In chapter 1, two chiral and one racemic fluorescent dimeric zinc complex {$[Zn_2(\emph{slys}H)_2Cl_2]\cdot(CH_3OH)_2\cdot(H_2O)_3 (\bf{1})$, $[Zn_2(\emph{slys}H)_2 (NO_3)_2]\cdot(H_2O)_3 (\bf{2})$, $[Zn_2(\emph{rslys}H)_2(\mu-OAc)_2] (\bf{3})$} are compared herein. Presently, $\bf{3}$ has been synthesized by an one-pot reaction in which the D-/L- lysine-based Schiff base ligand [$\emph{slys}$ = 6-amino-2-{(2-hydroxybenzylidene)amino}hexanoate] is generated $\emph{in situ}$. These compounds have been characterized by single-crystal X-ray diffraction and by various spectroscopic techniques. The structures of previously reported compounds $\bf{1}$ and $\bf{2}$ are closely related in which two zinc centers possess two phenolate-bridges and an axial chloride or nitrate ligand. The novel compound $\bf{3}$ differs structurally through the presence and coordination mode of two bridging acetate groups spanning the dizinc core and formally releasing the phenolate bridging Schiff base ligands. These compounds ($\bf{(1 ? 3)}$) are highly blue fluorescent, either as solids or dissolved species. Under neutral and aqueous conditions (pH 7.4; 0.01 M HEPES buffer, $H_2O$:MeOH = 9:1), the quantum yields are $\Phi;_F$ = 0.17 ($\bf{1}$), 0.21 ($\bf{2}$) ($\lambda_{ex}$ = 352 nm, $\lambda_{em}$ = 452 nm), $Φ_F$ = 0.16 ($\bf{3}$) ($$\lambda$_{ex}$ = 354 nm, $\lambda_{em}$ 452 nm). Complex $\bf{3}$ metal ion detection capability (i.e., $Na^+$,$K^+$, $Ca^{2+}$, $Mg^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Mn^{2+}$, $Cu^{2+}$, $Pb^{2+}$, $Ag^+$, $Hg^{2+}$, and $Cd^{2+}$) was gauged in aqueous media at physiological pH facilitated by the similarity of its starting photophysical properties with those of $\bf{1}$ and $\bf{2}$. These dizinc species were all found to act as highly selective fluorescent ON-OFF probes for $Cu^{2+}$ through the direct displacement of two zinc ions in aqueous media at physiological pH range. The phenolate-bridged compounds $\bf{1}$ and $\bf{2}$, however, showed better selectivity towards $Cu^{2+}$ over competitive ions, $Ni^{2+}$ and $Co^{2+}$ than the acetate-bridged compound $\bf{3}$.
In chapter 2, the mononuclear complex $[Cu(\emph{rslys}H)(OAc)]\cdot4.5H_2O (\bf{1}) [\emph{rslys}$=6-amino-2-[(2-hydroxybenzylidene)amino]-hexanoate] has been prepared via an easy “one-pot” synthetic method in which the corresponding D/L-lysine-derived Schiff base ligand is generated $\emph{in situ}$. Further, the dinuclear acetate-bridged Cu(II) complex, $[Cu_2(\emph{rslys})_2(\mu-OAc)]\cdot(OH)\cdot6H_2O (\bf{2})$ was obtained as a minor product along with the mononuclear compound from an “one pot” crystallization. These complexes have been characterized by UV/vis, IR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction. The molecular structures of $\bf{2}$ confirm its dimeric nature with dicopper(II) phenolate and acetate-bridge environments. Variable-temperature magnetic analysis revealed a weak antiferromagnetic coupling interaction for the dicopper species, mediated by the phenolate and bridging acetate groups. Large numbers of solvent water molecules are present in the lattice of mononuclear compound $\bf{1}$. The carboxylate oxygen of the Schiff base ligand and terminal -$NH_2$ groups engage in intermolecular hydrogen bonding with solvent water molecules, giving one- to three-dimensional (1- to 3-D) networks. The lattice water molecules form cyclic octameric water clusters and 1-D polymeric water cluster chains, which also assist the formation of 3-D hydrogen-bonded networks. Also in compound $\bf{2}$, 3-D hydrogen bonded networks are observed, but in contrast to the cyclic octanuclear water clusters and 1-D cluster chain for $\bf{1}$, infinite P- and M-helical water cluster chains and two-dimensional (2-D) sheets are present. A hexadecanuclear water cluster may be regarded as a formal building units for the 2-D sheet. The racemic D-/L-lysine used herein as a source of the Schiff base ligand led to racemic hydrogen-bonded networks containing enantiomeric complexes of D- and L-lysine Schiff base ligands in the packing structures for compounds $\bf{1}$ and $\bf{2}$.
In chapter 3, the compounds $Zn_2(\emph{slys})_2Cl_2 (\bf{1})$, $Zn_2(\emph{rslys}H)_2($\mu$-OAc)_2 (\bf{2})$, [$H_2\emph{slys}$ = 6-amino-2-{(2-hydroxybenzylidene)amino} hexanoic acid], $Ca_2(\emph{smet})_2Cl_2$ ($\bf{3}$) and $Mg_2(\emph{smet})_2Cl_2$ ($\bf{4}$) [$H_2 \emph{smet}$= 4-methylsulfanyl-2-{(2-hydroxybenzylidene)amino} butanoic acid] and $Mg(\emph{s-Boc-lys})Cl_2$ ($\bf{5}$), [$H_2 \emph{s-Boc-lys}$=6-$N^{\epsilon}$-(tert-butoxycarbonyl)amino-2-{(2-hydroxybenzylidene)amino} hexanoic acid] were synthesized by an “one-pot” method in which the corresponding L-Lysine, L-methionine and Boc-protected L-Lysine derived Schiff base ligand are generated $\emph{in situ}$. All compounds have been characterized by $^1H$ NMR spectroscopy and ESI-MS spectrometry. Compound $\bf{1}$ was investigated for its use as a dopamine senor, dopamine is biologically important. Also, compound $\bf{2}$ was investigated for its response with different anions; and finally PPi and ATP showed major, remarkable changes in UV-vis spectra and emission spectra. Compound $\bf{3}$ reveals that it exists as $H_2\emph{smet}$ in an aqueous solution (MeOH/$H_2O$=9:1), and additional 1 equiv. of $Ca^{2+}$ fully quenched the fluorescence of $\bf{3}$. Additionally, the presence of $Mg^{2+}$ and $Zn^{2+}$ enhanced the fluorescence of compound $\bf{3}$ around 20-fold and 37-fold, respectively. For compound $\bf{4}$ and $\bf{5}$, although only characterization was mentioned in this paper, these will be investigated in terms of either metal cation or anion sensing in this group in the future.
1장에서는, [$[Zn_2(\emph{slys}H)_2Cl_2]\cdot(CH_3OH)_2\cdot(H_2O)_3 (\bf{1})$, $[Zn_2(\emph{slys}H)_2 (NO_3)_2]\cdot(H_2O)_3 (\bf{2})$, $[Zn_2(\emph{rslys}H)_2(\mu-OAc)_2] (\bf{3})$들의 구조가 비교되었다. 이 중 $[Zn_2(\emph{rslys}H)_2(\mu-OAc)_2](\bf{3})$ 원팟 합성법에 의하여 새롭게 합성되었으며, 리간드 [$\emph{slys}$ = 6-amino-2-{(2-hydroxybenzylidene)amino}hexanoate]는 반응 중 생성되었다.
물질($\bf{3}$)의 구조는 단결정 X-선 회절분석과 여러가지 분광분석법에 의하여 분석되었고, 물질 $\bf{1}$, $\bf{2}$의 구조와 비교되었다. 물질 1,2는 두 중심 금속이 두개의 강한 phenolate-브릿지 리간드에 의하여 연결되어있으며, 물질 $\bf{3}$은 두 중심 금속이 다소 약한 두개의 acetate-브릿지 리간드에 의하여 연결되어 있음이 밝혀졌다.
물질들($\bf{1-3}$)은 고체, 액체 상태 모두에서 강한 청색의 형광을 띠며, 중성 수용액 상태 (pH 7.4)에서 각각 형광 수율, $Φ_F$ = 0.17 ($\bf{1}$), 0.21 ($\bf{2}$) ($\lambda_{ex}$ = 352 nm, $\lambda_{em}$ = 452 nm), $\Phi_F$ = 0.16 ($\bf{3}$) ($\lambda_{ex}$ = 354 nm, $\lambda_{em}$ 452 nm)을 나타내었다.
물질 $\bf{3}$은 경쟁적인 여러가지 금속 이온들과 비교하였을 때, 구리 이온에 대하여 강한 형광 ON-OFF 선택성을 보였으며, 이 결과는 물질 $\bf{1}$,$\bf{2}$의 특성과 일치한다.
2장에서는, 단핵체인 $[Cu(rslysH)(OAc)].4.5H_2O (\bf{1})$, 이핵체인 $[Cu_2(\emph{rslys})_2(\mu-OAc)]\cdot(OH)\cdot6H_2O (\bf{2}) [\emph{rslys}$=6-amino-2-[(2-hydroxybenzylidene)amino]-hexanoate] 이 개발되었다. 이 두 물질은 원팟 합성법으로 합성되었으며, 원팟에서 물질 $\bf{1}$은 주생성물로, 물질 $\bf{2}$는 부생성물로 결정화되었다.
물질들의 구조는 자외선 분광법, 질량분석법, 적외선 분광법, 단결정 X-선 회절분석법에 의하여 밝혀졌다.
물질 $\bf{2}$의 구조를 보면, 두 중심 금속이 phenolate와 acetate 브릿지 리간드에 의하여 연결되어있으며, 이 두 금속 사이의 자기적 특성을 측정해 보았을 때, 약한 반강자성을 띠는 것을 확인하였다.
물질 $\bf{1}$에는 격자 안에 많은 물 분자가 존재하는데, 이 물분자는 카복실기의 산소 분자와 쉬프 염기 리간드의 질소 분자가 수소 결합 하도록 도와주며, 이 결합에 의하여 물질이 1, 3차원적 구조를 띠게 된다.
격자의 물 분자들은 팔핵체의 물 클러스터로 존재하며 1-D 클러스터 체인을 형성한다. 그리고 체인이 확장하여 3-D 수소 결합 네트워크를 형성한다.
물질 $\bf{2}$에는 3-D 수소 결합 네트워크가 관찰되었으며, 물질 1과는 달리, 2-D에서 무한 P- 와 M- 나선형의 물 클러스터 체인을 형성하였다. 물 클러스터는 통합적으로 2-D 면에서 십육핵체로 존재한다.
물질 $\bf{1}$,$\bf{2}$의 합성에는 라세미의 D-/L- 라이신이 사용되었기 때문에 D-와 L- 라이신 쉬프 염기 리간드를 모두 포함한 광학이성질체로 구성된 수소 결합 네트워크가 관찰되었다.
3장에서는, $Zn_2(\emph{slys})_2Cl_2 (\bf{1})$, $Zn_2(\emph{rslys}H)_2(\mu-OAc)_2 (\bf{2})$, [$H_2\emph{slys}$ = 6-amino-2-{(2-hydroxybenzylidene)amino} hexanoic acid], $Ca_2(\emph{smet})_2Cl_2 (\bf{3})$, $Mg_2(\emph{smet})_2Cl_2 (\bf{4})$, [$H_2smet$ = 4-methylsulfanyl-2-{(2-hydroxybenzylidene)amino} butanoic acid], Mg($\emph{s-Boc-lys}$)Cl ($\bf{5}$), [H_2$\emph{s-Boc-lys}$=6-$N^{\epsilon}$-(tert-butoxycarbonyl)amino-2-{(2-hydroxybenzylidene)amino} hexanoic acid] 가 원팟 합성법에 의하여 합성되었으며, 물질의 구조는 $^1H$ NMR 분광광도법과 ESI-질량 분석법에 의하여 밝혀졌다.
물질 $\bf{1}$은 생물학적으로 중요한 물질인 도파민의 검출에 시도되었으며, 물질 $\bf{2}$는 다양한 음이온과의 반응을 통하여 PPi와 ATP에 형광 ON-OFF 선택성을 갖는 것을 관찰하였다.
물질 $\bf{3}$은 마그네슘과 아연 이온을 첨가함으로써 형광이 각각 20배, 37배 증가한 것을 확인하였다. 물질 $\bf{4}$와 $\bf{5}$에 대해서는 NMR 분광광도법에 의한 구조 분석만 이루어진 상태이지만, 나아가 다양한 금속이온이나 음이온에 대한 선택성과 감도를 분석해 볼 것이다.
