**3. Experimental Section**

#### *3.1. Materials and Methods*

Glutaric acid (≥99.0%) was obtained from Tokyo Chemical Industry Co., Ltd. and used without further purification. Anhydrous ZnCl2, ZnO, FeCl3, CoCl2, AlCl3, and anhydrous tetrahydrofuran (≥99.9%) were purchased from Sigma-Aldrich (Seoul, South Korea) and used as received. Propylene oxide (≥99.9%, PO) was received from Sigma-Aldrich and was distilled over CaH2 before use. CO2 gas (99.999) was received from Shinyang gas Industries, Korea. Powder X-ray diffraction

(PXRD) measurements were performed using a Bruker D8 Focus X-ray powder di ffractometer (Billerica, MA, USA) using CuK α radiation at room temperature. A Hitachi (Tokyo, Japan.) FE-SEM S-4800 and TEM-Talos; F 200X system were used to study the morphologies of the catalysts. The Fourier-transform-infrared (FT-IR) spectra were measured on Nicolet iS 50 (Thermo Fisher Scientific, Waltham, MA, USA) spectrometer. Metal contents in the catalysts were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES) (iCAP-Q, Thermo Fisher Scientific, Waltham, MA, USA) and a microwave-assisted acid digestion system (MARS6, CEM/U.S.A). Bruker Ascend 400 MHz spectrometer was used for measuring the 1H and 13C NMR spectra of the products. Gel Permeation Chromatography (GPC) analysis was performed using a Waters 717 plus instrument equipped with a Waters 515 HPLC Pump (Milford, MA, USA). The columns were eluted with THF at a flow rate of 1.00 mL/min at 35 ◦C. GPC curves were calibrated using polystyrene standard with molecular weight ranges from 580 to 660,500. A 2960 Simultaneous DSC-TGA instrument (TA instruments, New Castle, DE, USA) was used for the Thermogravimetric Analysis (TGA) with a heating rate of 10 ◦C/min from 25 ◦C to 500 ◦C under Nitrogen atmosphere. A PerkinElmer DSC 4000 instrument (Waltham, MA, USA) was used to perform the Di fferential Scanning Calorimetric (DSC) tests with a heating rate of 10 ◦C/min from 20 ◦C to 120 ◦C under Nitrogen atmosphere.

#### *3.2. Synthesis of std-ZnGA*

std-ZnGA was synthesized by following a published report with slight modification [62]. ZnO (100.0 mmol) was suspended in toluene (150 mL) in a 250-mL round-bottom flask equipped with a Dean-Stark trap and a reflux condenser. Glutaric acid (98.0 mmol) was added to this mixture and refluxed at 60 ◦C with vigorous stirring for 4 h. After 4 h, heating was stopped and the reaction mixture cooled to room temperature. The white precipitate was filtered and washed with excess of acetone. The resulting product was dried under vacuum at 130 ◦C, delivering 19.00 g of ZnGA (99.2%). The elemental analysis result, calculated (observed) for C5H6O4Zn (%) was C, 30.72(29.89); H, 3.09(3.05); O, 32.74(33.10).

#### *3.3. General Procedure for Preparing Metal Treated Catalysts*

#### 3.3.1. Preparation of Metal Chloride Stock Solutions

The metal chloride stock solutions were prepared by dissolving about 40 to 50 μmol of the corresponding metal chloride in anhydrous THF under argon atmosphere.

#### 3.3.2. Metal Treatment of std-ZnGA

To a dispersion of std-ZnGA (0.5 g, 2.55 mmol) in 20.0 mL of anhydrous THF was added a desired amount of the selected metal chloride as a solution in THF under Ar atm. The white suspension was stirred at ambient temperature for 30 min. After that, the white solid was separated by filtration followed by washing with THF (30.0 mL × 2) and acetone (30.0 mL × 2). The resulting solid was dried under vacuum at 60 ◦C for 10 h.

#### *3.4. General Procedure for the Copolymerization of CO2 and PO*

All copolymerization reactions were carried out in a pre-dried 100 mL stainless steel autoclave reactor equipped with a magnetic stirrer and a programmable temperature controller. In a typical reaction, 20.0 mL of PO was added to 200.0 mg of the desired catalyst under Ar atmosphere and then pressurized with CO2 to 2.0 MPa at room temperature. The mixture was stirred at 60 ◦C for 40 h. After cooling the reactor to room temperature, CO2 was slowly released. A small fraction was taken for 1H NMR analysis and the remaining mass was dissolved in dichloromethane (DCM) and treated with 1.25 M methanolic HCl solution (1.0 mL × 3). The addition of excess methanol to the solution afforded the polymer as a white precipitate and was dried under vacuum at 60 ◦C.
