Half-Sandwich Tungsten Complexes with Metal- and η⁵-Cyclopentadienyl-Bound Functional Stannyl Groups and Their Transformation into Ansa Complexes

Abstract

We report the introduction of two stannyl groups into a half-sandwich tungsten complex and their subsequent functionalization in order to generate useful precursors for the formation of diverse ansatype tungsten complexes. Bis-stannylation is achieved by treatment of the dilithiated species Li-[W(η 5 -C 5 H 4 Li)(CO) 3 ] (7) with 2 equiv of Me 3 SnCl, yielding [{Me 3 Sn(η 5 -C 5 H 4 )}(OC) 3 W(SnMe 3 )] (8). Successive chlorination is achieved by use of Me 2 SnCl 2 and SnCl 4 3 2OEt 2 and enables the selective formation of [{Me 3 Sn(η 5 -C 5 H 4 )}(OC) 3 W(SnMe 2 Cl)] ( 10), [{ClMe 2 Sn(η 5 -C 5 H 4 )}(OC) 3 -W(SnMe 2 Cl)] ( 11), and [{ClMe 2 Sn(η 5 -C 5 H 4 )}(OC) 3 W(SnMeCl 2 )] ( 12). The reaction of 11 with sodium amalgam gives a product mixture, consisting of the tristanna-bridged ansa complex [{η 1 -SnMe 2 -SnMe 2 -SnMe 2 -(η 5 -C 5 H 4 )}(CO) 3 W] (13) and the cyclic dinuclear tungsten compound [{Me 2 Sn-(η 5 -C 5 H 4 )}-(OC) 3 W] 2 ( 14). Ring closure of 12 was achieved upon reaction with Na 2 S to yield [{η 1 -Sn(Cl)Me-S-SnMe 2 -(η 5 -C 5 H 4 )}(CO) 3 W] (15), which displays a chiral, tungsten-bound tin center. All new compounds have been fully characterized by elemental analyses and, in solution, by IR and multinuclear NMR spectroscopy. The crystal structures of complexes 8, 11, 12, 14, and 15 were presented and discussed, showing Sn-W bond lengths of 2.8481(5) (8), 2.7586(3) (11), 2.7256(3) (12), 2.8180(3) ( 14), and 2.7662(2) A ˚(15).

Iron ansa half sandwich complexes bearing a bridging distannadiyl moiety

“…The ring strain within the ansa bridge provides the driving force for cleavage reactions of the tinetin bond, such as the insertion of elemental chalcogens [32,33,38,39]. Therefore, 2 was treated with sulphur, grey selenium and elemental tellurium to yield the desired 1,3-distanna-2-chalcogena-ansa compounds in good yields of 61e75% (Scheme 4).…”

Coordination Chemistry of the Tris(pentafluoroethyl)stannate(II) Anion, [Sn(C2F5)3]–

“…The C-Sn-C bond angles range from 96.2(3) to 104.4(3)°and are on average (100.8°) as expected larger than for the free [Sn(C 2 F 5 ) 3 ] -[91.3(av)°]. However, the Sn-Zn-Sn angle of 158.04(4)°clearly deviates from linearity, which is due to additional interactions 255.29 (6) [W(CO) 3 {η 5 -C 5 H 4 (SnMe 3 )}(SnMe 3 )] [12] 284.81(5) [W(CO) 3 Cp(SnClBu 2 )] [13] 279.59(5) [W(CO) 3 Cp(SnClMe 2 )] [13] 278.66(3) [W(CO) 3 Cp{Sn(C 2 F 5 ) 3 }] 273.94(6) [W(CO) 3 {η 5 -C 5 H 4 (SnClMe 2 )}(SnCl 2 Me)] [12] 272.56(3) [W(CO) 3 Cp(SnCl 3 )] [13] 272.44 (3) [Fe(CO) 2 {η 5 -C 5 H 4 (SiMe 3 )}{Sn(OH) t Bu 2 }] [14] 253.4(1) [Fe(CO) 2 {η 5 -C 5 H 4 (SiMe 3 )}(SnCl t Bu 2 )] [14] 252.9(2) [Fe(CO) 2 Cp{Sn(C 2 F 5 ) 3 }] 247.18(4) [Fe(CO) 2 Cp(SnCl 2 Ph)] [15] 246.7(2) [Fe(CO) 2 Cp(SnBr 3 )] [16] 246.2 (2) [Ni(CO) 3 between the zinc atom and three fluorine atoms of two ancillary [Zn{Sn(C 2 F 5 ) 3 } 2 ] (1) molecules which range from 265.8(6) pm to 275.8(5) pm. The Sn-C bond lengths, which range from 221.1(9) pm to 223.5(9) pm, experience a shortening with respect to the anion [Sn(C 2 F 5 ) 3 ] -[226.5(av) pm], and nicely matches with the corresponding distances in the stannane HSn(C 2 F 5 ) 3 [220.6(av) pm].…”

“…[W(CO) 3 {η 5 -C 5 H 4 (C 2 H 4 NMe 2 )}(SnCy 3 )] [21] 1987, 1911, 1891 [W(CO) 3 {η 5 -C 5 H 4 (C 2 H 4 NMe 2 )}(SnPh 3 )] [21] 1992, 1916, 1894 [W(CO) 3 Cp*(SnClMe 2 )] [13] 1997, 1927, 1901 [W(CO) 3 Cp(SnClBu 2 )] [13] 1999, 1981 [W(CO) 3 Cp(SnClMe 2 )] [13] 2010, 1940, 1911 [W(CO) 3 {η 5 -C 5 H 4 (SnMe 3 )}(SnClMe 2 )] [12] 2010, 1940, 1911 [W(CO) 3 {η 5 -C 5 H 4 (SnClMe 2 )}(SnClMe 2 )] [12] 2016, 1944, 1915 [W(CO) 3 {η 5 -C 5 H 4 (SnMe 3 )}(SnMe 3 )] [12] 2016, 1947, 1915 [W(CO) 3 Cp{Sn(C 2 F 5 ) 3 …”

“…The oxidative addition of HSnR 3 to transition metal carbonyls like [Os 3 (CO) 12 ] with formation of [OsH(CO) 3 (SnR 3 )] and cleavage represents an additional literature known procedure for the synthesis of stannyl complexes. [25] In keeping with this, we treated HSn(C 2 F 5 ) 3 The complex exhibits the geometry of a three-legged piano stool with two CO and one stannyl leg.…”

An anionic nucleophilic d4 carbyne complex

“…The WRC bond-length of W1-C1 1.834(4) Å, is unremarkable, falling within the normal range for neopentylidyne complexes although all previous structural studies involved this ligand bound to high-valent tungsten. While there are copious structural data available for tungsten stannyl complexes, the only two trimethylstannyl examples [W(SnMe 3 )(CO) 2 (Z-C 5 H 4 SnMe 3 )] (W-Sn = 2.8481(5) Å) 12 and [W(SnMe 3 )(CO) 5 ] À (2.810(8) Å) 13 have far shorter W-Sn bonds than found in 2 (2.9332(3) Å), a manifestation of the superlative trans influence of carbyne ligands.…”