Organometallics 1990, 9, 1871-1876 N, 7.83. Found: C, 55.82; H, 4.45; N, 7.72. (p) Synthesis of [(C6H5)2B(OH)(pz)W'
1871
Exchange rate constants for each temperature were determined by matching the theoretical spectra to experimentalspectra. The rate constants k were then used to calculate the energy of activation AG* at each temperature T,by using the Eyring equation:
NNCHCHCHCH&HCHCHCH3)(C0)2] (7b). Na(C&6)2B(pz)2 (0.16 g, 0.49 mmol) was added to W(CO)2(CH3CN)2(93-C5H7)Br
a -
(0.27 g, 0.50 mmol) in 50 mL of CH2C12,and the mixture was stirred at 23 OC for 30 min. The solvent was then removed in vacuo, and 'H NMR spectra of the residues showed the presence of [(C6Hd2B(pz)2W(C0)2(r13-CsH,)] (5b) and 7b. 'H NMR for 5b (400 MHz, CDC13): 6 0.50 (d, 1 H, H2),0.60 (d, 1 H, H6), 2.80 (m, 1 H, H4), 5.29 (d, 1 H, H'), 5.35 (d, 1 H, H6),6.20 (m, 1 H, HI). The residue was chromatographed through a neutral alumina column, and a yellow band consisting of an unknown organic component was eluted off the column. Elution of the top immobile brown band with CH3CN produced a gold-yellow band of 7b. Removal of the solvent under reduced pressure gave a yellow solid, which was recrystallized from a saturated CH2C12-hexane solution to yield yellow block-shaped crystals of 7b (0.063 g, 0.10 mmol). IR (Nujol): u(C0) 1950 (s), 1871 (s) cm-'. 'H NMR (400 MHz, CDClJ: 6 1.93 (d, 3 H, CH3), 2.08 (dt, 1 H, H'), 2.38 (t, 1 H, H3), 2.65 (t, 1 H, H2),4.62 (dd, 1 H, H4),5.30 (d, 1 H, H6),6.0-8.2 (16 H, Ph PZ),JI
