Crystallization of 1â¶2 silver(I) halide/pseudo
halideâ¶1,3-bis(diphenylphosphino)propane (dppp) mixtures from
acetonitrile have resulted in the isolation of a novel series of neutral
complexes, [AgX(dppp-P,Pâ²)(dppp-P)]
(X = Cl, Br, I or CN) containing co-ordinated anion and
uni- and bi-dentate dppp ligands. In contrast, the thiocyanate and
nitrate complexes precipitate as ionic
[Ag(dppp-P,Pâ²)
2
]X with unco-ordinated
anion and bidentate phosphine ligands, a structural type previously
found for other 1â¶2 silver(I)â¶diphosphine
complexes. The complexes have been characterized by single-crystal X-ray
structure determinations and solid-state
31
P
cross-polarization magic angle spinning (CP MAS) NMR spectroscopy. The
salt [Ag(dppp-P,Pâ²)
2
]SCN is obtained
as crystals suitable for X-ray studies from pyridine, crystallizing as a
sesqui-pyridine solvate in the monoclinic space group
P2
1
/c with
a = 10.691(2),
b = 24.75(2),
c = 22.360(4) Ã
,
β = 108.38(1)°. The neutral AgXP
3
complexes (X = Cl, Br, I or CN) are isomorphous,
crystallizing in the monoclinic space group C2/c, with
a â 21.8, b â 10.3,
c â 45 Ã
,
β â 95°. The solid-state
31
P CP MAS
spectra are consistent with the structural results; the tetrahedral SCN
and NO
3
complexes give a similar broad complex multiplet
centred at δ -6, whereas the spectra of the neutral
AgXP
3
complexes are interpretable as A
2
BMX spin
systems with signals assignable to the non-co-ordinated (δ
-23), bidentate (δ ca. 13) and unidentate (δ
ca. 3) phosphorus atoms. For the latter
1
J(PâAg) couplings are in the range 288 Hz
(CN) to 367 Hz (Br). Solution
31
P NMR studies on these
complexes show that both neutral and ionic complexes exist in
equilibrium in solution, with the position of the equilibrium dependent
on the nature of the anion X. The potential significance to the
antitumour activity of bis-chelated 1â¶2
silver(I)âdiphosphine complexes is discussed.
在
乙腈中,从1â¶2
银(I)卤化物/伪卤化物â¶1,3-双(
苯基膦)
丙烷(dppp)混合物的结晶化反应中,成功分离出一系列新型中性配合物,[AgX(dppp-P,Pâ²)(dppp-P)](X = Cl, Br, I或CN),这些配合物包含协调阴离子以及单牙和双牙的dppp
配体。相比之下,
硫氰酸盐和
硝酸盐配合物则以离子形式沉淀为[Ag(dppp-P,Pâ²)₂]X,含有未协调的阴离子和双牙
膦配体,这种结构类型先前已在其他1â¶2
银(I)â¶
双膦配合物中发现。通过单晶X射线结构测定和固态31P交叉极化魔角旋转(CP MAS) NMR光谱对这些配合物进行了表征。盐[Ag(dppp-P,Pâ²)₂]SCN从
吡啶中获得,形成适用于X射线研究的晶体,以单斜空间群P21/c结晶,单位晶胞参数为a = 10.691(2),b = 24.75(2),c = 22.360(4) Å,β = 108.38(1)°。中性AgXP₃配合物(X = Cl, Br, I或CN)是等晶型的,在单斜空间群C2/c中结晶,a ≈ 21.8,b ≈ 10.3,c ≈ 45 Å,β ≈ 95°。固态31P CP MAS光谱与结构结果一致;四面体SCN和NO₃配合物的光谱给出一个类似的宽复合多重峰,位于δ -6,而中性AgXP₃配合物的光谱则可解释为A₂BMX自旋系统,信号可归于未协调的(δ -23)、双牙(δ约为13)和单牙(δ约为3)
磷原子。对于后者,1J(P–Ag)的耦合范围为288 Hz(CN)至367 Hz(Br)。对这些配合物的溶液31P NMR研究表明,中性和离子配合物在溶液中处于平衡状态,平衡位置取决于阴离子X的性质。讨论了双螯合1â¶2
银(I)–
双膦配合物对抗肿瘤活性的潜在意义。