Synthetic and structural studies on organomolybdenum and organotunsten complexes containing bismuth. X-Ray crystal structures of [BiCl{Mo(CO)₃(η-C₅H₅)}₂] and [BiCl{Mo(CO)₂(CNBu^t)(η-C₅H₅)}₂]

Abstract

The reaction between BiCI, and 3 equivalents of Na[ M o ( CO),(q-C,H,)] affords the trimolybdenumbismuth complex [ Bi{Mo(C0),(q-C,H5)},],(1 ), which has been characterised b y spectroscopic methods. The corresponding reaction involving 2 equivalents of Na [ Mo(CO)~(~-C,H,)] affords the disubstituted product [BiCI{Mo(CO),(q-C,H,)},],(3), which has been characterised b y X-ray diffraction. The molecular structure comprises a trigonal pyramidal bismuth atom bonded to one chlorine and two M o ( CO),(q-C,H,) fragments and containing a stereochemically active lone pair at the apex of the pyramid. The two crystallographically independent molecules have similar conformations but a weak intermolecular Bi 9 CI interaction, which is present for both molecules, is significantly different in each case. Treatment of a solution of compound (1 ) with 0.5 equivalent of BiCI, affords (3) and when pure samples of (3) are treated with 1 equivalent of BiCI, a redistribution reaction is also observed forming [ BiCI,{ M o ( CO),(q-C,H,)}].A similar range of compounds has been synthesised containing the methylcyclopentadienyl ligand. The analogous tungsten chemistry has also been investigated and similar tri-, di-, and mono-tungsten-bismuth compounds have been synthesised. Slight differences between the molybdenum and tungsten systems are observed, however, under the reaction conditions employed and these are discussed in terms of the possible mechanisms involved. Finally, the reactions between BiCI, and 2 equivalents of the carbonyl-substituted anions [Mo(CO),L(q-C,H,)]-(L = ButNC, MeNC, or PPh,) have been examined. These result in the dimolybdenum-bismuth complexes [BiCl{Mo( CO),L(q-C,H,)},], L = ButNC (15), M e N C (16), or PPh, (17). The first t w o complexes exist as mixtures of isomers, viz, cis,trans and trans,trans with regard to the stereochemistry at the molybdenum centres, whilst the latter exists as the trans,trans form. The cis,trans form of (1 5) was characterised by X-ray diffraction. The structure is similar t o that observed for compound (3) except that no short intermolecular B i CI interactions are present. Spectroscopic and analytical data for the complexes are presented.

Transition-Metal-Substituted Dichlorobismuthanes as Starting Materials for Novel Bismuth−Transition-Metal Clusters

“…The cluster core of 9 shows some structural similarities to that of the monoanionic complex [(μ-H)Fe 2 (CO) 6 Bi 2 {Fe(CO) 4 }] - , containing an additional H-bridge between the Fe atoms . The Bi−Mo bond length of 2.915(2) Å in 9 is consistent with the few examples of structurally characterized molecules containing molybdenum−bismuth bonds, such as [{Cp(CO) 3 Mo} 2 BiCl] (average Bi−Mo = 2.951 Å) 7 Molecular structure of [{Fe 2 (CO) 6 }{Fe(CO) 4 }{μ 3 -BiMo(CO) 3 Cp‘ ‘} 2 ] ( 9 ) (showing 30% probability ellipsoids; hydrogen atoms are omitted for clarity).…”

“…To investigate in which way reactions would differ if one were to exchange the Fe(CO) 2 Cp‘ ‘ group in [{Cp‘ ‘(CO) 2 Fe}BiCl 2 ] ( 1b ) with a Mo(CO) 3 Cp‘ ‘ unit, we investigated the molybdenum-substituted analogue [{Cp‘ ‘(CO) 3 Mo}BiCl 2 ] ( 7 ) as a starting material as well in the reactions with two of the above-mentioned metalates. Compound 7 was prepared in high yields according to a two-step synthesis described by Norman et al for the preparation of [{Cp(CO) 3 Mo}BiCl 2 ] . First, BiCl 3 is reacted with 2 equiv of Na[Mo(CO) 3 Cp‘ ‘] to yield [{Cp‘ ‘(CO) 3 Mo} 2 BiCl].…”

“…This is due to the steric demand of the di- tert- butylcyclopentadienyl ligands. Hence, compound 10 , together with [{Cp‘ ‘(CO) 2 Fe} 2 BiCl] and [{Cp(CN t Bu)(CO) 2 Mo} 2 BiCl], is the only example of a structurally characterized monomeric chlorobismuth complex.

8 Molecular structure of [{Cp‘ ‘(CO) 3 Mo} 2 BiCl] ( 10 ) (showing 30% probability ellipsoids; hydrogen atoms are omitted for clarity).

…”

Synthesis, Structure, and Reactivity of Iodo-Functionalized Heterobimetallic Alkoxides of Tin(IV): X-ray Crystal Structures of [I2Sn{Al(OPri)4}2], [I2Sn{Ti(OPri)5}2], [I3Sn{Zr(OPri)5(PriOH)}], and [I2Sn{Mo(C5H5)(CO)3}2]

“…However, the 13 C{ 1 H} NMR spectrum shows three additional resonances (1:1:1) in the diagnostic region of carbonyl carbon atoms, indicating a static conformation about each Mo center. The solution (CDCl 3 ) IR spectrum exhibits three distinct carbonyl stretching frequencies (ν 2031, 2009, 1952 cm -1 ), as observed in a number of related complexes based on cyclopentadienylmetal tricarbonyl fragments (e.g., [BiCl{Mo(CO) 3 (C 5 H 5 )} 2 ]) …”