## 1 Introduction  
Metal-organic frameworks (MOFs) are porous materials that have attracted much attention in the past two decades due to their tunable structure and pore size. Applications for MOFs have been found in energy storage, chemical separation, chemical sensing, catalysis, and the biomedical field [1; 2; 3; 4; 5]. MOFs have been synthesized using many techniques including: slow evaporation, diffusion, direct mixing, solvothermal, ionothermal, sonochemical, mechanochemical, electrochemical, microwave, microfluidic synthesis, and dry-gel conversion [4]. Many of these synthetic methods involve the use of structurally directing solvents such as dimethylformamide, diethylformamide, and dimethylamine (DMF, DEF, and DMA, respectively) which are, however, problematic because they are toxic or carcinogenic [6; 7; 8; 9]. These solvents also cause environmental issues when synthesizing MOFs on an industrial scale because volatile organic compounds are a major source of industrial pollution. As solvent replacement options, ionic liquids (ILs), which are salts that are liquid below 100 \({}^{\circ}\)C and possess a negligible vapor pressure making them inflammable, have been successfully used to synthesize MOFs [10; 11]. However, many ILs are corrosive, their toxicity to human health and the environment is not well established, and their cost limits their use on an industrial scale [12]. Nonionic surfactants have been widely used as an additive in MOF synthesis, in addition to organic solvents, to affect the crystal size, shape, and surface properties as well as pore morphology. However, only in the last few years have surfactants, mainly polyethylene glycol (PEG), been explored as the main reaction media for MOFs [12; 13; 14; 15; 16; 17; 18; 19; 20]. Beyond MOF synthesis, polyethylene glycol (PEG) has been employed as an efficient \"green solvent\" for synthetic chemistry for many years, since it possesses a very low vapor pressure similar to ionic liquids, but is nontoxic and biodegradable [21; 22]. PEG can dissolve a wide range of solutes as exemplified in intense recent research to employ PEG as a solvent for multi-component (\"one-pot\") synthesis reactions [23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42]. Even mineral salts may be soluble in PEG [43]. Very intriguingly, surfactant-thermal synthesis has provided interesting results in the structure and purification of MOFs. In the reaction between zinc acetate and trimesic acid, with all other reaction conditions the same, varying the surfactant media from PEG 400 to octanoic acid changed the connectivity and crystal structure of the MOFs produced [18]. In another instance, nickel nitrate was reacted with bipyridine and H\({}_{4}\)L in water and resulted in a mixture of two products. However, when the reaction was repeated in a PEG 400 (400 denotes the average molecular weight) and water mixture, pure product 1 was produced, whereas, in n-octanoate, pure product 2 was produced [19]. These examples demonstrate that utilizing PEG as the reaction medium for MOF synthesis may influence the MOF structure, crystal size and shape, as well as, pore size and shape, all of which are very important for the separating, sensing, storing, and catalyzing ability of MOFs [18; 19; 44]. Microwave synthesis has also been shown to be a valuable tool in MOF synthesis as well as a synthetic variation that can impact crystal and pore size and shape [1; 44]. One of the most widely studied MOFs, (HKUST-1) Cu\({}_{3}\)(BTC)\({}_{2}\), has been synthesized via microwave irradiation under a variety of conditions in traditional solvents [45; 46; 47; 48; 49]. Cu\({}_{3}\)(BTC)\({}_{2}\) has also been synthesized at room temperature in surfactants [50]. This study explores the combination of the two environmentally friendly methodologies of using nonionic surfactants and microwave heating for the synthesis of MOFs.