TY - JOUR
T1 - Reactions of co-ordinated ligands. Part 42. The synthesis and reactions of cationic η4-tetraphenylcyclobutadieneruthenium complexes; X-ray crystal structures of [Ru(NCMe)(η4-C4Ph4)(η-C 5H5)][BF4] and [Ru{η5-CH(Ph)C(Ph)C(Ph)C(Ph)O}(η-C5H5)]
AU - Crocker, Mark
AU - Froom, Simon F.T.
AU - Green, Michael
AU - Nagle, Katharine R.
AU - Orpen, A. Guy
AU - Thomas, Dianne M.
PY - 1987
Y1 - 1987
N2 - Addition of Ag[BF4] to a solution of [Ru2(CO)4(η-C5H5)2] and PhC2Ph in CH2Cl2 results in the formation of the η4-cyclobutadiene complex [Ru(CO)(η4-C4Ph4)(η-C5H 5)][BF4] (1). U.v. irradiation of a solution of (1) in MeCN gives [Ru(NCMe)(η4-C4Ph4)(η-C 5H5)][BF4] (2), structurally identified by X-ray crystallography. The η4-tetraphenylcyclobutadiene ligand is not co-ordinated symmetrically to the ruthenium as is indicated by Ru-C distances of 2.192(2), 2.208(3), 2.177(2), and 2.175(2) Å, a distortion which is related to the frontier orbitals presented by the d6 Ru(η-C5H5)L+ fragment (L = MeCN). The mechanism of formation of (1) is discussed. Tetramethylammonium bromide and chloride also react with (1) on u.v. irradiation in CH2Cl2 to form [RuX(η4-C4Ph4)(η-C5H 5)] [X = Br (4) or Cl (5)]. These complexes are also formed when (2) is reacted thermally with the corresponding halide anions. A related reaction occurs between (2) and the thiolate anion of Na[SC6H4Me-4] forming [Ru(SC6H4Me-4)(η4-C4Ph 4)(η-C5H5)], however, the presence of water in this latter reaction leads to an unusual ring-opening reaction and the formation of [Ru{η5-CH(Ph)C(Ph)C(Ph)C(Ph)O}(η-C5H5)] (7) whose structure was elucidated by X-ray crystallography. A η5(5 e)-bonded butadienolato ligand has been generated by nucleophilic attack of hydroxide ion on the η4-C4Ph4 ligand leading to ring-opening of an η3-cyclobutenyl complex. Protonation of (7) affords [Ru{η6-C6H5(CH 2CPh=CPhCOPh)}(η-C5H5)][BF4] (8). Mixed C5-C6 sandwich cations are also formed on u.v. irradiation of (1) in the presence of alkynes RC2R, and in this way [Ru(η6-C6Ph6)(η-C5H 5)][BF4] (9), [Ru(η6-C6Ph5Me)(η-C5H 5)][BF4] (10), [Ru(η6-C6Ph4Me2)(η-C 5H5)][BF4] (11), and [Ru{η6-C6Ph4(CO2Me) 2}(η-C5H5)][BF4] (12) are obtained in good to moderate yield. Complex (9) is also formed on reaction of (5) with PhC2Ph and Ag[BF4], providing insight into this novel ring-expansion reaction. The related cationic complex [Ru(η6-C6Et6)(η-C5H 5)][BF4] (13) is formed in low yield on reaction of EtC2Et with [Ru2(CO)4(η-C5 H5)2] and Ag[BF4]. The low-temperature 100.6-MHz 13C-{1H} n.m.r. spectrum of (13) is discussed in terms of rotational movement of the ethyl groups. Treatment of (9) and (11) with K[BHBus3] leads to selective attack on the η-cyclopentadienyl ring and the formation of [Ru(η4-C5H6)(η6-C 6Ph6)] (14) and [Ru(η4-C5H6)(η6-C 6Ph4Me2)] (15). The reduction of (9) with Na-Hg in thf gives (14) and [Ru(η5-exo-C6Ph6H)(η-C 5H5)].
AB - Addition of Ag[BF4] to a solution of [Ru2(CO)4(η-C5H5)2] and PhC2Ph in CH2Cl2 results in the formation of the η4-cyclobutadiene complex [Ru(CO)(η4-C4Ph4)(η-C5H 5)][BF4] (1). U.v. irradiation of a solution of (1) in MeCN gives [Ru(NCMe)(η4-C4Ph4)(η-C 5H5)][BF4] (2), structurally identified by X-ray crystallography. The η4-tetraphenylcyclobutadiene ligand is not co-ordinated symmetrically to the ruthenium as is indicated by Ru-C distances of 2.192(2), 2.208(3), 2.177(2), and 2.175(2) Å, a distortion which is related to the frontier orbitals presented by the d6 Ru(η-C5H5)L+ fragment (L = MeCN). The mechanism of formation of (1) is discussed. Tetramethylammonium bromide and chloride also react with (1) on u.v. irradiation in CH2Cl2 to form [RuX(η4-C4Ph4)(η-C5H 5)] [X = Br (4) or Cl (5)]. These complexes are also formed when (2) is reacted thermally with the corresponding halide anions. A related reaction occurs between (2) and the thiolate anion of Na[SC6H4Me-4] forming [Ru(SC6H4Me-4)(η4-C4Ph 4)(η-C5H5)], however, the presence of water in this latter reaction leads to an unusual ring-opening reaction and the formation of [Ru{η5-CH(Ph)C(Ph)C(Ph)C(Ph)O}(η-C5H5)] (7) whose structure was elucidated by X-ray crystallography. A η5(5 e)-bonded butadienolato ligand has been generated by nucleophilic attack of hydroxide ion on the η4-C4Ph4 ligand leading to ring-opening of an η3-cyclobutenyl complex. Protonation of (7) affords [Ru{η6-C6H5(CH 2CPh=CPhCOPh)}(η-C5H5)][BF4] (8). Mixed C5-C6 sandwich cations are also formed on u.v. irradiation of (1) in the presence of alkynes RC2R, and in this way [Ru(η6-C6Ph6)(η-C5H 5)][BF4] (9), [Ru(η6-C6Ph5Me)(η-C5H 5)][BF4] (10), [Ru(η6-C6Ph4Me2)(η-C 5H5)][BF4] (11), and [Ru{η6-C6Ph4(CO2Me) 2}(η-C5H5)][BF4] (12) are obtained in good to moderate yield. Complex (9) is also formed on reaction of (5) with PhC2Ph and Ag[BF4], providing insight into this novel ring-expansion reaction. The related cationic complex [Ru(η6-C6Et6)(η-C5H 5)][BF4] (13) is formed in low yield on reaction of EtC2Et with [Ru2(CO)4(η-C5 H5)2] and Ag[BF4]. The low-temperature 100.6-MHz 13C-{1H} n.m.r. spectrum of (13) is discussed in terms of rotational movement of the ethyl groups. Treatment of (9) and (11) with K[BHBus3] leads to selective attack on the η-cyclopentadienyl ring and the formation of [Ru(η4-C5H6)(η6-C 6Ph6)] (14) and [Ru(η4-C5H6)(η6-C 6Ph4Me2)] (15). The reduction of (9) with Na-Hg in thf gives (14) and [Ru(η5-exo-C6Ph6H)(η-C 5H5)].
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U2 - 10.1039/DT9870002803
DO - 10.1039/DT9870002803
M3 - Article
AN - SCOPUS:37049077774
SP - 2803
EP - 2814
IS - 11
ER -