Treatment of the neutral chloropalladium(II) complexes
[PdClPPh
2
CHC(R)âNâNC(R)+
+
CH
2
PPh
2
}] (R = Bu
t
1a or Ph 1b) with two equivalents of
Li[N(SiMe
3
)
2
]
gave the novel dipalladium(II) complexes
[Pd[PPh
2
CHC(R)âNâNC(R)
CHPPh
2
]}
2
] (R = Bu
t
2a or Ph 2b) containing two palladiumâcarbon bonds, five fused
chelate rings and enamine type (CCâN) moieties.
Treatment
of the chloroplatinum(II) complex
[PtClPPh
2
CHC(Bu
t
)âNâ+
+
NC(Bu
t
)CH
2
PPh
2
}] 1c with
an excess of KOBu
t
in dimethyl sulfoxide (dmso) gave what
was
probably the species
[PtPPh
2
CHC(Bu
t
)âNâN
C(Bu
t
)CHPPh
2
}(dmso)] 3 containing
both a co-ordinated and an unco-ordinated phosphine. The
dipalladium(II) complex 2a or 2b underwent electrophilic
attack at the enamine carbon with acids (HX) to give salts of type
[Pd[PPh
2
CH
2
C(R)NâNC+
+
(R)CHPPh
2
]}
2
]X
2
4
(R = Bu
t
or Ph;
X = trifluoroacetate, chloride or picrate); these, when
treated with sodium methoxide, deprotonated at the methylene carbon to
give the neutral complex 2a or 2b. Treatment of 2a with less than 2
equivalents of trifluoroacetic acid gave the monoprotonated complex
[PdPPh
2
CHC(Bu
t
)NâNC+
+
(Bu
t
)CHPPh
2
}PPh
2
CH
2
C(Bu
t
)NâNC(Bu
t
)
CHPPh
2
}][O
2
CCF
3
] 5a, mixed with
2a
and 4a. Complex 2a with Br
2
or MeI underwent attack at the
enamine carbon CCâN to give the corresponding
bromo or methyl derivatives
[Pd[PPh
2
CH(R)CBu
t
NâN
C(Bu
t
)CHPPh
2
]}
2
]X
2
(R = Br, X = Br 6a; R = Me,
X = I 6b) respectively. When the methyl-substituted salt
was treated with KOBu
t
it gave the neutral
dipalladium(II) complex
[PdCl[PPh
2
C(Me)
C(Bu
t
)âNâNC(Bu
t
)CHPPh
+
+
2
]}
2
] 7. The crystal structure of 2a was
determined.
用两个当量的 Li[N(SiMe 3 ) 2 ]处理中性
氯钯(II)络合物[PdClPPh 2 CHC(R)âNâNC(R)+ + CH 2 PPh 2 } ](R = Bu t 1a 或 Ph 1b),得到含有两个
钯碳键的新型二
钯(II)络合物[Pd[PPh 2 CHC(R)âNâNC(R) CHPPh 2 ]} 2 ](R = Bu t 2a 或 Ph 2b)、2 ](R = Bu t 2a 或 Ph 2b)含有两个
钯碳键、五个融合螯合环和烯
胺类(CCâN)分子。
在
二甲亚砜(dmso)中用过量的 KOBu t 处理
氯铂(II)络合物 [PtClPPh 2 CHC(Bu t )âNâ+ + NC(Bu t )CH 2 PPh 2 }] 1c,得到的可能是同时含有一个配位膦和一个非配位膦的物种 [PtPPh 2 CHC(Bu t )âNâN C(Bu t )CHPPh 2 }(dmso)]3。二
钯(II)络合物 2a 或 2b 的烯胺碳与酸 (HX) 发生亲电作用,生成[Pd[PPh 2 CH 2 C(R)NâNC+ + (R)CHPPh 2 ]} 2 ]X 2 4(R = Bu t 或 Ph;X =
三氟乙酸盐、
氯化物或
苦味酸盐)类型的盐;这些盐经
甲醇钠处理后,亚甲基碳去质子化,生成中性络合物 2a 或 2b。用少于 2 个当量的
三氟乙酸处理 2a,可得到
单质子化络合物 [PdPPh 2 CHC(Bu t )NâNC+ + (Bu t )CHPPh 2 }PPh 2 CH 2 C(Bu t )NâNC(Bu t ) CHPPh 2 }][O 2 CCF 3 ] 5a,并与 2a 和 4a 混合。络合物 2a 与 Br 2 或 MeI 在烯胺碳 CCâN 上发生反应,分别得到相应的
溴或甲基衍
生物 [Pd[PPh 2 CH(R)CBu t NâN C(Bu t )CHPPh 2 ]} 2 ]X 2(R = Br,X = Br 6a;R = Me,X = I 6b)。当甲基取代盐用 KOBu t 处理时,得到中性二
钯(II)配合物 [PdCl[PPh 2 C(Me) C(Bu t )âNâNC(Bu t )CHPPh + + 2 ]} 2 ]。7.确定了 2a 的晶体结构。