Luminescent Pyrene-decorated Organotin Compounds:Observation of

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Luminescent Pyrene-decorated Organotin Compounds:Observation of Monomer-and Excimer Emission Mrituanjay D Pandey, Ramesh K Metre, Subrata Kundu, Bani Mahanti, Arun Kumar, Kandasamy Gopal, and Vadapalli Chandrasekhar Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.8b01856 • Publication Date (Web): 08 Feb 2019 Downloaded from http://pubs.acs.org on February 11, 2019

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Crystal Growth & Design

Luminescent Pyrene-decorated Organotin Compounds:Observation of Monomer-and Excimer Emission Mrituanjay D. Pandey*#,Ramesh K. Metre$, Subrata Kundu†, Bani Mahanti€, Arun Kumar†, Kandasamy Gopal*£and Vadapalli Chandrasekhar*†‡

†Department

of Chemistry, Indian Institute of Technology –Kanpur, Kanpur – 208016,

India; ‡Tata Institute of Fundamental Research, Hyderabad – 500107, India

#Department

of Chemistry, Institute of Science, Banaras Hindu University, Varanasi,

UP-221 005, India $Department

of Chemistry, Indian Institute of Technology – Jodhpur, Jodhpur – 342011, India

€Department

of Chemistry-Ångstrom Laboratory, Uppsala University, Sweden;

ACS Paragon Plus Environment

1

Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

£Department

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of Chemistry, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam,

Kerala – 690525, India.

ABSTRACT: Pyrene-decorated luminescent organotin compounds, Ph3SnO2CPyr (1), [(Bz2Sn)2(µ3-O)(µ-OH)(O2CPyr)]2∙2EtOH (2) and t-Bu2Sn[O2CPyr]2 (3) were synthesized from a one-pot reaction between pyrene-1-carboxylic acid (PyrCO2H) and appropriate organotin precursors. The molecular and crystal structures of 1-3 were determined by single-crystal X-ray diffraction analysis which reveal rich supramolecular architectures in their crystal structures. The luminescence properties of these compounds were studied in solution as well as in the solid state. While in the solid-state all the compounds reveal excimer bands, in solution, strong monomer emission is seen. Fluorescence life-time measurements revealed (365 nm) that the average life-times of 1-3 in solution could be estimated as 4.97 ns (1), 4.69 ns (2) and 6.93 ns (3).


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KEYWORDS: organotin compounds, pyrene, excimer, luminescence, supramolecular interactions.

Introduction In recent years, there is an increasing interest in organooxotin compounds because of their applications in various fields including catalysis and biological activity.1-5Another important reason for this interest is the presence of a large structural diversity among such compounds.6-11In the last few decades a wide variety of structurally diverse organooxotin assemblies (drums, O-capped clusters, cubes, double-O-capped cluster, tetranuclear cages, foot-ball cages, hydroxyl-bridged dimers, and butterfly clusters) have been prepared and structurally characterized by using relatively simple synthetic methodologies that involve a variation in the nature of the protic acid/organotin precursor or their stoichiometric ratio.6-11 Also, at the same time new applications of such compounds are being continuously discovered12-18and recently, much attention has also been focused on their luminescent


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properties. Accordingly, pyrene-appended fluorescent chromophores are of considerable interest19-24because of the fact that pyrene group possesses a high quantum yield and can form excimers even at relatively low concentrations.25-27Unlike other excimer-forming fluorophores such as naphthalene,28-29absorption and fluorescence spectra of pyrene do not overlap and reduces the FRET formation or energy migration. In addition, the applications of the excimeric species have strong correlation with physical state and environment.30-31Therefore, triggering new molecules with different chromophoric environment are important.21,32-33Several examples of pyrene-containing organic dendrimers are reported in the literature but pyrene units decorated on inorganic platforms are less explored.21,32-33 Recently, we have reported some pyrene-decorated organostannoxanes ranging from macrocycles to cages by the reactions of pyrene-1-sulfonic acid (PyrSO3H) and various organotin substrates.39In continuation of this interest, we have now investigated the corresponding reactions involving the strongly coordinating pyrene-1-carboxylic acid (PyrCO2H) for the study of divergent structural types of organostannoxanes as well as their

interesting

photophysical

properties.

The

main

advantages

of

using


4

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organostannoxanes as supports for the pyrene carboxylate periphery are: (i) single-step, high-yield synthesis, (ii) the number of pyrene carboxylate ligands per molecule can be tuned by the choice of organotin precursor along with a variation of the stoichiometry of the reaction involving PyrCO2H and (iii) the organostannoxane core is inert and does not influence the electronic and photophysical properties of the pyrene-appended compounds.34-39 Accordingly, herein, we report the synthesis, structure and photophysical properties of three luminescent organotin-supported pyrene-1-carboxylates, Ph3SnO2CPyr (1), [(Bz2Sn)2(µ3-O)(µ-OH)(O2CPyr)]2∙2EtOH (2) and t-Bu2Sn[O2CPyr]2 (3). All the three complexes 1-3were characterized by various spectroscopic techniques (IR, multinuclear NMR and ESI-HRMS) and single-crystal X-ray diffraction techniques.

Results and Discussion Synthetic aspects The pyrene-decorated organotin compounds 1-3 were synthesized from a one-pot reaction between PyrCO2H and appropriate organotin precursors (Scheme 1). Compound


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1 was synthesized by a stoichiometric reaction between Ph3SnCl with PyrCO2H in ethanol at room temperature in good yield. In this reaction potassium hydroxide was used as the hydrochloride (HCl) scavenger. Compound 1 is a discrete mononuclear derivative having one pyrene-1-carboxylate unit which was confirmed by the

119Sn

NMR study that shows

a single resonance at –114 ppm.1-11,34-39In the ESI-MS, 1 showed peaks for [(Ph)3Sn]+ (m/z 351.0166) and [(Ph3Sn)2(O2CH)]+ (m/z 745.0294). Similarly, the corresponding reaction involving Bz3SnCl in place of Ph3SnCl afforded a tetranuclear derivative 2 where one of the benzyl groups on tin is cleaved34-39and has a ladder arrangement involving the (Sn-O)4 motif with only two pyrene carboxylates. Due to its poor solubility, the 1H and 119Sn

NMR studies of 2 could not be carried out. However, ESI-MS of 2 reveal the

presence of fragments of the molecule [(Bz2Sn)2(O)(O2CPyr)(H2O)2(MeOH)2]+ (m/z 964.9660) and [BzSn(O2CPyr)(OH)H2O]+ (m/z 490.9139). The reaction between [t-Bu2SnO]3 and PyrCO2H in a 1:6 molar ratio in refluxing toluene with a continuous removal of water by Dean-Stark apparatus afforded a mononuclear tin derivative 3 having two pyrene carboxylate moieties. The formation of compound 3 was confirmed by a 119Sn NMR study that shows a single resonance at –218 ppm.34-40The ESI-MS of 3 reveals relevant ion


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peaks

for

[(t-Bu)2Sn(O2CPyr)2.2H2O]+(m/z

760.3839),

[(t-Bu)2Sn(O2CPyr)]+

(m/z

479.1065) and [(t-Bu)2Sn(O2CPyr)(O2CH).2H2O.Na]+ (m/z 565.5698).

Ph3SnCl KOH EtOH

Sn 1

O

O

CO2H

[t-Bu2SnO]3 Toluene - H2O

- KCl - H2O

Bz3SnCl KOH EtOH

O

Sn

O

O O

3 - KCl - H2O

H O

O Sn O O

O Sn

Sn O

O

Sn

O H

2

Scheme 1. Synthesis of organotin pyrene-carboxylates 1-3.

Table 1. Selected bond lengths and bond angles for 1-3.

Compound

Bond lengths (Å)

Bond angles (º)


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O1-Sn1-C30 93.8(3) Sn1-O1 2.083(5)

O1-Sn1-C24 115.0(3)

Sn1-C30 2.107(7)

C30-Sn1-C24 110.0(3)

Sn1-C24 2.109(6)

O1-Sn1-C18 110.3(3)

Sn1-C18 2.119(8)

C30-Sn1-C18 111.2(3)

O1-C17 1.323(1)

C24-Sn1-C18 114.7(3)

O2-C17 1.238(1)

C17-O1-Sn1 107.8(5) O1-Sn1-C30 93.8(3)

2

Sn1-O3 2.054(3)

O3-Sn1-O4 73.23(10)

Sn1-O4 2.127(3)

O3-Sn1-O3* 72.64(11)

Sn1-O3* 2.128(2)

O4-Sn1-O3* 145.70(10)

Sn2-O3 2.014(3)

Sn2-O3-Sn1 110.95(11)

Sn2-C25 2.136(4)

Sn2-O3-Sn1*

Sn2-O2 2.168(3) Sn2-O4 2.169(3) O2-C17 1.292(5)

141.69(13) Sn1-O3-Sn1* 107.36(11) Sn1-O4-Sn2 102.54(11)

O3-Sn1* 2.128(2) 3

Sn1-O1* 2.099(2)

O1*-Sn1-O1 81.43(12)

Sn1-O1 2.099(2)

O1*-Sn1-C21

Sn1-C21 2.181(5)

106.61(12) O1-Sn1-C21 106.61(12)


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Sn1-C18 2.193(5)

O1*-Sn1-18 106.78(12)

Sn1-O2* 2.549(2)

O1-Sn1-C18 106.78(12)

Sn1-O2 2.549(2)

C21-Sn1-C18 135.46(19) O1*-Sn1-O2* 55.07(8)

Symmetry for compound 2: * = -x+1, -y+1, -z+2; symmetry for compound 3: * = -x+2, y, z

Molecular and Crystal Structures of 1-3 The molecular structures of 1-3were determined by their single crystal X-ray diffraction analysis. Selected bond parameters of 1-3are listed in Table 1. The molecular structure of 1 reveals that it is a mononuclear discrete molecule (Figure 1a) having a pentacoordinate tin at the center (Sn1) with distorted trigonal bipyramidal geometry (O1, C18 and C24: equatorial positions; O2 and C30: axial position). Pyrene carboxylate unit is coordinated to Sn1 in an anisobidentate chelating coordination mode (Sn1-O1 2.083(5) and Sn1-O2 2.706(6) Å). Interestingly, two of the hydrogens (H2 and H10) of the pyrene unit are intra-molecularly hydrogen-bonded with its own carboxylate oxygens (C2-H2--O1: 2.356(6) Å and 101.5(6)º; C10-H10---O2: 2.211(6) Å and 126.2(6)º), a feature that


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seems to be responsible for the near planar arrangement of the pyrene and carboxylate units (dihedral angle between the carboxylate plane (O1, C17 and O2) and pyrene plane (C1-C14) is 10.6(4)º; Figure 1a). Similarly, one of the hydrogen atoms of the phenyl unit (H19) is also intra-molecularly hydrogen-bonded with the carboxylate oxygens (C19-H19--O2: 2.433(6) Å and 129.0(6)º). The crystal structure of 1 reveals that it forms a dimeric structure as a result of intermolecular interactions viz. two C-H---O (C26-H26---O2: 2.801(6) Å and 139.3(6)º), and one edge-to-edge π-stacking interaction (C25---C26 3.502(6) Å) (Figure 1b). These dimeric structures are interconnected by a C-H---O interaction (C21-H21---O1: 2.806(6) Å and 138.4(6)º) to form the one-dimensional tapelike structure. Such one-dimensional tapes are interconnected through pyrene-stacking interactions (two different types of π-stacking interactions) to form a three-dimensional structure (Figure 1b). A closer view of these pyrene-stacking interactions is shown in Figure 1c (parallel displaced stacking: C13---π 3.356(8) Å and edge-to-edge stacking: C8---C10 3.571(2); C9---C14 3.508(2) Å).


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Figure 1. (a) Molecular structure of 1 with 50% of ellipsoidal probability. (b) View of the three-dimensional supramolecular network. (c) Closer view of pyrene-stacking interactions.

Compound 2 crystalized in the triclinic crystal system in the P-1 space group and contains two independent Sn centers (Sn1 and Sn2; Figure 2a). Both the tin centers are pentacoordinate in a distorted trigonal bipyramidal geometry. The carbon atoms on each tin occupy the equatorial positions. The structure of 2 has two μ3-oxo bridges (O3 and O3*) that centrally bridge the four tin atoms along with two other μ-hydroxo bridges (O4 and O4*) which are present on either end. Over all, the structure contains a dimeric tetraorganodistannoxane unit, {(R2Sn)2(μ3-O)(μ-OH)}2 that possesses a ladder-type architecture which is well documented in the literature1-11,34-37and also reported when PyrSO3– was used as the ligand.39The structure of 2 contains two pyrene carboxylate units that coordinate to exocyclic tin centers in a monodentate fashion. On each side of the ladder structure, one of the two benzyl units was found to have an intra-molecular


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edge-to-edge π-stacking interaction with the pyrene unit (C2---C40* 3.557(7); C3---C41* 3.635(7) Å; Figure 2a). However, no intra-molecular C-H---O interactions could be detected such as what are present in 1 (vide supra) and 3 (vide infra). This intra-molecular π-stacking interaction may be responsible for the out-of-plane arrangement of the carboxylate ligands with respect to the pyrene plane (dihedral angle between the carboxylate plane (O1, C17 and O2) and pyrene plane (C1-C14) is 45.5(2)º). The crystal structure of 2 reveals a two-dimensional supramolecular network through C-H---O (C25H25B---O1: 2.651(4) Å and 123.0(4)º) and C-H---π (C9-H9---π: 2.840(4) Å and 172.5(4)º) interactions (Figure 2b).


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Figure 2. (a) Molecular structure of 2 with 50% of ellipsoidal probability, unlabeled atoms are symmetry related with respect to labeled atoms. Six of the eight phenyl of benzyl units were removed for clarity. (b) Two-dimensional supramolecular network formed by C-H--O and C-H---π interactions.

Compound 3 crystallized in the orthorhombic crystal system (Cmc21 space group). The molecular structure contains one tin center (Sn1) which is bonded with two tert-butyl and two pyrene carboxylate units where both the carboxylate groups binds to the tin center through an anisobidentate chelating mode (Sn1-O1 2.099(2) and Sn1-O2 2.549(2) Å; Figure 3a). Unlike

the structures of 1 and 2, the structure of 3 contains a hexa-

coordinated tin center (Sn1) in a skewed-trapezoidal geometry.1-11,34-40Similar to the structure of 1, the pyrene-carboxylate unit in 3 displays two intra-molecular C-H---O hydrogen-bonding interactions (C3-H3---O2: 2.261(2) Å and 124.3(2)º; C14-H14---O1: 2.347(2) Å and 102.3(2)º) which are responsible for the near planar arrangement of the pyrene and carboxylate units (dihedral angle between the carboxylate plane (O1, C17


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and O2) and pyrene plane (C1-C14) is 15.2(2)º; Figure 3a). Similarly, in each pyrene carboxylate unit, one of the carboxylate oxygen (O2) is involved in two intra-molecular CH---O hydrogen-bonding interactions with two of the hydrogens (H19C and H22B) of two different tert-butyl units (C19-H19C---O2: 2.295(2) Å and 133.1(2)º; C22-H22B---O2: 2.445(2) Å and 122.3(2)º). All the molecules of 3in the crystal are interconnected by an interesting type of tilted π-stacking interactions (pyrene-stacking; C4---π 3.337(3) and C6--π 3.385(3) Å; dihedral angle between the two pyrene planes are 40.4(3)º) to form the three-dimensional network (Figure 3b). Closer view of one of the sets of pyrene-stacking interactions (C4---C15 3.411(5); C4---C16 3.401(4); C6---C1 3.692(4) and C6---C1 3.405(5) Å) is shown in Figure 3c.


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Figure 3. (a) Molecular structure of 3 with 50% of ellipsoidal probability. (b) View of threedimensional supramolecular network formed from pyrene-stacking (tilted π-stacking) interactions. (c) Closer view of one set of pyrene-stacking interactions.

Photophysical Studies


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UV-Vis absorption spectra of all the compounds were recorded in a mixture of wateracetonitrile (1:1) solutions in 10–5 M concentrations (Figure 4). These spectra are characterized by the presence of strong pyrene π–π* transitions in four different regions (λmax (ε = 105)): for 1: 206 (2.94), 234 (0.58 sh), 243 (0.80), 265 (0.84), 277 (0.47), 315 (0.15 sh), 329 (0.35) and 345 (0.50); for 2: 207 (3.08), 235 (1.0 sh), 243 (1.52), 265 (0.56), 276 (0.92), 316 (0.30 sh), 329 (0.65) and 344 (0.88); for 3: 208 (3.20), 235 (1.46 sh), 243 (2.0), 266 (0.75), 277 (1.15), 315 (0.34 sh), 329 (0.76) and 345 (1.04).


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Figure 4. Absorption spectra of 1-3 in a water-acetonitrile (1:1) solution (10.0 µM).

The absorbance of 2 is higher than 3 followed by 1. This trend is consistent with the number of aromatic units present in each of these compounds.39The emission spectra of 1-3 were recorded in solution (water-acetonitrile in 1:1 mixture) as well as in the solid state after exciting at 365 nm (Figure 5). The fluorescence emission spectra (solution) showed two peaks at 390 nm and 408 nm. Similar to the trends observed in the corresponding absorption spectra, the fluorescence intensity is higher in 2 followed by 3 and 1.39The peaks observed in the solution phase of the compounds are typically characterized as monomer emission of the pyrene moiety. In contrast to the solution spectra, the solid-state spectra showed structure-less red-shifted broad bands at 515 nm.39These are assigned as excimer bands and originate due to the close proximity of pyrene moieties. The absence of excimer peaks in solution for 2 and 3 which contain two pyrene units, is ascribed to the rigidity of the stannoxane motifs which prevent intramolecular pyrene-pyrene interaction.


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Figure 5. Photoluminescence spectra of crystals of 1-3in water-acetonitrile (1:1) solution (10.0 µM) (solid line) and solid-state fluorescence spectra (dotted line). The excitation wavelength is 365 nm.

The fluorescence quantum yields of the compounds for 1, 2 and 3 are 0.10, 0.26 and 0.18 respectively with respect to anthracene.39,41 The higher quantum yield in 2 is probably due to its higher fluorescence intensity. Fluorescence life time measurements


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of all the three compounds have been studied. The fluorescence decay curves for 1, 2 and 3 were measured by TCSPC method in acetonitrile solution (1 mM) at 365 nm (Figure 6). We have observed the average decay times of 4.97 ns, 4.69 ns and 6.93 ns for 1, 2 and 3 respectively.

Figure 6. Fluorescence decay curves of 1 (a), 2 (b) and 3 (c) measured by TCSPC method in acetonitrile solution (1 mM). Fluorescence decay monitored at 365 nm.


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Summary We have successfully demonstrated the assembly of luminescent pyrene-decorated organotin compounds. Compounds 1-3 show a very rich supramolecular organization in their solid-state owing to multiple intermolecular interactions. Photophysical studies of compounds 1-3 show that their absorption and emission are highly dependent on the number of chromophores as well as on the nature of the pyrene stacking interactions. These studies underscore the utility of organostannoxane platforms for building new types of molecular materials.

EXPERIMENTAL SECTION:

Reagents and General Procedures: Solvents and other general reagents used in this work were purified according to standard procedures.42Bz3SnCl and [t-Bu2SnO]3 were prepared according to literature procedures.43-44Pyrene-1-carboxylic acid (PyrCO2H) and Ph3SnCl were purchased from Aldrich chemicals and used without further purification.


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Instrumentation: Melting points were measured using a JSGW melting point apparatus and are uncorrected. IR spectra were recorded from 4000 to 400 cm-1 on a Bruker FT-IR vector 22 model using KBr pellets. 1H and 119Sn NMR spectra were obtained on a JEOL DELTA2 500 model spectrometer operating at 500 MHz (for 1H) and 149 MHz (for 119Sn) and chemical shifts were referenced with respect to tetramethylsilane (for 1H) and tetramethyltin (for

119Sn).

ESI-HRMS analyses were performed on a Waters Micromass

Quattro Micro triple quadrupole mass spectrometer. Electrospray ionization (positive, full scan mode) mass spectra were obtained in methanol solutions using a cone voltage of 28-36 V. Absorption spectra were recorded on a Perkin-Elmer-Lambda 20 UV-vis spectrometer. The measurements were carried out at room temperature using a 10 mm quartz cell. Fluorescence spectra were recorded on a Varian Luminescence Cary spectrometer. Fluorescence lifetime measurements was done by time correlated single photon counting (TCSPC) method, at the two emission maxima in a FluoroLog 3, model FL-3.21, Horiba JobinYvon nanosecond time resolved spectrofluorimeter where 340 nm nanoLED was used as the excitation source. The decay was measured at 365 nm.


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Synthesis of 1: To a mixture of PyrCO2H (0.045 g, 0.181 mmol) and KOH (0.011 g, 0.19 mmol) in 60 mL of ethanol-water (5:1) solution, Ph3SnCl (0.070 g, 0.181 mmol) was added all at once. The reaction mixture was stirred at room temperature for 24 h, filtered and the filtrate was kept for slow evaporation to afford single crystals of compound 1. Yield: 0.089 g (83 %). Mp.: 148-150 °C. IR (KBr, ν/cm-1): 3633 (m), 3406(m, br), 3064 (m), 1560 (s) 1527 (m), 1480 (w), 1427 (s), 1396(s), 722 (s), 693 (s). 1H NMR (500 MHz, DMSO-D6,

δ/ppm): 9.45 (1H), 8.84 (1H), 8.24-7.27 (m, 22H).

119Sn

NMR (186.51 MHz, DMSO-

D6,δ/ppm): –114 (s). ESI-HRMS (m/z (%)): 351.0166 [Ph3Sn]+ (100), 745.0294 [(Ph3Sn)2(O2CH)]+ (70).

Synthesis of 2: To a clear solution mixture of PyrCO2H (0.052 g, 0.21 mmol) and KOH (0.015 g, 0.26 mmol) in 60 mL of ethanol-water (5:1) solution, Bz3SnCl (0.090 g, 0.21 mmol) was added all at once. The reaction mixture was stirred at room temperature for 24 h, filtered and the filtrate was kept for slow evaporation to afford single crystals of compound 2. Yield: 0.084 g (91 %). Mp.:>230 °C (dec). IR (KBr, ν/cm-1): 3632 (m), 3385(m, br), 3037 (m), 1912 (w) 1634 (m), 1588 (s) 1559 (s), 1526(s), 1395 (s), 1359 (m),


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1148 (w, br), 853 (s), 834 (m), 794 (m), 753 (m), 708 (s). ESI-HRMS (m/z (%)): 964.9660 [(Bz2Sn)2(O)(O2CPyr)(H2O)2(MeOH)2]+ (8), 490.9139 [BzSn(O2CPyr)(OH)H2O]+ (12).

Synthesis of 3: A mixture of [t-Bu2SnO]3 (0.060 g, 0.078 mmol) and PyrCO2H (0.116 g, 0.468 mmol) in toluene (70 mL) was refluxed for 6 h by using a Dean-Stark apparatus. Reaction mixture was then cooled, filtered and evaporated in vacuo which gave a yellow solid. Single crystals of 3 were grown from its CHCl3 solution by slow evaporation. Yield: 0.148 g (87%). Mp: >220 °C (dec). IR (KBr, cm-1): 3450 (m, br), 3042 (w), 1977 (w) 2927 (w), 2850 (m), 1913 (w), 1590(s), 1571(s), 1386 (s), 1335 (s), 1302 (s), 1137 (m), 857 (s), 844 (m), 751 (m), 711 (m) 644 (m), 460 (m). 1H NMR (500 MHz, CDCl3, δ/ppm): 9.45 (2H), 8.83 (2H), 8.23-8.11 (m, 10H), 8.05-7.97 (4H), 1.59 (18H). 119Sn NMR (185.51 MHz, CDCl3, δ/ppm): –218.18 (s).ESI-HRMS (m/z (%)): 760.3839 [(t-Bu)2Sn(O2CPyr)2.2H2O]+ (45), 479.1065 [(t-Bu)2Sn(O2CPyr)]+ (9), 565.5698 [(t-Bu)2Sn(O2CPyr)(O2CH).2H2O.Na]+ (14).

Table 2. Crystal data of cell refinement parameters for 1-3.


26

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Compound

1

2

3

Empirical formula

C35H24O2Sn

C94H88O10Sn4

C42H36O4Sn

Formula weight (g)

595.23

1852.40

723.42

Temperature (K)

100(2)

293(2)

100(2)

Triclinic, P -1

Triclinic, P-1

a(Å)

9.194(5)

11.474(5)

27.541(5)

b(Å)

10.088(5)

12.026(5)

15.512(2)

cell c(Å)

15.500(5)

16.092(5)

7.6520(11)

α ()

104.869(5)

69.455(5)

90

β ()

94.460(5)

73.814(5)

90

γ ()

110.673(5)

82.458(5)

90

Volume (Å ), Z

1277.3(10), 2

1995.4(14), 1

3269.0(9), 4

F(000)

600

932

1480

Crystal system, Space group

Unit dimensions

3

Crystal size (mm3)

Orthorhombic,

Cmc21

0.08 x 0.04 x 0.26 x 0.24 x 0.018

x

0.016

0.03

0.22

0.014

 collection range ()

2.27 to 28.35

2.33 to 25.50

2.58 to 25.49

Limiting indices

‒12 ≤ h ≤ 8,

‒9 ≤ h ≤ 13,

‒32 ≤ h ≤ 22,

‒13 ≤ k ≤ 13,

‒14 ≤ k ≤ 14,

‒18 ≤ k ≤ 17,

‒20 ≤ l ≤ 15

‒19 ≤ l ≤ 19

‒9 ≤ l ≤ 8

x


27


Reflections

collected

/ 8379 / 6020

Page 28 of 38

10605 / 7217

8657 / 3108

unique

[Rint = 0.0247]

[Rint = 0.0317]

[Rint = 0.0389]

Completeness to (%)

99.4

97.1

99.6

Absorption correction

Empirical

Empirical

Empirical

6020 / 0 / 343

7217 / 0 / 495

3021 / 1 / 224

Goodness-of-fit on F2

1.152

1.056

1.049

Final R indices [I> 2(I)]

R1 = 0.0614,

R1 = 0.0371,

R1 = 0.0306,

wR2 = 0.1597

wR2 = 0.0919

wR2 = 0.0666

R1 = 0.0947,

R1 = 0.0450,

R1 = 0.0342,

wR2 = 0.2536

wR2 = 0.1047

wR2 = 0.0688

Data

/

Restrains

Parameters

R indices (all data)

/

1.403

Largest diff. Peak and ‒2.967 hole (e. Å‒3)

and 1.453 ‒0.600

and

0.697 and ‒0.517

X-Ray Crystallography: Single-crystal X-ray diffraction data for compounds 1-3 were collected using a graphite monochromated Mo-Kα radiation (λ = 0.71073 Å) on a Bruker APEX diffractometer. The structure was solved by direct methods and refined by fullmatrix least squares on F2.45All non-H atoms were refined anisotropically. Hydrogen atoms were included in calculated positions, assigned isotropic thermal parameters and


28

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allowed to ride on their parent carbon atoms. All calculations were carried out using the SHELXTL package.46-47The details pertaining the data collection of the crystals are given in Table 2. CCDC 1884692 (1), 1884693 (2) and 1884694 (3) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: +44-1223/336-033; E-mail: [email protected]].

AUTHOR INFORMATION

Corresponding Author *[email protected]; [email protected]

ACKNOWLEDGMENT


29


Page 30 of 38

We thank the Department of Science and Technology (DST), India for financial support. VC thankful to DST for a JC Bose National Fellowship. MDP is thankful to DST-SERB (EMR/2016/001779) for a project grant.

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For Table of Contents Use Only Luminescent Pyrene-decorated Organotin Compounds: Observation of Monomer- and Excimer Emission Mrituanjay D. Pandey*, Ramesh K. Metre, SubrataKundu, BaniMahanti, Arun Kumar, Kandasamy Gopal* and Vadapalli Chandrasekhar*


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SYNOPSIS: Pyrene-decorated luminescent organotin compounds, Ph3SnO2CPyr (1), [(Bz2Sn)2(µ3-O)(µ-OH)(O2CPyr)]2∙2EtOH (2) and t-Bu2Sn[O2CPyr]2 (3) reveal a rich supramolecular architecture and excimer emission in the solid-state and a strong monomer emission in solution.


38

Luminescent Pyrene-decorated Organotin Compounds:Observation of

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