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The heavier pnictogen and chalcogen analogues of isocyanic and cyanic acids and their dimers: A high level ab initio study
Author(s) -
Zhang Zhong,
Liu Chencheng,
Tian Ge,
Chen Zuqing,
Pu Liang,
King Robert Bruce
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25989
Subject(s) - chemistry , ab initio , chalcogen , ring (chemistry) , crystallography , endothermic process , ab initio quantum chemistry methods , dimer , monomer , stereochemistry , computational chemistry , molecule , organic chemistry , adsorption , polymer
The CCSD(T)/cc‐pVTZ//CCSD/cc‐pVTZ method is used to determine the geometries and energetics of the isomers HXCY vs HY─CX (XN, P, As; YO, S) and their dimers from chain dimerizations and head‐to‐head or head‐to‐tail [2 + 2] cyclodimerizations. The HO─CX structures with CX triple bonds lie at energies at least 18.5 kcal/mol above their HXCO isomers. However, the energy differences between the HXCS and HS─CX 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 (XP, As; YO, S) series are higher than those of the corresponding isomeric lowest energy cyclodimers. For (HXCO) 2 (XP, As), the lowest energy structures are the head‐to‐head dimers h PO and h AsO containing a C─C─XX ring. For (HXCS) 2 (XP, As), the lowest energy structures are the head‐to‐head dimers g PS and g AsS with a CCXS ring.