inorganic chemistry

and exhibit high-emission quantum yields, their use in electrically
driven devices has been exploited. The researchers demonstrated
that crystalline, waveguiding, semiconducting, and electrolumines-
centnanowires can be self-assembled through extended intermolec-
ular interactions, and ambipolar organic, light-emitting field effect
transistor devices emitting in the red or NIR region have been
fabricated by solution processing (Fig. 12).
Che et al. ( 215 ) extended the assembly into aqueous
environments, describing the preparation of supramolecular
polyelectrolytes by self-organization of cationic organoplatinum
(II) complexes in water through extended PtPt and hydropho-
bic interactions (Fig. 13). Aligned films and discrete uniaxial
microfibers with cofacial molecular orientations were readily pro-
duced with these phosphorescent viscoelastic mesophases.
Even more interesting are the crystalline, wheel-shaped super-
structures described by Cheet al.( 216 ), which grow through a
wire-to-wheel metamorphism process involving a ligand-substi-
tution reaction (Fig. 14). Organometallic molecules and non-
covalent intermolecular metal–metal and ligand–ligand
interactions were employed to construct submicrometer-sized
nonlinear superstructures. Due to the optoelectronic properties
of organoplatinum(II) complexes, novel mesoscopic applications
based on the superstructures could be envisaged. The interplay
between closed-shell PtPt interactions and electrostatic/Cou-
lombic interactions leads to the formation of organoplatinum(II)
superstructures with diverse morphologies. The preliminary
studies carried out have shown that the reported metamorphism

R^1 C

N

Ar

N

N

N

C

Pt

R^3 R^3

R^3 = Me, R^4 = H

R^3 = Me, R^4 = NMe 2

R^4 R^3 = H, R^4 = OMe

OTf–

+

X–

Pt

N

N

R^2 + R (^1) = R (^2) = H
R^1 = R^2 = H
R^1 = F, R^2 = H
R^1 = H, R^2 = COOEt
R^1 = R^2 = H Ar = N
X = PF 5
X = OTfX = ClO
4
X = PF 6
X = PF 6
400 500 600
l(nm)
700 800
Ar =
N
N
Pt N
PF 6 –

• /cm
  Ar =
  FIG. 12. Molecular structure of Pt(II) complexes and their emission
  in organic light-emitting field effect transistors. Reproduced with the
  permission of Wiley-VCH, Ref. ( 214 ).
  PHOTOPHYSICS OF MOLECULAR ASSEMBLIES 75