Keiji Okada

5.4k total citations · 1 hit paper
249 papers, 4.4k citations indexed

About

Keiji Okada is a scholar working on Organic Chemistry, Materials Chemistry and Electronic, Optical and Magnetic Materials. According to data from OpenAlex, Keiji Okada has authored 249 papers receiving a total of 4.4k indexed citations (citations by other indexed papers that have themselves been cited), including 126 papers in Organic Chemistry, 74 papers in Materials Chemistry and 59 papers in Electronic, Optical and Magnetic Materials. Recurrent topics in Keiji Okada's work include Magnetism in coordination complexes (53 papers), Electron Spin Resonance Studies (38 papers) and Porphyrin and Phthalocyanine Chemistry (34 papers). Keiji Okada is often cited by papers focused on Magnetism in coordination complexes (53 papers), Electron Spin Resonance Studies (38 papers) and Porphyrin and Phthalocyanine Chemistry (34 papers). Keiji Okada collaborates with scholars based in Japan, United States and Germany. Keiji Okada's co-authors include Masatoshi Kozaki, Masaji Oda, Shuichi Suzuki, Katsura Okubo, Takeji Takui, Kazunobu Sato, Naoto Morita, M. Kuratsu, Daisuke Shiomi and Toshihiro Okamoto and has published in prestigious journals such as Journal of the American Chemical Society, Angewandte Chemie International Edition and The Journal of Chemical Physics.

In The Last Decade

Keiji Okada

241 papers receiving 4.3k citations

Hit Papers

align trajectories

What are hit papers?

Hit papers significantly outperform the citation benchmark for their cohort. A paper qualifies if it has ≥500 total citations, achieves ≥1.5× the top-1% citation threshold for papers in the same subfield and year (this is the minimum needed to enter the top 1%, not the average within it), or reaches the top citation threshold in at least one of its specific research topics.

Photosensitized decarboxylative Michael addition through N-(acyloxy)phthalimides via an electron-transfer mechanism

1991 381 citations Keiji Okada et al. profile →

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name	h						Papers	Cites
Keiji Okada Japan	33	2.4k	1.6k	945	827	647	249	4.4k
Hoa Phan Singapore	38	2.6k 1.1×	2.1k 1.3×	899 1.0×	929 1.1×	245 0.4×	120	4.3k
Carlo Corvaja Italy	25	984 0.4×	1.2k 0.7×	623 0.7×	436 0.5×	771 1.2×	154	2.7k
Piotr Kaszyński United States	34	2.5k 1.0×	1.3k 0.8×	1.0k 1.1×	377 0.5×	745 1.2×	223	4.5k
Michel Sliwa France	33	810 0.3×	2.0k 1.2×	400 0.4×	666 0.8×	782 1.2×	129	3.8k
Charles W. Spangler United States	30	1.2k 0.5×	2.3k 1.4×	1.2k 1.2×	1.2k 1.5×	749 1.2×	132	4.6k
Paul M. Lahti United States	36	1.3k 0.6×	1.7k 1.1×	1.4k 1.5×	1.9k 2.3×	845 1.3×	219	4.7k
Chensheng Ma Hong Kong	35	1.6k 0.7×	1.8k 1.1×	288 0.3×	1.3k 1.5×	1.2k 1.8×	94	4.1k
Seigo Yamauchi Japan	36	952 0.4×	2.3k 1.4×	828 0.9×	734 0.9×	1.8k 2.7×	176	4.5k
Nina P. Gritsan Russia	36	2.4k 1.0×	1.0k 0.6×	1.0k 1.1×	348 0.4×	1.8k 2.8×	195	4.2k
Dmitry S. Yufit United Kingdom	34	2.1k 0.9×	1.5k 0.9×	652 0.7×	923 1.1×	421 0.7×	192	4.1k

Countries citing papers authored by Keiji Okada

Since Specialization

Citations

This map shows the geographic impact of Keiji Okada's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Keiji Okada with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Keiji Okada more than expected).

Fields of papers citing papers by Keiji Okada

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Keiji Okada. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Keiji Okada. The network helps show where Keiji Okada may publish in the future.

Co-authorship network of co-authors of Keiji Okada

This figure shows the co-authorship network connecting the top 25 collaborators of Keiji Okada. A scholar is included among the top collaborators of Keiji Okada based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Keiji Okada. Keiji Okada is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

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20 of 20 papers shown

Wada, Koji, Takuya Ogaki, T. Sakata, et al.. (2025). Magic Blue‐Promoted Synthesis of a Highly Planar Tetraphenylbenzidine: Evaluation of Its Fundamental Properties and Unraveling the Intriguing Mechanism for Its Formation. Asian Journal of Organic Chemistry. 14(8).

Wada, Tomoyuki, Keiji Okada, Daisuke Shiomi, et al.. (2022). A Molecule Having 13 Unpaired Electrons: Magnetic Property of a Gadolinium(III) Complex Coordinated with Six Nitronyl Nitroxide Radicals. Inorganic Chemistry. 61(7). 3018–3023. 5 indexed citations

Ueda, Akira, Shuichi Suzuki, Keiji Okada, et al.. (2012). Chiral Stable Phenalenyl Radical: Synthesis, Electronic‐Spin Structure, and Optical Properties of [4]Helicene‐Structured Diazaphenalenyl. Angewandte Chemie International Edition. 51(27). 6691–6695. 77 indexed citations

Kozaki, Masatoshi & Keiji Okada. (2011). Construction and Functionalization of Dendrimers with Conjugated Backbones. Journal of Synthetic Organic Chemistry Japan. 69(10). 1145–1157. 2 indexed citations

Sato, Maria Notomi, et al.. (2010). Clinical evaluation of bovine adenosine deaminase activities in the colostrums. 1(4). 197–202. 1 indexed citations

Okada, Keiji, Kōichiro Tanaka, M. Kuratsu, et al.. (2007). Preparation, structure, and magnetic interaction of a Mn(hfac)₂-bridged [2-(3-pyridyl)(nitronyl nitroxide)–Mn(hfac)₂]₂chain complex. Chemical Communications. 2485–2487. 17 indexed citations

Toyoda, Kazuhiro, et al.. (2006). Development of an Inspection Equipment for Detecting Convex Defect in the Turbine Housings. DENKI-SEIKO. 77(3). 197–205.

Kozaki, Masatoshi, et al.. (2006). Preparation, Properties, and Reduction of a Novel TCNQ-Type Thienoquinoid. Organic Letters. 8(23). 5235–5238. 12 indexed citations

Kuratsu, M., Masatoshi Kozaki, & Keiji Okada. (2005). 2,2′:6′,2′′:6′′,6‐Trioxytriphenylamine: Synthesis and Properties of the Radical Cation and Neutral Species. Angewandte Chemie International Edition. 44(26). 4056–4058. 94 indexed citations

10.

Krylov, Vladimír, et al.. (2005). Effect of Protein Supplement Source on Porcine Oocyte Maturation and Subsequent Embryonic Development after Parthenogenetic Activation. Folia Biologica. 51(2). 29–33. 5 indexed citations

11.

Okada, Keiji, et al.. (2004). Simplified Method Using Rumen Ammonium Nitrogen as a Blood-test Reagent. Journal of the Japan Veterinary Medical Association. 57(7). 435–439. 2 indexed citations

12.

Sato, Jun, Jun Yasuda, Reeko SATO, et al.. (2002). High Level of Serum Alkaline Phosphatase Activity and Isoenzymes in Cases of Canine Pyometra. Journal of the Japan Veterinary Medical Association. 55(6). 367–370. 3 indexed citations

13.

Okada, Keiji, et al.. (2001). Changes in Quantity, Components, and Properties of Postpartum Milk in Japanese Black Cows. Journal of the Japan Veterinary Medical Association. 54(3). 185–190. 2 indexed citations

14.

Nakai, Tadashi, Keiji Okada, Shinichi Kawaguchi, et al.. (1998). Crystallization and preliminary X-ray characterization of aspartate aminotransferase from an extreme thermophile, Thermus thermophilus HB8. Acta Crystallographica Section D Biological Crystallography. 54(5). 1032–1034. 3 indexed citations

15.

Nagata, Harunori, et al.. (1997). COMBUSTION CHARACTERISTICS OF FIBROUS FUELS FOR DRY TOWEL HYBRID ROCKET MOTOR. 13(1). 11–16. 24 indexed citations

16.

Okada, Keiji, et al.. (1997). Fluctuation of Blood Chemical Components in Dairy Cows before and after Feeding. Journal of the Japan Veterinary Medical Association. 50(4). 220–223. 2 indexed citations

17.

Okada, Keiji, et al.. (1997). Blood Ammonia and Blood Lactic Acid Levels in Dairy Cows after Feeding of Surplus Crude Protein or Starch. Journal of the Japan Veterinary Medical Association. 50(12). 705–708. 2 indexed citations

18.

Sato, Jun, et al.. (1995). Urinary N-acetyl-^|^beta;-D-glucosaminidase Concentration and its Isozyme in a Diabetic Japanese Black Cow. Journal of the Japan Veterinary Medical Association. 48(6). 391–395.

19.

Ohkata, Katsuo, Keiji Okada, & Kin‐ya Akiba. (1995). Conformational features and chemical behavior of 5H, 7H‐dibenzo[B,g][1,5] dithiocin oxides: 1,5‐Oxygen shift via a dithiodication intermediate. Heteroatom Chemistry. 6(2). 145–153. 5 indexed citations

20.

Akiba, Kin‐ya, Keiji Okada, & Katsuo Ohkata. (1986). Formation of ammoniophosphoranes by transannular interaction in dibenz[c,f][1,5]azaphosphocine system. Tetrahedron Letters. 27(43). 5221–5224. 11 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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