This study analyzed existing research on integrating Large Language Models (LLMs) into the Internet of Things (IoT) through a bibliometric review and content analysis. Scopus and Web of Science data were analyzed using VOS Viewer and Bibliometrix. The study reviewed 64 papers by 238 researchers from 51 journals. Through content analysis, five key themes emerged: (1) integrating LLMs for data processing and transformation in IoT, (2) LLMs in IoT security, (3) LLM optimization in IoT systems, (4) LLMs for conversational and user interaction in IoT, and (5) LLMs for decision-making and data analysis in IoT. A layered framework for LLM in IoT was also presented, mapping the current research landscape and guiding future studies.