**6.1. The complexing of the metal chelate compound with PU matrix according to the electron spectroscopy**

The electron spectroscopy allows analyse both character of complexing of metal chelate compound with the polymer matrix and state of metal chelate compound in PU. The electron spectra of transition and rare-earth metal chelate compound in PU indicate presence of the band of *d-d*-transitions for the transition metal chelate compound introduced into PU (fig.14) and band of π-π-transitions for the rare-earth metal chelate compounds introduced into PU. That points on saving of chelate structure of the complexes in polymer matrix. While the change the band intensity, its broadening and shift to a long-wave region testifies their participation in complexing with PU.

Bottom-Up Nanostructured Segmented Polyurethanes with Immobilized in situ Transition and Rare-Earth Metal Chelate Compounds – Polymer Topology – Structure and Properties Relationship 71

**Figure 15.** The adsorption band of LPU+1%Cu(tfacac)2 with Gaussian components allocation.

compound" complexes.

donor groups.

EPR signal intensity.

of the copper nearest environment.

The maxima of *xz d* and *yz d* transitions of Cu(2+) ion in copper chelate compounds, immobilized in PU matrix are shifted to the long-wave region, as compared to corresponding transitions of copper chelate compounds in solution (table 6). Visible broadening of the <sup>2</sup> *<sup>z</sup> d* component of absorption band of Cu (2+) chelate compounds in PU indicates the prevalence of axial coordination of macro ligand in "PU-metal chelate

**6.2. Complex formation in the "polymer-modifier" system according to EPR data** 

The EPR data confirm the complexing between the metal chelate compound and PU functional groups. The state of paramagnetic Cu(2+) containing chelate compounds in PU can be directly analyzed using EPR due to sensitivity of spin-electron parameters АII and gII (see table 7) of the tetragonal copper chelate compounds to symmetry and chemical nature

Decreasing of АII and increasing gII of Cu(acac)2, Cu(tfacac)2, Cu(eacac)2 and (Cu2Zn2(NH3)2Br2(HDea)4)Br2 immobilized in PU as compared with undisturbed compounds indicate the participation of the modifiers in the complexing with PU electron

Figure 16 illustrates the representative EPR spectra of some copper containing modifiers both isolated and immobilized in PU with different topology (linear and cross-linked). The EPR spectra of polyheteronuclear powdered crystalline samples have anisotropic shape with weakly resolved HFS due to broadening of the spectrum components and possible tetrahedral distortion of the copper ion surrounding in the polyatomic complex. Immobilization of such chelate compounds in a PU network resulted in decreasing of the

**Figure 14.** The electron spectra of transition metal chelate compounds in dichloromethane (a) and LPU (b): Cu(tfacac)2 (1), 1%Cr(acac)3 (2), Cu(eacac)2 (3); Co(acac)3 (4); LPU Cu(tfacac)2 (ε = 28 l/molsm) (1); LPU-1%Cr(acac)3 (ε = 33 l/molsm) (2); LPU-1%Cu(eacac)2 (ε = 40 л/ l/molsm) (3); LPU-1%Co(acac)3(ε = 117 l/molsm) (4)

Figure 14 represents comparison of electron spectra in the visible region of the LPU films with 1%wt. of transition metal (copper, chrome, cobalt) chelate compounds (fig. 14, a) and the spectra of this metal chelate compounds dissolved (c= 10-2 M) in dichloromethane (CH2Cl2) (fig. 14, b).

In addition to described above changes in electron spectra the influence of fluorine on complex ability of metal chelate compound in PU is evident due to, the rise of absorption level (ε = 40 l/molcm) and hypsohromic shift of maxima of band of d-d-transitions for LPU - 1% Cu(eacac)2 as compared with LPU-1% Cu(tfacac)2 that have fluorine in ligand (ε = 28 l/molcm). Fig. 15 illustrates the detailed analysis of electron transitions of copper ion in β-diketonates (4 transitions for D2h symmetry). Calculated maxima positions of Gaussian components of adsorption band corresponding to electron d-d-transitions of copper ion for Cu(tfacac)2 and Cu(eacac)2 in solution and in PU are listed in the table 6.


**Table 7.** The allocation of Gaussian components of copper chelate compounds adsorption band.

117 l/molsm) (4)

(CH2Cl2) (fig. 14, b).

System

introduced into PU. That points on saving of chelate structure of the complexes in polymer matrix. While the change the band intensity, its broadening and shift to a long-wave region

**Figure 14.** The electron spectra of transition metal chelate compounds in dichloromethane (a) and LPU (b): Cu(tfacac)2 (1), 1%Cr(acac)3 (2), Cu(eacac)2 (3); Co(acac)3 (4); LPU Cu(tfacac)2 (ε = 28 l/molsm) (1); LPU-1%Cr(acac)3 (ε = 33 l/molsm) (2); LPU-1%Cu(eacac)2 (ε = 40 л/ l/molsm) (3); LPU-1%Co(acac)3(ε =

Figure 14 represents comparison of electron spectra in the visible region of the LPU films with 1%wt. of transition metal (copper, chrome, cobalt) chelate compounds (fig. 14, a) and the spectra of this metal chelate compounds dissolved (c= 10-2 M) in dichloromethane

In addition to described above changes in electron spectra the influence of fluorine on complex ability of metal chelate compound in PU is evident due to, the rise of absorption level (ε = 40 l/molcm) and hypsohromic shift of maxima of band of d-d-transitions for LPU - 1% Cu(eacac)2 as compared with LPU-1% Cu(tfacac)2 that have fluorine in ligand (ε = 28 l/molcm). Fig. 15 illustrates the detailed analysis of electron transitions of copper ion in β-diketonates (4 transitions for D2h symmetry). Calculated maxima positions of Gaussian components of adsorption band corresponding to electron d-d-transitions of copper ion for

<sup>2</sup> *чн <sup>z</sup> d d* 2 2 *чн x y*

**Table 7.** The allocation of Gaussian components of copper chelate compounds adsorption band.

Cu(tfacac)2 in CH2Cl2 13658 15386 17930 19579 LPU -1% Cu(tfacac)2 13435 15179 16322 17628 Cu(eacac)2 in CH2Cl2 13715 15376 16686 18261 LPU-1% Cu(eacac)2 12771 14497 16059 17738

υ, cm-1

*d d чн xz d d чн yz d d*

Cu(tfacac)2 and Cu(eacac)2 in solution and in PU are listed in the table 6.

testifies their participation in complexing with PU.

**Figure 15.** The adsorption band of LPU+1%Cu(tfacac)2 with Gaussian components allocation.

The maxima of *xz d* and *yz d* transitions of Cu(2+) ion in copper chelate compounds, immobilized in PU matrix are shifted to the long-wave region, as compared to corresponding transitions of copper chelate compounds in solution (table 6). Visible broadening of the <sup>2</sup> *<sup>z</sup> d* component of absorption band of Cu (2+) chelate compounds in PU indicates the prevalence of axial coordination of macro ligand in "PU-metal chelate compound" complexes.

#### **6.2. Complex formation in the "polymer-modifier" system according to EPR data**

The EPR data confirm the complexing between the metal chelate compound and PU functional groups. The state of paramagnetic Cu(2+) containing chelate compounds in PU can be directly analyzed using EPR due to sensitivity of spin-electron parameters АII and gII (see table 7) of the tetragonal copper chelate compounds to symmetry and chemical nature of the copper nearest environment.

Decreasing of АII and increasing gII of Cu(acac)2, Cu(tfacac)2, Cu(eacac)2 and (Cu2Zn2(NH3)2Br2(HDea)4)Br2 immobilized in PU as compared with undisturbed compounds indicate the participation of the modifiers in the complexing with PU electron donor groups.

Figure 16 illustrates the representative EPR spectra of some copper containing modifiers both isolated and immobilized in PU with different topology (linear and cross-linked). The EPR spectra of polyheteronuclear powdered crystalline samples have anisotropic shape with weakly resolved HFS due to broadening of the spectrum components and possible tetrahedral distortion of the copper ion surrounding in the polyatomic complex. Immobilization of such chelate compounds in a PU network resulted in decreasing of the EPR signal intensity.


Bottom-Up Nanostructured Segmented Polyurethanes with Immobilized in situ Transition and Rare-Earth Metal Chelate Compounds – Polymer Topology – Structure and Properties Relationship 73

(g)

(h)

(i)

**Figure 16.** EPR – spectra of matrix isolated Cu(eacac)2 (a), Cu(acac)2 (b), (Cu2Zn2(NH3)2Br2(HDea)4)Br2

(f)

(d)

(e)

According to EPR data obtained using complex spin probe (Kozak et al., 2006) it was demonstrated that in cobalt containing CPU the complexes "polymer-metal chelate compound" of two types are formed. The analysis of rotational diffusion of nitroxyl spin probe TEMPO (see table 2) reveals the decreasing of PU segmental mobility due metal chelate compound introduction and/or it content increasing. The dynamic of solvent molecules diffusion in swelled CPU-0, CPU-5%Co films and in probe liquid was analysed to compare the ratio of one-particle and collective modes of the solvent

(c) in chloroform-toluene at -196oC; LPU with 1%wt. of Cu(eacac)2 (d), Cu(acac)2 (e), (Cu2Zn2(NH3)2Br2(HDea)4)Br2 (f) and CPU with 1%wt. of Cu(eacac)2 (g), Cu(acac)2 (h),

(Cu2Zn2(NH3)2Br2(HDea)4)Br2 (i).

(c)

(a)

(b)

molecules motion.

1)undisturbed Cu(2+) complex in glassy matrix chloroform/toluene (40/60) (at -196oC)

2) powder of polycrystalline sample

\* (Lipatova & Nizelskii, 1972)

**Table 8.** Electron-spin parameters of isolated and polymer immobilized copper complexes.

The most reasonable explanation for this effect is distortion of the modifier's symmetry or geometry in PU-CuZn. The shape of EPR signal in PU network modified with (Cu2Zn2(NH3)2Br2(HDe)4)Br2 indicates formation of complexes of various content and structure.

## **6.3. Low molecular probes dynamic and formation of additional network of the coordination bonds in metal containing polyurethanes**

Using QENS and EPR with paramagnetic probes of various natures it was shown that complex formation of metal containing modifier with macro chains results in appearance of additional spatial obstacles for probe diffusion as compared with metal free network. The dynamic of low molecular probes and complex formation in the nanostructured polyurethane network containing Co (3+) chelate compounds immobilized *in situ* were analyzed.

Bottom-Up Nanostructured Segmented Polyurethanes with Immobilized in situ Transition and Rare-Earth Metal Chelate Compounds – Polymer Topology – Structure and Properties Relationship 73

72 Polyurethane

CPU-1% Сu(tfacac)2

LPU-1% Сu(tfacac)2

System **gII**

CPU-1% CuZn 2,370

2) powder of polycrystalline sample \* (Lipatova & Nizelskii, 1972)

structure.

analyzed.

**AII 10-4**

172

162

132

LPU-1%CuZn - - - - - -

The most reasonable explanation for this effect is distortion of the modifier's symmetry or geometry in PU-CuZn. The shape of EPR signal in PU network modified with (Cu2Zn2(NH3)2Br2(HDe)4)Br2 indicates formation of complexes of various content and

**6.3. Low molecular probes dynamic and formation of additional network of the** 

Using QENS and EPR with paramagnetic probes of various natures it was shown that complex formation of metal containing modifier with macro chains results in appearance of additional spatial obstacles for probe diffusion as compared with metal free network. The dynamic of low molecular probes and complex formation in the nanostructured polyurethane network containing Co (3+) chelate compounds immobilized *in situ* were

**Table 8.** Electron-spin parameters of isolated and polymer immobilized copper complexes.

1Cu(eacac)2 \* 2,276 187 2,055 22 2,128 68 CPU-1% Cu(eacac)2 2,249 150 - - - - LPU-1% Cu(eacac)2 2,298 173 - - - - 1Cu(acac)2 \* 2,250 189 2,052 24 2,118 75 CPU-1% Cu(acac)2 2,269 182 - - - - LPU-1% Cu(acac)2 2,254 188 2,052 29 2,119 82 2(Cu2Zn2(NH3)2Br2(HDea)4)Br2 2,370 122 - - - -

1Cu(tfасас)2 \* 2,271 187 2,052 23 - -

2,275 2,290

2,283 2,302

2,300

1)undisturbed Cu(2+) complex in glassy matrix chloroform/toluene (40/60) (at -196oC)

**coordination bonds in metal containing polyurethanes** 

**<sup>с</sup>m-1 <sup>g</sup>**┴

**A**┴**10-4**

151 2,059 21 2,131

141 2,049 19 2,127

<sup>142</sup>- - - -

**cm-1 g0**

2,136

2,133

**a0\*10-4 cm-1**

> 71 64

> 67 60

**Figure 16.** EPR – spectra of matrix isolated Cu(eacac)2 (a), Cu(acac)2 (b), (Cu2Zn2(NH3)2Br2(HDea)4)Br2 (c) in chloroform-toluene at -196oC; LPU with 1%wt. of Cu(eacac)2 (d), Cu(acac)2 (e), (Cu2Zn2(NH3)2Br2(HDea)4)Br2 (f) and CPU with 1%wt. of Cu(eacac)2 (g), Cu(acac)2 (h), (Cu2Zn2(NH3)2Br2(HDea)4)Br2 (i).

According to EPR data obtained using complex spin probe (Kozak et al., 2006) it was demonstrated that in cobalt containing CPU the complexes "polymer-metal chelate compound" of two types are formed. The analysis of rotational diffusion of nitroxyl spin probe TEMPO (see table 2) reveals the decreasing of PU segmental mobility due metal chelate compound introduction and/or it content increasing. The dynamic of solvent molecules diffusion in swelled CPU-0, CPU-5%Co films and in probe liquid was analysed to compare the ratio of one-particle and collective modes of the solvent molecules motion.


Bottom-Up Nanostructured Segmented Polyurethanes with Immobilized in situ Transition and Rare-Earth Metal Chelate Compounds – Polymer Topology – Structure and Properties Relationship 75

The essential increasing of luminescence intensity of the rare-earth metal in the polyurethane environmental is a way for creation of new optically active materials. The intensity of PU-Eu luminescence depends both on the europium chelate compound content and polymer topology. Contrary to LPU the relationship of luminescence intensity *vs.*

Increasing of the polyurethane conductivity to semi-conducting level is caused by the drastic increasing of macro chain mobility in the presence of polyheteronuclear modifiers.

The results obtained indicate significant influence of structural organization of the modified polyurethane on its properties. The effect is caused by complex formation between metal chelate compound and functional groups of the forming polymer. The analysis of dynamic of low molecular probes and complex formation in the nanostructured polyurethane gives experimental evidence of existence of additional coordination bond network in metal-

Conductivity level of LPU is at least one order lower then conductivity of CPU.

*Institute of Macromolecular Chemistry National Academy of Sciences of Ukraine, Ukraine* 

We would like to express our sincere gratitude to Professor Svetlana B. Meshkova (A. V. Bogatsky Physic-Chemical Institute of National Academy of Sciences of Ukraine, Odessa) and Professor Vladimir N. Kokozay (Taras Shevchenko Kyiv University) for synthesized heteroligand rare-earth metal's and polyheteronuclear chelate compounds,

Bershein, V.A. & Yegorov, V.M. (1990). *Differential Scanning Calorimetry in Polymer Physic*. (in

Buchachenko, A. L., Wasserman, A.M., Alexandrova, T.A. et al. (1980). Spin Probe Studies in Polymer Solids, In: *Molecular Motions in Polymers by ESR*, R.F. Boyer & S.E. Keinath, (Eds.), 33-42, ISBN 3718600129, Harwood Academic Publisher, Chur,

Bulavin, L.A.; Karmazina, Т.V.; Klepko, V.V.; Slisenko, V.I. (2005). Neutron spectroscopy of condensed medium . (in Russ.). Akademperiodica, ISBN 966-360-009-8,

Russ.). Chemistry, ISBN 5-7245-0555-X, St. Petersburg

modifier percentage in CPUs is linear.

contained polyurethanes.

**Acknowledgement** 

respectively.

**8. References** 

Switzerland

Kyiv

Nataly Kozak and Eugenia Lobko

**Author details** 

where DF – one-particle ("Frenkel ") diffusion coefficient ;

DL – collective ("Lagrangian") diffusion coefficient.

**Table 9.** The diffusion parameters of the probe molecules in the swelled PU films

The sharp decreasing of both the general and one-particle component of diffusion coefficient for the metal containing PU as compared with the metal-free PU indicates the appearance of the spatial hindrances for the liquid molecule dynamics.
