Table 1. Polymerization of rac-Lactide Catalyzed by Formazanate Zinc Alkoxide Complex 2^a.

entry	[LA]:[Zn]	[Co]:[Zn]	conv. (%)	time (h)	Mnb,c	Mwb,c	ĐMd
1	50:1	-	<1	12	n.d.	n.d.	n.d.
2	50:1	0.5	93	19	12.9	24.6	1.9
3	50:1	1	94	4	6.5	11.4	1.8
4	50:1	2	97	2	5.9	9.5	1.6
5	50:1	4	97	1	4.6	7.2	1.6
6	100:1	1	97	4	11.5	21.0	1.8
7	250:1	1	98	14	14.6	25.4	1.7
8	500:1	1	90	14	17.1	28.6	1.7

^aConditions: [2] = 5 mM, 25 °C, 1,3,5-trimethoxybenzene as internal standard, CD₂Cl₂ solvent; n.d. = not determined.

^bReported in 10³ g mol^–1.

^cDetermined by GPC in THF, calibrated versus polystyrene standards.

^dĐ_M = M_w/M_n (see also ref (23)).