Synthesis And Study Of Optical Resolution Of Chiral Porphyrinato Phthalocyaninato Complexes

Phthalocyanines and porphyrins are two important classes of pigments which have found their applications in various disciplines. Both series belong to a cyclic tetrapyrrole family in which the four isoindole or pyrrole nitrogen atoms are able to complex with a range of metal ions. With large metal centers which favor octa-coordination (e.g. rare earths, actinides, group 4 transition metals, and main group elements such as In, Sn, As, Sb, and Bi), sandwich-type complexes in the form of double-and triple-deckers can be formed. Due to the intramolecular-interactions and the intrinsic nature of the metal centers, these novel complexes display characteristic features, which cannot be found in their non-sandwich counterparts, enabling them to be used in different areas. They are versatile materials for electrochromic displays, field effect transistors, gas sensors and as structural and spectroscopic models for the special pair found in the bacterial photosynthetic reaction centers.Chiral porphyrinic compounds are abundant in living systems. Due to their fundamental importance in many biological processes, chiral porphyrins (Pors) have been extensively studied in view of biomimetic synthetic models over the past few decades. The phthalocyanine counterparts have only been reported recently. Our research work has been focused on the synthesis, characterization and resolution of chiral macrocyclic tetrapyrrole compounds include the following three parts:1. Amino Acid Modified Mixed (Porphyrinato) (Phthalocyaninato) Rare Earth Double-Decker Complexes:Synthesis and spectroscopic studiesPorphyrins play essential roles in hemoglobin, cytochrome, chlorophyll and other biological macromolecules and participate in the process of a series of important biological systems. Studies of molecular design, synthesis and application using the unique structure and properties features of porphyrin has been subject to chemical, biological, and medical scientists. Previously, researchers have synthesized a series of porphyrin derivatives, trying to simulate the physiological characteristics, so far, it is still limited to relatively simple derivatives, which have very strong hydrophobicity.. The use of amino acids on the porphyrin ring was modified to be closer to the natural structure and properties of porphyrin compounds. Amino acid is the major component of proteins; the introduction of amino acid side chain makes the whole porphyrin molecule to specific protein molecules demonstrating selective recognition. According to our knowledge, only few studies on monomeric porphyrin (or phthalocyanine) complexes modified by amino acid have been reported. We have prepared a new series of sandwich type mixed (porphyrinato) (phthalocyaninato) rare earth double-decker complexes [EuⅢH{Pc(α-3-OC5H(11))4}{TriBPP(NHR)}] (R= H, C8H(17)) (1,2), [HoⅢH{Pc(α-3-OC5H(11))4}{TriCIPP(NHR)}] (R= H, C8H(17)) (5,6), [HoⅢH{Pc(α-3-OC5H(11))4}{TriBPP(NHR)}] (R= H, C8H(17)) (9,10) [HoⅢH{Pc(α-OC4H9)8}{TriBPP(NHR)}] (R-H, C8H(17)) (13,14) and the corresponding amino acid modified double-deckers [EuⅢH{Pc(αa-3-OC5H(11))4}{TriBPP(NR-L-Phe-Boc)}] (R= H, C8H(17)) (3,4), [HoⅢH{Pc(α-3-OC5H(11))4}{TriClPP(NR-L-Phe-Boc)}] (R= H, C8H(17)) (7,8), [HoⅢH{Pc(α-3-OC5H(11))4}{TriBPP(NR-L-Phe-Boc)}] (R-H, C8H(17)) (11,12) [HoⅢH{Pc(α-OC4H9)8}{TriBPP(NR-L-Phe-Boc)}] (R= H, C8H(17)) (15,16) for the first time. These complexes have been fully characterized by elemental analyses and a wide range of spectroscopic methods, including Mass, UV-Vis and NMR.2. Mixed (Phthalocyaninato)(Porphyrinato) Rare Earth Double-Decker Complexes with C4-Chirality:Synthesis, Optical Resolution, and Absolute Configuration AssignmentWe are motivated to design and prepare new chiral sandwich-type phthalocyaninato and porphyrinato rare earth complexes with a view to creating novel applications in material science and catalysis. The strategy towards chiral sandwich-type tetrapyrrole rare earth complexes involves utilization of 1,8,15,22-tetrakis(alkoxy)-substituted phthalcoyanine ligand with C(4h) symmetry. This tetrapyrrole ligand possesses a single-handed rotational arrangement of the substituted pattern, actually two enantiotopic faces. As a result, attachment of the entity on either side of the Pc ring will eliminate the mirror plane of C(4h) symmetry and lead to chiral molecules with a C4 or even further decreased symmetry, C2 or C5. In the present chapter, we describe the synthesis and first optical resolution of mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes [HMⅢ{Pc(α-3-OC5H(11))4}{TOAPP}] [M= Y (1), Ho (2)] with C4 symmetry, by using a chiral HPLC technique combined with the formation of their diastereotopic mixture, utilizing L-Boc-Phe-OH as the chiral resolving agent. The absolute configurations of these C4-chiral complexes were assigned by comparing experimental CD spectra with simulated one on the basis of time-dependent density functional theory.3. Synthesis and Optical Resolution of Naphthalene-Substituted Chiral PorphyrinThere has been a growing interest in optically active tetrapyrrole derivatives because of their biological relevance and various potential applications. Chiral porphyrins, ranging from synthetic to naturally occurring analogues, have been extensively studied over the past few decades. A series of hydroxylation and epoxidation selectively catalyzed by cytochrome P450 has been reported recently. Catalysts of chiral metalloporphyrin have attracted great interest in chemists, and the most important challenge is the synthesis of chiral catalysts. For the meso-substituted naphthyl porphyrin, rotation of the naphthyl along the C (meso)-C (nph) bond is restricted only in one side of the porphyrin ring and perturbed due to the steric hindrance. We have prepared two novel meso-naphthyl substituted chiral porphyrins: ZnPor(Ph)(Nph)(PhOC(16)H(33)) (1) and ZnPor(Ph)(dNph)(PhOH) (2), which have been characterized by Mass, UV-Vis and NMR. Resolution of the two complexes using a chiral HPLC technique has been failed. Synthesis and optical resolution of novel chiral porphyrins, study of their performance as asymmetric catalysis will be the focus of future work.