POP-Type MMX-Chain Compounds with Binary Countercations and Vapochromism - Material Designs and New Physical Properties in MX-and MMX-Chain Compounds - page 214

Fig. 10.10 'Polarized Raman
spectra of
(NC 4 N) 2 [Pt 2 (pop) 4 I]·4H 2 O
(296 K, green ) and
(NC 4 N) 2 [Pt 2 (pop) 4 I] (340 K,
red ) with polarization of light
parallel to the chain axis

Fig. 10.11 Optical
conductivity spectra of
(NC 4 N) 2 [Pt 2 (pop) 4 I] 4H 2 O
(296 K, green ) and
(NC 4 N) 2 [Pt 2 (pop) 4 I] (340 K,
red ) with polarization of light
parallel to the chain axis. The
insets show the corresponding
microscope images for the
single crystal taken in
reflection mode

and structural analysis of (NC 4 N) 2 [Pt 2 (pop) 4 I] were achieved by the slow diffusion
of starting materials in methanol solution [ 66 ]. d (Pt-I-Pt) of (NC 4 N) 2 [Pt 2 (pop) 4 I] is
5.859 ˚ , which is in the region of CDW state in the phase diagram (Fig. 10.6 )[ 51 ].
This structure is consistent with the double peaks attributed to CDW state observed
in polarized Raman spectra shown above. In (NC 4 N) 2 [Pt 2 (pop) 4 I], the pop ligands
and NC 4 N 2+ ions arrange so as to fill in the vacancy of water molecules. Since the
general volume of water molecule is approximately 30 ˚ 3 , the total volume of eight
water molecules in unit cell of compound (NC 4 N) 2 [Pt 2 (pop) 4 I]

4H 2 O is approxi-

mately 240 ˚ 3 . However,

the difference between the lattice volume of