求翻译 化学类文献Design and synthesis: 6-Phenyl-2,2’-bipyridine (HC^

求翻译 化学类文献
Design and synthesis: 6-Phenyl-2,2’-bipyridine (HC^N^N)
and 1,3-di(pyridin-2-yl)benzene (HN^C^N) represent the
basic designs of common p-conjugated tridentate cyclometalating
ligands for cyclometalated PtII systems. However,
these well-established ligand systems are difficult to be further
modified or functionalised. The presence of a 1-pyrazolyl-
NH on the new cyclometalating ligand, HL1, enables its
easy functionalisation by nucleophilic substitution.[14] We
demonstrated this by direct alkylation of the 1-pyrazolyl-
NH site on HL1 with 1,5-dibromopentane to generate HL2
in good yield. Further nucleophilic substitution of the terminal
alkyl bromide on HL2 by PPh3 yielded the triphenylphosphonium-
functionalised cyclometalating ligand, triphenyl{
5-[3-(6-phenylpyridin-2-yl)-1H-pyrazol-1-yl]pentyl}phosphonium
bromide (HL3) (Scheme 1). The chloride salt of
HL3 was obtained by simple metathesis. The corresponding
cyclometalated PtII–chloride complex, [Pt(L3)Cl]+, was obtained
in good yield by direct metalation of HL3 (chloride
salt) with K2PtCl4 in glacial acetic acid. All of the new ligands
and the cycloplatinated complex reported have been
fully characterised by 1H NMR spectroscopy and mass spectrometry.
Linear photophysical studies: Electronic transition spectra
of [Pt(L3)Cl]+ in various solvents are shown in Figure 1A.
Spectroscopic properties of the complex show strong resemblances
to its related [Pt(L1)Cl] complex. The UV-visible
region is dominated by intense absorption bands at around
275–375 nm with extinction coefficients (e) in the order of
104 dm3mol\21cm\21 and a less intense band at around 380–
410 nm with e in the order of 103 dm3mol\21cm\21. With reference
to previous spectroscopic studies of the analogous [Pt-
ACHTUNGTRENUNG(C^N^N)Cl] and [Pt(L1)Cl] complexes, absorption bands at
275–375 nm are attributed to intraligand (p(L)!p*(L))
transitions, whereas the lower energy absorption band at
380–410 nm is assigned the spin-allowed dp(Pt)!p*(L)
metal-to-ligand charge-transfer (1MLCT) transition. The
lmax of the lower energy band is solvent dependent and
shifts from 387 nm in methanol to 393 nm in chloroform.
This supports the assignment that the absorption band is
from a charge-transfer transition.

设计和合成：6苯基-2,2’-二吡啶（HC∧N∧N）和1,3-二（吡啶-2-yl）苯（HN∧C∧N）代表用于环金属铂II系统的普通π共轭三齿环金属配体.可是,这些成熟的配体系统难于进一步改性或官能化.1-吡唑基-NH在新的环金属配体HL1上的存在使其能通过亲核取代而容易的官能化.[14] 我们通过在HL1上的1-吡唑基-NH场所用1,5-直接烷化而演示了这一点.对在HL2上的端二溴戊酮用PPh3进一步亲核取代产生了三苯基膦官能化的环金属配体、三苯基｛5[3-(6-苯基吡啶-2-yl)-1H吡唑-1-yl]正戊基｝溴化膦（HL3）（方案1）HL3的氯化物盐用简单的置换获得.相应的环金属铂II氯化物氯化物[Pt(L3)Cl]+通过HL3（氯化物盐）与K2PtCl4在冰醋酸中的直接烷化作用以良好的产率获得.所有报道的新配体和环铂化络合物都已经用1H核磁共振光谱法和质谱法充分表征过.
线性光物理研究：[Pt(L3)Cl]+在不同溶剂中的电子跃迁光谱示于图1A中.络合物的光谱学性质表明了对其相关的[Pt(L1)Cl]+络合物有强烈的相似性.其紫外可见光区大约275～375nm由强烈的吸收带主导,消光系数（ε）在104dm3mol－1cm－1的量级,而在380～410nm的不太强的吸收带,ε在103dm3mol－1cm－1的量级.参考以前对模拟的[Pt(C∧N∧N)Cl]+和[Pt(L1)Cl]+络合物的光谱学研究,在275～375nm处的吸收带归因于配体内的 跃迁,而在380～410nm出的较低吸收带则归因于自旋允许的 金属到配体的电荷转移（1MLCT）迁移.较低能带的λmax是与溶剂有关的,从甲醇的387nm漂移到氯仿的393nm.这支持了吸收带来自于电荷转移的说法.