Stannyl complexes

In terms of relative Co—C bond energies, those in the trihalomethyl complexes Co(OEP)CX3 are observed to be qualitatively weaker than in Co-alkyl porphyrin complexes. The high thermal stability of the cobalt porphyrin stannyl complexes was interpreted as an indication that, surprisingly, the Co—Sn bond is stronger than the Co—C bond in Co(Por)(alkyl) complexes. " ... 

Spiro stannyl complexes can be prepared116 from tetraalkynyltin compounds Sn(C=CR)4 (R = Me, Et, n-Pr, i -Pr, n-Bu) upon reaction with BEt3. This synthesis route involves a TT-coordinated diorganotin compound, 72, as an intermediate which, upon heating in toluene, gives the spiro compound 73. 

FIGURE 56. Preparation of silyl plumbyl and silyl stannyl complexes of iron. Reproduced from Reference 168 by permission of Elsevier Sequoia S.A. 

D-glucal (10) and di-(tributyltin) oxide in dry benzene are refluxed using a Dean-Stark trap. Under these conditions stannyl complex 36 of the D-glucal is formed. Ogawa was the first to report on the stereoselective stannylation.12... 

Then the other hydroxy groups are benzylated. If (Bu3Sn)20 and BnBr are used for benzylation the 4-OH unprotected sugar 45 is formed, because of a stannyl complex which acts as in the case of 39. 

In an interesting report, 1,2-dibromocyclohexane cleaves the Hg—Sn bond in Hg[Sn(CH2(Bu-f)3)] to form Hg, BrSn(CH2(Bu-f)3) and cyclohexene. Also noteworthy is the formation of carbene complexes (7 -arene)(CO)2Cr CR2 formed in the substitution/elimination reactions of stannyl complexes K[( -arene)(CO)2CrSnPh3] with activated C—X bond in organic dihalogeno derivatives R2CX2 or ionic halides [R2CX]Y . 

Hydride abstractions (equations 166 and 16 ) and oxidative additions to form mixed silyl/stannyl complexes (equation 168) are also reported. 

In the majority its complexes, 8-HO-quinoline (LH) is a chelating [N,0] donor, but in complexes R3Sn(L) (R = Me, Et, Pr , Bu , Ph) the ligand is coordinated in a monodentate fashion through the oxygen alone in solution according to Sn NMR data" while for tricyclohexyl stannyl complexes of substituted 8-hydroxyquinolines chelation is observed." The substituted ligand in complexes (161) acts as a chelate." ... 

A relationship between the W—Sn bond length and the magnitude of y ( W," Sn) has been proposed for tungstenocene-stannyl complexes. 

A Bm-containing molybdenum stannyl complex has been synthesized by oxidative addition of [Me2Sn(Bm)]Cl to Mo(0) precursors (Fig. 5.14) or through reactions of halostannanes with Na[Mo-(CO)3(Bm)]. The crystal structure of [Mo(CO)3(SnMe2Cl)(Bm)] in which Bm bridges both molybdenum and tin centers is also reported.26... 

X-ray structures of the mcsilylcnc complex show that the Sn-H bond is coordinated in an /2 fashion as for the Mn complexes (dSaH = 2.02(4) A85 1.95 A86 and is 327.6 Hz, which along with the values correspond to a less activated bond than in MeCpMn(CO)2(HSnPh3). Bis(stannyl) complexes are formed as in Eq. 

The coordinatively unsaturated stannyl complexes Os (SnR3)Cl(CO)(PPh3)2 reacts with Na[Me2NCS2] to give the dithiocarbamate complex Os(SnR3)(S2CNMe2)(CO)(PPh3)2. This reacts with I2 at the Sn-C bondsT ... 

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