Luận án tiến sĩ: Syntheses, quantum chemical modeling, and spectroscopic properties of wirelike, luminescent mono- and bi-metallic rhenium(I) carbyne complexes

SYNTHESES, QUANTUM CHEMICAL MODELING, AND SPECTROSCOPIC PROPERTIES OF WIRELIKE, LUMINESCENT MONO- AND BI-METALLIC RHENIUM() CARBYNE COMPLEXES BY JING YANG B., Chemistry, Beijing Normal University, P., Chemistry, Beijing Normal University, P. China, 2000 DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY CHEMISTRY The University of New Mexico Albuquerque, New Mexico May 2006 UMI Number: 3220899 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted.

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ProQuest Information and Learning Company 300 North Zeeb Road P. Box 1346 Ann Arbor, MI 48106-1346 Jing Yang Candidate Chemistry Department This dissertation is approved, and it is acceptable in quality and form for publication on microfilm: Approved by the Dissertation Committee:. Watut— Dean, Graduate School APR 2 1 2006 Date Copyright by Jing Yang, 2006 All Rights Reserved ili Dedicated to my Husband, Shenghong, my sons, David and Kevin, and my parents. IV ACKNOWLEDGEMENTS I would like to thank to my advisor, Dr.

Since I enrolled to his class, and then joined into this group, he kept giving me warm and helpful guidance and encouragements both on my class learning and research. Whenever I meet any problem, he always lavished his time and effort to carefully teach me. His preciseness, sagacity, acuity and endless enthusiasm on research make a good example to me to be a great scientist. At the same time, he also guided me how to be a nice person with his excellent personality.

All above made me feel comfortable and confident to study abroad. I always tell my friends that I am so lucky to have this nice advisor. I also very enjoyed and will cherish forever the time when I worked with the enthusiastic group members. I want to thank Ted for his unselfish helps when I was a novice in the lab.

He taught me most of the spectroscopic experiments I have done. Many thanks should go to Dr. Luke Emmert, who taught me with great patience for the time- resolved infrared measurements, and the operation and maintenance of lasers in use. He also pointed out many important issues that I ignored.

I happily worked with Jason on the luminescence measurements. His experience on the spectroscopic studies was a rich database for me. Ryan helped me to solve many problems about the calculations on the cluster. Wacholtz and Dr.

Basemen gave some helpful discussions. All of my group members are truly wonderful and warmhearted people, and I really appreciate it. My family deserves a place here as well. My husband, Shenghong, takes care of me with his pure and interminable love.

I am also grateful to the love, encouragement and support from my parents, Hongzhi Yang and Zhufen Cai, and my younger sister, Hui Yang. I can’t imagine that I would have been able to finish my long way of pursuing without their love and strong support. Finally, I would like to thank everybody at Chemistry Department of University of New Mexico because all of you enriched my life and made my experience here extraordinary. vi SYNTHESES, QUANTUM CHEMICAL MODELING, AND SPECTROSCOPIC PROPERTIES OF WIRELIKE, LUMINESCENT MONO- AND BI-METALLIC RHENIUM(E) CARBYNE COMPLEXES BY JING YANG ABSTRACT OF DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY CHEMISTRY The University of New Mexico Albuquerque, New Mexico May 2006 SYNTHESES, QUANTUM CHEMICAL MODELING, AND SPECTROSCOPIC PROPERTIES OF WIRELIKE LUMINESCENT MONO- AND BI-METALLIC RHENIUM() CARBYNE COMPLEXES By Jing Yang B., Chemistry, Beijing Normal University, P., Chemistry, Beijing Normal University, P., Chemistry, The University of New Mexico, U., 2006 ABSTRACT A series of conjugated luminescent polyalkynyl organometallic complexes with mono- and bi-rhenium(I) centers that contain fac-tricarbonyl ligands and 4,4-/-butyl-2,2'- bipyridine metal chelating units have been synthesized using the Eglington coupling reaction.

These molecules contain varying numbers of —(acetylene),- groups (n = 1 - 3 for mono-metallic compounds, and n = 4 - 6 for the bimetallic compounds) directly attached to the metal centers. The scientific motivation for this dissertation arises from a Vill concerted and systematic effort to create photoactive molecular wires that can serve as model systems for the understanding of electron and charge transfer through pseudo-one- dimension sp carbon chains. Therefore, the energy conduction and charge transfer properties were studied as a function of repeat acetylene units. The photophysical and spectroscopic properties of these novel molecular wires have been fully examined.

Steady-state emission and luminescence lifetime measurements have revealed that all mono- and bi-Re(I) center metallic compounds display single exponential behavior except two notable cases, compounds Re(CC)»:SiMe; and Re(CC)4Re. In the mono-metallic compounds, the absorption spectra indicated that the Sy — Ti, charge transfer transition is the lowest energy absorption, and there are strong spin allowed ligand (carbon-carbon triple bond) {TK transitions for these monometallic compounds, which exhibit a red-shift as the acetylene length gets longer. Steady-state emission spectra and luminescent lifetime measurements obtained at 77 K as well as the quantum chemical modeling studies revealed that an admixture of °LLCT (f4c=c — Ty) & ÌMLCT (dre —> Tỉ bpy) constitutes the lowest emitting triplet manifold for all monometallic compounds after the laser excitation. Both the conjugation effect (in terms of number of acetylene units) and the o-donating property of the terminal group play important roles in determining the lowest-emitting manifolds.

The spectroscopic properties of bi-metallic compounds are more complicated. The observations from the excitation wavelength dependence of the steady-state emission measurements at both 77 K and 298 K, but relatively invariant of the excitation wavelength in solution strongly suggested that there exist cis- and ¢rans-conformational ix isomers in these molecules. Based on DFT calculations, these conformers are highly mixed. They are trapped in the solid matrices, but are averaged out in fluid solutions.

The TRIR data and computation results have revealed that lowest emitting excited state for these three bi-metallic compounds is an admixture of a dominant amount of “LLCT (Rc-c —> T ạy) and a tiny amount of °MLCT (dite > 7 bpy) transitions. The quantum chemical modeling also yields the information of the symmetry properties in the excited state of these bimetallic compounds. However, this issue cannot be fully addressed directly from the spectroscopic data. TABLE OF CONTENTS ACKNOWLEDGEMENTS.QQQ nnnn nh» nhàng M ABSTRACT.c L Q 2n HS HS TT nh TK Ko nh nhe HH vi TABLEOEFCONTENTS.-LQQQQQQ cece ee eee eee HH nh Hy khen xi LIST OF FIGURES.

TQ nh nn HT HH nh nh nh hen hen kg XVI 05/9). eee nee ern eae sane e a eee eet XXIi CHAPTER ONE: INTRODUCTION.1 Development of Molecular DeVIC€S.- óc à ng Hà ra 1 (002900) 11. ees kg HH thớt 3 1.-- càng HH HH HH rệt 6 1.3 Conjugated Hydrocarbon Molecules Systems with Metal Centers.1 Homo-Bimetallic Systems.2 Hetero-Bimetallic Systems.3 Multiple Metallic Šystems. 28 CHAPTER TWO: EXPERIMENTAL PROCEDURES.1 Chemicals and SOÏV€TIES.

SH HH re 36 2.2 Rhenium Monometallic Compounds.--c-cc s2 se 42 XI 2.3 Rhenium Bimetallic Cormpounds.1 Room Temperature Absorption Spectroscopy .2 Steady State Emission SDeCfTOSCODV.3 Luminescence LIÍ€tiImeS. cà ng TH ng 51 2.4 Excitation SD€CITOSCODV. nh HH HH HH KH Hy 56 2.5 77K Fourier Transformed Infrared (FTIR) and Time-Resolved Infrared (TRIR) SpectTOSCODY. TH HH ng ha 56 2.cccccccccccsccssscssevcvssseeccsesecceeeussssevccsseescsunscsuvsececeseseauaesceeeeensssensss 60 CHAPTER THREE: THE FUNDAMENTALS OF SPECTROSCOPY.1 Absorption and Emission ŠD€CfTOSCODY.

ánh ng na 62 3.1 Jablonski Diagram for General Cases.2 Energy Transfer Processes in the Organometallic Complexes.3 Spin Selection Rul€. -- Sàn HH HH HH như.2 Vibrational SD€CfTOSCODV. SH HH HH Hit 67 3.1 Selection RuÌes.- HH“ HH HH KH KH ky 67 3.- LH HH ng net 69 3.3 Time-Resolved Infrared ŠSpectfrOSCODY. 75 XI CHAPTER FOUR: INTRODUCTION OF AB INITIO QUANTUM 0:0).1 Fundamental of Molecular Orbital TheOry.2 Hartree-Fock TheOrV.- óc 5 HH HH ng ng HH ĐH cư 79 4.3 Density Functional TH€OFy.

óc HH KH HH HH HH rệt 83 4.4 Basis Sets nh ố ố ố .5 Effective Core Potentials (ECPS). HH ng ng ng nh kg xà 90 4.6 Electronic Excited States CalculafIOTS. 93 CHAPTER FIVE: SPECTROSCOPIC STUDY AND COMPUTATIONAL RESULTS OF fac-Rhenium(1)(CO);(4,4 -t-butyl-2,2 -bipyridine) CL 00. HH ng TH KH Hư HH96 5.3 Time-resolved ÏnfTared.

--- --- ca kg Hà de, 99 5. - --sk sk nh HH HH HH 102 5.4 Discussions and ConcÌÏuSIOT.- -- + << +4 vn * HH HH HH HH rry 106 1. 109 xiii CHAPTER SIX: SPECTROSCOPIC STUDY AND CHEMICAL MODELING OF MONO-RE(D CENTERED CARBYNE ®00)/040 20.1 Absorption SD€CITA.- - HH ng gà 114 3#6N N eo.1 State Assignments, Acetylene Length Effect and Terminal Group 507-1000.2 Computational Methods Compar1son.5 Summary and ConcÌuSIOTI. - - ¿<2 + 211 3E 9 9t 2 HH th rệt 146 6.

147 CHAPTER SEVEN: SPECTROSCOPIC CHARACTERIZATION AND CHEMICAL MODELING OF WIRELIKE LUMINESCENT BIMETALLIC RHENIUM(@) CARBYNES: [Re(Bu2bpy)(CO)3]2(C=C)_, n = 4, 5, AND 6.2 Results and [DDIsCUSSIOT. óc càng g2 HH H0 HH cá g1 vn 150 7.1 Electronic Absorption SD€CTTa.- cu» ng 150 XIV 7.2 Excitation Wavelength Dependence in PMMA Matrices .3 Wavelength Dependence of the Excitation Spectra in PMMA 0/5117 .4 Steady-State Emission Spectra in THF Solution.5 Lifetimes of Samples in PMMA Matrices and in THF Solutions.6 Infrared Spectra at 77K. cà LH nh HH nhe rời 167 7.7 Excited State Infrared Signatur€s.- HH HH Ha HH nhờ 171 I599oö0 ch.10 Orbital Nature and Charge Transfer Properties. 193 CHAPTER EIGHT: FUTURE DIRECTIONS.--- Án HH HH HH HH ng.

ng” HH HH Tà 1111141481111 1k6 198 L6) 1si14-1801/0e i0: 0111. 199 Appendix I NMR Specfra. g HH He 200 Appendix II Relative Spectral Irradiance Standardization. 232 XV LIST OF FIGURES Figure 1.1 MWNTs and SWNTs Images (From REF-16 and 19).2 AFM Image of a 3 um Long Single Wall Carbon Nanotube (From REF- Figure 1.4 AFM Image of an M-DNA Bundle on the Surface of Gold Electrode (scale bar: 1 Um) (From REE-2 Ï).5 Molecular Structures of Pt Containing Polymers (From REF-38) .6 Molecular Formula and Emission Spectra of Compound [Re(‘Buzbpy)(CO)3(C=CC=C)Re(‘Bu2bpy)(CO); in degassed THF at 298 K with Excitation Wavelength at 380 nm (---) and 480 nm (—) (From Figure 1.7 Molecular Formula and Absorption Spectra of Polyynediyl Complexes (CHạC];) and (inset) Relationship between Amax (eV) and 1/n (n = number of alkynyl units) (From REE-44).-- --- c c nh HH 16 Figure 1.8 The Three Most Effective Charge Transfer Molecules (From REE-50) .9 Molecular Structure and Abbreviations of the Ru(II) ~ Re(I) Complexes 00006:(8.1 Abbreviations for Rhenium (1) Tricarbonyl Diimine Acetylide Complexes Figure 2.3 Schematic Mechanism of Eglinton Coupling Reaction.4 Schematic Diagram for Steady State Emission Apparafus.5 Schematic Diagram for Luminescence Lifetime Apparatus.6 Schematic Diagram for Excitation Experiments Apparatus.7 Schematic Diagram for Time-Resolved Infrared Experiments Apparatus.1 Jablonski Diagram for Transition Processes: solid arrows — radiative processes; dashed arrows — non-radiative processes; So, S¡, S; - the singlet electronic states; T, - a triplet electronic state; v — vibrational states within each electronic state; A - absorption; B — internal conversion; C — vibrational relaxation; D — intersystem crossing; E — fluorescence; F ~ phosphorescence; G — non-radiative deCay.2 Schematic Orbital Diagram of Available Transitions of d° Metal in the Octahedral Crystal Ligand Field: a — metal-centerd dd transition; b — metal-to-ligand charge transfer; c — ligand-to-metal charge transfer; d — ligand mn transtion if within the same ligand or ligand-to-ligand charge transfer if occurring between two different ligands.3 The Antisymmtric Stretch Mode for the Acetylene Groups.1 Room Temperature Absorption Spectrum in THF.2 Excitation and Emission Spectra in PMMA at 77 K.

Excitation: solid line, monitoring at 580 nm; Emission spectrum: dashed line, excited at 408 nm Figure 5.