Table 3. Polymerization of rac-LA with, [L_TH-M(OⁱPr)₂] Initiators, Generated In Situ from the Reaction of [L_TH-MCl₂] Complexes and [LiOⁱPr].

runa	catalyst	T (°C)	conv.b (%)	Mnc (g mol–1) × 103 (calcd)	Mnd (g mol–1) × 103 (GPC)	PDId	Pre
1	LiOiPr	0	97.2	14.0	13.1	1.25	0.56
2	LiOiPr	25	96.4	13.9	8.94	1.25	0.54
3	[LTHZn(OiPr)2]	0	96.6	13.9	6.273	1.25	0.74
4	[LTHPd(OiPr)2]	0	96.3	13.9	8.564	1.25	0.61
5	[LTHCd(OiPr)2]	0	95.7	13.8	5.347	1.25	0.54
6	[LTHZn(OiPr)2]	25	96.2	13.9	5.400	1.25	0.58
7	[LTHPd(OiPr)2]	25	96.5	13.9	6.409	1.25	0.54
8	[LTHCd(OiPr)2]	25	95.4	13.8	4.358	1.25	0.54

^aSpecifications: [catalyst] 0.0625 mmol; [rac-LA]/[LiOⁱPr]/[catalyst] 100:2:1; solvent (CH₂Cl₂) 5.00 mL; polymerization time 20 min.

^bConversion rate (%) was determined by ¹H NMR spectroscopy in the presence of tetralin.

^cCalculated using [{molecular weight of rac-LA} × {(mol concentration of used rac-LA)/(mol concentration of catalyst)}] × [conversion].

^dDetermined by gel permeation chromatography (GPC) in chloroform, relative to the poly(methyl methacrylate) standard.

^eProbability of heterotactic enchainment (P_r) was calculated using ¹H NMR spectroscopic data.^71,72