forms, the complex possesses a distorted square-planar geome-
try. Investigation of the orange form's crystal packing revealed
the presence of solvent molecules in lattice voids, with PtPt
distances averaging 3.75 Å and a zigzag arrangement between
nearest neighbor metal centers. However, the red form is devoid
of solvent within the crystal lattice and contains complexes
stacked with an almost linear arrangement of Pt(II) ions having
an average distance of 3.33 Å. These results evidently demon-
strate that sorption of methanol vapor induces a change in inter-
molecular contacts and PtPt interactions in going from red to
orange. Disruption of the d^8 – d^8 interactions shifts the emitting
state from a triplet MMLCT state in the red form to one in which
the HOMO corresponds to a more localized metal orbital in the
00+–Light20 μm48100 200
Time(s)300 4000Current (mA)
3(^6) Dip-pull approach
Slow volatilization
12
Voltage (V)
345
Current (nA)
FIG. 27. Top left: image of the device. Inset: luminescence image of
microwires. Top right: I–V curves of microwires produced by slow evap-
oration (red line) and dip-and-pull approach (black line). Bottom left:
schematic diagram of the device used for the detection of light. Bottom
right: photocurrent of the device (excitation wavelength: 450 nm),
which can be switched on/off rapidly by illumination under voltage bias
of 0.5 V. Reproduced with the permission of the Royal Society of Chem-
istry ( 244 ).
PHOTOPHYSICS OF MOLECULAR ASSEMBLIES 91