SCHEDULED MAINTENANCE
Synthesis, isomerism and supramolecular chemistry of diphenylmethanimine complexes of the coinage metals
Abstract
The reactions of [AuCl(SMe
2
)] or
[AuBr(C
4
H
8
S)] with 1 equivalent of
diphenylmethanimine led to the formation of the complexes
[AuCl(Ph
2
C![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
NH)] 1a,
[Au(Ph
2
CNH)
2
][AuCl
2
] 1b
and [Au(Ph
2
CNH)
2
][AuBr
2
]
2, respectively. Treatment of 1a, 1b with KI in
the two-phase system dichloromethane–water induced a redox process to
give Au
0
and
[Au(Ph
2
CNH)
2
][I
3
] 3. The
same result was obtained when AuI and Ph
2
CNH were
allowed to react under anhydrous and oxygen-free conditions.
Copper(I) iodide reacted with an excess of
Ph
2
CNH with formation of the complex
[CuI(Ph
2
CNH)] 4. Bis(diphenylmethanimine)
complexes of gold,
[Au(Ph
2
CNH)
2
]BF
4
5, and
silver, [Ag(Ph
2
CNH)
2
]BF
4
6, were prepared by the reaction of 2 equivalents of the ketimine
and [Au(PhCN)
2
]BF
4
or AgBF
4
in
dichloromethane or tetrahydrofuran solutions, respectively. The crystal
structures of the complexes 1a, 1b, 2,
3, 5 and 6 have been determined. The
(Ph
2
CNH)AuCl units of compound 1a form infinite
zigzag chains via weak
Au · · · Au contacts
[3.3633(5) Å]. In 1b two AuCl
2
-
anions and two (Ph
2
CNH)
2
Au
+
cations form a tetranuclear Z-type unit with
Au · · · Au contacts of
3.1944(5)
[Au(1) · · · Au(2)],
3.604(1)
[Au(1) · · · Au(2′)]
and 3.392(1)Å
[Au(1) · · · Au(1
′)]. The
N–H · · · Cl
geometry suggests hydrogen bonding between the hydrogen and chlorine atoms
of neighbouring ions. The bromine compound 2 is isostructural to
the chloride 1b with slightly longer
Au · · · Au distances.
Compound 3 shows bis(diphenylmethanimine)gold(I)
cations and triiodide anions with no anomalies in the packing and in bond
distances and angles. The geometry of the silver(I) and
gold(I) complexes 5 and 6 are quite similar
except for the observation that the Au–N bond is 0.11 Å
shorter than the Ag–N bond, which suggests that two-co-ordinate
gold(I) is indeed smaller than two-co-ordinate
silver(I) in systems with nitrogen-containing ligands, as
previously observed for phosphine complexes.
NH)] 1a,
[Au(Ph
2
CNH)
2
][AuCl
2
] 1b
and [Au(Ph
2
CNH)
2
][AuBr
2
]
2, respectively. Treatment of 1a, 1b with KI in
the two-phase system dichloromethane–water induced a redox process to
give Au
0
and
[Au(Ph
2
CNH)
2
][I
3
] 3. The
same result was obtained when AuI and Ph
2
CNH were
allowed to react under anhydrous and oxygen-free conditions.
Copper(I) iodide reacted with an excess of
Ph
2
CNH with formation of the complex
[CuI(Ph
2
CNH)] 4. Bis(diphenylmethanimine)
complexes of gold,
[Au(Ph
2
CNH)
2
]BF
4
5, and
silver, [Ag(Ph
2
CNH)
2
]BF
4
6, were prepared by the reaction of 2 equivalents of the ketimine
and [Au(PhCN)
2
]BF
4
or AgBF
4
in
dichloromethane or tetrahydrofuran solutions, respectively. The crystal
structures of the complexes 1a, 1b, 2,
3, 5 and 6 have been determined. The
(Ph
2
CNH)AuCl units of compound 1a form infinite
zigzag chains via weak
Au · · · Au contacts
[3.3633(5) Å]. In 1b two AuCl
2
-
anions and two (Ph
2
CNH)
2
Au
+
cations form a tetranuclear Z-type unit with
Au · · · Au contacts of
3.1944(5)
[Au(1) · · · Au(2)],
3.604(1)
[Au(1) · · · Au(2′)]
and 3.392(1)Å
[Au(1) · · · Au(1
′)]. The
N–H · · · Cl
geometry suggests hydrogen bonding between the hydrogen and chlorine atoms
of neighbouring ions. The bromine compound 2 is isostructural to
the chloride 1b with slightly longer
Au · · · Au distances.
Compound 3 shows bis(diphenylmethanimine)gold(I)
cations and triiodide anions with no anomalies in the packing and in bond
distances and angles. The geometry of the silver(I) and
gold(I) complexes 5 and 6 are quite similar
except for the observation that the Au–N bond is 0.11 Å
shorter than the Ag–N bond, which suggests that two-co-ordinate
gold(I) is indeed smaller than two-co-ordinate
silver(I) in systems with nitrogen-containing ligands, as
previously observed for phosphine complexes.
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