Reactions of Doubly Bridged Biscyclopentadienes with Molybdenum (Tungsten) Carbonyl

Abstract

Dimolybdenum complexes (X)(Y)[(η5-C5H3)Mo(CO)3]2 [Y = Me2Si, X = Me2C, (CH2)5C, CH2; Y = Ph2Si, X= Me2C] and desilylation products (X)[(η5-C5H4)Mo(CO)3]2 were obtained from the reactions of carbon and silicon doubly bridged biscyclopentadiene ligands (X)(Y)(C5H4)2 with Mo(CO)6 in refluxing xylene. When these ligands reacted with W(CO)6, under similar conditions, in addition to ditungsten complexes (X)(Y)[(η5-C5H3)W(CO)3]2 [X = Me2C; Y = Me2Si, Ph2Si] and desilylation products (X)[(η5-C5H4)W(CO)3]2, a class of structurally novel complexes (X)(η5-C5H3)(η5,η1-C5H3)[(Y)W(CO)3][W(CO)3] [for X = Me2C, (CH2)5C; Y = Me2Si] with a W−Si bond were also isolated. The reactions of carbon and germanium doubly bridged biscyclopentadiene ligands (X)(Me2Ge)(C5H4)2 [X = Me2C, (CH2)5C] with Mo(CO)6 or W(CO)6 gave similar novel complexes (X)(η5-C5H3)(η5,η1-C5H3)[(Me2Ge)M(CO)3][M(CO)3] [X = Me2C, (CH2)5C; M = Mo, W] with a M−Ge bond. The reactions also produced degermylation products. However, the corresponding dimolybdenum or ditungsten complexes were not isolated in these cases. The molecular structures of 2, 6, 8, 10, 11, 13, 14, 15, 19, 21, 22, 25t, and 26t have been determined by X-ray diffraction. The M−M distances in complexes 2 [3.4328(12) Å], 8 [3.453(2) Å], and 11 [3.403(2) Å] are conspicuously elongated and are in fact the longest ever reported among the biscyclopentadienyl dimolybdenum or ditungsten complexes. The factors affecting the structures of dimolybdenum or ditungsten complexes are discussed.

Synthesis and structures of the silyl bridged bis(indenyl) diruthenium complexes and a novel indenyl nonanuclear ruthenium cluster Ru9(μ6-C)(CO)14(μ3-η5:η2:η2-C9H7)2

“…However, when the reactions of the silyl bridged bis(indene) ligands with Ru 3 (CO) 12 were done in refluxing heptane, decane, decalin, DME or even methyl isobutyl ketone [7], only the desilylation product [C 9 H 7 Ru(CO)] 2 (l-CO) 2 puzzled us a long time. Recently, we found that xylene as solvent for the reaction of silyl or germyl bridged biscyclopentadiene ligands with metal carbonyl can significantly depress the desilylation or degermylation reaction [8]. So xylene was chosen as solvent for the reactions of the silyl bridged bis(indenyl) ligands with Ru 3 (CO) 12 , and the expected products were obtained.…”

Reactions of (Me2C)(Me2Si)[(η5‐C5H3)­Mo(CO)3]2 with Phosphanylalkynes: Rearrangement of Phosphanylalkynes into Phosphido‐Substituted Vinylidenyl Ligands by Cleavage of the P–C(alkyne) Bond and Formation of a P–C(alkene) Bond

“…Melting points are uncorrected. 1 (1), [7] Ph n P(CϵCPh) 3-n (n = 0, 1, 2), [12] Ph 2 P(O)CϵCPh, [19] and FcCϵCH [20] were prepared by literature methods. 131.7,131.6,131.2,131.1,130.4,130.0,129.0,128.9,128.8,128.6,128.1,125.4,123.6,123.5 (Ph) 2 (70 mg, 0.22 mmol) in toluene (30 mL) was heated at reflux for 6 h. During this time the solution turned from deep green to dark brown.…”

“…[6] We recently reported that the Me 2 C and Me 2 Si doubly bridged bis(cyclopentadienyl) dinuclear molybdenum carbonyl complex (Me 2 C)(Me 2 Si)[(η 5 -C 5 H 3 )Mo(CO) 3 ] 2 (1) contained an unusually long Mo-Mo bond length, [7] which is a good precursor for the synthesis of other new dinuclear molybdenum complexes, and led to a number of interesting but not always predictable reactions. More recently, our research has focused on the reactions of complex 1 with a series of unsaturated organic molecules.…”

Ferrocene bridged and substituted tetramethylcyclopentadienyl (or indenyl) carbonyl complexes of iron, ruthenium, and molybdenum

“…Dinuclear metal complexes are often postulated as simple models with which to study the interactions of molecules with metal surfaces [4,5]. For the bridged bis(cyclopentadienyl) metal carbonyl dimers, the nature of a bridge has important effect on the metal-metal bond and its reactivity [6][7][8][9][10][11][12][13][14][15][16]. The single carbon bridged bis(cyclopentadienyl) dinuclear iron, molybdenum and tungsten carbonyl complexes in general have the shortest metal-metal bonds [6][7][8][9][10], while the carbon and silicon doubly bridged bis(cyclopentadienyl) dinuclear iron, molybdenum and tungsten carbonyl complexes have the longest metal-metal bonds [9,11].…”

“…For the bridged bis(cyclopentadienyl) metal carbonyl dimers, the nature of a bridge has important effect on the metal-metal bond and its reactivity [6][7][8][9][10][11][12][13][14][15][16]. The single carbon bridged bis(cyclopentadienyl) dinuclear iron, molybdenum and tungsten carbonyl complexes in general have the shortest metal-metal bonds [6][7][8][9][10], while the carbon and silicon doubly bridged bis(cyclopentadienyl) dinuclear iron, molybdenum and tungsten carbonyl complexes have the longest metal-metal bonds [9,11]. As a part of systematic study the structure-reactivity relationship of the bridged bis(cyclopentadienyl) metal carbonyl dimers, especially the effect of the bridge on the metal-metal bond length and its reactivity [9,[11][12][13], in this work a series of ferrocene bridged bis(tetramethylcyclopentadienyl) trinuclear metal carbonyl complexes were synthesized and characterized by X-ray diffraction analysis.…”