TY - JOUR

T1 - Metal-mediated reactions between dialkylcyanamides and acetamidoxime generate unusual (nitrosoguanidinate)nickel(II) complexes

AU - Bikbaeva, Zarina M.

AU - Novikov, Alexander S.

AU - Suslonov, Vitalii V.

AU - Bokach, Nadezhda A.

AU - Kukushkin, Vadim Yu

PY - 2017/8/14

Y1 - 2017/8/14

N2 - The nitrosoguanidinate complexes [Ni{NHC(NR2)NN(O)}2] (R2 = Me21, (CH2)4O 2, (CH2)43, (CH2)54, (Me)Ph 5, Ph26, (p-MeC6H4)27) were obtained in low-to-moderate (12-26%) yields but reproducible yields in an unexpected metal-mediated reaction in MeOH between the nickel salt NiCl2·2H2O, N,N-disubstituted cyanamides NCNR2, and the amidoxime MeC(NOH)NH2. These complexes were formed along with a spectrum of cyanamide-oxime coupling products. The IR and X-ray data indicate the delocalization within the NNO and NCN systems of the nitrosoguanidinate ligand. This delocalization was additionally confirmed by inspection of Wiberg bond indices for the selected bonds. In the X-ray structure of 5, the rare metallophilic contacts Ni⋯Ni between stacks of the square-planar complexes were detected and these non-covalent interactions were studied by non-relativistic and relativistic DFT calculations and topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method). The estimated strength of the Ni⋯Ni interactions is 1.3-1.9 kcal mol-1 and they are mostly determined by crystal packing effects and weak attractive interactions between adjacent metal centers due to the overlapping of their d(z)2 and pz orbitals.

AB - The nitrosoguanidinate complexes [Ni{NHC(NR2)NN(O)}2] (R2 = Me21, (CH2)4O 2, (CH2)43, (CH2)54, (Me)Ph 5, Ph26, (p-MeC6H4)27) were obtained in low-to-moderate (12-26%) yields but reproducible yields in an unexpected metal-mediated reaction in MeOH between the nickel salt NiCl2·2H2O, N,N-disubstituted cyanamides NCNR2, and the amidoxime MeC(NOH)NH2. These complexes were formed along with a spectrum of cyanamide-oxime coupling products. The IR and X-ray data indicate the delocalization within the NNO and NCN systems of the nitrosoguanidinate ligand. This delocalization was additionally confirmed by inspection of Wiberg bond indices for the selected bonds. In the X-ray structure of 5, the rare metallophilic contacts Ni⋯Ni between stacks of the square-planar complexes were detected and these non-covalent interactions were studied by non-relativistic and relativistic DFT calculations and topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method). The estimated strength of the Ni⋯Ni interactions is 1.3-1.9 kcal mol-1 and they are mostly determined by crystal packing effects and weak attractive interactions between adjacent metal centers due to the overlapping of their d(z)2 and pz orbitals.

KW - AB-INITIO CALCULATIONS

KW - X-RAY CRYSTALLOGRAPHY

KW - ZETA BASIS-SETS

KW - METALLOPHILIC INTERACTIONS

KW - CRYSTAL-STRUCTURE

KW - COORDINATION CHEMISTRY

KW - COMPUTATIONAL ANALYSIS

KW - SOLID-STATE

KW - L-ARGININE

KW - LIGANDS

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UR - http://proxy.library.spbu.ru:2123/full_record.do?product=WOS&search_mode=GeneralSearch&qid=1&SID=E6YPETXDOmph7uZMvQn&page=1&doc=1

U2 - 10.1039/c7dt01960b

DO - 10.1039/c7dt01960b

M3 - Article

AN - SCOPUS:85026737745

VL - 46

SP - 10090

EP - 10101

JO - Dalton Transactions

JF - Dalton Transactions

SN - 1477-9226

IS - 30

ER -