Three 15N-labelled trans-Pt(II) amine complexes with isopropylamine (15N-ipa), methylamine (15N-ma) and dimethylamine (15N-dma) have been prepared and characterized. 2D [1H,15N] HSQC NMR spectroscopy was used to obtain the rate and equilibrium constants for the aquation of trans-[PtCl2(15N-ipa)(15N-ma)] (15N-1), trans-[PtCl2(15N-dma)(15N-ma)] (15N-2) and trans-[PtCl2(15N-dma)(15N-ipa)] (15N-3) in 100 mM NaClO4 solutions at 298 K. New 15N shift ranges for H2N–PtII–N and HN–PtII–N groups are reported. Formation of the diaqua complex was not observed for 3 and accounted for <2% of the species at equilibrium for 1 and 2. The first aquation step is significantly faster for 2 (k1 = 14 × 10−5 s−1) than for the two complexes with the bulkier ipa ligand (k1 = 5.5 × 10−5 s−1 (1), 6.1 × 10−5 s−1 (3)), but 2 is the least aquated of the three complexes at equilibrium. The pKa values for the monoaqua adducts of 1–3 are similar (5.98, 5.85 and 5.91, respectively) and 0.4 pH units lower than the related cis complex cis-[PtCl2(dma)2], indicating a smaller proportion of more reactive aqua species will exist at physiological pH. The pKa values for the diaqua adduct of 2 (4.59 and 7.98) are 0.3–0.6 pH units higher than those of 1 (4.31 and 7.30) and 3 (4.28 and 7.29), which have very similar values. The speciation profiles of 1–3, calculated on the basis of the calculated equilibrium and dissociation constants, indicate that <1% hydrolyzed species will exist under physiological conditions in cancer cells. The cytotoxicity of 1–3 (non-15N-labelled) was assessed in three cancer lines (SF268, MCF-7 and NCI-H460). The new trans-Pt(II) diamine complex 2 is more active than 1 and 3 in all cases and is more potent than cisplatin in the MCF-7 adenocarcinoma cell line.
已制备并表征了三种 15N 标记的反式 Pt(II) 胺与
异丙胺 (15N-ipa)、
甲胺 (15N-ma) 和
二甲胺 (15N-dma) 的配合物。 2D [1H,15N] HSQC NMR 光谱用于获得反式-[PtCl2(15N-ipa)(15N-ma)] (15N-1)、反式-[PtCl2(15N-)
水化的速率和平衡常数dma)(15N-ma)] (15N-2) 和反式-[PtCl2(15N-dma)(15N-ipa)] (15N-3) 在 100 mM NaClO4 溶液中,298 K。
H2N 的新 15N 位移范围–报道了 PtII-N 和 HN-PtII-N 基团。 3 中没有观察到双
水复合物的形成,并且在 1 和 2 的平衡状态下占物种的 <2%。 2 (k1 = 14 × 10−5 s−1) 的第一个水化步骤明显快于 2 的水化步骤。两个具有较大 ipa 配体的配合物(k1 = 5.5 × 10−5 s−1 (1), 6.1 × 10−5 s−1 (3)),但 2 是平衡时三个配合物中水合度最低的。 1-3 的单水加合物的 pKa 值相似(分别为 5.98、5.85 和 5.91),并且比相关顺式复合物 cis-[PtCl2(dma)2] 低 0.4 个 pH 单位,表明更具反应性的水的比例较小物种将在生理pH值下存在。 2 的二水加合物的 pKa 值(4.59 和 7.98)比 1(4.31 和 7.30)和 3(4.28 和 7.29)的 pKa 值高 0.3-0.6 个 pH 单位,这两个值非常相似。根据计算的平衡和解离常数计算出的 1-3 的形态分布表明,在生理条件下癌细胞中将存在 <1% 的水解物质。在三种癌症系(SF268、MCF-7 和 NCI-H460)中评估了 1-3(非 15N 标记)的细胞毒性。新的反式 Pt(II) 二胺复合物 2 在所有情况下都比 1 和 3 更活跃,并且在 MCF-7 腺癌细胞系中比
顺铂更有效。