There are over fifty examples in which the inner coordination spheres about the Pt(II) atoms of the Pt(η3-X3L)(PL) type are formed by variable combinations of donor atoms of tridentate ligands. Each η3-ligand creates two metallocyclic rings. The complexes based on membered metallocyclic rings can be divided into four groups: 1. 6+6-Membered Metallocyclic Rings, 2. 6+5-Membered Metallocyclic Rings, 3. 5+6-Membered Metallocyclic Rings, and 4. 5+5-Membered Metallocyclic Rings.
1. 6+6-Membered Metallocyclic Rings
There are only three examples in which a η
3-ligand creates such rings (
Table 1). In [Pt(η
3-C
22H
11F
6N
3O
2–O
1,N
1,O
2)(PPh
3)] (at 173 K)
[1][4], the η
3-ligand forms a metallocyclic ring of the O
1C
3N
1C
3O
2 type with common ligating N
1 atoms. The values of the chelate L-Pt-L angles are 90.6° (O
1-Pt-N
1) and 90.2° (N
1-Pt-O
2). The O
1C
2NN
1C
3O
2 type with the respective chelate angles of 88.2° (O
1-Pt-N
1) and 90.0° (N
1-Pt-O
2) was found in [Pt(η
3-C
14H
10N
2O
3–O
1,N
1,O
2)(PPh
3)] (at 150 K)
[2][5]. The remaining L-Pt-L angles open in the following order (mean values): 88.1° (O
2-Pt-P) < 89.0° (O
1-Pt-P) < 176.0° (N
1-Pt-P) < 177.7° (O
1-Pt-O
2). The monodentate PPh
3 displayed square-planar geometry about each Pt(II) atom. The Pt-L bond distance increased in the following order (mean values): 1.995 Å (Pt-O
1 trans to O
2) < 1.996 Å (Pt-O
2) < 2.010 Å (Pt-N
1) < 2.254 Å (Pt-P).
Table 1.
Structural data for Pt(η
3
-X
3
)(Y) derivatives.
a
—6+6-membered metallocyclic rings.
Complex |
Chromophore
Chelate Rings
τ | 4 | | b |
Pt -L | c |
(Å) |
L-Pt-L | c |
,S)(PPh)] toluene [8], [Pt(η-CHNOS–O,N,S)(PPh)] (at 100 K) () [9], and [Pt(η-CHNOS–O,N,S)(PPh)] [7] (). In each of them, the η-ligand creates six- and five-membered metallocyclic rings with a common ligating N atom of the OCNNCS type. The values of the respective chelate angles (mean values) are 92.3° (O-Pt-N) and 84.6° (N-Pt-S). The remaining L-Pt-L bond angles open in the following order (mean values): 90.7° (O-Pt-P) < 92.4° (S-Pt-P) < 175.8° (N-Pt-P) < 175.9° (O-Pt-S). Interestingly, the mean values of both trans-O-Pt-S and N-Pt-P angles are equal. The Pt-L bond distance increases (mean values) in the following order: 2.028 Å (Pt-O trans to S) < 2.035 Å (Pt-N trans to P) < 2.244 Å (Pt-S) < 2.259 Å (Pt-P).
Figure 2. Structure of [Pt(η
3-C
9H
9N
3OS–O
1,N
1,S
1)(PPh
3)]
[6][9].
Table 2. Structural data for Pt(η3-X3)(Y) derivatives. a—6+5-membered metallocyclic rings.
Complex |
Chromophore
Chelate Rings
τ | 4 | | b |
Pt -L | c |
(Å)
(°) |
L-Pt-L Ref. |
c |
| (°) |
Ref. |
[Pt(η | 3 | -C | 22 | H | 11 | F | 6 | N | 3 | O | 2 | -O | 1 | ,N | 1 | ,O |
[Pt(η | 32 | )(PPh | 3 | )]
(at 173 K) |
-C | 16 | H | 14 | N | 2 | OS | 2 | -O | 1 | ,N | 1 | ,SPtO | 1 | N | 1 | O | 2 | P (O | 1 | C | 3 | N | 1 | C | 3 | O | 2 | )
0.032 |
1 | )(PPh | 3 | )] |
PtO | 1 | N | 1 | S | 1 | P (O | 1 | C | 3 | N | 1 | NCS | 1 | )
0.016O | 1 | 1.994(2)
N | 1 | 2.021(2)
O | 2 | 2.004(2)
P 2.256(2) |
O | 1 | 1.992
N | 1 | 2.034
S | 1 | 2.245
P 2.258O | 1 | ,N | 1 | 90.6 | d |
N | 1 | ,O | 2 | 90.2 | d |
O | 1 | ,O | 2 | 179.0
O | 1 | ,P 90.6
O | 2 | ,P 87.5
N | 1 | ,P 177.0 |
O | 1 | ,N | 1 | 91.2 | d |
N | 1 | ,S | 1 | 85.0 | e |
O | 1 | ,S | 1 | 176.0
O | 1 | ,P 89.0
S | 1 | ,P 93.1
N | 1 | ,P 178.1 | [1] | [4] |
[ | 4 | ] | [ | 7] |
[Pt(η | 3 | -C | 14 | H | 10 | N | 2 | O | 3 | -O | 1 | ,N | 1 | ,O | 2 | )(PPh | 3 | )]
(at 150 K) |
PtO | 1 | N |
[Pt(η | 3 | -C | 16 | H | 13 | N | 3 | O | 3 | S | 2 | -O | 1 | ,N | 1 | ,S | 1 | )(PPh | 3 | )]
(at 200 K) | 1 | O | 2 | P (O | 1 | C | 2 | NN | 1 | C | 3 | O | 2 | )
0.024 |
PtO | 1 | N | 1 | S | 1 | P (O | 1 | C | 3 | N | 1 | NCS | 1 | )
0.018O | 1 | 1.995(2)
N | 1 | 2.000(2)
O | 2 | 1.988(2)
P 2.251(2) |
O | 1 | 2.001
NO | 1 | ,N | 1 | 88.2 | d |
N | 1 | ,O | 2 | 90.0 | d |
O | 1 | ,O | 2 | 176.5
O | 1 | ,P 89.0
O | 2 | ,P 90.7
N | 1 | ,P 175.0 |
[2] | [5] |
[Pt{η | 3 | -C | 12 | H | 24 | S | 3 | -S | 1 | ,S | 2 | ,S | 3 | }(PPh | 3 | )]BF | 4 |
PtS | 1 | S | 2 | S | 3 | P (S | 1 | C | 3 | S | 2 | C | 3 | S | 3 | )
0.035 |
S | 1 | 2.330(2)
S | 2 | 2.339(2)
S | 3 | 2.336(2)
P 2.332(2) |
S | 1 | ,S | 2 | 87.1(2) | d |
S | 2 | ,S | 3 | 89.5(2) | d |
S | 1 | ,S | 3 | 176.3(2)
S | 1 | ,P 91.1(2)
S | 3 | ,P 92.3(1)
S | 2 | ,P 171.0(2) |
[3] | [6] |