Dual Emission and Multi-Stimuli-Response in Iridium ( III ) Complexes with Aggregation-Induced Enhanced Emission : Application to Quantitative CO 2 Detection

Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1-11, Barcelona 08028, Spain. Department of Chemistry, Birla Institute of Technology and Science, Pilani Campus, Pilani, Rajasthan, India. Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Sector 81, S. A. S. Nagar, Manauli PO, Mohali, Punjab, 140306, India. Kimika Facultatea, Euskal Herriko Unibertsitatea (UPV/EHU), Donostia International Physics Center, Paseo Manuel de Lardizabal, 4, Donostia 20018, Spain. IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain.


TABLE OF CONTENTS
• Tables S5-S7.Energy, wavelength, intensity (arbitrary units) and assignation of the most intense transitions of the calculated stick spectra of 1-3 respectively.
• Table S8.Normal modes of vibration that contribute to the simulated emission spectra together with their frequency and their nature.• Table S9.Relative energies (in kcal/mol) of different protonated forms of complexes 1 and 4.
• Scheme S1.Complexes 1 and 4 with labels of N atoms corresponding to Table S8 protonated sites.
• Table S10.Selected geometrical parameters of the optimized S 0 and T 1 state of the 2H.
• Figure S39.Representation of the molecular orbital diagram of complex 2 in its neutral and protonated forms.
• Table S11.Excitation energies (in eV) to the two lowest lying triplet states of complex 2 and its protonated form (2H).

Section 2. Absorption and Emission Spectroscopy Emission color calculation
From the experimental emission spectra, the perceived colors by the human eye may be estimated following a very simple procedure using the standard CIE (2º) 1931 color space, which allows calculating the xy chromaticity coordinates [1].The overlap between the emission spectra, ε(λ), and the color matching function, !(!) in the visible range yields the X tristimulus value (equation 1).For the numerical integration, a 1 nm increment is sufficient to attain accurate results.The Y and Z tristimulus values may be calculated analogously with the corresponding !(!) and !(!) color matching functions (CMFs).These CMFs describe the observer in a given color space, characterizing its chromatic response.Their values may be found tabulated in the literature [2].
(1) Finally, the x and y chromaticity coordinates are calculated as: (2)

Molecular geometries
In both structures, the crystal monomer and the optimized singlet ground state, the angles between trans ligands are very similar and in the range of 170-180º.The largest differences arise in the Ir-C, Ir-N and Ir-Cl bond lengths, which are overestimated by ~0.05-0.09Å in the optimized geometries.Intermolecular effects in the crystal could be responsible for the difference in the Ir-Cl bond length but donʼt seem to be responsible for the differences in the Ir-C and Ir-N bond lengths, thus, we attribute these to the inherent approximations of the computational methodology.Superposition of both structures reveals that the phosphine ligands are practically identical in both geometries.Comparison of the two phosphine ligands in the complex reveals that they are enantiomers, with the iridiumʼs equatorial plane acting as the mirror plane (Figure S20).

Molecular orbitals
From the HOMO to HOMO-7 (Figure S29), there are only two orbitals that do not have participation of the iridium atom.That is, HOMO-3 which is a combination of the nonbonding orbital of the nitrogen atom of the imine unit with the px orbital of the chloride ligand, and HOMO-5 which is a π-orbital of the phenyl ring of the Schiff base ligand.LUMO+1 is mainly a dz 2 type orbital with some participation of π-type orbitals of the phenyl rings of the phosphines and lies ~0.6 eV above the LUMO due to the anti-bonding interaction with the lone pair of the phosphorous.The dx 2 -y 2 type orbital on the other hand, appears rather high in energy due to strong anti-bonding interactions with orbitals of the hydride ligand, the phosphorus atoms and the nitrogen of the Schiff base.

Emission spectra of 1-3
Our calculations predict the 3 MLLCTz/LC state as the one responsible for the phosphorescence emission of complexes 1-3.For all three complexes there is a nice agreement between experimental emission spectra and the simulated vibrationally resolved phosphorescence profiles (Figures 6, S32 and S33).Each spectrum has clearly three peaks at the short wavelength region and several less intense shoulders at long wavelengths.The relative positions of the well-resolved peaks in the emission band are correctly reproduced by our calculations, but the relative intensities are, in some cases, not correctly estimated, especially for the peak just above 500 nm.Although the peak at ~550 nm is also the most intense in our calculations, the relative intensities with the two neighboring peaks are over and underestimated, respectively.The blue shift of the 0-0 transition with respect to the convoluted peak at ~500 nm is due to the presence of nearby transitions which contribute to the bandʼs intensity.
For complexes 1-3, the main vibrational mode responsible for the structured emission is related to the stretching of the C=N bond in the Schiff base, with a computed frequency of ~1470-1450 cm -1 (Figure S34).The distortion associated with this mode is in fact the main geometrical modification along the molecular relaxation on the T 1 state potential energy surface from the Franck-Condon region.Although this vibrational progression is the one that apparently causes the overall shape of the emission spectra, there are also other normal modes contributing to the emission profiles (Tables S5-S8).Apart from the C=N vibronic progression, there are combinations of modes of the iminie unit with modes involving the phenyl rings of the PPh 3 ligands.Since the modifications in the ancillary ligand of complexes 1-3 do not have a great impact on the C=N stretching mode, the peaks of the vibrational progressions in the emission spectra are similarly spaced out in the three complexes and the relative intensities are alike.The main effect of the substitution is therefore in tuning the energy of the electronic transition from the T 1 state back to the ground state, and not in the modification of the overall shape of the emission spectrum.

Figure S32
. Simulated (solid) and experimental (dashed) emission spectra of complex 1 together with the calculated stick spectrum obtained at the B3LYP/LANL2DZ,6-31G(d) computational level.Both spectra have been normalized and the calculated spectrum has been blue shifted by 0.09 eV to superimpose the most intense peaks.The 202 normal mode of vibration corresponds to the C=N stretching mode of the imine.

Figure S33
. Simulated (solid) and experimental (dashed) emission spectra of complex 3 together with the calculated stick spectrum obtained at the B3LYP/LANL2DZ,6-31G(d) computational level.Both spectra have been normalized and the calculated spectrum has been blue shifted by 0.12 eV to superimpose the most intense peaks.The 210 normal mode of vibration corresponds to the C=N stretching mode of the imine.

Figure S34
. Displacement vectors of the normal mode responsible for the vibronic progressions observed in the emission spectra of complex 2. The triphenylphosphine ligands have been omitted for greater clarity.

Torsion of the Schiff base ligand in complex 4
To further explore the nature of the lowest spin singlet electronic transition in complex 4, which corresponds to the intra-ligand charge transfer singlet state ( 1 ILCT) localized on the Schiff base ligand, we compute its energy profile in benzene and DMSO along the molecular torsion of the diphenylamine donor group in the Schiff base ligand (Figure S35).Our results (Figure S36) indicate that the potential energy minimum of 1 ILCT corresponds to the same dihedral angle between the phenyl rings of the donor group and the planar Schiff base ligand obtained for the optimized ground state.Moreover, this picture is virtually the same for the two explored solvents.These results force us to rule out the formation of a twisted intramolecular charge transfer (TICT) state.Table S11.Excitation energies (in eV) to the two lowest lying triplet states of complex 2 and its protonated form (2H).

•
Torsion of the Schiff base ligand in complex 4 • Figure S35.Molecular torsion in the Shiff base ligand of complex 4. • Figure S36.Energy profiles of S 0 and S 1 of complex 4 in benzene and DMSO.• Figure S37.Side view of the C-H•••Cl interactions of 2 shown in Figure 11 between a complex in the reference chain (red) and complexes of the blue chains.• Figure S38.Optimized S 0 geometry of 2H.

Figure
Figure S1.( 1 H, 31 P and 13 C) NMR spectra and HRMS (a, b, c and d), respectively for 1.

Figure
Figure S6.( 1 H and 13 C) NMR spectra (a and b), respectively for DEA+CIL.

Figure S11 .
Figure S11.Particle size distribution of nano-aggregates of complexes 1-4 (a-d) in a THF/water mixture with a 90% of water fraction.

Figure S15 .
Figure S15.Emission decay profiles of 4 in benzene at different emission maxima (a) at 450 nm and (b) at 535 nm.

Figure S16 .
Figure S16.Emission decay profiles of 4 in DCM at different emission maxima (a) at 450 nm and (b) at 535 nm.

Figure S17 .
Figure S17.Emission decay profiles of 4 in THF at different emission maxima (a) at 450 nm and (b) at 535 nm at fw=0% and (c) at 535 nm at fw=90%.

Figure S18 .
Figure S18.Emission decay profiles of 4 in DMSO at different emission maxima maxima (a) at 450 nm and (b) at 535 nm at fw=0% and (c) at 535 nm at fw=90%.

Figure S23 .
Figure S23.Absorption spectra of 4 in (a) ACN and (b) DMSO with different water fractions.

Figure S24 .
Figure S24.Thin film reversal of emission color upon TFA/Et 3 N exposure and emission spectra of complexes 2 (a and b) and 3 (c and d).The photographs were taken under a wavelength excitation of 365 nm .

Figure S25 .
Figure S25.Emission spectra of 1-4 in DCM in presence of TFA.

Figure S28 .
Figure S28.Different views of the superposition of the crystalʼs monomer (green) of complex 2 with the optimized ground state (blue) and lowest triplet state (red) at the B3LYP/LANL2DZ,6-31G(d) level.Hydrogen atoms have been omitted for the sake of clarity.

Figure S35 .
Figure S35.Molecular torsion in the Schiff base ligand of complex 4.

Figure S36 .
Figure S36.Energy profiles of the ground (S 0 ) and 1 ILCT (S 1 ) states of complex 4 along the molecular torsion in benzene (left) and DMSO (right) computed at the CAM-B3LYP level.

Figure S37 .
Figure S37.Side view of the C-H•••Cl interactions of 2 shown in Figure 11 between a complex in the reference chain (red) and complexes of the blue chains.

Figure S38 .Figure S39 .
Figure S38.Optimized S 0 geometry of 2H.Hydrogen atoms of the PPh 3 ligands are omitted for the sake of clarity.

Table S1 .
Lifetime measurement data in different solvents

Table S3 .
Data relative to the most intense electronic transitions of the simulated absorption spectra of 2 computed at the B3LYP/LANL2DZ,6-31G(d) level.

Table S5 .
Energy, wavelength, intensity (arbitrary units) and assignation of the most intense transitions of the calculated stick spectra of complex 1, blue-shifted by 0.09 eV.

Table S6 .
Energy, wavelength, intensity (arbitrary units) and assignation of the most intense transitions of the calculated stick spectra of complex 2, blue-shifted by 0.12 eV.

Table S7 .
Energy, wavelength, intensity (arbitrary units) and assignation of the most intense transitions of the calculated stick spectra of complex 3, blue-shifted by 0.12 eV.

Table S8 .
Vibration normal modes that contribute to the simulated emission spectra together with their frequency and nature.