Organometallic Chemistry is an interdisciplinary science which continues to grow at a rapid pace. Although there is continued interest in synthetic and structural studies, the last decade has seen a growing interest in the potential of organometallic chemistry to provide answers to problems in synthetic organic chemistry, the development of new materials and catalysis.

This Specialist Periodical Report aims to reflect these current interests, and since Volume 34 provides both comprehensive and critical reviews of the recent literature. Topics examined in this volume include heterocyclic carbene compounds, coinage metals and paddlewheel compounds.

This volume constitutes the proceedings of the 4th International United Information Systems Conference, UNISCON 2012, which was held in Yalta, Ukraine, during June 1-3, 2012. UNISCON 2012 was affiliated with the 8th International Conference on ICT in Education, Research, and Industrial Applications, ICTERI 2012. The 14 full papers, four short papers, and three extended abstracts presented with a keynote speech were carefully reviewed and selected from 96 submissions. The topical sections covered are: data management; applications; modeling and semantics; and social issues in information systems.