Aminoacid N-substituted 1,4,7-triazacyclononane and 1,4,7,10-tetraazacyclododecane Zn2+, Cd2+ and Cu2+ complexes. A preparative, potentiometric titration and NMR spectroscopic studyElectronic supplementary information (ESI) available: Titration curve for H333+ alone and in the presence of Zn2+, Cd2+ and Cu2+. Fig. S2: Distribution variation of 3 and derived species with pH in the presence of Zn2+. See http://www.rsc.org/suppdata/dt/b4/b401763c/
作者:Sally E. Plush、Stephen F. Lincoln、Kevin P. Wainwright
DOI:10.1039/b401763c
日期:——
The pKas and Zn2+, Cd2+ and Cu2+ complexation constants (K) for 1,4,7-tris[(2″S)-acetamido-2″-(methyl-3″-phenylpropionate)]-1,4,7-triazacyclononane, 1, 1,4,7-tris[(2″S)-acetamido-2″-(1″-carboxy-3″-phenylpropane)]-1,4,7-triazacyclononane, H32, 1,4,7-tris[(2″S)-acetamido-2″-(methyl-3″-(1H-3-indolyl)propionate)]-1,4,7-triazacyclononane, 3, and 1,4,7,10-tetrakis[(2″S)-acetamido-2″-(methyl-3″-phenylpropionate)]-1,4,7,10-tetraazacyclododecane, 4, 1,4,7,10-tetrakis[(2″S)-acetamido-2″-(1″-carboxy-3″-phenylpropane)]-1,4,7,10-tetraazacyclododecane, H45, in 20 ∶ 80 v/v water–methanol solution are reported. The pKas within the potentiometric detection range for H313+
= 8.69 and 3.59, for H623+
= 9.06, 6.13, 4.93 and 4.52, H333+
= 8.79 and 3.67, H444+
= 8.50, 5.62 and 3.77 and for H854+
= 9.89, 7.06, 5.53, 5.46, 4.44 and 4.26 where each tertiary amine nitrogen is protonated. The complexes of 1: [Zn(1)]2+
( 9.00), [Cd(1)]2+
(6.49), [Cd(H1)]3+
(4.54) and [Cu(1)]2+
(10.01) are characterized by the log(K/dm3 mol−1) values shown in parentheses. Analogous complexes are formed by 3 and 4: [Zn(3)]2+
(10.19), [Cd(3)]2+
(8.54), [Cu(3)]2+
(10.77), [Zn(4)]2+
(11.41)
[Cd(4)]2+
(9.16), [Cd(H4)]3+
(6.16) and [Cu(4)]2+
(11.71). The tricarboxylic acid H32 generates a greater variety of complexes as exemplified by: [Zn(2)−]
(10.68)
[Zn(H2)]
(6.60)
[Zn(H22)+]
(5.15), [Cd(2)]−
(4.99), [Cd(H2)]
(4.64), [Cd(H22)]+
(3.99), [Cd(H32)]2+
(3.55), [Cu(2)]−
(12.55)
[Cu(H2)]
(7.66), [Cu(H22)]+
(5.54) and [Cu2(2)]4−
(3.23). The complexes of H45 were insufficiently soluble to study in this way. The 1H and 13C NMR spectra of the ligands are consistent with formation of a predominant Zn2+ and Cd2+
Δ or Λ diastereomer. The preparations of the new pendant arm macrocycles H32, 3, 4 and H45 are reported.
报告了1,4,7-三[(2"S)-乙酰氨基-2"-(甲基-3"-苯丙酸酯)]-1,4,7-三氮杂环癸烯(H32)、1,4,7-三[(2"S)-乙酰氨基-2"-(1" -羧基-3"-苯丙烷)]-1,4,7-三氮杂环癸烯、1,4,7-三[(2"S)-乙酰氨基-2"-(甲基-3"-(1H-3-吲哚基)丙酸酯)]-1,4,7-三氮杂环癸烯(3)、以及1,4,7,10-四[(2"S)-乙酰氨基-2"-(甲基-3"-苯丙酸酯)]-1,4,7,10-四氮杂环十二烷(4)、1,4,7,10-四[(2"S)-乙酰氨基-2"-(1"-羧基-3"-苯丙烷)]-1,4,7,10-四氮杂环十二烷(H45)在20:80体积比的水-甲醇溶液中的pKa值及Zn²⁺、Cd²⁺和Cu²⁺的配合常数(K)已被报告。在电位测定范围内,H313⁺的pKa = 8.69和3.59,H623⁺的pKa = 9.06、6.13、4.93和4.52,H333⁺的pKa = 8.79和3.67,H444⁺的pKa = 8.50、5.62和3.77,以及H854⁺的pKa = 9.89、7.06、5.53、5.46、4.44和4.26,其中每个三级胺氮被质子化。这些复合物的1: [Zn(1)]²⁺(9.00)、[Cd(1)]²⁺(6.49)、[Cd(H1)]³⁺(4.54)和[Cu(1)]²⁺(10.01)具有括号中给出的log(K/dm³ mol⁻¹)值。3和4形成类似的复合物:[Zn(3)]²⁺(10.19)、[Cd(3)]²⁺(8.54)、[Cu(3)]²⁺(10.77)、[Zn(4)]²⁺(11.41)、[Cd(4)]²⁺(9.16)、[Cd(H4)]³⁺(6.16)和[Cu(4)]²⁺(11.71)。三羧酸H32产生了更多种类的复合物,例如:[Zn(2)⁻](10.68)、[Zn(H2)](6.60)、[Zn(H22)⁺](5.15)、[Cd(2)]⁻(4.99)、[Cd(H2)](4.64)、[Cd(H22)⁺](3.99)、[Cd(H32)]²⁺(3.55)、[Cu(2)]⁻(12.55)、[Cu(H2)](7.66)、[Cu(H22)⁺](5.54)和[Cu2(2)]⁴⁻(3.23)。H45的复合物溶解性不足,无法以这种方式进行研究。配体的1H和13C NMR光谱与以Zn²⁺和Cd²⁺为主的Δ或Λ立体异构体的形成一致。报告了新型侧臂大环H32、3、4和H45的制备。