Table 1 Results of rac-DL polymerization by yttrium catalysts 4a–e and BnOH initiator

Run	Catalyst	[rac-DL]/[4]	Time (min)	Conv.^a (%)	M_n^b (kg mol⁻¹)	Ð^b (M_w/M_n)	I^{* c} (%)	P _m ^d	[mm]^d (%)	T_m^e (°C)
1	4a	20/1	20	100	4.77	1.17	74	0.91	87	128/136
2	4a	50/1	20	100	10.9	1.05	80	0.93	87	133/143
3	4a	100/1	20	100	23.0	1.04	75	0.94	89	136/145
4	4a	200/1	20	100	32.0	1.03	108	0.93	89	146
5	4b	100/1	20	100	25.1	1.03	69	0.95	89	147
6	4b	200/1	20	100	37.3	1.01	93	0.95	88	147
7	4c	100/1	20	100	25.7	1.11	67	0.96	93	153/157
8	4c	200/1	20	100	52.7	1.14	66	0.96	94	156
9	4d	100/1	20	100	20.1	1.07	86	0.99	98	161
10	4d	200/1	20	100	37.4	1.07	92	>0.99	>99	164
11	4d	400/1	20	100	64.3	1.02	107	>0.99	>99	169
12	4d	800/1	60	98	119	1.03	113	>0.99	>99	170
13	4d	1200/1	30	71	154	1.01	95	>0.99	>99	171
14	4e	100/1	20	100	23.7	1.03	73	0.88	79	121
15	4e	200/1	20	100	43.6	1.24	79	0.89	79	122

Conditions: rac-DL = 0.138 g (0.80 mmol), [rac-DL] = 1.0 M; DCM as the solvent, V_solvent = 0.8 mL (except for run 13 where V_solvent = 0.4 mL); room temperature; yttrium catalyst 4 to BnOH initiator ratio fixed at 1/1, and the amount varied according to the [rac-DL]/[4] ratio
^aConversions of monomers measured by ¹H NMR spectra of the quenched solution in benzoic acid/chloroform
^bWeight-average molecular weights (M_w), number-average molecular weights (M_n), and dispersity indices (Ð = M_w/M_n) determined by GPC coupled with an 18-angle light scattering detector at 40 °C in chloroform
^cThe initiation efficiency I* = M_n(calcd)/M_n(exptl), where M_n(calcd) = MW(rac-DL) × [rac-DL]/[4] × conv (%) + MW of chain-end groups (BnOH) = 172.18 × [rac-DL]/[4] × conv (%) + 108.14
^dP_m is the probability of meso linkages between HB units, and mm is isotactic triad made up of two adjacent meso diads, determined by ¹³C{¹H} NMR spectroscopy
^eT_m measured by DSC with the cooling and second heating rate of 10 °C min⁻¹ for samples produced by 4c–d, 5 °C min⁻¹ for samples produced by 4a–b, or 2 °C min⁻¹ for samples produced by 4e

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