The heavier pnictogen and chalcogen analogues of isocyanic and cyanic acids and their dimers: A high level ab initio study. Issue 1 (18th June 2019)

• Record Type: Journal Article
• Authors: Zhang, Zhong; Liu, Chencheng; Tian, Ge; Chen, Zuqing; Pu, Liang; King, Robert Bruce
• Is Part Of: International journal of quantum chemistry. Volume 120:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-18
• Subjects: dimerisation -- pnictogen analogue -- chalcogen analogues -- cyanic acid -- cyclodimerisation; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25989
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: The CCSD(T)/cc‐pVTZ//CCSD/cc‐pVTZ method is used to determine the geometries and energetics of the isomers HXCY vs HY─CX (XN, P, As; YO, S) and their dimers from chain dimerizations and head‐to‐head or head‐to‐tail [2 + 2] cyclodimerizations. The HO─CX structures with CX triple bonds lie at energies at least 18.5 kcal/mol above their HXCO isomers. However, the energy differences between the HXCS and HS─CX isomers are found to be particularly small, especially in the [H, P, C, S] and [H, As, C, S] systems. For (HNCY)2, the lowest energy dimers are the chain isomers, which lie ~11 kcal/mol below the lowest energy cyclic dimers a NO containing a NCNC ring and c NS containing a NCSC ring. Formation of the remaining dimers through dimerization from two monomers is predicted to be endothermic and thus thermodynamically disfavored. However, the energies of the chain isomers in the other (HXCY)2 (XP, As; YO, S) series are higher than those of the corresponding isomeric lowest energy cyclodimers. For (HXCO)2 (XP, As), the lowest energy structures are the head‐to‐head dimers h PO and h AsO containing a C─C─XX ring. For (HXCS)2 (XP, As), the lowest energy structures are the head‐to‐head dimers g PS and g AsS with a CCXS ring. Abstract : The CCSD(T)/cc‐pVTZ//CCSD/cc‐pVTZ method is used to determine the geometries and energetics of the isomers HXCY vs HY─CX (XN, P, As; YO, S) and their dimers from chain dimerizations and head‐to‐head or head‐to‐tail [2 + 2] cyclodimerizations. The energy differences between the HXCS and HS─CX isomers are particularly small. For (HNCY)2, the lowest energy dimers are the chain isomers. However, in the other (HXCY)2 (XP, As; YO, S) isomeric cyclodimers are the lowest energy structures.