm^?1 on passing from ambient pressure to 40 kbars. To understand this puzzling result theoretical calculations of ?E_u(π)/?R_eq and ?E_u(π)/?R_ax have been performed where R_eq and R_ax mean the equatorial and axial Cu²⁺–Cl^? distances of the elongated CuCl₆^4? complex, respectively. All results indicate that ?E_u(π)/?R_eq and ?E_u(π)/?R_ax for R_eq=228 pm and R_ax=297 pm are indeed negative. Moreover ab initio complete active space self‐consistent field (CASSCF/CASPT2) and density functional calculations lead to ?E_u(π)/?R_ax values, which are about 10 times smaller than those of ?E_u(π)/?R_eq. From the ensemble of experimental and theoretical results, it is concluded that a pressure of 40 kbars gives rise to a decrement of ≈25 pm of the axial distance and at the same time to an increase of ≈7 pm of the equatorial one. It is stressed that the present study on a diluted Jahn–Teller impurity lies far beyond the current possibilities of X‐ray absorption structure techniques. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Dual Catalysis with Copper and Rhenium for Trifluoromethylation of Propargylic Alcohols: Efficient Synthesis of α‐Trifluoromethylated Enones

Trifluoromethylation of propargylic alcohols to provide (Z)‐α‐trifluoromethylated enones and β‐unsubstituted α‐trifluoromethylated enones proceeded with high yield and selectivity in the presence of CuI/Re₂O₇. The Z isomer was formed under kinetic control, though it is less stable than the E isomer in terms of steric repulsion.     

New Insights on the Mechanism of Thermal Cleavage of Unsaturated Bicyclic Diaziridines: A DFT Study

A DFT calculations are carried out at UB3LYP/6‐311++G (3df, 2p) levels of theory to study electrocyclic thermal cleavage of four (R) derivatives of unsaturated bicyclic diaziridines, 1_X‐R , to produce corresponding (Z) and (E) azomethine imides ( 2_X‐Z , 2_X‐E , 3_X‐Z and 3_X‐E ), where X=H, Me, t‐Bu and Ph. Cleavage of 1_X‐R series to form the most stable 3_X‐Z product, (path 2) is found the favored procedure because of delocalized negative charge on five atoms and lower steric effect in related transition state. According to IRC calculations in paths 1 and 2, C⁶ N¹ bond is cleaved before the rate determinating step (transition state). The stability of unsaturated bicyclic diaziridines and their corresponding (Z) and (E) azomethine imides is in the following order in gas phase and chloroform, tetrahydrofuran, and acetone solvents: 3_X‐Z < 3_X‐E < 2_X‐Z < 2_X‐E < 1_X‐R < 1_X‐S .     

Carbon-13 n.m.r. study of 31P?13C spin–spin coupling constants in dichloro- and monochloro-vinyl phosphate derivatives

Carbon-13 chemical shifts and J(PC) coupling constants of 29 vinyl phosphate derivatives are presented. In the series of compounds (R₁O)₂P(O)OC¹(R)?C²X₂ (where 3 in R indicates the first carbon of the R₂ substituent) large differences were found between the ³J(P, O, C-1, C-3) and ³J(P, O, C-1, C-2) coupling constants of the chlorinated (X?CI) and the unsubstituted (X?H) derivatives. A possible explanation of this phenomenon is given on the basis of Jameson's s bond character theory. Strong stereospecificity of ³J(P, O, C-1, C-3) coupling constants was observed in the series of compounds (R₁O)₂ P(O)OC¹(R)?C²HR₃. Coupling constants varied between 3.2–4.9 Hz in the E isomers, while peaks could not be resolved in the Z isomers. The ³J(P, O, C-1, C-2) coupling constants were regularly 20–30% greater in the Z than in the E isomers.     

Interaction dipole moment in Rg–Xe (Rg = He, Ne, Ar, and Kr) heterodiatoms from conventional ab initio and density functional theory calculations

We have obtained interaction dipole moment curves for the rare gas heterodiatoms Rg...Xe (Rg = He, Ne, Ar, and Kr) from conventional ab initio and density functional theory calculations with flexible Gaussian-type basis sets. All methods seem to reproduce fairly similar dipole moment curves for all pairs. Our best values for the interaction dipole moment (at the respective experimental equilibrium separation R _e) were obtained at the coupled-cluster theory with single, double, and perturbatively linked triple excitations level of theory: μ_int(RgXe)/eα₀ = − 0.0025(He), − 0.0047(Ne), − 0.0055(Ar), and − 0.0037(Kr). The same trend (in absolute terms) is observed at the MP2 level of theory for the derivative of the dipole moment at R _e, as (dμ_int (RgXe)/dR) _e /e = 0.0043 (He), 0.0082 (Ne), 0.0091 (Ar), and 0.0059 (Kr). Around R _e , μ_int(HeXe) ≡ μ_HeXe varies at the MP2 level of theory as [μ_HeXe(R) − μ_HeXe(R _e)]/ea₀ = 0.0043(R − R _e) − 0.0033(R − R _e)² + 0.0018(R − R _e)³ − 0.0005(R − R _e)⁴.     

Contraction of the well-tempered Gaussian basis sets: The first-row diatomic molecules

The well-tempered Gaussian basis sets (14s 10p) for atoms from lithium to neon were contracted and used in restricted Hartree–Fock calculations on 13 systems: Li₂(Σ), B₂(Σ), C₂(Σ), N₂(Σ), O₂(Σ), F₂(Σ), Ne₂(Σ), LiF(Σ), BeO(Σ), BF(Σ), CN^?(Σ), CO(Σ), and NO⁺(Σ). Spectroscopic constants (R_e, ω_e, ω_ex_e, B_e, α_e, and k_e) and one-electron properties (dipole, quadrupole, and octupole moments at the center of mass and electric field, electric field gradient, potential, and electron density at the nuclei) were evaluated and compared with the Hartree–Fock results. The largest contracted basis set (7_s6_p3_d) gives results very close to the Hartree–Fock values; the remaining differences are attributed to the absence of the f functions in the present basis sets. For Ne₂, the interaction energy was calculated; the magnitude of the basis-set superposition error was found to be very small (less than 3 μE_h at 2.8 a₀ and less than 2 μE_h at 5.0 a₀).     

Steric effect on the formation of columnar phases in β-diketonate copper(II) complexes

A systematic study of the mesomorphic properties of three series of copper(II) complexes based on β-diketonate ligands containing branched side chains is reported. These disc-like compounds have four, six and eight flexible alkoxy side chains appended to the central core, in which two or four side chains were substituted by bulkier secondary alkoxy groups: 1-methylbutyloxy R ' = C₅(2°) or 1-methylheptyloxy R ' = C₈(2°). The mesomorphic results indicated that at least eight side chains are required to form stable columnar mesophases; other compounds with four or six side chains are not mesogenic regardless of the combination of the carbon length on the alkoxy or secondary alkoxy groups of the side chains. The compounds 3 with shorter R ' = C₅(2°) side chains were all non-mesogenic regardless of the carbon length of three alkoxy side chains (R = C₈, C₁₀, C₁₂) used. However, when the longer 1-methylheptyloxy side chain R ' = C₈(2°) was substituted, the compounds 3b-3e with various alkoxy groups (R = C₆, C₇, C₈, C₁₀, C₁₂) exhibited columnar phases. The mesophases were characterized and identified as columnar hexagonal phases (Col_h), as expected, by thermal analysis and optical polarized microscopy. The presence of the introduced secondary alkoxy groups apparently appeared to influence the formation of columnar phases. The clearing points were relatively lower than other similar copper(II) compounds not substituted by secondary alkoxy side chains.