Design, Synthesis and Properties of Metal Complexes and Coordination Polymers for [2+2] Photo Cycloaddition Reactions to Higher Dimensional Structures RAGHAVENDER MEDISHETTY M.Sc., Banaras Hindu University, Varanasi, India A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY NATIONAL UNIVERSITY OF SINGAPORE 2014 I Declaration I, hereby declare that this thesis is my original work and it has been written by me in its entirety, under the supervision of Prof Jagadese J Vittal at Department of Chemistry, National University of Singapore, during January 2010 to January 2014 I have duly acknowledged all the sources of information used for this thesis This thesis has not been submitted for any degree at any other University The content of the thesis has been partly published in: Medishetty, R., Koh, L L., Kole, G K & Vittal, J J Solid-State Structural Transformations from 2D Interdigitated Layers to 3D Interpenetrated Structures Angew Chem Int Ed 50, 10949-10952 (2011) Medishetty, R., Jung, D., Song, X., Kim, D., Lee, S S., Lah, M S & Vittal, J J Solvent-Induced Structural Dynamics in Noninterpenetrating Porous Coordination Polymeric Networks Inorg Chem 52, 2951-2957 (2013) Medishetty, R., Yap, T T S., Koh, L L & Vittal, J J Thermally reversible single-crystal to single-crystal transformation of mononuclear to dinuclear Zn2+ complexes by [2+2] cycloaddition reaction Chem Commun 49, 9567-9569 (2013) Medishetty, R., Tandiana, R., Koh, L L & Vittal, J J Assembly of 3D Coordination Polymers from 2D Sheets by [2+2] Cycloaddition Reaction Chem Eur J., (2014) DOI: 10.1002/chem.201304246 RAGHAVENDER MEDISHETTY -Name Signature Date II Acknowledgements I sincerely thank my supervisor Prof Jagadese J Vittal for his scientific guidance and moral support His passion, knowledge, vision, constant encouragement and constructive criticism inspired and helped me throughout this journey of learning The regular enriching discussions with him showed a huge positive impact on shaping my thinking and attitude towards science and helped to enjoy my research Without his help this dissertation would not have been possible I would like to express sincere gratitude to Dr Mangayarkarasi for her great moral support and inspiration I thank Anjana for her direct and indirect motivation and support I would also thank all the past and present group members Dr Abdul, Dr Wei Lee, Dr Mir, Dr Saravanan, Dr Goutam, Dr Jeremiah, Shahul, Thio Yude, Hong Sheng, Juleiha, Dr Ming Hui I also thank all the undergraduate and exchange students, especially Rika, Terence, Zhaozhi, Caroline, In-Hyeok, Khushboo for their help and support My thanks are also extended to the staff of CMMAC facilities for their help and patience Especially to Ms Geok Kheng Tan, Ms Hong Yimian for X-ray crystallographic data and Dr Lip Lin Koh, for structure solution and refinement I would like to thank to all our collaborators, especially Prof P Naumov, Dr M S Lah and Prof S S Lee, from Abu Dhabi, UAE and S Korea Words are not enough to thank my parents for their unconditional love, care and constant encouragement throughout my life I am also grateful to my brother for his inspiration and support III My deepest gratitude to god-gifted friends Ashok, Rama, Jana and Vamsi for their great friendship, who made me feel, Singapore very comfortable as my home Many thanks to my current and previous friends in Singapore, Anand, Durga, Deva, Gopal, Dr Vasu, Venu and many more for their help and association I want to pay my deep regards and gratitude to all my teachers and friends who made this journey most enjoyable, interesting with their sharing and teachings Last but not least, I thank NUS for presidential graduate fellowship for my Ph D studies IV To My Beloved Parents V TABLE OF CONTENTS Declaration II Acknowledgements III Table of Contents VI Summary XII List of Tables XV List of Figures XVI List of Schemes XXII List of Abbreviations XXIII Publications XXV List of conferences and workshops XXVII Chapter 1: Introduction 1.1 Crystal Engineering 1-2 1.2 Coordination complexes and polymers 1-4 1.3 Solid state reactions 1-10 1.4 [2+2] photo cycloaddition 1-12 1.5 Topochemical reactions 1-13 1.6 Solid state [2+2] photo cycloaddition reaction in various 1-14 compounds 1.6.1 Photoreactivity of metal complexes using bidentate 1-15 ligand 1.6.2 Photoreactivity in CPs using bidentate ligand 1-19 1.6.3 Photoreactivity in metal complexes using monodentate 1-23 ligand 1.6.4 Photoreactivity in CPs using monodentate ligand 1-24 1.7 Reversibility of cyclobutane ring 1-25 1.8 [2+2] cycloaddition reaction to monitor the structural 1-27 transformations in CPs 1.8.1 Anisotropic movements of 1D CPs by desolvation 1-27 1.8.2 Transformation of a linear CP to a ladder structure by 1-29 thermal dehydration VI 1.9 Mechanochemical reactions 1-31 1.10 Cohen’s reaction cavity 1-32 1.10 Aims of this dissertation 1-33 1.11 References 1-35 Chapter 2: Single Crystals Dance Under UV Light: The First Example of a Photosalient Effect Triggered by [2+2] Cycloaddition Reaction 2.1 Introduction 2-2 2.2 Results and discussion 2-3 2.2.1 Structural description 2-3 2.2.2 Photoreactivity 2-5 2.2.3 Kinematic analysis 2-11 2.2.4 Solid state kinetics of photoreaction 2-15 2.3 Summary 2-17 2.4 Experimental details 2-18 2.5 References 2-21 Supplementary Information 2-25 Chapter 3: Thermally reversible single-crystal-to-single-crystal transformation of mononuclear to dinuclear Zn2+ complexes by [2+2] cycloaddition reaction 3.1 Introduction 3-2 3.2 Results and discussion 3-4 3.2.1 Structural description of [ZnBr2(4spy)2] (III-1) 3-4 3.2.2 Photoreactivity of III-1 3-7 3.2.3 Reversibility of dimer complex 3-10 3.2.4 Structural description of [ZnBr2(2F-4spy)2] (III-4) 3-15 3.3 Photoluminescence properties 3-21 3.4 Summary 3-23 3.5 Experimental details 3-24 3.6 References 3-27 Supplementary Information 3-30 VII Chapter 4: Role of Substituents on the Photoreactivity of HydrogenBonded 1D Coordination Polymers and Their Transformation to 2D Layered Structures 4.1 Introduction 4-2 4.2 Results and discussion 4-4 4.2.1 Structural description of 4-4 [Cd(bdc)(4spy)2(H2O)]2H2O2DMF 4.2.2 Structural Transformation due to Desolvation 4-6 4.2.3 Structural Description of [Cd(bdc)(2F-4spy)2(H2O)]2F- 4-13 4spy 4.2.4 Structural Description of [Cd(bdc)(2NO2- 4-22 4spy)2(H2O)]DMF 4.2.5 Structural Description of [Cd(bdc)(3NO2- 4-23 4spy)2]0.25DMF2.125H2O 4.3 Summary 4-27 4.4 Experimental details 4-28 4.5 References 4-31 Supplementary Information 4-34 Chapter Section 1: Assembly of 3D Coordination Polymers from 2D Sheets by [2+2] Cycloaddition Reactions 5.1.1 Introduction 5.1-3 5.1.2 Results and discussion 5.1-5 5.1.2.1 Structural description of [Zn2(bdc)2(4vpy)2] (V-1) 5.1-5 5.1.2.2 Structural description of [Zn2(bdc)2(2F-4spy)2]⋅MeOH 5.1-8 5.1.2.3 Photoreactivity of [Zn2(bdc)2(2F-4spy)2]⋅MeOH 5.1-10 5.1.2.4 Structural description of [Zn2(bdc)2(rctt-2F-ppcb)] 5.1-13 5.1.2.5 Structural description of [Zn2(bdc)2(4spy)2] 0.5MeOH 5.1-14 5.1.2.6 Photoreactivity of [Zn2(bdc)2(4spy)2] 0.5MeOH 5.1-17 5.1.2.7 Photoluminescence studies 5.1-19 Summary 5.1-22 5.1.3 VIII 5.1.4 Experimental details 5.1-23 5.1.5 References 5.1-26 Supplementary Information 5.1-29 Section 2: Solid-State Structural Transformations from 2D Interdigitated Layers to 3D Interpenetrated Structures 5.2.1 Introduction 5.2-2 5.2.2 Results and discussion 5.2-3 5.2.2.1 Structural description of [Zn2(cca)2(4spy)2] 5.2-3 5.2.2.2 Structural description of [Zn2(cca)2(4spy)2] 5.2-6 5.2.2.3 Structural description and photoreactivity of 5.2-9 [Zn2(ndc)2(4spy)2] 5.2.3 Summary 5.2-10 5.2.4 Experimental details 5.2-11 5.2.5 References 5.2-13 Supplementary Information 5.2-17 Chapter 6: Asymmetric Solid State [2+2] Photo Cycloaddition Reaction: 'Phenyl-Olefin' Dimerization 6.1 Introduction 6-2 6.2 Results and discussion 6-4 6.2.1 Structural description of [Zn2(toluate)4(2F-4spy)2] 6-4 6.2.2 Photoreactivity of VI-1 6-6 6.2.3 Structural description of [Zn2(toluate)4(4spy)2] (VI-3) 6-12 6.3 Summary 6-14 6.4 Experimental details 6-14 6.5 References 6-16 Supplementary Information 6-18 Chapter 7: Solvent Induced Structural Dynamics in Non- Interpenetrating Porous Coordination Polymeric Network 7.1 Introduction 7-2 7.2 Results and discussion 7-3 IX 7.2.1 Structural description of [Zn(PNMI)]•2DMA 7-5 7.2.2 Guest replacement by SCSC process 7-6 7.2.3 Structural description of [Cd(PNMI)]•0.5DMA•5H2O 7-12 7.3 Gas sorption studies 7-14 7.4 Summary 7-18 7.5 Experimental details 7-19 7.6 References 7-22 Supplementary Information 7-26 Chapter 8: Suggestions for Future work 8.1 Future scope of the work 8.2 8.2 References 8.3 X Solvent induced structural dynamics in PCP Chapter Figure 7- 11 Isosteric heat of adsorption CO2 (a) and CH4 (b) for VII-2 calculated by viral equation 7.4 Summary During the solvothermal synthesis, DPNI was partially hydrolyzed to PNMI and provided two structurally similar yet distinct MOF structures showing large rhomboidal channels all aligned in parallel The structure of VII-1 is built from paddle-wheel SBU while isotypical VII-2 and VII-3 are made up of onedimensional aggregates of M(O2C-C)2 in the framework The guest molecules in VII-1a can be exchanged with EtOH in an SCSC manner to VII-1b which in turn has been successfully used to exchange with ethylene glycol, triethylene glycol and allyl alcohol without destroying its single crystal nature These SCSC exchanges are accompanied by reduction of the volume of the unit cell up to 16% and the void volume up to 33.1% The decrease in the void volume suggests that the soft and flexible nature of the structure and the retention of the structure upon removal of the solvents were shown by the PXRD experiments In order to investigate this behavior, sorption studies were undertaken and found that all these activated MOFs exhibits very low or no uptake of H2 and N2 gases at bar and 77 K, but better adsorption of CO2 with hysteresis On the other hand, the 7-18 Solvent induced structural dynamics in PCP Chapter activated VII-2 shows selective CO2 uptake over H2, N2, Ar and CH4 and hence would be promising for separation of gas mixtures Table 7- Crystallographic information of VII-1a - VII-1e, VII-2 and VII-3 VII-1a VII-1b VII-1c Molecul C19H8N2O6 C19H8N2O6Zn C19H8N2O6Zn ar Zn•2C4H9N •1.25(C2H6O) •0.5(C2H6O2)• formula O 0.375(H2O) 0.75(H2O) P21/c P21/c P21/c P21/c P21/n P21/n P21/n aÅ 5.6364(6) 5.5871(2) 5.6137(2) 5.5797(4) 5.6415(14) 4.9738(5) 5.0169(3) bÅ 25.301(3) 25.9462(9) 26.3769(9) 25.9231(2) 27.633(7) 24.836(3) 24.9851(17) cÅ 18.8863(2) 17.4983(7) 17.1499(6) 16.7931(1) 14.847(4) 20.663(2) 20.6949(17) β 95.470(2) 96.031(2) 96.820(2) 98.575(4) 100.149(4) 95.903(3) 95.721(4) VÅ 2681.0(5) 2522.6(2) 2521.5(2) 2401.9(3) 2278.3(10) 2538.9(4) 2581.1(3) Z 2 2 1.486 1.290 1.473 1.590 1.547 1.586 1.210 µ mm-1 0.974 1.016 1.036 1.087 1.134 0.923 0.550 GOF 1.036 1.082 1.090 1.095 1.076 1.068 1.129 Final R1 0.0607 0.0550 0.0530 0.0501 0.0656 0.0774 0.1058 0.1578 for 0.1746 for 0.1584 for 0.1159 for 0.1677 for 0.1362 for 0.3005 for 3974>2(I) 4761>2(I) 3961>2(I) 3790>2(I) 3382>2(I) 4615>2(I) 4246>2(I) Space group Dcalcd g.cm-3 wR2 7.5 VII-1d C19H8N2O6Zn •( C6H14O4) VII-1e C19H8N2O6 Zn•1.25(C3 H6O)•H2O VII-2 VII-3 C19H8N2O6Cd • 0.5(C4H9NO) C19H8N2O6 Mn•0.75(C3 H7NO) •5H2O Experimental details Sorption Measurements All gas sorption isotherms were measured using a BELSORP-max (BEL Japan, Inc.) with a standard volumetric technique using N2 (with purity of 99.999%), Ar (99.9999%), H2 (99.9999%), CO2 (99.999%) and CH4 (99.95%) as adsorbates The compound VII-1 and VII-3 were activated at RT for around a day under vacuum and compound VII-2 was activated at 150°C for 14 hrs under vacuum 7-19 Solvent induced structural dynamics in PCP Chapter and studied the gas sorption studies The adsorption data in the pressure range lower than ~ 0.1 P/P0 were fitted to the Brunauer−Emmett−Teller (BET) equation to determine the BET specific surface area The entire set of adsorption data was used to obtain the Langmuir specific surface area Synthesis of [Zn(PNMI)]•2DMA (1•2DMA, VII-1a): A mixture of Zn(NO3)2•6H2O (3.7 mg, 0.0125 mmol) and DPNI (5 mg, 0.0125 mmol) were added to DMA (2 mL), pyridine (1 mL) and water (0.5 mL) in 20 mL glass vial and the reaction solution was sonicated until it gave a clear solution and then placed it in a programmable oven and heated it at 120°C for 48 h, followed by cooling to room temperature at the rate of 5°C.h -1 Light Yellow needle-shaped crystals were obtained These crystals were washed with DMA, water and dried under vacuum Yield: 38% (based on DPNI) Calcd for C19H8N2O6Zn•2C4H9NO (FW = 599.91): C, 54.06; H, 4.37; N, 9.34 Found: C, 54.28, H, 4.43, N, 9.27 Selected IR (KBr): ν (cm-1) = 3404 (s), 1707 (m), 1661 (s), 1570 (s), 1442 (s), 1381 (s), 1352 (s), 1242 (s), 1195 (m), 863 (m), 816 (m), 775 (s), (m) TG weight loss observed: 29.7%; calculated: 29.1% (for the loss of DMA molecules) Synthesis of [Zn(PNMI)]•1.25EtOH•0.375H2O (VII-1b): The single crystals of compound 1a were soaked in ethanol for two days The DMA molecules in the solvent channels have been exchanged with ethanol and water retaining the single crystallinity suitable for X-ray data collection TG weight loss observed: 17.73%; Calculated: 18.07% (for the loss of 1.25 EtOH and 0.375 H2O molecules) 7-20 Solvent induced structural dynamics in PCP Chapter Synthesis of [Cd(PNMI)]•0.5DMA•5H2O (VII-2•0.5DMA•5H2O): A mixture of Cd(NO3)2•4H2O (7.7 mg, 0.025 mmol) and DPNI (10 mg, 0.025 mmol) were added to 1.5 mL DMA, mL water and mL methanol in 20 mL scintillation vial and heated at 90°C for 48 h followed by cooling to room temperature at the rate of 4°C.h-1, resulted in light yellow block crystals which were filtered and washed with fresh DMA and methanol and dried at room temperature Yield: 80% (based on DPNI) Elemental analysis (%) Calcd for C19H8N2O6Cd (472.69) (desolvated sample): C, 48.28; H, 1.71; N, 5.93 Found: C, 48.53; H, 2.22; N, 5.97 Selected IR (KBr): ν (cm-1) = 3433 (m), 1710 (m), 1663 (s), 1588 (s), 1438 (m), 1380 (s), 1241 (m), 775 (s), 659 (m), 439 (m) TG weight loss observed: 24.0%; calculated: 22.0% (for the loss of half DMA and five water molecules) Synthesis of [Mn(PNMI)]•0.75DMF (VII-3•0.75DMF): A mixture of Mn(ClO4)2•4H2O (4.25 mg, 0.025 mmol) and DPNI (5 mg, 0.0125 mmol) in mL DMF, mL water and 100 µL of 1M HClO4 kept in 20 mL scintillation vial and heated at 80°C for 48 h followed by cooling to room temperature at the rate of 4°C.h-1 resulted in light yellow crystals of VII-2 which were washed with fresh DMF and water and dried at room temperature Yield: 62% (based on DPNI) Calcd for C19H8N2O6Mn (415.21) (desolvated sample): C, 54.96; H, 1.94; N, 6.75 Found: C, 54.96; H, 2.18; N, 6.71 Selected IR (KBr): ν (cm-1) = 3404 (s), 1707 (m), 1661 (s), 1570 (s), 1442 (s), 1381 (s), 1352 (s), 1242 (s), 1195 (m), 863 (m), 816 (m), 775 (s) Caution! Perchlorate salts are potentially explosives Although we did not have any unpleasant experience probably due to the usage of a very small amount, care should be taken to avoid any untoward experience 7-21 Solvent induced structural dynamics in PCP Chapter 7.6 References [1] a) J.-R Li, R J Kuppler, H.-C Zhou, Chem Soc Rev 2009, 38, 14771504; b) M P Suh, H J Park, T K Prasad, D.-W Lim, Chem Rev 2011, 112, 782-835; c) K Sumida, D L Rogow, J A Mason, T M McDonald, E D Bloch, Z R Herm, T.-H Bae, J R Long, Chem Rev 2011, 112, 724781; d) J.-R Li, J Sculley, H.-C Zhou, Chem Rev 2011, 112, 869-932; e) L E Kreno, K Leong, O K Farha, M Allendorf, R P Van Duyne, J T Hupp, Chem Rev 2012, 112, 1105–1125; f) M Nagarathinam, K Saravanan, E J H Phua, M V Reddy, B V R Chowdari, J J Vittal, Angew Chem Int Ed 2012, 51, 5866-5870; g) M Yoon, R Srirambalaji, K Kim, Chem Rev 2011, 112, 1196-1231 [2] a) N Stock, S Biswas, Chem Rev 2011, 112, 933-969; b) A Schoedel, L Wojtas, S P Kelley, R D Rogers, M 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sorption studies Figure S7- 1H NMR spectrum of the crystals of VII-1 in D6-DMSO, which were soaked in 1:1:1 (volume) EG, TEGly and allylalcohol for two days and filtered and rinsed with ethanol As the compound is insoluble in DMSO, a very small amount of HNO was added just to dissolve the crystals The hump around ppm is due to acidic water/HNO3 7-26 Solvent induced structural dynamics in PCP Chapter Figure S7- TGA of compound VII-1a Figure S7- TGA of compound VII-2 Figure S7- TGA of compound VII-2 after exchanging lattice solvent with methanol and water 7-27 Solvent induced structural dynamics in PCP Chapter Figure S7- TGA of compound VII-3 Figure S7- Gas sorption isotherms for compound VII-1 (olive), VII-2 (blue) and VII-3 (red) CO2 sorption (square) at 195K, N2 (circle) and H2 (triangle) sorptions at 77K Adsorption branch: filled symbols, desorption branch: open symbols 7-28 Solvent induced structural dynamics in PCP Chapter Figure S7- CO2 sorption isotherms for compound VII-1 (olive), VII-2 (blue) and VII-3 (red) at 196K Adsorption branch: filled symbols, desorption branch: open symbols DMA Ethanol Ethylene glycol Triethylene glycol Allylalcohol Figure S7- Framework structures of VII-1 with different solvents showing the contraction in the pore as explained in Table 7-2 7-29 Suggestions for future work Chapter Chapter Suggestions for Future Work 8-1 Suggestions for future work 8.1 Chapter Future scope of the work This dissertation described several very interesting results with the monodentate photoreactive 4spy ligand and its derivatives The photoreactivity of these metal complexes and CPs demonstrate the synthesis of highly strained cyclobutane derivative compounds using solid state synthesis, especially, photoreactivity of monodentate ligand leading to the photo polymerization of Zn2+ complexes along with the transformation of lower-dimensional CPs to higherdimensional CPs Similar studies can be further extended to explore the use of other metal ions, counter anions and other co-ligands containing C=C bonds to engineer further interesting compounds Chapter demonstrated the serendipitous photosalient behavior of metal complexes This work can be further extended by using substituents on both benzoic acid and 4spy ligand along with the metals atoms systematically These studies will provide foundation for such an interesting photomechanical behavior of these compounds, along with the correlation with the solid state packing pattern These fundamentals would really helpful for the design and synthesis of actuator materials which would convert the photoenergy into mechanical energy In chapter 3, reversibility of photodimer has been described by heating the photodimer at 220˚C in a stereospecific manner These studies can be further extended using different substituents which could lower the reversible temperature By lowering this temperature, these reversible photoreactive compounds can be used for applications, such as rewriting drives, thermo-optical 8-2 Suggestions for future work Chapter switches and so on Further, IR lasers may be attempted instead of heating to cleave the cyclobutane rings The styrylpyridine derivatives are well known for their photo physical properties in solution state, such as multi-photon absorption and photoluminescence.[1] Though in chapter and chapter 5, photoluminescence properties of these metal complexes and CPs have been presented, further studies are needed to evaluate their properties of these compounds in the solid state Most interestingly, novel asymmetric ‘phenyl-olefin’ hetero dimerization has been discussed chapter Due to the time constraints for PhD thesis submission, this work has not been completed Therefore further studies may be conducted to understand the basis of this very hitherto unknown hetero cycloaddition reaction This information would extend the limitations of solid state photo cycloaddition reactions from olefins to other hetero photo cycloaddition reactions and the activation of aromatic rings These studies would be helpful in the environmentally benign green syntheses of highly strained bicyclic compounds and derivatives by solid-state cycloaddition reactions in quantitative yields 8.2 References: [1] a) Q Zheng, G S He, T.-C Lin, P N Prasad, J Mater Chem 2003, 13, 2499-2504; b) Q Zheng, H Zhu, S.-C Chen, C Tang, E Ma, X Chen, Nat Photon 2013, 7, 234-239 8-3 ... representation of transformation of 1D CP 1-22 into 3D MOF through photo cycloaddition reaction Figure 1- 11 PSM of 3D MOF through solid state [2+2] photo 1-23 cycloaddition reaction Figure 1- 12 Photo cycloaddition. .. PSM of 3D MOF through solid state [2+2] photoreaction 1.6.3 Photoreactivity in metal complexes using monodentate ligand Compared to the bidentate ligands, photoreactivity of monodentate ligands... 1.6.1 Photoreactivity of metal complexes using bidentate 1-15 ligand 1.6.2 Photoreactivity in CPs using bidentate ligand 1-19 1.6.3 Photoreactivity in metal complexes using monodentate 1-23 ligand