Substitution of one metal catalyst for another is not as straightforward as simply justifying this change based on the availability and/or cost of the metals. Methodologies to properly assess options for reaction design, including multiple factors like a metal's availability, cost, or environmental indicators have not advanced at the pace needed, leaving decisions to be made along these lines more challenging. Isolated indicators can lead to conclusions being made in too hasty a fashion. Therefore, an extensive life cycle-like assessment was performed documenting that the commonly held view that methods using earth-abundant metals (and in this case study, Ni) are inherently green replacements for methods using palladium in cross-coupling reactions, and Suzuki–Miyaura couplings, in particular, is an incomplete analysis of the entire picture. This notion can be misleading, and unfortunately derives mainly from the standpoint of price, and to some degree, relative natural abundance associated with the impact of mining of each metal. A more accurate picture emerges when several additional reaction parameters involved in the compared couplings are considered. The analysis points to the major impact that use of organic solvents has in these couplings, while the metals themselves actually play subordinate roles in terms of CO₂-release into the environment and hence, the overall carbon footprint (i.e., climate change). The conclusion is that a far more detailed analysis is required than that typically being utilized.

中文翻译：

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地球储量丰富的金属替代 Pd 在交叉偶联反应中的影响


用一种金属催化剂替代另一种金属催化剂并不像简单地根据金属的可用性和/或成本证明这种改变的合理性那么简单。正确评估反应设计方案的方法，包括金属的可用性、成本或环境指标等多种因素，尚未按照所需的速度取得进展，使得沿着这些方向做出的决策更具挑战性。孤立的指标可能会导致过于仓促地得出结论。因此，进行了广泛的类似生命周期的评估，记录了普遍持有的观点，即使用地球丰富的金属（在本案例研究中为镍）的方法本质上是在交叉偶联反应中使用钯的方法的绿色替代品，铃木–尤其是宫浦耦合，是对整个图景的不完整分析。这种概念可能会产生误导，不幸的是，它主要源于价格的观点，并且在某种程度上，与每种金属开采的影响相关的相对自然丰度。当考虑比较耦合中涉及的几个附加反应参数时，会出现更准确的情况。分析指出了有机溶剂的使用对这些偶联产生的主要影响，而金属本身实际上在 CO ₂ 释放到环境中以及因此的总体碳足迹（即、气候变化）。结论是，需要比通常使用的分析更详细的分析。