(CsH4CHO)Na+與W(C0)6反應得（CO）5-C5H4CHO)W:Na+. 後者與CH3I作用得1t合物（C0)3(CH3)W（η5-C5H4CH0)(2). 2的結構已由X-ray繞射法解析出晶體參數如下：Space group, P_1; triclinic; a= 7.791(2), b = 11.455(3), c = 12.819(3)A，α＝ 98.16(2），戶＝ 98.74(2），γ＝ 104.85(2）。﹔Z= 2. X-ray結晶體中可觀察到兩種conformation－配位在金屬鋪上的甲基與五環上甲隘的位向相同的cisoid及位向相反的transoid conformation. Cisoid 2其五環上甲腔基的碳的為1.95°多然transoid 2其為-0.82° 經由二維異核相對應NMR光譜儀，1t合物2五環C(2-5）的13c化學位移得以確認文中以B3LYP correlation-exchange的理論計算法得出的電子密度分佈情形，其結果呼應由13CNMR 1c學位移所得之Cp(W)的電子密度分佈。

Reaction of sodium formylcyclopentadienide with hexacarbonyltungsten led to (CO)3(Ș5-C5H4CHO)WNa. Treatment of the metal carbonyl anion with methyl iodide led to (CO)3(CH3)W(Ș5-C5H4CHO) 2. The structure of 2 has been determined by X-ray diffraction studies: space group, P-1; monoclinic; a = 7.791(2), b = 11.455(3), c = 12.819(3) Å, Į = 98.16(2), ȕ = 98.74(2), Ȗ = 104.85(2)° ; Z = 2. Both cisoid and trasoid conformations of the methyl ligand toward the formyl carbon were observed. The twist angles are 80.7° and 154.0° for methyl ligands in cisoid and transoid 2, respectively. The exocyclic carbon is bent toward the tungsten atom with an angle ș of 1.95° in cisoid conformation, whereas in transoid conformation the exocyclic carbon is turned away from the tungsten atom with an angle ș of –0.82°. The chemical shifts of C(2,5) and C(3,4) on the Cp ring has been assigned using two-dimensional HetCOR NMR spectroscopy. The electron density distribution in the cyclopentadienyl ring of the Cp(W) was discussed on the basis of 13C NMR data and compared with calculations via the density functional B3LYP exchange-correlation method.