Terminal Donor Research Articles

Formation of frontier orbitals and the nature of electron transitions in dication-polyenes, analogs of cyanine dyes

By spectral and quantum chemical methods the nature of the electron transitions in three types of linear conjugated compounds including polyenes, their dications, and polymethine cations containing indolenine and 2,6-diphenylthiopyrylium residues as terminal groups were studied. It was shown that in going from neutral molecules to polymethine cations and polyene-dications a regular downward shift of the energy gap occurred and the decrease in interaction of orbitals of the terminal donor residues. Due to that the electron transitions in polyene dications are degenerate and have high energy in contrast to the deeply colored dications of polymethine dyes.

Single center experience transplanting kidneys from deceased donors with terminal acute renal failure

Transplantation of kidneys from deceased donors with terminal acute renal failure (ARF) is uncommon. We reviewed retrospectively our single-center experience with transplantation of ARF donor kidneys. From January 2007 through September 2008, we transplanted 25 kidneys from 17 ARF donors; 22 kidneys were from standard criteria donors. Mean donor age was 34 years. Mean admission and terminal donor serum creatinine values were 1.3 mg/dL and 3.1 mg/dL. All but 2 kidneys were placed on pump preservation; mean cold ischemia time was 27 hours. The recipient group had a mean age of 49 years and a mean waiting time of 24 months. Patient and graft survival rates were 100% and 92%, respectively, with a mean follow-up of 12 months. Delayed graft function occurred in 8 patients (32%), mean initial duration of stay was 6 days, 3 patients (12%) required re-operation, 3 patients (12%) had acute rejection, and 8 patients (32%) developed infections. Mean 1- and 12-month recipient serum creatinine and glomerular filtration rate values were 1.9 mg/dl (45 mL/min) and 1.5 mg/dl (50 mL/min), respectively. Kidneys from deceased donors with terminal ARF have excellent short-term outcomes and represent another potential method to safely expand the donor pool.

Donor–Acceptor‐Substituted Oligo(1,4‐phenylene)s

Abstractmagnified imageOligo(para‐phenylene)s (DAOPPs) 2a–2d (n=1–4) with terminal donor–acceptor substitution (D=C6H13O, A=NO2) were prepared by applying Suzuki cross‐couplings for chain extension and end capping. The push–pull effect induces short‐reaching polarizations of the chain consisting of conjugated but twisted benzene rings, which was studied by NMR measurements. Electron excitation from the ground‐state S0 to the more planar first‐excited singlet state S1 is combined with a strong intramolecular charge transfer (ICT), which is documented by the red shift of the long‐wavelength absorption (charge‐transfer band) for short chains (one or two repeat units, n = 1 or 2). The opposite influence of decreasing ICT and increasing conjugation length leads to a bathochromic series (λmax(n+1)≥λmax(n)) with a fast saturation of λmax (n). The effective conjugation length nECL=4 corresponds to λ∞ 349 nm. These results are discussed in the context of other oligo(para‐phenylene)s (OPPs).

Hydrocarbon-bridged Metal Complexes, LIII [1]. Trinuclear (cis-Dichloro-ethylenediamine) Platinum(II) Complexes from Amides of Tricarboxylic Acids and 1,2,4-Triaminobutane

The coupling of the tricarboxylic acids, 1,3,5-benzene-tricarboxylic acid, cis,cis-1,3,5-cyclohexane- tricarboxylic acid and of citric acid, with rac-N1,N2-di-Boc-1,2,4-triaminobutane affords the corresponding triamides which were deprotected. From the novel tris(bidendate) ligands with three terminal ethylenediamine donors the tris(cis-dichloro platinum) complexes were obtained

Solid‐State Gas Sensors Developed from Functional Difluoroboradiazaindacene Dyes

This article describes the synthesis and characterization of several new difluoroboradiazaindacene (BODIPY) dyes functionalized at the central 8-position by a phenyliodo, phenylheptynoate or phenylheptynoic fragment and at the 3- or 3/5-position(s) by 4-dimethylaminophenylstyryl residue(s). Single-crystal structural determinations confirm the planarity of the dyes, while the absorption and fluorescence spectroscopic properties are highly sensitive to the state of protonation (or alkylation) of the terminal anilino donor group(s). Reversible color tuning from green to blue for absorption and from colorless (i.e., near-IR region) to red for fluorescence is obtained on successive addition of acid and base. The difunctionalized derivative is especially interesting in this respect and shows two well-resolved pK(a) values of 5.10 and 3.04 in acetonitrile. Addition of the first proton causes only small spectral changes and deactivates the molecule towards addition of the second proton. It is this latter step that accommodates the large change in absorption and emission properties, due to the reversible extinction of the intramolecular charge-transfer character inherent to this type of dye. The main focus of the work is the covalent anchoring of the dyes to inert, porous polyacrylate beads so as to form a solid-state sensor suitable for analysis of gases or flowing liquids. The final material is highly stable--its performance is undiminished after more than one year--and fully reversible over many cycles. The sensitivity is such that reactions can be followed by the naked eye and the detection limit is about 600 ppb for HCl and about 80 ppb for ammonia. Trace amounts of diphosgene can be detected, as can alkylating agents. The sensing action is indiscriminate and also operates when the beads are dispersed in aqueous media.

Second-sphere hydrogen-bonding in heteroditopic mercaptopyridinium copper(I) frameworks

A series of Cu(I) complexes of 4-mercaptopyridine (LH) are reported that form three-dimensional hydrogen-bonded frameworks in the solid-state. The 4-mercaptopyridine ligands co-ordinate to the Cu(I) cations via thiolate donors, leaving a pyridinium hydrogen-bond donor available for interaction with the relevant counter-anions. Four new Cu(I) complexes, [Cu2(LH)6]·2Cl 1, [Cu2(LH)6]·SiF6·2MeOH 2, [Cu4(LH)10]·4NO3·MeOH·H2O 3 and {[Cu6(LH)13]·2BF4·2SiF6·7.5MeOH}∞4 are reported and have been structurally characterised by single crystal X-ray diffraction. In each case hydrogen-bonded arrays are formed via N–H⋯anion hydrogen-bonds or by including hydrogen-bonding to guest solvent molecules. Whereas compound 1 adopts a rutile-like structure with [Cu2(LH)6]2+ and Cl− nodes adopting six- and three-connected arrangements, respectively, compounds 2 and 3 adopt six-connected nets of α-Po (41263) topology. Compound 4 forms a thiolate bridged co-ordination polymer constructed from repeating units of six Cu(I) centres connected by ten bridging and three terminal thiolate-bound LH donors, with complex hydrogen-bonding observed between the polymer cation and counter-anions.

Ligand directed self-assembly vs. metal ion coordination algorithm—when does the ligand or the metal take control?

Polyfunctional hydrazone ligands with multidentate terminal donor groups offer metal ions many donor choices, and the coordination outcome depends mainly on the identity of the metal ion. Co(ii) and Ni(ii) prefer to adopt largely undistorted, six-coordinate geometries, while Cu(ii) can easily adapt to a variety of coordination situations (e.g. CN 4-6), and will optimize its coordination number and stereochemistry based on all the available donors. Ni(ii) and Co(ii) form simple [2 x 2] [M(4)-(micro(2)-O)(4)] square grids with such ditopic hydrazone ligands, and ignore other coordination options, while Cu(ii) tries to bind to all the available donors, and forms extended and 2D structures based on linked Cu(ii) triads rather than grids. Ni(ii) is also reluctant to compromise its desire to maximize its crystal field stabilization energy (CFSE) by binding to 'weak' ligands, and with a tetratopic pyrazole bis-hydrazone ligand it ignores the oxygen donors in favour of nitrogen, forming a novel trinuclear, triangular cluster. Also, reaction of a linear Ni(ii)(3) complex of a tetratopic pyridazine bis-hydrazone ligand with NiN(6) coordination spheres with Cu(ii), leads exclusively to a square Cu(12) grid based complex, and complete displacement of nickel. Structural and magnetic properties are highlighted, and metal-ligand interactions are discussed in detail.

Electronic and Vibronic Contributions to Two‐Photon Absorption in Donor–Acceptor–Donor Squaraine Chromophores

Many squaraines have been observed to exhibit two-photon absorption at transition energies close to those of the lowest energy one-photon electronic transitions. Here, the electronic and vibronic contributions to these low-energy two-photon absorptions are elucidated by performing correlated quantum-chemical calculations on model chromophores that differ in their terminal donor groups (diarylaminothienyl, indolenylidenemethyl, dimethylaminopolyenyl, or 4-(dimethylamino)phenylpolyenyl). For squaraines with diarylaminothienyl and dimethylaminopolyenyl donors and for the longer examples of 4-(dimethylamino)phenylpolyenyl donors, the calculated energies of the lowest two-photon active states approach those of the lowest energy one-photon active (1B(u)) states. This is consistent with the existence of purely electronic channels for low-energy two-photon absorption (TPA) in these types of chromophores. On the other hand, for all squaraines containing indolinylidenemethyl donors, the calculations indicate that there are no low-lying electronic states of appropriate symmetry for TPA. Actually, we find that the lowest energy TPA transitions can be explained through coupling of the one-photon absorption (OPA) active 1B(u) state with b(u) vibrational modes. Through implementation of Herzberg-Teller theory, we are able to identify the vibrational modes responsible for the low-energy TPA peak and to reproduce, at least qualitatively, the experimental TPA spectra of several squaraines of this type.

A Synthetic Analogue of Rieske‐Type [2Fe‐2S] Clusters

}] (3) were formed as a byproduct andidentified by X-ray diffraction (Figure S38 in the SupportingInformation). Compound 2 was crystallized for X-ray dif-fraction (Figure 1, top) by diffusion of diethyl ether into aDMF solution. Prominent intracore distances and angles, aswell as bond lengths and angles to the terminal donor atoms,are in agreement with the corresponding values determinedfor the related homoleptic {N

A hybrid molecular machine

A versatile example of a molecular machine is described. The stationary part is an iron protoporphyrin complex, bearing two movable side chains with terminal donor groups. Changing the pH or the electrochemical potential, as well as the injection of CO, alters the affinity of the donor groups toward the metal ion, thus promoting intra-molecular motion of the pendant arms. The possibility of controlling the molecular motion through inputs of different nature, changeable at will, makes this system the first example of a hybrid molecular machine.

Synthesis, crystal structures, and antimicrobial activity of a pair of isostructural dinuclear copper(II) complexes derived from 4-nitro-2-[(2-diethylaminoethylimino)methyl]phenol

A pair of isostructural azido- or thiocyanato-bridged centrosymmetric dinuclear copper(II) complexes, [Cu2L2(μ1,3-N3)2] (1) and [Cu2L2(μ1,3-NCS)2] (2), derived from the Schiff base ligand 4-nitro-2-[(2-diethylaminoethylimino)methyl]phenol (HL), have been synthesized and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Each Cu atom in the complexes is five-coordinate in a square pyramidal geometry by one O and two N atoms of one Schiff base ligand, and by two terminal donor atoms from two bridging azide or thiocyanate ligands. Both the azide and thiocyanate ligands adopt end-to-end bridging mode in the complexes. The distance between the two copper atoms is 5.205(2) A for (1) and 5.515(2) A for (2). The antimicrobial activity of the complexes has been tested.

Optical properties of stilbene-type dyes containing various terminal donor and acceptor groups

A series of “D-π-A” stilbene-type dyes, named as trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-methylpyridinium iodide (DHEASPI-C1), trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-butylpyridinium bromide (DHEASPBr-C4), trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-octylpyridinium bromide (DHEASPBr-C8) and trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-dodecylpyridinium bromide (DHEASPBr-C12), respectively, have been synthesized and their optical properties have been experimentally investigated. When DHEASPI-C1 are compared with trans-4-[p-(N,N-diethylamino) styryl]-N-methylpyridinium iodide (DEASPI) and trans-4-[p-(N-hydroxyethyl-N-ethylamino) styryl]-N-methylpyridinium iodide (HEASPI), both the electronegativity of two hydroxyl and intra-molecular hydrogen bond decrease the donor ability of the ethyl chain, there are obvious blue shifts both in single-photon absorption spectra, fluorescence spectra and two-photon excited fluorescence spectra. Interestingly, fluorescence intensity of DHEASPI-C1 is the biggest. There are little shifts from DHEASPBr-C4 to DHEASPBr-C8 and to DHEASPBr-C12 in their spectra. As dyes’ two-photon excited fluorescence spectra were concerned, pumped by 1064nm, <130fs mode-locked Nd:YAG laser, their peak locations were between 613 and 623nm.

Synthesis of a family of heterocyclic ligands derived from bisphenols: new flexible bridging ligands for use in metallosupramolecular chemistry

The preparations are described of 35 new bridging ligands from five bisphenols through coupling each with seven different heterocyclic units. X-ray crystal structures of five representative examples revealed different conformations in the solid state with the terminal nitrogen donors being separated by distances ranging from 8 to 23 Å.

Triethylenetetramine penta- and hexa-acetamide ligands and their ytterbium complexes as paraCEST contrast agents for MRI

The ligand triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetamide (ttham) was synthesized with the aim of forming lanthanide complexes suitable as contrast agents for magnetic resonance imaging applications utilizing the chemical exchange-dependent saturation transfer (CEST) effect. It was designed to exclude water molecules from the first coordination sphere and provide a high number of CEST active amide protons per lanthanide ion. The ligand was characterized by its protonation behavior and its complexation properties with ytterbium ions in aqueous solution. The basicity of the ttham backbone amine protons decreases in the order N(central(1)) > N(terminal(1)) > N(terminal(2)) > N(central(2)), as deduced from NMR titration experiments and from a comparison of its protonation constants with those of two ttham derivatives, in which either a terminal (N-benzyl-triethylenetetramine-N,N',N'',N''',N'''-pentaacetamide, 1bttpam) or a central acetamide group (N'-benzyl-triethylenetetramine-N,N,N'',N''',N'''-pentaacetamide, 4bttpam) is substituted with a benzyl group. This protonation sequence results from the combined influence of inductive effects, the intramolecular hydrogen bonding network, and the Coulomb repulsion between protonated ammonium groups. The ytterbium complex of ttham, [Yb(ttham)]Cl(3), is coordinatively frustrated. Due to steric constraints, in addition to the four backbone nitrogen atoms, only three of the four symmetry-equivalent terminal acetamide donors can coordinate simultaneously to the ytterbium ion, and the dangling fourth one exchanges quickly with the other three. The ytterbium complexes of a total of five ligands (ttham, 1bttpam, 4bttpam, 2,2',2''-triaminotriethylaminehexaacetamide (ttaham), and diethylenetriamine-N,N,N',N'',N''-pentaacetamide (dtpam)) were studied with respect to their CEST properties. In solution, all of these complexes have a low symmetry. The presence of multiple magnetically different amide groups in each complex prevents the realization of very high CEST effects. These results nevertheless form an excellent basis for a further optimization of this class of ligands.

Synthesis, structure, spectra and reactivity of iron(iii) complexes of facially coordinating and sterically hindering 3N ligands as models for catechol dioxygenases

A series of 1 : 1 iron(III) complexes of sterically hindered and systematically modified tridentate 3N donor ligands have been isolated and studied as functional models for extradiol-cleaving catechol dioxygenases. All of them are of the type [Fe(L)Cl(3)], where L is N-methyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L1), N-ethyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L2), N-benzyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L3), N,N-dimethyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L4), N'-methyl-N'-(pyrid-2-ylmethyl)-N,N-dimethylethylenediamine (L5), N'-ethyl-N'-(pyrid-2-ylmethyl)-N,N-dimethylethylenediamine (L6) and N'-benzyl-N'-(pyrid-2-ylmethyl)-N,N-dimethylethylenediamine (L7). They have been characterized by elemental analysis and spectral and electrochemical methods. The X-ray crystal structures of the complexes [Fe(L2)Cl(3)] 2, [Fe(L3)Cl(3)] 3 and [Fe(L7)Cl(3)] 7 have been successfully determined. All the three complexes possess a distorted octahedral coordination geometry in which the ligand is facially coordinated to iron(III) and the chloride ions occupy the remaining coordination sites. Upon replacing the N-ethyl group on the terminal nitrogen donor in 2 by the bulky N-benzyl group as in 3, the terminal Fe-N bond distance increases slightly from 2.229(5) A to 2.244(5) A. Upon incorporating the sterically demanding N-benzyl group on the central nitrogen donor in 4 to obtain 7, the central Fe-N(amine) bond distance increases from 2.181(5) A to 2.299(2) A. The catecholate adducts [Fe(L)(DBC)(Cl)] and [Fe(L)(DBC)(Sol)](+), where H(2)DBC is 3,5-di-tert-butylcatechol and Sol = solvent (H(2)O/DMF), have been generated in situ and their spectral and redox properties and dioxygenase activities have been studied in N,N-dimethylformamide and dichloromethane solutions. The adducts [Fe(L)(DBC)(Sol)](+) undergo cleavage of DBC(2-) in the presence of molecular oxygen to afford both intra- and extradiol cleavage products. The extradiol products are higher in dichloromethane than in DMF solution and the extradiol to intradiol product selectivity (E/I, 7.2 : 1-18.5 : 1) observed decreases upon increasing the steric bulk of N-alkyl substituent on the terminal nitrogen atom and upon incorporating an N-alkyl substituent on the central nitrogen atom. The plot of log(k(O(2))) vs. energy of the low energy catecholate-iron(III) LMCT band is linear, which is consistent with the proposal that the LMCT band energy corresponds to the energy needed for a spin-inversion process at the iron center upon dioxygen attack. Also, the rate of oxygenation is dictated by the solvent as well as the Lewis acidity of the iron(III) center, as shown by the linear plot of log(k(O(2))) vs.E(1/2) of the Fe(III)/Fe(II) redox potentials of the [Fe(L)(Sol)(3)](3+) complexes.

Group-12 metal complexes with isomeric 1-(diphenylphosphino)-1′-[N-(pyridylmethyl)carbamoyl]ferrocenes: coordination polymers vs. finite multinuclear coordination assemblies

The isomeric ferrocene phosphine-carboxamides, 1-(diphenylphosphino)-1'-{[N-(2-pyridyl)-methyl]carbamoyl}ferrocene (1) and 1-(diphenylphosphino)-1'-{[N-(4-pyridyl)methyl]carbamoyl}ferrocene (2) have been studied as ligands in group-12 metal bromide complexes. The reactions of 1 with CdBr2 x 4H2O and HgBr(2) at 1:1 mole ratio gave the discrete tetracadmium complex [Cd2(micro-Br)2(-1kappa2O,N2)2[micro-1kappa2O,N2:2kappaP-(C5H4N)CH2NHC(O)fcPPh2-CdBr3]2] (7; fc = ferrocene-1,1'-diyl) and the halogeno-bridged dimer [[Hg(micro-Br)Br(-kappaP)]2] (8), respectively. In the presence of acetic acid, the CdBr2-1 system furnished a zwitterionic complex featuring protonated 1 as the P-monodentate donor, [CdBr3[Ph2PfcC(O)NHCH2(C5H4NH)-kappaP]] x H2O (6 x H2O). Under neutral conditions, compound , whose terminal donor groups are better arranged for the formation of extended assemblies, gave rise to one-dimensional coordination polymers [MBr2[micro(P,N)-]](n) (M = Cd, 4; M = Hg, ). The crystal structures of 2 x H2O, its corresponding phosphine oxide (3 x H2O), and complexes 4, 5, 6 x H2O, and have been determined, revealing extensive hydrogen bonding interactions in the solid state.

Theoretical study of one-photon and two-photon absorption properties for 2,1,3-benzothiadiazole-based red-fluorescent dyes

We have theoretically investigated a series of D-π-A-π-D type 2,1,3-benzothiadiazoles (BTD)-based fluorescent dyes by using DFT(B3LYP/6-31G(d)) and ZINDO/SOS methods. The geometrical and electronic structures, one-photon absorption (OPA), and two-photon absorption (TPA) properties have been studied in detail. The calculated results indicate that conjugation length, π-electron bridges and terminal electron-donating groups (D) are three important factors for influencing OPA and TPA properties. Both oscillator strength ( f) of one-photon absorption and two-photon absorption cross-section values increase by degrees with the strength of terminal electron donors from molecule 1a to 1e. When increasing π-conjugation length between the BTD unit and the amino groups, two-photon absorption cross-section values of molecules 2–6 are enhanced about 1.5–2.6 times relative to 1c. Thereinto, the molecule 5 with additional ethyne π-conjugated bridge shows a larger two-photon absorption cross-section (270 GM) in comparison with ethene, benzene, thiophene and phenylethene π-conjugated bridge. The possible reason is discussed in detail by three-level energy model. Finally, we design a molecule 5′ with additional ethyne π-conjugated bridge and asymmetrical electron-donating groups, its two-photon absorption cross-section (336 GM) is larger than any other molecules in this system because the asymmetry makes Δ μ 0 n increased obviously. The calculations also show low-energy transition arising from charge-transfer makes one-photon and two-photon absorption of these BTD derivatives locate in longer wavelength regions (420–550 nm for OPA and 690–880 nm for TPA). So our theoretical findings demonstrate that D-π-A-π-D type BTD derivatives are promising molecules that can be assembled to a series of materials with large TPA cross-section and emitting spectra in the red region.

Donor/Acceptor Effects on the Linear and Nonlinear Optical Properties of Geminal Diethynylethenes (g‐DEEs)

AbstractA series of geminal diethynylethenes (g‐DEEs) with electron‐donating and/or electron‐accepting (D/A) groups were synthesized via a Pd‐catalyzed cross‐coupling sequence. The UV/VIS spectra for donor–acceptor (D–A) functionalized g‐DEEs 5, 8, and 11 show distinctive absorption trends attributable to intramolecular charge‐transfer (ICT). The bond‐length‐alternation (BLA) index for the cross‐conjugated enediyne framework varies slightly with different terminal substituents as determined by density‐functional theory (DFT) calculations and single‐crystal X‐ray analysis. Ultrafast third‐order optical nonlinearities for the g‐DEEs were measured by the differential optical Kerr effect (DOKE) technique and show that terminal donor–acceptor substitution of g‐DEEs enhances molecular second hyperpolarizabilities (γ) in comparison to donor or acceptor g‐DEEs. A small increase in the two‐photon‐absorption cross‐section (σ(2)) is observed in the series 9–11 as a result of increased functionalization. The effects of donor/acceptor substitution on electron delocalization along the cross‐conjugated enediyne structure are evaluated on the basis of natural‐bond‐orbital (NBO) analysis. Solid‐state structures of the four derivatives 3b, 4b, 7 and 8 were characterized by single‐crystal X‐ray structural analysis and show an asymmetric unit cell for one derivative, D–A g‐DEE 8.

Synthesis, Characterisation and Crystal Structure of a Copper(II) Dichromate Complex with the N,N’-Bis(2-pyridylmethylene)butane- 1,4-diamine Schiff Base Ligand

The new complex Cu[L1]Cr2O7has been synthesised with the N,N′-bis(2-pyridylmethylene) butane-1,4-diamine Schiff base L1, [NC5H4CH=N(CH2)4N=CHC5H4N], and characterised with elemental analyses and different spectroscopic and electrochemical studies. The structure of the new complex has been established by single crystal X-ray diffraction. The complex crystallises in the monoclinic system with space group P21/c having cell parameters a = 14.7(5), b = 9.22(2), c = 16.2(5) Å , β = 116.9(1)°, and Z = 4. The Cr2O7 2− unit is bonded through one terminal oxygen donor end to the central Cu(II) chelated by the Schiff base ligand.

Synthesis, characterization and photolysis studies on liquid crystalline poly[4-(4′- x-biphenyl)yl-4″-( m-methacryloyloxyalkyloxy) cinnamate]’s

Three series of side chain liquid crystalline polymers containing terminally substituted biphenyl cinnamoyl esters were synthesized and characterized. The para position in the cinnamoyl group was connected with polymer backbone through various even numbers of methylene spacers. The terminal electron acceptor and donor substituted biphenyl groups were linked to cinnamoyl group through ester linkages. Polarizing microscopic and DSC studies confirm the formation of thermotropic mesophase up on heating. All the polymers exhibited nematic/grainy mesophases. The TGA and DSC studies showed that the nature of the terminal substituents have significant effect on mesophase temperatures as well as in thermal stability of these liquid crystalline polymers. UV light promoted photocrosslinking studies reveal that the clear involvement on photocrosslinking efficiency, although they are linked to the olefinic bond of cinnamoyl group through their ester linkage. It is observed that electron-donating group accelerate the photocrosslinking rate, while acceptor group retard the phase of the reaction on the other hand, the unsubstituted polymers show an intermediate rate.